Adding Zero
[Since 0.8.4] - [ -P Structures/AddZero ] - [ Online docs ]
Adding 0 is useless, as 0 is the neutral element for addition. Besides, when one of the argument is an integer, PHP triggers a cast to integer.
It is recommended to make the cast explicit with (int) .
<?php
// Explicit cast
$a = (int) foo();
// Useless addition
$a = foo() + 0;
$a = 0 + foo();
// Also works with minus
$b = 0 - $c; // drop the 0, but keep the minus
$b = $c - 0; // drop the 0 and the minus
$a += 0;
$a -= 0;
?>
Adding zero is also reported when the zero is a defined constants.
If it is used to type cast a value to integer, then casting with (int) is clearer.
Ambiguous Array Index
[Since 0.8.4] - [ -P Arrays/AmbiguousKeys ] - [ Online docs ]
Indexes should not be defined with different types than int or string.
Array indices only accept integers and strings, so any other type of literal is reported. In fact, null is turned into an empty string, booleans are turned into an integer, and real numbers are truncated (not rounded).
<?php
$x = [ 1 => 1,
'1' => 2,
1.0 => 3,
true => 4];
// $x only contains one element : 1 => 4
// Still wrong, immediate typecast to 1
$x[1.0] = 5;
$x[true] = 6;
?>
They are indeed distinct, but may lead to confusion.
See also array.
Array Index
[Since 0.8.4] - [ -P Arrays/Arrayindex ] - [ Online docs ]
List of all indexes used in arrays.
<?php
// Index
$x['index'] = 1;
// in array creation
$a = array('index2' => 1);
$a2 = ['index3' => 2];
?>
Multidimensional Arrays
[Since 0.8.4] - [ -P Arrays/Multidimensional ] - [ Online docs ]
Simply, arrays of arrays.
<?php
$x[1][2] = $x[2][3][4];
?>
See also Type array and
Using Multidimensional Arrays in PHP.
Multiple Index Definition
[Since 0.8.4] - [ -P Arrays/MultipleIdenticalKeys ] - [ Online docs ]
Indexes that are defined multiple times in the same array.
<?php
// Multiple identical keys
$x = array(1 => 2,
2 => 3,
1 => 3);
// Multiple identical keys (sneaky version)
$x = array(1 => 2,
1.1 => 3,
true => 4);
// Multiple identical keys (automated version)
$x = array(1 => 2,
3, // This will be index 2
2 => 4); // this index is overwritten
?>
They are indeed overwriting each other. This is most probably a typo.
PHP Arrays Index
[Since 0.8.4] - [ -P Arrays/Phparrayindex ] - [ Online docs ]
List of indexes used when manipulating PHP arrays in the code.
<?php
// HTTP_HOST is a PHP array index.
$ip = 'http'.$_SERVER['HTTP_HOST'].'/'.$row['path'];
//'path' is not a PHP index
?>
Classes Names
[Since 0.8.4] - [ -P Classes/Classnames ] - [ Online docs ]
List of all classes, as defined in the application.
<?php
// foo is in the list
class foo {}
// Anonymous classes are not in the list
$o = class { function foo(){} }
?>
Constant Definition
[Since 0.8.4] - [ -P Classes/ConstantDefinition ] - [ Online docs ]
List of class constants being defined.
<?php
// traditional way of making constants
define('aConstant', 1);
// modern way of making constants
const anotherConstant = 2;
class foo {
// Not a constant, a class constant.
const aClassConstant = 3;
}
?>
See also PHP Constants.
Empty Classes
[Since 0.8.4] - [ -P Classes/EmptyClass ] - [ Online docs ]
Classes that do no define anything at all. This is probably dead code.
Classes that are directly derived from an exception are omitted.
<?php
//Empty class
class foo extends bar {}
//Not an empty class
class foo2 extends bar {
const FOO = 2;
}
//Not an empty class, as derived from Exception
class barException extends \Exception {}
?>
Magic Methods
[Since 0.8.4] - [ -P Classes/MagicMethod ] - [ Online docs ]
List of PHP magic methods being used. The magic methods are
__call(), __callStatic(), __get(), __set(), __isset(), __unset(), __sleep(), __wakeup(), __toString(), __invoke(), __set_state(), __clone() and __debugInfo().
__construct and __destruct are omitted here, as they are routinely used to create and destroy objects.
<?php
class foo{
// PHP Magic method, called when cloning an object.
function __clone() {}
}
?>
See also Magic Method.
Forgotten Visibility
[Since 0.8.4] - [ -P Classes/NonPpp ] - [ Online docs ]
Some classes elements (property, method, constant) are missing their explicit visibility.
By default, it is public. It should at least be mentioned as public, or may be reviewed as protected or private.
Class constants support also visibility since PHP 7.1.
final, static and abstract are not counted as visibility. Only public, private and protected. The PHP 4 var keyword is counted as undefined.
Traits, classes and interfaces are checked.
<?php
// Explicit visibility
class X {
protected sconst NO_VISIBILITY_CONST = 1; // For PHP 7.2 and later
private $noVisibilityProperty = 2;
public function Method() {}
}
// Missing visibility
class X {
const NO_VISIBILITY_CONST = 1; // For PHP 7.2 and later
var $noVisibilityProperty = 2; // Only with var
function NoVisibilityForMethod() {}
}
?>
See also Visibility and Understanding The Concept Of Visibility In Object Oriented PHP.
Non Static Methods Called In A Static
[Since 0.8.4] - [ -P Classes/NonStaticMethodsCalledStatic ] - [ Online docs ]
Static methods have to be declared as such (using the static keyword). Then, one may call them without instantiating the object.
PHP 7.0, and more recent versions, yield a deprecated error : Non-static method A::B() should not be called statically .
PHP 5 and older doesn't check that a method is static or not : at any point, the code may call one method statically.
<?php
class x {
static public function sm( ) { echo __METHOD__.\n; }
public public sm( ) { echo __METHOD__.\n; }
}
x::sm( ); // echo x::sm
// Dynamic call
['x', 'sm']();
[\x::class, 'sm']();
$s = 'x::sm';
$s();
?>
It is a bad idea to call non-static method statically. Such method may make use of special
variable $this, which will be undefined. PHP will not check those calls at compile time,
nor at running time.
It is recommended to update this situation : make the method actually static, or use it only
in object context.
Note that this analysis reports all static method call made on a non-static method,
even within the same class or class hierarchy. PHP silently accepts static call to any
in-family method.
<?php
class x {
public function foo( ) { self::bar() }
public function bar( ) { echo __METHOD__.\n; }
}
?>
See also Static Keyword.
Old Style Constructor
[Since 0.8.4] - [ -P Classes/OldStyleConstructor ] - [ Online docs ]
PHP classes used to have the method bearing the same name as the class acts as the constructor. That was PHP 4, and early PHP 5.
The manual issues a warning about this syntax : Old style constructors are DEPRECATED in PHP 7.0, and will be removed in a future version. You should always use __construct() in new code.
<?php
namespace {
// Global namespace is important
class foo {
function foo() {
// This acts as the old-style constructor, and is reported by PHP
}
}
class bar {
function __construct() { }
function bar() {
// This doesn't act as constructor, as bar has a __construct() method
}
}
}
namespace Foo\Bar{
class foo {
function foo() {
// This doesn't act as constructor, as bar is not in the global namespace
}
}
}
?>
This is no more the case in PHP 5, which relies on __construct() to do so. Having this old style constructor may bring in confusion, unless you are also supporting old time PHP 4.
Note that classes with methods bearing the class name, but inside a namespace are not following this convention, as this is not breaking backward compatibility. Those are excluded from the analyze.
See also Constructors and Destructors.
Static Methods
[Since 0.8.4] - [ -P Classes/StaticMethods ] - [ Online docs ]
List of all static methods.
<?php
class foo {
static public function staticMethod() {
}
public function notStaticMethod() {
}
private function method() {
// This is not a property
new static();
}
}
?>
Static Methods Called From Object
[Since 0.8.4] - [ -P Classes/StaticMethodsCalledFromObject ] - [ Online docs ]
Static methods may be called without instantiating an object. As such, they never interact with the special variable '$this', as they do not depend on object existence.
Besides this, static methods are normal methods that may be called directly from object context, to perform some utility task.
To maintain code readability, it is recommended to call static method in a static way, rather than within object context.
<?php
class x {
static function y( ) {}
}
$z = new x( );
$z->y( ); // Readability : no one knows it is a static call
x::y( ); // Readability : here we know
?>
Static Properties
[Since 0.8.4] - [ -P Classes/StaticProperties ] - [ Online docs ]
List of all static properties.
<?php
class foo {
static public $staticProperty = 1;
public $notStaticProperty = 2;
private function method() {
// This is not a property
new static();
}
}
function bar() {
// This is not a static property
static $staticVariable;
//....
}
?>
Constants With Strange Names
[Since 0.8.4] - [ -P Constants/ConstantStrangeNames ] - [ Online docs ]
List of constants being defined with names that are incompatible with PHP standards.
<?php
// Define a valid PHP constant
define('ABC', 1);
const ABCD = 2;
// Define an invalid PHP constant
define('ABC!', 1);
echo defined('ABC!') ? constant('ABC!') : 'Undefined';
// Const doesn't allow illegal names
?>
See also PHP Constants.
Constants Usage
[Since 0.8.4] - [ -P Constants/ConstantUsage ] - [ Online docs ]
List of constants being used.
<?php
const MY_CONST = 'Hello';
// PHP_EOL (native PHP Constant)
// MY_CONST (custom constant)
echo PHP_EOL . MY_CONST;
?>
Constants
[Since 0.8.4] - [ -P Constants/Constantnames ] - [ Online docs ]
List of PHP constants being defined.
<?php
// with const
const X = 1;
// with `define() <https://www.php.net/define>`_
define ('Y', 2);
?>
True False Inconsistant Case
[Since 0.8.4] - [ -P Constants/InconsistantCase ] - [ Online docs ]
TRUE or true or True is the favorite.
Usually, PHP projects choose between ALL CAPS True/False, or all lowercase True/False. Sometimes, the project will have no recommendations.
When your project use a vast majority of one of the convention, then the analyzer will report all remaining inconsistently cased constant.
<?php
$a1 = true;
$a2 = true;
$a3 = true;
$a4 = true;
$a5 = true;
$a6 = true;
$a7 = true;
$a8 = true;
$a9 = true;
$a10 = true;
// This convention is inconsistence with the rest
$b1 = TRUE;
?>
Magic Constant Usage
[Since 0.8.4] - [ -P Constants/MagicConstantUsage ] - [ Online docs ]
There are eight magical constants that change depending on where they are used. For example, the value of __LINE__ depends on the line that it's used on in your script. These special constants are case-insensitive.
+ __LINE__
+ __FILE__
+ __DIR__
+ __FUNCTION__
+ __CLASS__
+ __TRAIT__
+ __METHOD__
+ __NAMESPACE__
<?php
echo 'This code is in file '__FILE__.', line '.__LINE__;
?>
See alsoMagic Constants.
PHP Constant Usage
[Since 0.8.4] - [ -P Constants/PhpConstantUsage ] - [ Online docs ]
List of PHP constants being used.
<?php
const MY_CONST = 'Hello';
// PHP_EOL (native PHP Constant)
// MY_CONST (custom constant, not reported)
echo PHP_EOL . MY_CONST;
?>
See also Predefined Constants.
Defined Exceptions
[Since 0.8.4] - [ -P Exceptions/DefinedExceptions ] - [ Online docs ]
This is the list of defined exceptions.
<?php
class myException extends \Exception {}
// A defined exception
throw new myException();
// not a defined exception : it is already defined.
throw new \RuntimeException();
?>
See also Exceptions.
Thrown Exceptions
[Since 0.8.4] - [ -P Exceptions/ThrownExceptions ] - [ Online docs ]
Usage of throw keyword.
<?php
throw new MyException('Error happened');
?>
See also Exceptions.
ext/apc
[Since 0.8.4] - [ -P Extensions/Extapc ] - [ Online docs ] - [ PHP older than 7.0]
Extension Alternative PHP Cache.
The Alternative PHP Cache (APC) is a free and open opcode cache for PHP. Its goal is to provide a free, open, and robust framework for caching and optimizing PHP intermediate code.
This extension is considered unmaintained and dead.
<?php
$bar = 'BAR';
apc_add('foo', $bar);
var_dump(apc_fetch('foo'));
echo PHP_EOL;
$bar = 'NEVER GETS SET';
apc_add('foo', $bar);
var_dump(apc_fetch('foo'));
echo PHP_EOL;
?>
See also Alternative PHP Cache.
ext/bcmath
[Since 0.8.4] - [ -P Extensions/Extbcmath ] - [ Online docs ]
Extension BC Math.
For arbitrary precision mathematics PHP offers the Binary Calculator which supports numbers of any size and precision up to 2147483647-1 (or 0x7FFFFFFF-1) decimals, represented as strings.
<?php
echo bcpow('2', '123');
//10633823966279326983230456482242756608
echo 2**123;
//1.0633823966279E+37
?>
See also BC Math Functions.
ext/bzip2
[Since 0.8.4] - [ -P Extensions/Extbzip2 ] - [ Online docs ]
Extension ext/bzip2.
Bzip2 Functions for PHP.
<?php
$file = '/tmp/foo.bz2';
$bz = bzopen($file, 'r') or die('Couldn\'t open $file for reading');
bzclose($bz);
?>
See also Bzip2 Functions.
ext/calendar
[Since 0.8.4] - [ -P Extensions/Extcalendar ] - [ Online docs ]
Extension ext/calendar.
The calendar extension presents a series of functions to simplify converting between different calendar formats.
<?php
$number = cal_days_in_month(CAL_GREGORIAN, 8, 2003); // 31
echo "There were {$number} days in August 2003";
?>
See also Calendar Functions.
ext/crypto
[Since 0.8.4] - [ -P Extensions/Extcrypto ] - [ Online docs ]
Extension ext/crypto (PECL).
Objective PHP binding of OpenSSL Crypto library.
<?php
use Crypto\Cipher;
use Crypto\AlgorihtmException;
$algorithm = 'aes-256-cbc';
if (!Cipher::hasAlgorithm($algorithm)) {
die('Algorithm $algorithm not found' . PHP_EOL);
}
try {
$cipher = new Cipher($algorithm);
// Algorithm method for retrieving algorithm
echo 'Algorithm: ' . $cipher->getAlgorithmName() . PHP_EOL;
// Params
$key_len = $cipher->getKeyLength();
$iv_len = $cipher->getIVLength();
echo 'Key length: ' . $key_len . PHP_EOL;
echo 'IV length: ' . $iv_len . PHP_EOL;
echo 'Block size: ' . $cipher->getBlockSize() . PHP_EOL;
// This is just for this example. You should never use such key and IV!
$key = str_repeat('x', $key_len);
$iv = str_repeat('i', $iv_len);
// Test data
$data1 = 'Test';
$data2 = 'Data';
$data = $data1 . $data2;
// Simple encryption
$sim_ct = $cipher->encrypt($data, $key, $iv);
// init/update/finish encryption
$cipher->encryptInit($key, $iv);
$iuf_ct = $cipher->encryptUpdate($data1);
$iuf_ct .= $cipher->encryptUpdate($data2);
$iuf_ct .= $cipher->encryptFinish();
// Raw data output (used base64 format for printing)
echo 'Ciphertext (sim): ' . base64_encode($sim_ct) . PHP_EOL;
echo 'Ciphertext (iuf): ' . base64_encode($iuf_ct) . PHP_EOL;
// $iuf_out == $sim_out
$ct = $sim_ct;
// Another way how to create a new cipher object (using the same algorithm and mode)
$cipher = Cipher::aes(Cipher::MODE_CBC, 256);
// Simple decryption
$sim_text = $cipher-><?>
See also pecl crypto and php-crypto.
ext/ctype
[Since 0.8.4] - [ -P Extensions/Extctype ] - [ Online docs ]
Extension ext/ctype.
Ext/ctype checks whether a character or string falls into a certain character class according to the current locale.
<?php
$strings = array('AbCd1zyZ9', 'foo!#$bar');
foreach ($strings as $testcase) {
if (ctype_alnum($testcase)) {
echo "The string $testcase consists of all letters or digits.\n";
} else {
echo "The string $testcase does not consist of all letters or digits.\n";
}
}
?>
See also Ctype funtions.
ext/curl
[Since 0.8.4] - [ -P Extensions/Extcurl ] - [ Online docs ]
Extension curl.
PHP supports libcurl, a library created by Daniel Stenberg. It allows the connection and communication to many different types of servers with many different types of protocols.
<?php
$ch = curl_init("http://www.example.com/");
$fp = fopen("example_homepage.txt", "w");
curl_setopt($ch, CURLOPT_FILE, $fp);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_exec($ch);
curl_close($ch);
fclose($fp);
?>
See also Curl for PHP and
curl.
ext/date
[Since 0.8.4] - [ -P Extensions/Extdate ] - [ Online docs ]
Extension ext/date.
These functions allows the manipulation of date and time from the server where the PHP scripts are running.
<?php
$dt = new DateTime('2015-11-01 00:00:00', new DateTimeZone('America/New_York'));
echo 'Start: ', $dt->format('Y-m-d H:i:s P'), PHP_EOL;
$dt->add(new DateInterval('PT3H'));
echo 'End: ', $dt->format('Y-m-d H:i:s P'), PHP_EOL;
?>
See also Date and Time.
ext/dba
[Since 0.8.4] - [ -P Extensions/Extdba ] - [ Online docs ]
Extension ext/dba.
These functions build the foundation for accessing Berkeley DB style databases.
<?php
$id = dba_open('/tmp/test.db', 'n', 'db2');
if (!$id) {
echo 'dba_open failed'.PHP_EOL;
exit;
}
dba_replace('key', 'This is an example!', $id);
if (dba_exists('key', $id)) {
echo dba_fetch('key', $id);
dba_delete('key', $id);
}
dba_close($id);
?>
See also Database (dbm-style) Abstraction Layer.
ext/dom
[Since 0.8.4] - [ -P Extensions/Extdom ] - [ Online docs ]
Extension Document Object Model.
The DOM extension allows the manipulation of XML documents through the DOM API with PHP.
<?php
$dom = new DOMDocument('1.0', 'utf-8');
$element = $dom->createElement('test', 'This is the root element!');
// We insert the new element as root (child of the document)
$dom->appendChild($element);
echo $dom->saveXML();
?>
See also Document Object Model.
ext/enchant
[Since 0.8.4] - [ -P Extensions/Extenchant ] - [ Online docs ]
Extension Enchant.
Enchant is the PHP binding for the Enchant spelling library. Enchant steps in to provide uniformity and conformity on top of all spelling libraries, and implement certain features that may be lacking in any individual provider library.
<?php
$tag = 'en_US';
$r = enchant_broker_init();
$bprovides = enchant_broker_describe($r);
echo 'Current broker provides the following backend(s):'.PHP_EOL;
print_r($bprovides);
$dicts = enchant_broker_list_dicts($r);
print_r($dicts);
if (enchant_broker_dict_exists($r,$tag)) {
$d = enchant_broker_request_dict($r, $tag);
$dprovides = enchant_dict_describe($d);
echo 'dictionary $tag provides:'.PHP_EOL;
$wordcorrect = enchant_dict_check($d, 'soong');
print_r($dprovides);
if (!$wordcorrect) {
$suggs = enchant_dict_suggest($d, 'soong');
echo 'Suggestions for "soong":';
print_r($suggs);
}
enchant_broker_free_dict($d);
} else {
}
enchant_broker_free($r);
?>
See also Enchant spelling library and
Enchant.
ext/ereg
[Since 0.8.4] - [ -P Extensions/Extereg ] - [ Online docs ] - [ PHP older than 7.0]
Extension ext/ereg.
<?php
if (ereg ('([0-9]{4})-([0-9]{1,2})-([0-9]{1,2})', $date, $regs)) {
echo $regs[3].'.'.$regs[2].'.'.$regs[1];
} else {
echo 'Invalid date format: '.$date;
}
?>
See also Ereg.
ext/exif
[Since 0.8.4] - [ -P Extensions/Extexif ] - [ Online docs ]
Extension EXIF : Exchangeable image file format.
The EXIF extension manipulates image meta data.
<?php
echo 'test1.jpg:<br />';
$exif = exif_read_data('tests/test1.jpg', 'IFD0');
echo $exif===false ? 'No header data found.<br />' : 'Image contains headers<br />';
$exif = exif_read_data('tests/test2.jpg', 0, true);
echo 'test2.jpg:<br />';
foreach ($exif as $key => $section) {
foreach ($section as $name => $val) {
echo $key.$name.': '.$val.'<br />';
}
}
?>
See also Exchangeable image information.
ext/fdf
[Since 0.8.4] - [ -P Extensions/Extfdf ] - [ Online docs ]
Extension ext/fdf.
Forms Data Format (FDF) is a format for handling forms within PDF documents.
<?php
$outfdf = fdf_create();
fdf_set_value($outfdf, 'volume', $volume, 0);
fdf_set_file($outfdf, 'http:/testfdf/resultlabel.pdf');
fdf_save($outfdf, 'outtest.fdf');
fdf_close($outfdf);
Header('Content-type: application/vnd.fdf');
$fp = fopen('outtest.fdf', 'r');
fpassthru($fp);
unlink('outtest.fdf');
?>
See also Form Data Format.
ext/fileinfo
[Since 0.8.4] - [ -P Extensions/Extfileinfo ] - [ Online docs ]
Extension ext/fileinfo.
This module guesses the content type and encoding of a file by looking for certain magic byte sequences at specific positions within the file.
<?php
$finfo = finfo_open(FILEINFO_MIME_TYPE); // return mime type ala mimetype extension
foreach (glob('*') as $filename) {
echo finfo_file($finfo, $filename) . PHP_EOL;
}
finfo_close($finfo);
?>
See also Filinfo.
ext/filter
[Since 0.8.4] - [ -P Extensions/Extfilter ] - [ Online docs ]
Extension filter.
This extension filters data by either validating or sanitizing it.
<?php
$email_a = 'joe@example.com';
$email_b = 'bogus';
if (filter_var($email_a, FILTER_VALIDATE_EMAIL)) {
echo 'This ($email_a) email address is considered valid.'.PHP_EOL;
}
if (filter_var($email_b, FILTER_VALIDATE_EMAIL)) {
echo 'This ($email_b) email address is considered valid.'.PHP_EOL;
} else {
echo 'This ($email_b) email address is considered invalid.'.PHP_EOL;
}
?>
See also Data filtering.
ext/ftp
[Since 0.8.4] - [ -P Extensions/Extftp ] - [ Online docs ]
Extension FTP.
The functions in this extension implement client access to files servers speaking the File Transfer Protocol (FTP) as defined in RFC 959.
<?php
// set up basic connection
$conn_id = ftp_connect($ftp_server);
// login with username and password
$login_result = ftp_login($conn_id, $ftp_user_name, $ftp_user_pass);
// check connection
if ((!$conn_id) || (!$login_result)) {
echo 'FTP connection has failed!';
echo 'Attempted to connect to $ftp_server for user $ftp_user_name';
exit;
} else {
echo 'Connected to $ftp_server, for user $ftp_user_name';
}
// upload the file
$upload = ftp_put($conn_id, $destination_file, $source_file, FTP_BINARY);
// check upload status
if (!$upload) {
echo 'FTP upload has failed!';
} else {
echo 'Uploaded $source_file to $ftp_server as $destination_file';
}
// close the FTP stream
ftp_close($conn_id);
?>
See also FTP.
ext/gd
[Since 0.8.4] - [ -P Extensions/Extgd ] - [ Online docs ]
Extension GD for PHP.
This extension allows PHP to create and manipulate image files in a variety of different image formats, including GIF, PNG, JPEG, WBMP, and XPM.
<?php
header("Content-type: image/png");
$string = $_GET['text'];
$im = imagecreatefrompng("images/button1.png");
$orange = imagecolorallocate($im, 220, 210, 60);
$px = (imagesx($im) - 7.5 * strlen($string)) / 2;
imagestring($im, 3, $px, 9, $string, $orange);
imagepng($im);
imagedestroy($im);
?>
See also Image Processing and GD.
ext/gmp
[Since 0.8.4] - [ -P Extensions/Extgmp ] - [ Online docs ]
Extension ext/gmp.
These functions allow for arbitrary-length integers to be worked with using the GNU MP library.
<?php
$pow1 = gmp_pow('2', 131);
echo gmp_strval($pow1) . PHP_EOL;
$pow2 = gmp_pow('0', 0);
echo gmp_strval($pow2) . PHP_EOL;
$pow3 = gmp_pow('2', -1); // Negative exp, generates warning
echo gmp_strval($pow3) . PHP_EOL;
?>
See also GMP and GNU MP library.
ext/gnupgp
[Since 0.8.4] - [ -P Extensions/Extgnupg ] - [ Online docs ]
Extension GnuPG.
This module allows you to interact with gnupg.
<?php
// init gnupg
$res = gnupg_init();
// not really needed. Clearsign is default
gnupg_setsignmode($res,GNUPG_SIG_MODE_CLEAR);
// add key with passphrase 'test' for signing
gnupg_addsignkey($res,"8660281B6051D071D94B5B230549F9DC851566DC","test");
// sign
$signed = gnupg_sign($res,"just a test");
echo $signed;
?>
See also Gnupg Function for PHP and
GnuPG.
ext/hash
[Since 0.8.4] - [ -P Extensions/Exthash ] - [ Online docs ]
Extension for HASH Message Digest Framework.
Message Digest (hash) engine. Allows direct or incremental processing of arbitrary length messages using a variety of hashing algorithms.
<?php
/* Create a file to calculate hash of */
file_put_contents('example.txt', 'The quick brown fox jumped over the lazy dog.');
echo hash_file('md5', 'example.txt');
?>
See also HASH Message Digest Framework.
ext/iconv
[Since 0.8.4] - [ -P Extensions/Exticonv ] - [ Online docs ]
Extension ext/iconv.
With this module, you can turn a string represented by a local character set into the one represented by another character set, which may be the Unicode character set.
<?php
$text = "This is the Euro symbol '€'.";
echo 'Original : ', $text, PHP_EOL;
echo 'TRANSLIT : ', iconv("UTF-8", "ISO-8859-1//TRANSLIT", $text), PHP_EOL;
echo 'IGNORE : ', iconv("UTF-8", "ISO-8859-1//IGNORE", $text), PHP_EOL;
echo 'Plain : ', iconv("UTF-8", "ISO-8859-1", $text), PHP_EOL;
?>
See also Iconv, and
libiconv.
ext/json
[Since 0.8.4] - [ -P Extensions/Extjson ] - [ Online docs ]
Extension JSON.
This extension implements the JavaScript Object Notation (JSON) data-interchange format. PHP implements a superset of JSON as specified in the original RFC 7159.
<?php
$arr = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 4, 'e' => 5);
echo json_encode($arr);
?>
See also JavaScript Object Notation and JSON.
ext/kdm5
[Since 0.8.4] - [ -P Extensions/Extkdm5 ] - [ Online docs ]
Extension kdm5 : Kerberos V .
These package allows you to access Kerberos V administration servers. You can create, modify, and delete Kerberos V principals and policies.
<?php
// Extracted from the PHP Manual
$handle = kadm5_init_with_password(afs-1, GONICUS.LOCAL, admin/admin, password);
print <h1>get_principals</h1>\n;
$principals = kadm5_get_principals($handle);
for( $i=0; $i<count($principals); $i++)
print $principals[$i]<br>\n;
print <h1>get_policies</h1>\n;
$policies = kadm5_get_policies($handle);
for( $i=0; $i<count($policies); $i++)
print $policies[$i]<br>\n;
print <h1>get_principal burbach@GONICUS.LOCAL</h1>\n;
$options = kadm5_get_principal($handle, burbach@GONICUS.LOCAL );
$keys = array_keys($options);
for( $i=0; $i<count($keys); $i++) {
$value = $options[$keys[$i]];
print $keys[$i]: $value<br>\n;
}
$options = array(KADM5_PRINC_EXPIRE_TIME => 0);
kadm5_modify_principal($handle, burbach@GONICUS.LOCAL, $options);
kadm5_destroy($handle);
?>
See also Kerberos V and Kerberos: The Network Authentication Protocol.
ext/ldap
[Since 0.8.4] - [ -P Extensions/Extldap ] - [ Online docs ]
Extension ext/ldap.
LDAP is the Lightweight Directory Access Protocol, and is a protocol used to access 'Directory Servers'. The Directory is a special kind of database that holds information in a tree structure.
<?php
// basic sequence with LDAP is connect, bind, search, interpret search
// result, close connection
echo '<h3>LDAP query test</h3>';
echo 'Connecting ...';
$ds=ldap_connect('localhost'); // must be a valid LDAP server!
echo 'connect result is ' . $ds . '<br />';
if ($ds) {
echo 'Binding ...';
$r=ldap_bind($ds); // this is an 'anonymous' bind, typically
// read-only access
echo 'Bind result is ' . $r . '<br />';
echo 'Searching for (sn=S*) ...';
// Search surname entry
$sr=ldap_search($ds, 'o=My Company, c=US', 'sn=S*');
echo 'Search result is ' . $sr . '<br />';
echo 'Number of entries returned is ' . ldap_count_entries($ds, $sr) . '<br />';
echo 'Getting entries ...<p>';
$info = ldap_get_entries($ds, $sr);
echo 'Data for ' . $info['count'] . ' items returned:<p>';
for ($i=0; $i<$info['count']; $i++) {
echo 'dn is: ' . $info[$i]['dn'] . '<br />';
echo 'first cn entry is: ' . $info[$i]['cn'][0] . '<br />';
echo 'first email entry is: ' . $info[$i]['mail'][0] . '<br /><hr />';
}
echo 'Closing connection';
ldap_close($ds);
} else {
echo '<h4>Unable to connect to LDAP server</h4>';
}
?>
See also Lightweight Directory Access Protocol.
ext/libxml
[Since 0.8.4] - [ -P Extensions/Extlibxml ] - [ Online docs ]
Extension libxml.
These functions/constants are available as of PHP 5.1.0, and the following core extensions rely on this libxml extension: DOM, libxml, SimpleXML, SOAP, WDDX, XSL, XML, XMLReader, XMLRPC and XMLWriter.
<?php
// $xmlstr is a string, containing a XML document.
$doc = simplexml_load_string($xmlstr);
$xml = explode(PHP_EOL, $xmlstr);
if ($doc === false) {
$errors = libxml_get_errors();
foreach ($errors as $error) {
echo display_xml_error($error, $xml);
}
libxml_clear_errors();
}
function display_xml_error($error, $xml)
{
$return = $xml[$error->line - 1] . PHP_EOL;
$return .= str_repeat('-', $error->column) . '^'.PHP_EOL;
switch ($error->level) {
case LIBXML_ERR_WARNING:
$return .= 'Warning ',$error->code.': ';
break;
case LIBXML_ERR_ERROR:
$return .= 'Error '.$error->code.': ';
break;
case LIBXML_ERR_FATAL:
$return .= 'Fatal Error '.$error->code.': ';
break;
}
$return .= trim($error->message) .
PHP_EOL.' Line: '.$error->line .
PHP_EOL.' Column: '.$error->column;
if ($error->file) {
$return .= "\n File: $error->file";
}
return $return.PHP_EOL.PHP_EOL.'--------------------------------------------'.PHP_EOL.PHP_EOL;
}
?>
See also libxml.
ext/mbstring
[Since 0.8.4] - [ -P Extensions/Extmbstring ] - [ Online docs ]
Extension ext/mbstring .
mbstring provides multibyte specific string functions that help you deal with multibyte encodings in PHP.
<?php
/* Convert internal character encoding to SJIS */
$str = mb_convert_encoding($str, "SJIS");
/* Convert EUC-JP to UTF-7 */
$str = mb_convert_encoding($str, "UTF-7", "EUC-JP");
/* Auto detect encoding from JIS, eucjp-win, sjis-win, then convert str to UCS-2LE */
$str = mb_convert_encoding($str, "UCS-2LE", "JIS, eucjp-win, sjis-win");
/* "auto" is expanded to "ASCII,JIS,UTF-8,EUC-JP,SJIS" */
$str = mb_convert_encoding($str, "EUC-JP", "auto");
?>
See also Mbstring.
ext/mcrypt
[Since 0.8.4] - [ -P Extensions/Extmcrypt ] - [ Online docs ]
Extension for mcrypt.
This extension has been deprecated as of PHP 7.1.0 and moved to PECL as of PHP 7.2.0.
This is an interface to the mcrypt library, which supports a wide variety of block algorithms such as DES, TripleDES, Blowfish (default), 3-WAY, SAFER-SK64, SAFER-SK128, TWOFISH, TEA, RC2 and GOST in CBC, OFB, CFB and ECB cipher modes. Additionally, it supports RC6 and IDEA which are considered 'non-free'. CFB/OFB are 8bit by default.
<?php
# --- ENCRYPTION ---
# the key should be random binary, use scrypt, bcrypt or PBKDF2 to
# convert a string into a key
# key is specified using hexadecimal
$key = pack('H*', 'bcb04b7e103a0cd8b54763051cef08bc55abe029fdebae5e1d417e2ffb2a00a3');
# show key size use either 16, 24 or 32 byte keys for AES-128, 192
# and 256 respectively
$key_size = strlen($key);
echo 'Key size: ' . $key_size . PHP_EOL;
$plaintext = 'This string was AES-256 / CBC / ZeroBytePadding encrypted.';
# create a random IV to use with CBC encoding
$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
# creates a cipher text compatible with AES (Rijndael block size = 128)
# to keep the text confidential
# only suitable for encoded input that never ends with value 00h
# (because of default zero padding)
$ciphertext = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key,
$plaintext, MCRYPT_MODE_CBC, $iv);
# prepend the IV for it to be available for decryption
$ciphertext = $iv . $ciphertext;
# encode the resulting cipher text so it can be represented by a string
$ciphertext_base64 = base64_encode($ciphertext);
echo $ciphertext_base64 . PHP_EOL;
# === WARNING ===
# Resulting cipher text has no integrity or authenticity added
# and is not protected against padding oracle attacks.
# --- DECRYPTION ---
$ciphertext_dec = base64_decode($ciphertext_base64);
# retrieves the IV, iv_size should be created using mcrypt_get_iv_size()
$iv_dec = substr($ciphertext_dec, 0, $iv_size);
# retrieves the cipher text (everything except the $iv_size in the front)
$ciphertext_dec = substr($ciphertext_dec, $iv_size);
# may remove 00h valued characters from end of plain text
$plaintext_dec = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key,
$ciphertext_dec, MCRYPT_MODE_CBC, $iv_dec);
echo $plaintext_dec . PHP_EOL;
?>
See also extension mcrypt and mcrypt.
ext/mongo
[Since 0.8.4] - [ -P Extensions/Extmongo ] - [ Online docs ]
Extension MongoDB driver (legacy).
<?php
// connect
$m = new MongoClient();
// select a database
$db = $m->comedy;
// select a collection (analogous to a relational database\'s table)
$collection = $db->cartoons;
// add a record
$document = array( 'title' => 'Calvin and Hobbes', 'author' => 'Bill Watterson' );
$collection->insert($document);
// add another record, with a different 'shape'
$document = array( 'title' => 'XKCD', 'online' => true );
$collection->insert($document);
// find everything in the collection
$cursor = $collection->find();
// iterate through the results
foreach ($cursor as $document) {
echo $document['title'] . PHP_EOL;
}
?>
Note : this is not the MongoDB driver. This is the legacy extension.
See also ext/mongo manual and
MongdDb.
ext/mssql
[Since 0.8.4] - [ -P Extensions/Extmssql ] - [ Online docs ]
Extension MSSQL, Microsoft SQL Server.
These functions allow you to access MS SQL Server database.
<?php
// Connect to MSSQL
$link = mssql_connect('KALLESPC\SQLEXPRESS', 'sa', 'phpfi');
if (!$link || !mssql_select_db('php', $link)) {
die('Unable to connect or select database!');
}
// Do a simple query, select the version of
// MSSQL and print it.
$version = mssql_query('SELECT @@VERSION');
$row = mssql_fetch_array($version);
echo $row[0];
// Clean up
mssql_free_result($version);
?>
See also Microsoft SQL Server and Microsoft PHP Driver for SQL Server.
ext/mysql
[Since 0.8.4] - [ -P Extensions/Extmysql ] - [ Online docs ] - [ PHP older than 7.0]
Extension for MySQL (Original MySQL API).
This extension is deprecated as of PHP 5.5.0, and has been removed as of PHP 7.0.0. Instead, either the mysqli or PDO_MySQL extension should be used. See also the MySQL API Overview for further help while choosing a MySQL API.
<?php
$result = mysql_query('SELECT * WHERE 1=1');
if (!$result) {
die('Invalid query: ' . mysql_error());
}
?>
See also Original MySQL API and MySQL.
ext/mysqli
[Since 0.8.4] - [ -P Extensions/Extmysqli ] - [ Online docs ]
Extension mysqli for MySQL.
The mysqli extension allows you to access the functionality provided by MySQL 4.1 and above.
<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
printf('Connect failed: %s\n', mysqli_connect_error());
exit();
}
$city = 'Amersfoort';
/* create a prepared statement */
if ($stmt = $mysqli->prepare('SELECT District FROM City WHERE Name=?')) {
/* bind parameters for markers */
$stmt->bind_param('s', $city);
/* execute query */
$stmt->execute();
/* bind result variables */
$stmt->bind_result($district);
/* fetch value */
$stmt->fetch();
printf('%s is in district %s\n', $city, $district);
/* close statement */
$stmt->close();
}
/* close connection */
$mysqli->close();
?>
See also MySQL Improved Extension and MySQL.
ext/odbc
[Since 0.8.4] - [ -P Extensions/Extodbc ] - [ Online docs ]
Extension ODBC.
In addition to normal ODBC support, the Unified ODBC functions in PHP allow you to access several databases that have borrowed the semantics of the ODBC API to implement their own API. Instead of maintaining multiple database drivers that were all nearly identical, these drivers have been unified into a single set of ODBC functions.
<?php
$a = 1;
$b = 2;
$c = 3;
$stmt = odbc_prepare($conn, 'CALL myproc(?,?,?)');
$success = odbc_execute($stmt, array($a, $b, $c));
?>
See also ODBC (Unified), Unixodbc and IODBC.
ext/openssl
[Since 0.8.4] - [ -P Extensions/Extopenssl ] - [ Online docs ]
Extension Openssl.
This extension binds functions of OpenSS L library for symmetric and asymmetric encryption and decryption, PBKDF2 , PKCS7 , PKCS12 , X509 and other cryptographic operations. In addition to that it provides implementation of TLS streams.
<?php
// $data and $signature are assumed to contain the data and the signature
// fetch public key from certificate and ready it
$pubkeyid = openssl_pkey_get_public("file://src/openssl-0.9.6/demos/sign/cert.pem");
// state whether signature is okay or not
$ok = openssl_verify($data, $signature, $pubkeyid);
if ($ok == 1) {
echo "good";
} elseif ($ok == 0) {
echo "bad";
} else {
echo "ugly, error checking signature";
}
// free the key from memory
openssl_free_key($pubkeyid);
?>
See also ext/OpenSSL and OpenSSL.
ext/pcre
[Since 0.8.4] - [ -P Extensions/Extpcre ] - [ Online docs ]
Extension ext/pcre. PCRE stands for Perl Compatible Regular Expression. It is a standard PHP extension.
<?php
$zip_code = $_GET['zip'];
// Canadian Zip code H2M 3J1
$zip_ca = '/^([a-zA-Z]\d[a-zA-Z])\ {0,1}(\d[a-zA-Z]\d)$/';
// French Zip code 75017
$zip_fr = '/^\d{5}$/';
// Chinese Zip code 590615
$zip_cn = '/^\d{6}$/';
var_dump(preg_match($_GET['zip']));
?>
See also Regular Expressions (Perl-Compatible).
ext/pdo
[Since 0.8.4] - [ -P Extensions/Extpdo ] - [ Online docs ]
Generic extension PDO.
The PHP Data Objects (PDO) extension defines a lightweight, consistent interface for accessing databases in PHP.
<?php
/* Execute a prepared statement by passing an array of values */
$sql = 'SELECT name, colour, calories
FROM fruit
WHERE calories < :calories AND colour = :colour';
$sth = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
$sth->execute(array(':calories' => 150, ':colour' => 'red'));
$red = $sth->fetchAll();
$sth->execute(array(':calories' => 175, ':colour' => 'yellow'));
$yellow = $sth->fetchAll();
?>
See also PHP Data Object.
ext/pgsql
[Since 0.8.4] - [ -P Extensions/Extpgsql ] - [ Online docs ]
Extension PostGreSQL.
PostgreSQL is an open source descendant of this original Berkeley code. It provides SQL92/SQL99 language support, transactions, referential integrity, stored procedures and type extensibility.
<?php
// Connect to a database named 'mary'
$dbconn = pg_connect('dbname=mary');
// Prepare a query for execution
$result = pg_prepare($dbconn, 'my_query', 'SELECT * FROM shops WHERE name = $1');
// Execute the prepared query. Note that it is not necessary to escape
// the string 'Joe's Widgets' in any way
$result = pg_execute($dbconn, 'my_query', array('Joe\'s Widgets'));
// Execute the same prepared query, this time with a different parameter
$result = pg_execute($dbconn, 'my_query', array('Clothes Clothes Clothes'));
?>
See also PostgreSQL and PostgreSQL: The world's most advanced open source database.
ext/phar
[Since 0.8.4] - [ -P Extensions/Extphar ] - [ Online docs ]
Extension phar.
The phar extension provides a way to put entire PHP applications into a single file called a phar (PHP Archive) for easy distribution and installation.
<?php
try {
$p = new Phar('/path/to/my.phar', 0, 'my.phar');
$p['myfile.txt'] = 'hi';
$file = $p['myfile.txt'];
var_dump($file->isCompressed(Phar::BZ2));
$p['myfile.txt']->compress(Phar::BZ2);
var_dump($file->isCompressed(Phar::BZ2));
} catch (Exception $e) {
echo 'Create/modify operations on my.phar failed: ', $e;
}
?>
See also phar.
ext/posix
[Since 0.8.4] - [ -P Extensions/Extposix ] - [ Online docs ]
Extension POSIX.
Ext/posix contains an interface to those functions defined in the IEEE 1003.1 (POSIX.1) standards document which are not accessible through other means.
<?php
posix_kill(999459,SIGKILL);
echo 'Your error returned was '.posix_get_last_error(); //Your error was ___
?>
See also 1003.1-2008 - IEEE Standard for Information Technology - Portable Operating System Interface (POSIX(R)).
ext/readline
[Since 0.8.4] - [ -P Extensions/Extreadline ] - [ Online docs ]
Extension readline.
The readline functions implement an interface to the GNU Readline library. These are functions that provide editable command lines.
<?php
//get 3 commands from user
for ($i=0; $i < 3; $i++) {
$line = readline("Command: ");
readline_add_history($line);
}
//dump history
print_r(readline_list_history());
//dump variables
print_r(readline_info());
?>
See also ext/readline and
The GNU Readline Library.
ext/reflection
[Since 0.8.4] - [ -P Extensions/Extreflection ] - [ Online docs ]
Extension Reflection.
PHP comes with a complete reflection API that adds the ability to reverse-engineer classes, interfaces, functions, methods and extensions. Additionally, the reflection API offers ways to retrieve doc comments for functions, classes and methods.
<?php
/**
* A simple counter
*
* @return int
*/
function counter1()
{
static $c = 0;
return ++$c;
}
/**
* Another simple counter
*
* @return int
*/
$counter2 = function()
{
static $d = 0;
return ++$d;
};
function dumpReflectionFunction($func)
{
// Print out basic information
printf(
PHP_EOL.'===> The %s function '%s''.PHP_EOL.
' declared in %s'.PHP_EOL.
' lines %d to %d'.PHP_EOL,
$func->isInternal() ? 'internal' : 'user-defined',
$func->getName(),
$func->getFileName(),
$func->getStartLine(),
$func->getEndline()
);
// Print documentation comment
printf('---> Documentation:'.PHP_EOL.' %s',PHP_EOL, var_export($func->getDocComment(), 1));
// Print static variables if existant
if ($statics = $func->getStaticVariables())
{
printf('---> Static variables: %s',PHP_EOL, var_export($statics, 1));
}
}
// Create an instance of the ReflectionFunction class
dumpReflectionFunction(new ReflectionFunction('counter1'));
dumpReflectionFunction(new ReflectionFunction($counter2));
?>
See also Reflection.
ext/sem
[Since 0.8.4] - [ -P Extensions/Extsem ] - [ Online docs ]
Extension Semaphore, Shared Memory and IPC.
This module provides wrappers for the System V IPC family of functions. It includes semaphores, shared memory and inter-process messaging (IPC).
<?php
$key = ftok(__FILE__,'a');
$semaphore = sem_get($key);
sem_acquire($semaphore);
sem_release($semaphore);
sem_remove($semaphore);
?>
See also Semaphore, Shared Memory and IPC.
ext/session
[Since 0.8.4] - [ -P Extensions/Extsession ] - [ Online docs ]
Extension ext/session.
Session support in PHP consists of a way to preserve certain data across subsequent accesses.
<?php
session_start();
if (!isset($_SESSION['count'])) {
$_SESSION['count'] = 0;
} else {
$_SESSION['count']++;
}
?>
See also Session.
ext/shmop
[Since 0.8.4] - [ -P Extensions/Extshmop ] - [ Online docs ]
Extension ext/shmop.
Shmop is an easy to use set of functions that allows PHP to read, write, create and delete Unix shared memory segments.
<?php
// Create a temporary file and return its path
$tmp = tempnam('/tmp', 'PHP');
// Get the file token key
$key = ftok($tmp, 'a');
// Attach the SHM resource, notice the cast afterwards
$id = shm_attach($key);
if ($id === false) {
die('Unable to create the shared memory segment');
}
// Cast to integer, since prior to PHP 5.3.0 the resource id
// is returned which can be exposed when casting a resource
// to an integer
$id = (integer) $id;
?>
See also Semaphore, Shared Memory and IPC.
ext/simplexml
[Since 0.8.4] - [ -P Extensions/Extsimplexml ] - [ Online docs ]
Extension SimpleXML .
The SimpleXML extension provides a very simple and easily usable toolset to convert XML to an object that can be processed with normal property selectors and array iterators.
<?php
$xml = <<<'XML'
<?xml version='1.0' standalone='yes' ? >
<movies>
<movie>
<title>PHP: Behind the Parser</title>
<characters>
<character>
<name>Ms. Coder</name>
<actor>Onlivia Actora</actor>
</character>
<character>
<name>Mr. Coder</name>
<actor>El ActÓr</actor>
</character>
</characters>
<plot>
So, this language. It's like, a programming language. Or is it a
scripting language? All is revealed in this thrilling horror spoof
of a documentary.
</plot>
<great-lines>
<line>PHP solves all my web problems</line>
</great-lines>
<rating type="thumbs">7</rating>
<rating type="stars">5</rating>
</movie>
</movies>
XML;
$movies = new SimpleXMLElement($xml);
echo $movies->movie[0]->plot;
?>
See also SimpleXML.
ext/snmp
[Since 0.8.4] - [ -P Extensions/Extsnmp ] - [ Online docs ]
Extension SNMP.
The SNMP extension provides a very simple and easily usable toolset for managing remote devices via the Simple Network Management Protocol.
<?php
$nameOfSecondInterface = snmp3_get('localhost', 'james', 'authPriv', 'SHA', 'secret007', 'AES', 'secret007', 'IF-MIB::ifName.2');
?>
See also Net SNMP and SNMP.
ext/soap
[Since 0.8.4] - [ -P Extensions/Extsoap ] - [ Online docs ]
Extension SOAP.
The SOAP extension can be used to write SOAP Servers and Clients. It supports subsets of » SOAP 1.1, » SOAP 1.2 and » WSDL 1.1 specifications.
<?php
$client = new SoapClient("some.wsdl");
$client = new SoapClient("some.wsdl", array('soap_version' => SOAP_1_2));
$client = new SoapClient("some.wsdl", array('login' => "some_name",
'password' => "some_password"));
?>
See also SOAP and
SOAP specifications.
ext/sockets
[Since 0.8.4] - [ -P Extensions/Extsockets ] - [ Online docs ]
Extension socket.
The socket extension implements a low-level interface to the socket communication functions based on the popular BSD sockets, providing the possibility to act as a socket server as well as a client.
<?php
//Example #2 Socket example: Simple TCP/IP client
//From the PHP manual
error_reporting(E_ALL);
echo "<h2>TCP/IP Connection</h2>\n";
/* Get the port for the WWW service. */
$service_port = getservbyname('www', 'tcp');
/* Get the IP address for the target host. */
$address = gethostbyname('www.example.com');
/* Create a TCP/IP socket. */
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
if ($socket === false) {
echo 'socket_create() failed: reason: ' . socket_strerror(socket_last_error()) . PHP_EOL;
} else {
echo 'OK.'.PHP_EOL;
}
echo 'Attempting to connect to '$address' on port '$service_port'...';
$result = socket_connect($socket, $address, $service_port);
if ($result === false) {
echo 'socket_connect() failed.\nReason: ($result) ' . socket_strerror(socket_last_error($socket)) . '\n';
} else {
echo 'OK.'.PHP_EOL;
}
$in = ""HEAD / HTTP/1.1\r\n"";
$in .= ""Host: www.example.com\r\n"";
$in .= ""Connection: Close\r\n\r\n"";
$out = '';
echo 'Sending HTTP HEAD request...';
socket_write($socket, $in, strlen($in));
echo "OK.\n";
echo 'Reading response:\n\n';
while ($out = socket_read($socket, 2048)) {
echo $out;
}
echo 'Closing socket...';
socket_close($socket);
echo 'OK.\n\n';
?>
See also Sockets.
ext/spl
[Since 0.8.4] - [ -P Extensions/Extspl ] - [ Online docs ]
SPL extension.
The Standard PHP Library (SPL) is a collection of interfaces and classes that are meant to solve common problems.
<?php
// Example with FilesystemIterator
$files = new FilesystemIterator('/path/to/dir');
foreach($files as $file) {
echo $file->getFilename() . PHP_EOL;
}
?>
See also Standard PHP Library (SPL).
ext/sqlite
[Since 0.8.4] - [ -P Extensions/Extsqlite ] - [ Online docs ]
Extension Sqlite 2.
Support for SQLite version 2 databases. The support for this version of Sqlite is not maintained anymore. It is recommended to use SQLite3 .
<?php
if ($db = sqlite_open('mysqlitedb', 0666, $sqliteerror)) {
sqlite_query($db, 'CREATE TABLE foo (bar varchar(10))');
sqlite_query($db, 'INSERT INTO foo VALUES ("fnord")');
$result = sqlite_query($db, 'select bar from foo');
var_dump(sqlite_fetch_array($result));
} else {
die($sqliteerror);
}
?>
See also ext/sqlite and
SQLite.
ext/sqlite3
[Since 0.8.4] - [ -P Extensions/Extsqlite3 ] - [ Online docs ]
Extension Sqlite3.
Support for SQLite version 3 databases.
<?php
$db = new SQLite3('mysqlitedb.db');
$results = $db->query('SELECT bar FROM foo');
while ($row = $results->fetchArray()) {
var_dump($row);
}
?>
See also ext/sqlite3 and
Sqlite.
ext/ssh2
[Since 0.8.4] - [ -P Extensions/Extssh2 ] - [ Online docs ]
Extension ext/ssh2.
<?php
/* Notify the user if the server terminates the connection */
function my_ssh_disconnect($reason, $message, $language) {
printf("Server disconnected with reason code [%d] and message: %s\n",
$reason, $message);
}
$methods = array(
'kex' => 'diffie-hellman-group1-sha1',
'client_to_server' => array(
'crypt' => '3des-cbc',
'comp' => 'none'),
'server_to_client' => array(
'crypt' => 'aes256-cbc,aes192-cbc,aes128-cbc',
'comp' => 'none'));
$callbacks = array('disconnect' => 'my_ssh_disconnect');
$connection = ssh2_connect('shell.example.com', 22, $methods, $callbacks);
if (!$connection) die('Connection failed');
?>
See also SSH2 functions and
ext/ssh2 on PECL.
ext/standard
[Since 0.8.4] - [ -P Extensions/Extstandard ] - [ Online docs ]
Standards PHP functions.
This is not a real PHP extension : it covers the core functions.
<?php
/*
Our php.ini contains the following settings:
display_errors = On
register_globals = Off
post_max_size = 8M
*/
echo 'display_errors = ' . ini_get('display_errors') . PHP_EOL;
echo 'register_globals = ' . ini_get('register_globals') . PHP_EOL;
echo 'post_max_size = ' . ini_get('post_max_size') . PHP_EOL;
echo 'post_max_size+1 = ' . (ini_get('post_max_size')+1) . PHP_EOL;
echo 'post_max_size in bytes = ' . return_bytes(ini_get('post_max_size'));
function return_bytes($val) {
$val = trim($val);
$last = strtolower($val[strlen($val)-1]);
switch($last) {
// The 'G' modifier is available since PHP 5.1.0
case 'g':
$val *= 1024;
case 'm':
$val *= 1024;
case 'k':
$val *= 1024;
}
return $val;
}
?>
See also PHP Options/Info Functions.
ext/tidy
[Since 0.8.4] - [ -P Extensions/Exttidy ] - [ Online docs ]
Extension Tidy.
Tidy is a binding for the Tidy HTML clean and repair utility which allows you to not only clean and otherwise manipulate HTML documents, but also traverse the document tree.
<?php
`ob_start() <https://www.php.net/ob_start>`_;
?>
a html document
<?php
$html = `ob_get_clean() <https://www.php.net/ob_get_clean>`_;
// Specify configuration
$config = array(
'indent' => true,
'output-xhtml' => true,
'wrap' => 200);
// Tidy
$tidy = new tidy;
$tidy->parseString($html, $config, 'utf8');
$tidy->cleanRepair();
// Output
echo $tidy;
?>
See also Tidy and
HTML-tidy.
ext/tokenizer
[Since 0.8.4] - [ -P Extensions/Exttokenizer ] - [ Online docs ]
Extension Tokenizer.
The Tokenizer functions provide an interface to the PHP tokenizer embedded in the Zend Engine.
<?php
/*
* T_ML_COMMENT does not exist in PHP 5.
* The following three lines define it in order to
* preserve backwards compatibility.
*
* The next two lines define the PHP 5 only T_DOC_COMMENT,
* which we will mask as T_ML_COMMENT for PHP 4.
*/
if (!defined('T_ML_COMMENT')) {
define('T_ML_COMMENT', T_COMMENT);
} else {
define('T_DOC_COMMENT', T_ML_COMMENT);
}
$source = file_get_contents('example.php');
$tokens = token_get_all($source);
foreach ($tokens as $token) {
if (is_string($token)) {
// simple 1-character token
echo $token;
} else {
// token array
list($id, $text) = $token;
switch ($id) {
case T_COMMENT:
case T_ML_COMMENT: // we\'ve defined this
case T_DOC_COMMENT: // and this
// no action on comments
break;
default:
// anything else -> output 'as is'
echo $text;
break;
}
}
}
?>
See also tokenizer.
ext/wddx
[Since 0.8.4] - [ -P Extensions/Extwddx ] - [ Online docs ]
Extension WDDX.
The Web Distributed Data Exchange, or WDDX, is a free, open XML-based technology that allows Web applications created with any platform to easily exchange data with one another over the Web.
<?php
echo wddx_serialize_value("PHP to WDDX packet example", "PHP packet");
?>
See also Wddx on PHP and
WDDX.
ext/xdebug
[Since 0.8.4] - [ -P Extensions/Extxdebug ] - [ Online docs ]
Xdebug extension.
The Xdebug is a extension PHP which provides debugging and profiling capabilities.
<?php
class Strings
{
static function fix_string($a)
{
echo
xdebug_call_class().
"::".
xdebug_call_function().
" is called at ".
xdebug_call_`file() <https://www.php.net/file>`_.
":".
xdebug_call_line();
}
}
$ret = Strings::fix_string( 'Derick' );
?>
See also Xdebug.
ext/xmlreader
[Since 0.8.4] - [ -P Extensions/Extxmlreader ] - [ Online docs ]
Extension XMLReader.
The XMLReader extension is an XML Pull parser. The reader acts as a cursor going forward on the document stream and stopping at each node on the way.
<?php
$xmlreader = new XMLReader();
$xmlreader->xml("<xml><div>Content</div></xml>");
$xmlreader->read();
$xmlreader->read();
$xmlreader->readString();
?>
See also xmlreader.
ext/xmlrpc
[Since 0.8.4] - [ -P Extensions/Extxmlrpc ] - [ Online docs ]
Extension ext/xmlrpc.
This extension can be used to write XML-RPC servers and clients.
<?php
$request = xmlrpc_encode_request('method', array(1, 2, 3));
$context = stream_context_create(array('http' => array(
'method' => 'POST',
'header' => 'Content-Type: text/xml',
'content' => $request
)));
$file = file_get_contents('http://www.example.com/xmlrpc', false, $context);
$response = xmlrpc_decode($file);
if ($response && xmlrpc_is_fault($response)) {
trigger_error('xmlrpc: '.$response['faultString'].' ('.$response['faultCode']));
} else {
print_r($response);
}
?>
See also XML-RPC.
ext/xmlwriter
[Since 0.8.4] - [ -P Extensions/Extxmlwriter ] - [ Online docs ]
Extension ext/xmlwriter.
The XMLWriter extension wraps the libxml xmlWriter API inside PHP.
<?php
$xw = xmlwriter_open_memory();
xmlwriter_set_indent($xw, TRUE);
xmlwriter_start_document($xw, NULL, 'UTF-8');
xmlwriter_start_element($xw, 'root');
xmlwriter_write_attribute_ns($xw, 'prefix', '', 'http://www.php.net/uri');
xmlwriter_start_element($xw, 'elem1');
xmlwriter_write_attribute($xw, 'attr1', 'first');
xmlwriter_end_element($xw);
xmlwriter_full_end_element($xw);
xmlwriter_end_document($xw);
$output = xmlwriter_flush($xw, true);
print $output;
// write attribute_ns without start_element first
$xw = xmlwriter_open_memory();
var_dump(xmlwriter_write_attribute_ns($xw, 'prefix', 'id', 'http://www.php.net/uri', 'elem1'));
print xmlwriter_output_memory($xw);
?>
See also XMLWriter and Module xmlwriter from libxml2.
ext/xsl
[Since 0.8.4] - [ -P Extensions/Extxsl ] - [ Online docs ]
Extension XSL.
The XSL extension implements the XSL standard, performing XSLT transformations using the libxslt library.
<?php
// Example from the PHP manual
$xmldoc = new DOMDocument();
$xsldoc = new DOMDocument();
$xsl = new XSLTProcessor();
$xmldoc->loadXML('fruits.xml');
$xsldoc->loadXML('fruits.xsl');
libxml_use_internal_errors(true);
$result = $xsl->importStyleSheet($xsldoc);
if (!$result) {
foreach (libxml_get_errors() as $error) {
echo "Libxml error: {$error->message}\n";
}
}
libxml_use_internal_errors(false);
if ($result) {
echo $xsl->transformToXML($xmldoc);
}
?>
See also XSL extension;
ext/yaml
[Since 0.8.4] - [ -P Extensions/Extyaml ] - [ Online docs ]
Extension YAML.
This extension implements the YAML Ain't Markup Language (YAML) data serialization standard. Parsing and emitting are handled by the LibYAML library.
<?php
$addr = array(
'given' => 'Chris',
'family'=> 'Dumars',
'address'=> array(
'lines'=> '458 Walkman Dr.
Suite #292',
'city'=> 'Royal Oak',
'state'=> 'MI',
'postal'=> 48046,
),
);
$invoice = array (
'invoice'=> 34843,
'date'=> '2001-01-23',
'bill-to'=> $addr,
'ship-to'=> $addr,
'product'=> array(
array(
'sku'=> 'BL394D',
'quantity'=> 4,
'description'=> 'Basketball',
'price'=> 450,
),
array(
'sku'=> 'BL4438H',
'quantity'=> 1,
'description'=> 'Super Hoop',
'price'=> 2392,
),
),
'tax'=> 251.42,
'total'=> 4443.52,
'comments'=> 'Late afternoon is best. Backup contact is Nancy Billsmer @ 338-4338.',
);
// generate a YAML representation of the invoice
$yaml = yaml_emit($invoice);
var_dump($yaml);
// convert the YAML back into a PHP variable
$parsed = yaml_parse($yaml);
// check that roundtrip conversion produced an equivalent structure
var_dump($parsed == $invoice);
?>
See also YAML.
ext/zip
[Since 0.8.4] - [ -P Extensions/Extzip ] - [ Online docs ]
Extension ext/zip.
This extension enables you to transparently read or write ZIP compressed archives and the files inside them.
<?php
$zip = new ZipArchive();
$filename = './test112.zip';
if ($zip->open($filename, ZipArchive::CREATE)!==TRUE) {
exit('cannot open <$filename>');
}
$zip->addFromString('testfilephp.txt' . time(), '#1 This is a test string added as testfilephp.txt.'.PHP_EOL);
$zip->addFromString('testfilephp2.txt' . time(), '#2 This is a test string added as testfilephp2.txt.'.PHP_EOL);
$zip->addFile($thisdir . '/too.php','/testfromfile.php');
echo 'numfiles: ' . $zip->numFiles . PHP_EOL;
echo 'status:' . $zip->status . PHP_EOL;
$zip->close();
?>
See also Zip.
ext/zlib
[Since 0.8.4] - [ -P Extensions/Extzlib ] - [ Online docs ]
Extension ext/zlib.
<?php
$filename = tempnam('/tmp', 'zlibtest') . '.gz';
echo "<html>\n<head></head>\n<body>\n<pre>\n";
$s = "Only a test, test, test, test, test, test, test, test!\n";
// open file for writing with maximum compression
$zp = gzopen($filename, 'w9');
// write string to file
gzwrite($zp, $s);
// close file
gzclose($zp);
?>
See also Zlib.
Closures Glossary
[Since 0.8.4] - [ -P Functions/Closures ] - [ Online docs ]
List of all the closures in the code.
<?php
// A closure is also a unnamed function
$closure = function ($arg) { return 'A'.strtolower($arg); }
?>
See also The Closure Class.
Empty Function
[Since 0.8.4] - [ -P Functions/EmptyFunction ] - [ Online docs ]
Function or method whose body is empty.
Such functions or methods are rarely useful. As a bare minimum, the function should return some useful value, even if constant.
A method is considered empty when it contains nothing, or contains expressions without impact.
<?php
// classic empty function
function emptyFunction() {}
class bar {
// classic empty method
function emptyMethod() {}
// classic empty function
function emptyMethodWithParent() {}
}
class barbar extends bar {
// NOT an empty method : it overwrites the parent method
function emptyMethodWithParent() {}
}
?>
Methods which overwrite another methods are omitted. Methods which are the concrete version of an abstract method are considered.
Functions Glossary
[Since 0.8.4] - [ -P Functions/Functionnames ] - [ Online docs ]
List of all the defined functions in the code.
<?php
// A function
function aFunction() {}
// Closures (not reported)
$closure = function ($arg) { }
// Methods
class foo {
function aMethod() {}
}
?>
Recursive Functions
[Since 0.8.4] - [ -P Functions/Recursive ] - [ Online docs ]
Recursive functions are functions that calls itself.
<?php
// a recursive function ; it calls itself
function factorial($n) {
if ($n == 1) { return 1; }
return factorial($n - 1) * $n;
}
?>
Methods are not handled here.
Redeclared PHP Functions
[Since 0.8.4] - [ -P Functions/RedeclaredPhpFunction ] - [ Online docs ]
Function that bear the same name as a PHP function, and that are declared.
This is useful when managing backward compatibility, like emulating an old function, or preparing for newer PHP versions, like emulating new upcoming function.
<?php
if (version_compare(PHP_VERSION, 7.0) > 0) {
function split($separator, $string) {
return explode($separator, $string);
}
}
print_r( split(' ', '2 3'));
?>
Typehints
[Since 0.8.4] - [ -P Functions/Typehints ] - [ Online docs ]
List of all the types (classes or scalar) used in Typehinting.
<?php
// here, array, myObject and string are all typehints.
function foo(array $array, myObject $x, string $string) {
}
?>
See also Type declarations.
Methods Without Return
[Since 0.8.4] - [ -P Functions/WithoutReturn ] - [ Online docs ]
List of all the function, closures, methods that have no explicit return.
Functions that hold the void return type are omitted.
<?php
// With return null : Explicitly not returning
function withExplicitReturn($a = 1) {
$a++;
return null;
}
// Without indication
function withoutExplicitReturn($a = 1) {
$a++;
}
// With return type void : Explicitly not returning
function withExplicitReturnType($a = 1) : void {
$a++;
}
?>
See also return.
Empty Interfaces
[Since 0.8.4] - [ -P Interfaces/EmptyInterface ] - [ Online docs ]
Empty interfaces are a code smell. Interfaces should contains at least a method or a constant, and not be totally empty.
<?php
// an empty interface
interface empty {}
// an normal interface
interface normal {
public function i() ;
}
// a constants interface
interface constantsOnly {
const FOO = 1;
}
?>
See also Empty interfaces are bad practice and Blog : Are empty interfaces code smell?.
Interfaces Glossary
[Since 0.8.4] - [ -P Interfaces/Interfacenames ] - [ Online docs ]
List of all the defined interfaces in the code.
<?php
// interfaceName is reported
interface interfaceName {
function interfaceMethod() ;
}
?>
Aliases
[Since 0.8.4] - [ -P Namespaces/Alias ] - [ Online docs ]
List of all aliases used, to alias namespaces.
<?php
// This is an alias
use stdClass as aClass;
// This is not an alias : it is not explicit
use stdClass;
trait t {
// This is not an alias, it's a trait usage
use otherTrait;
}
?>
See also Using namespaces: Aliasing/Importing.
Namespaces Glossary
[Since 0.8.4] - [ -P Namespaces/Namespacesnames ] - [ Online docs ]
List of all the defined namespaces in the code, using the namespace keyword.
<?php
// One reported namespace
namespace one\name\space {}
// This global namespace is reported, as it is explicit
namespace { }
?>
Global namespaces are mentioned when they are explicitly used.
Autoloading
[Since 0.8.4] - [ -P Php/AutoloadUsage ] - [ Online docs ]
Usage of the autoloading feature of PHP.
<?php
spl_autoload_register('my_autoloader');
// Old way to autoload. Deprecated in PHP 7.2
function __autoload($class ) {}
?>
Defining the __autoload() function is obsolete since PHP 7.2.
See also __autoload.
Use Lower Case For Parent, Static And Self
[Since 0.8.4] - [ -P Php/CaseForPSS ] - [ Online docs ] - [ PHP older than 5.5]
The special parent, static and self keywords needed to be lowercase to be usable. This was fixed in PHP 5.5; otherwise, they would yield a 'PHP Fatal error: Class 'PARENT' not found'.
parent, static and self are traditionally written in lowercase only. Mixed case and Upper case are both valid, though.
<?php
class foo {
const aConstante = 233;
function method() {
// Wrong case, error with PHP 5.4.* and older
echo SELF::aConstante;
// Always right.
echo self::aConstante;
}
}
?>
Until PHP 5.5, non-lowercase version of those keywords are generating a bug.
Goto Names
[Since 0.8.4] - [ -P Php/Gotonames ] - [ Online docs ]
List of all goto labels used in the code.
<?php
GOTO_NAME_1:
// reports the usage of GOTO_NAME_1
goto GOTO_NAME_1;
UNUSED_GOTO_NAME_1:
?>
__halt_compiler
[Since 0.8.4] - [ -P Php/Haltcompiler ] - [ Online docs ]
__halt_compiler() usage.
<?php
// open this file
$fp = fopen(__FILE__, 'r');
// seek file pointer to data
fseek($fp, __COMPILER_HALT_OFFSET__);
// and output it
var_dump(stream_get_contents($fp));
// the end of the script execution
__halt_compiler(); the installation data (eg. tar, gz, PHP, etc.)
?>
Incompilable Files
[Since 0.8.4] - [ -P Php/Incompilable ] - [ Online docs ]
Files that cannot be compiled, and, as such, be run by PHP. Scripts are linted against various versions of PHP.
This is usually undesirable, as all code must compile before being executed. It may be that such files are not compilable because they are not yet ready for an upcoming PHP version.
<?php
// Can't compile this : Print only accepts one argument
print $a, $b, $c;
?>
Code that is not compilable with older PHP versions means that the code is breaking backward compatibility : good or bad is project decision.
When the code is used as a template for PHP code generation, for example at installation time, it is recommended to use a distinct file extension, so as to distinguish them from actual PHP code.
Labels
[Since 0.8.4] - [ -P Php/Labelnames ] - [ Online docs ]
List of all labels used in the code.
<?php
// A is label.
goto A:
A:
// A label may be used by several gotos.
goto A:
?>
Functions Removed In PHP 5.4
[Since 0.8.4] - [ -P Php/Php54RemovedFunctions ] - [ Online docs ] - [ PHP older than 5.4]
Those functions were removed in PHP 5.4.
<?php
// Deprecated as of PHP 5.4.0
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
$db_list = mysql_list_dbs($link);
while ($row = mysql_fetch_object($db_list)) {
echo $row->Database . "\n";
}
?>
See also Deprecated features in PHP 5.4.x.
Functions Removed In PHP 5.5
[Since 0.8.4] - [ -P Php/Php55RemovedFunctions ] - [ Online docs ] - [ PHP older than 5.5]
Those functions were removed in PHP 5.5.
+ php_logo_guid()
+ php_egg_logo_guid()
+ php_real_logo_guid()
+ zend_logo_guid()
+ mcrypt_cbc()
+ mcrypt_cfb()
+ mcrypt_ecb()
+ mcrypt_ofb()
<?php
echo '<img src="' . $_SERVER['PHP_SELF'] .
'?=' . `php_logo_guid() <https://www.php.net/php_logo_guid>`_ . '" alt="PHP Logo !" />';
?>
See also Deprecated features in PHP 5.5.x.
Throw
[Since 0.8.4] - [ -P Php/ThrowUsage ] - [ Online docs ]
List of thrown exceptions.
<?php
if ($divisor === 0) {
// Throw native exception
throw new DivisionByZeroError("Shouldn't divide by one");
}
if ($divisor === 1) {
// Throw custom exception
throw new DontDivideByOneException("Shouldn't divide by one");
}
?>
See also Exceptions.
Trigger Errors
[Since 0.8.4] - [ -P Php/TriggerErrorUsage ] - [ Online docs ]
List of situations where user errors are triggered.
PHP errors are triggered with trigger_error().
<?php
if ($divisor == 0) {
trigger_error('Cannot divide by zero', E_USER_ERROR);
}
?>
See also trigger_error.
Caught Expressions
[Since 0.8.4] - [ -P Php/TryCatchUsage ] - [ Online docs ]
List of caught exceptions.
<?php
// This analyzer reports MyException and Exception
try {
doSomething();
} catch (MyException $e) {
fixIt();
} catch (\Exception $e) {
fixIt();
}
?>
Break With 0
[Since 0.8.4] - [ -P Structures/Break0 ] - [ Online docs ] - [ PHP older than 5.4]
Cannot break 0, as this makes no sense. Break 1 is the minimum, and is the default value.
<?php
// Can't break 0. Must be 1 or more, depending on the level of nesting.
for($i = 0; $i < 10; $i++) {
break 0;
}
for($i = 0; $i < 10; $i++) {
for($j = 0; $j < 10; $j++) {
break 2;
}
}
?>
Break With Non Integer
[Since 0.8.4] - [ -P Structures/BreakNonInteger ] - [ Online docs ] - [ PHP older than 5.4]
When using a break, the argument of the operator must be a positive non-null integer literal or be omitted.
Other values were acceptable in PHP 5.3 and previous version, but this is now reported as an error.
<?php
// Can't break $a, even if it contains an integer.
$a = 1;
for($i = 0; $i < 10; $i++) {
break $a;
}
// can't break on float
for($i = 0; $i < 10; $i++) {
for($j = 0; $j < 10; $j++) {
break 2.2;
}
}
?>
Calltime Pass By Reference
[Since 0.8.4] - [ -P Structures/CalltimePassByReference ] - [ Online docs ] - [ PHP older than 5.4]
PHP doesn't allow when a value is turned into a reference at functioncall, since PHP 5.4.
Either the function use a reference in its signature, either the reference won't pass.
<?php
function foo($name) {
$arg = ucfirst(strtolower($name));
echo 'Hello '.$arg;
}
$a = 'name';
foo(&$a);
?>
error_reporting() With Integers
[Since 0.8.4] - [ -P Structures/ErrorReportingWithInteger ] - [ Online docs ]
Using named constants with error_reporting is strongly encouraged to ensure compatibility for future versions. As error levels are added, the range of integers increases, so older integer-based error levels will not always behave as expected. (Adapted from the documentation).
<?php
// This is ready for PHP next version
error_reporting(E_ALL & ~E_DEPRECATED & ~E_STRICT & ~E_NOTICE & ~E_WARNING);
// This is not ready for PHP next version
error_reporting(2047);
// -1 and 0 are omitted, as they will be valid even is constants changes.
error_reporting(-1);
error_reporting(0);
?>
See also directive error_reporting and
error_reporting.
Eval() Usage
[Since 0.8.4] - [ -P Structures/EvalUsage ] - [ Online docs ]
Using eval() is evil.
Using eval() is bad for performances (compilation time), for caches (it won't be compiled), and for security (if it includes external data).
<?php
// Avoid using incoming data to build the `eval() <https://www.php.net/eval>`_ expression : any filtering error leads to PHP injection
$mathExpression = $_GET['mathExpression'];
$mathExpression = preg_replace('#[^0-9+\-*/\(/)]#is', '', $mathExpression); // expecting 1+2
$literalCode = '$a = '.$mathExpression.';';
eval($literalCode);
echo $a;
// If the code code given to `eval() <https://www.php.net/eval>`_ is known at compile time, it is best to put it inline
$literalCode = '`phpinfo() <https://www.php.net/phpinfo>`_;';
eval($literalCode);
?>
Most of the time, it is possible to replace the code by some standard PHP, like variable variable for accessing a variable for which you have the name.
At worse, including a pregenerated file is faster and cacheable.
There are several situations where eval() is actually the only solution :
For PHP 7.0 and later, it is important to put eval() in a try..catch expression.
See also eval and
The Land Where PHP Uses `eval()
Exit() Usage
[Since 0.8.4] - [ -P Structures/ExitUsage ] - [ Online docs ]
Using exit or die() in the code makes the code untestable (it will break unit tests). Moreover, if there is no reason or string to display, it may take a long time to spot where the application is stuck.
<?php
// Throw an exception, that may be caught somewhere
throw new \Exception('error');
// Dying with error message.
die('error');
function foo() {
//exiting the function but not dying
if (somethingWrong()) {
return true;
}
}
?>
Try exiting the function/class with return, or throw exception that may be caught later in the code.
For Using Functioncall
[Since 0.8.4] - [ -P Structures/ForWithFunctioncall ] - [ Online docs ]
It is recommended to avoid functioncall in the for() statement.
<?php
// Fastest way
$nb = count($array);
for($i = 0; $i < $nb; ++$i) {
doSomething($i);
}
// Same as above, but slow
for($i = 0; $i < count($array); ++$i) {
doSomething($i);
}
// Same as above, but slow
foreach($portions as &$portion) {
// here, `array_sum() <https://www.php.net/array_sum>`_ doesn't depends on the $grade. It should be out of the loop
$portion = $portion / array_sum($portions);
}
$total = array_sum($portion);
foreach($portion as &$portion) {
$portion = $portion / $total;
}
?>
This is true with any kind of functioncall that returns the same value throughout the loop.
Forgotten Whitespace
[Since 0.8.4] - [ -P Structures/ForgottenWhiteSpace ] - [ Online docs ]
Forgotten whitespaces only bring misery to the code.
White spaces have been left at either end of a file : before the PHP opening tag, or after the closing tag.
Usually, such whitespaces are forgotten, and may end up summoning the infamous 'headers already sent' error. It is better to remove them.
<?php
// This script has no forgotten whitespace, not at the beginning
function foo() {}
// This script has no forgotten whitespace, not at the end
?>
See also How to fix Headers already sent error in PHP.
Iffectations
[Since 0.8.4] - [ -P Structures/Iffectation ] - [ Online docs ]
Affectations that appears in a condition.
Iffectations are a way to do both a test and an affectations.
They may also be typos, such as if ($x = 3) { ... }, leading to a constant condition.
<?php
// an iffectation : assignation in a If condition
if($connexion = mysql_connect($host, $user, $pass)) {
$res = mysql_query($connexion, $query);
}
// Iffectation may happen in while too.
while($row = mysql_fetch($res)) {
$store[] = $row;
}
?>
Multiply By One
[Since 0.8.4] - [ -P Structures/MultiplyByOne ] - [ Online docs ]
Multiplying by 1 is a fancy type cast.
If it is used to type cast a value to number, then casting (integer) or (real) is clearer. This behavior may change with PHP 7.1, which has unified the behavior of all hidden casts.
<?php
// Still the same value than $m, but now cast to integer or real
$m = $m * 1;
// Still the same value than $m, but now cast to integer or real
$n *= 1;
// make typecasting clear, and merge it with the producing call.
$n = (int) $n;
?>
See also Type Juggling
@ Operator
[Since 0.8.4] - [ -P Structures/Noscream ] - [ Online docs ]
@ is the 'no scream' operator : it suppresses error output.
<?php
// Set x with incoming value, or else null.
$x = @$_GET['x'];
?>
This operator is actually very slow : it will process the error all the way up, and finally decide not to display it. It is often faster to check the conditions first, then run the method without @ .
You may also set display_error to 0 in the php.ini : this will avoid user's error display, but will keep the error in the PHP logs, for later processing.
The only situation where @ is useful is when a native PHP function displays errors messages when error happens and there is no way to check it from the code.
This is the case with fopen(), stream_socket_server(), token_get_all().
See also Error Control Operators and
Five reasons why the shut-op operator should be avoided.
Not Not
[Since 0.8.4] - [ -P Structures/NotNot ] - [ Online docs ]
Double not makes a boolean, not a true .
This is a wrong casting to boolean. PHP supports (boolean) to do the same, faster and cleaner.
<?php
// Explicit code
$b = (boolean) $x;
$b = (bool) $x;
// Wrong type casting
$b = !!$x;
?>
See also Logical Operators and
Type Juggling.
include_once() Usage
[Since 0.8.4] - [ -P Structures/OnceUsage ] - [ Online docs ]
include_once() and require_once() functions should be avoided for performances reasons.
<?php
// Including a library.
include 'lib/helpers.inc';
// Including a library, and avoiding double inclusion
include_once 'lib/helpers.inc';
?>
Try using autoload for loading classes, or use include() or require() and make it possible to include several times the same file without errors.
Phpinfo
[Since 0.8.4] - [ -P Structures/PhpinfoUsage ] - [ Online docs ]
phpinfo() is a great function to learn about the current configuration of the server.
<?php
if (DEBUG) {
`phpinfo() <https://www.php.net/phpinfo>`_;
}
?>
If left in the production code, it may lead to a critical leak, as any attacker gaining access to this data will know a lot about the server configuration.
It is advised to never leave that kind of instruction in a production code.
phpinfo() may be necessary to access some specific configuration of the server : for example, Apache module list are only available via phpinfo(), and apache_get(), when they are loaded.
Using Short Tags
[Since 0.8.4] - [ -P Structures/ShortTags ] - [ Online docs ]
The code makes use of short tags. Short tags are the following : . A full scripts looks like that : .
It is recommended to not use short tags, and use standard PHP tags. This makes PHP code compatible with XML standards. Short tags used to be popular, but have lost it.
See also PHP Tags.
Strpos()-like Comparison
[Since 0.8.4] - [ -P Structures/StrposCompare ] - [ Online docs ]
The result of that function may be mistaken with an error.
strpos(), along with several PHP native functions, returns a string position, starting at 0, or false, in case of failure.
<?php
// This is the best comparison
if (strpos($string, 'a') === false) { }
// This is OK, as 2 won't be mistaken with false
if (strpos($string, 'a') == 2) { }
// strpos is one of the 26 functions that may behave this way
if (preg_match($regex, $string)) { }
// This works like above, catching the value for later reuse
if ($a = strpos($string, 'a')) { }
// This misses the case where 'a' is the first char of the string
if (strpos($string, 'a')) { }
// This misses the case where 'a' is the first char of the string, just like above
if (strpos($string, 'a') == 0) { }
?>
It is recommended to check the result of strpos() with === or !==, so as to avoid confusing 0 and false.
This analyzer list all the strpos()-like functions that are directly compared with == or !=. preg_match(), when its first argument is a literal, is omitted : this function only returns NULL in case of regex error.
The full list is the following :
- array_search()
- collator_compare()
- collator_get_sort_key()
- current()
- fgetc()
- file_get_contents()
- file_put_contents()
- fread()
- iconv_strpos()
- iconv_strrpos()
- imagecolorallocate()
- imagecolorallocatealpha()
- mb_strlen()
- next()
- pcntl_getpriority()
- preg_match()
- prev()
- readdir()
- stripos()
- strpos()
- strripos()
- strrpos()
- strtok()
- curl_exec()
In PHP 8.0, str_contains() will do the expected job of strpos(), with less confusion.
See also strpos not working correctly.
Throws An Assignement
[Since 0.8.4] - [ -P Structures/ThrowsAndAssign ] - [ Online docs ]
It is possible to throw an exception, and, in the same time, assign this exception to a variable.
However, the variable will never be used, as the exception is thrown, and any following code is not executed.
<?php
// $e is useful, though not by much
$e = new() Exception();
throw $e;
// $e is useless
throw $e = new Exception();
?>
The assignment should be removed.
var_dump()... Usage
[Since 0.8.4] - [ -P Structures/VardumpUsage ] - [ Online docs ]
var_dump(), print_r() or var_export() should not be left in any production code. They are debugging functions.
<?php
if ($error) {
// Debugging usage of var_dump
// And major security problem
var_dump($query);
// This is OK : the $query is logged, and not displayed
$this->log(print_r($query, true));
}
?>
They may be tolerated during development time, but must be removed so as not to have any chance to be run in production.
__toString() Throws Exception
[Since 0.8.4] - [ -P Structures/toStringThrowsException ] - [ Online docs ]
Magical method __toString() can't throw exceptions.
In fact, __toString() may not let an exception pass. If it throw an exception, but must catch it. If an underlying method throws an exception, it must be caught.
<?php
class myString {
private $string = null;
public function __construct($string) {
$this->string = $string;
}
public function __toString() {
// Do not throw exceptions in __toString
if (!is_string($this->string)) {
throw new Exception("$this->string is not a string!!");
}
return $this->string;
}
}
?>
A fatal error is displayed, when an exception is not intercepted in the __toString() function.
::
PHP Fatal error: Method myString::__toString() must not throw an exception, caught Exception: 'Exception message' in file.php
See also __toString().
Binary Glossary
[Since 0.8.4] - [ -P Type/Binary ] - [ Online docs ] - [ PHP 5.4 and more recent ]
List of all the integer values using the binary format.
<?php
$a = 0b10;
$b = 0B0101;
?>
Email Addresses
[Since 0.8.4] - [ -P Type/Email ] - [ Online docs ]
List of all the email addresses that were found in the code.
Emails are detected with regex : [_A-Za-z0-9-]+(\\.[_A-Za-z0-9-]+)*@[A-Za-z0-9]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})
<?php
$email = 'contact@exakat.io';
?>
Heredoc Delimiter Glossary
[Since 0.8.4] - [ -P Type/Heredoc ] - [ Online docs ]
List of all the delimiters used to build a Heredoc string.
In the example below, EOD is the delimiter.
<?php
$a = <<<EOD
heredoc
EOD;
?>
See also Heredoc.
Hexadecimal Glossary
[Since 0.8.4] - [ -P Type/Hexadecimal ] - [ Online docs ]
List of all the integer values using the hexadecimal format.
<?php
$hexadecimal = 0x10;
$anotherHexadecimal =0XAF;
?>
See also Integer Syntax.
Http Headers
[Since 0.8.4] - [ -P Type/HttpHeader ] - [ Online docs ]
List of HTTP headers use in the code.
<?php
header('Location: http://www.example.com/');
// Parseable headers are also reported
header('Location: http://www.example.com/');
// UnParseable headers are not reported
header('GarbagexxxxXXXXxxxGarbagexxxxXXXXxxx');
header($header);
?>
Those headers are mostly used with header() function to send to browser.
See also List of HTTP header fields.
HTTP Status Code
[Since 0.8.4] - [ -P Type/HttpStatus ] - [ Online docs ]
List of all the HTTP status codes mentioned in the code.
<?php
http_response_code(418);
header('HTTP/1.1 418 I\'m a teapot');
?>
See also List of HTTP status codes.
Malformed Octal
[Since 0.8.4] - [ -P Type/MalformedOctal ] - [ Online docs ] - [ PHP older than 7.0]
Those numbers starts with a 0, so they are using the PHP octal convention. Therefore, one can't use 8 or 9 figures in those numbers, as they don't belong to the octal base. The resulting number will be truncated at the first erroneous figure. For example, 090 is actually 0, and 02689 is actually 22.
<?php
// A long way to write 0 in PHP 5
$a = 0890;
// A fatal error since PHP 7
?>
Also, note that very large octal, usually with more than 21 figures, will be turned into a real number and undergo a reduction in precision.
See also Integers.
Md5 Strings
[Since 0.8.4] - [ -P Type/Md5String ] - [ Online docs ]
List of all the MD5 values hard coded in the application.
MD5 values are detected as hexadecimal strings, of length 32. No attempt at recognizing the origin value is made, so any such strings, including dummy '11111111111111111111111111111111' are reported.
<?php
// 32
$a = '0cc175b9c0f1b6a831c399e269771111';
?>
See also MD5.
Mime Types
[Since 0.8.4] - [ -P Type/MimeType ] - [ Online docs ]
List of Mime Types that are mentioned in the code.
<?php
$mimeType = 'multipart/form-data';
$mimeType = 'image/jpeg';
$mimeType = 'application/zip';
header('Content-Type: '.$mimeType);
?>
See also Media Type and
MIME.
Nowdoc Delimiter Glossary
[Since 0.8.4] - [ -P Type/Nowdoc ] - [ Online docs ]
List of all the delimiters used to build a Nowdoc string.
<?php
$nowdoc = <<<'EOD'
EOD;
?>
See also Nowdoc and
Heredoc.
Octal Glossary
[Since 0.8.4] - [ -P Type/Octal ] - [ Online docs ]
List of all the integer values using the octal format : an integer starting with an initial 0.
<?php
$a = 1234; // decimal number
$a = 0123; // octal number (equivalent to 83 decimal)
// silently valid for PHP 5.x
$a = 01283; // octal number (equivalent to 10 decimal)
?>
Putting an initial 0 is often innocuous, but in PHP, 0755 and 755 are not the same. The second is actually 1363 in octal, and will not provide the expected privileges.
See also Integers.
Perl Regex
[Since 0.8.4] - [ -P Type/Pcre ] - [ Online docs ]
List of all the Perl Regex (Pcre-style).
<?php
preg_match('/[abc]/', $haystack);
preg_replace('#[0-9A-Z]+#is', $y, $z);
?>
Regex are spotted when they are literals : dynamically built regex, (including /$x/) are not reported.
Internet Ports
[Since 0.8.4] - [ -P Type/Ports ] - [ Online docs ]
List of all the Internet ports mentioned in the code.
Ports are recognized based on a internal database of port. They are found in Integers.
<?php
// 21 is the default port for FTP
$ftp = ftp_connect($host, 21, $timeout = 90);
?>
See also List of TCP and UDP port numbers.
Special Integers
[Since 0.8.4] - [ -P Type/SpecialIntegers ] - [ Online docs ]
Short and incomplete list of integers that may hold special values.
<?php
// 86400 is the number of seconds in a day
$day = 86400;
// 1400 is the number of minutes in a day
$day = 1440;
?>
The list includes powers of 2, duration in various units, factorial, ASCII codes and years.
All strings
[Since 0.10.1] - [ -P Type/CharString ] - [ Online docs ]
Strings and heredocs in one place.
<?php
$string = 'string';
$query = <<<SQL
Heredoc
SQL;
?>
Unicode Blocks
[Since 0.8.4] - [ -P Type/UnicodeBlock ] - [ Online docs ]
List of the Unicode blocks used in string literals.
This is the kind of characters that can be found in the applications strings.
<?php
$a = zoo;
$b = ఒ; // Telugu character
$b = \u{0C12}; Same as above
$b = 人; // Chinese Mandarin character
$b = \u{4EBA}; Same as above?>
Note that Exakat only analyze PHP scripts : any translation available in a .po or external resource is not parsed and will not show.
See also Unicode block.
URL List
[Since 0.8.4] - [ -P Type/Url ] - [ Online docs ]
List of all the URL addresses that were found in the code.
<?php
// the first argument is recognized as an URL
ftp_connect('http://www.example.com/', $port, $timeout);
// the string argument is recognized as an URL
$source = 'https://www.other-example.com/';
?>
References
[Since 0.8.4] - [ -P Variables/References ] - [ Online docs ]
Variables that are references.
<?php
$a = '1'; // not a reference
$b = &$a; // a reference
?>
See also References.
Static Variables
[Since 0.8.4] - [ -P Variables/StaticVariables ] - [ Online docs ]
In PHP, variables may be static. They will survive after the function execution end, and will be available at the next function run. They are distinct from globals, which are available application wide, and from static properties, which are tied to a class of objects.
<?php
function foo() {
// static variable
static $count = 0;
echo ++$count;
}
class bar {
// This is not a static variable :
// it is a static property
static $property = 1;
}
?>
Variables With Long Names
[Since 0.8.4] - [ -P Variables/VariableLong ] - [ Online docs ]
VariablesLong collect all variables with more than 20 characters longs.
<?php
// Quite a long variable name
$There_is nothing_wrong_with_long_variable_names_They_tend_to_be_rare_and_that_make_them_noteworthy = 1;
?>
There is nothing wrong with long variable names. They tend to be rare, and that make them noteworthy.
See also Basics.
Non Ascii Variables
[Since 0.8.4] - [ -P Variables/VariableNonascii ] - [ Online docs ]
PHP allows certain characters in variable names. The variable name must only include letters, figures, underscores and ASCII characters from 128 to 255.
In practice, letters outside the scope of a-zA-Z0-9 are rare, and require more care when editing the code or passing it from OS to OS.
<?php
class 人 {
// An actual working class in PHP.
public function __construct() {
echo __CLASS__;
}
}
$人民 = new 人();
?>
See also Variables.
Used Once Variables
[Since 0.8.4] - [ -P Variables/VariableUsedOnce ] - [ Online docs ]
This is the list of used once variables.
<?php
// The variables below never appear again in the code
$writtenOnce = 1;
foo($readOnce);
?>
Such variables are useless. Variables must be used at least twice : once for writing, once for reading, at least. It is recommended to remove them.
In special situations, variables may be used once :
+ PHP predefined variables, as they are already initialized. They are omitted in this analyze.
+ Interface function's arguments, since the function has no body; They are omitted in this analyze.
+ Dynamically created variables ($$x, ${$this->y} or also using extract), as they are runtime values and can't be determined at static code time. They are reported for manual review.
+ Dynamically included files will provide in-scope extra variables.
The current analyzer count variables at the application level, and not at a method scope level.
Variables Variables
[Since 0.8.4] - [ -P Variables/VariableVariables ] - [ Online docs ]
A variable variable takes the value of a variable and treats that as the name of a variable.
PHP has the ability to dynamically use a variable.
<?php
// Normal variable
$a = 'b';
$b = 'c';
// Variable variable
$d = $$b;
// Variable variable in string
$d = "$\{$b\}";
?>
See also Variable variables.
Abstract Class Usage
[Since 0.8.4] - [ -P Classes/Abstractclass ] - [ Online docs ]
List of all abstract classes being used.
<?php
abstract class foo {
function foobar();
}
class bar extends foo {
// extended method
function foobar() {
// doSomething()
}
// extra method
function barbar() {
// doSomething()
}
}
?>
See also Classes abstraction.
Abstract Methods Usage
[Since 0.8.4] - [ -P Classes/Abstractmethods ] - [ Online docs ]
List of all abstract methods being used.
<?php
// abstract class
abstract class foo {
// abstract method
function foobar();
}
class bar extends foo {
// extended abstract method
function foobar() {
// doSomething()
}
// extra method
function barbar() {
// doSomething()
}
}
?>
See also Classes abstraction.
Clone Usage
[Since 0.8.4] - [ -P Classes/CloningUsage ] - [ Online docs ]
List of all clone situations.
<?php
$dateTime = new DateTime();
echo (clone $dateTime)->format('Y');
?>
See also Object cloning.
Final Class Usage
[Since 0.8.4] - [ -P Classes/Finalclass ] - [ Online docs ]
List of all final classes being used.
final may be applied to classes and methods.
<?php
class BaseClass {
public function test() {
echo 'BaseClass::test() called'.PHP_EOL;
}
final public function moreTesting() {
echo 'BaseClass::moreTesting() called'.PHP_EOL;
}
}
class ChildClass extends BaseClass {
public function moreTesting() {
echo 'ChildClass::moreTesting() called'.PHP_EOL;
}
}
// Results in Fatal error: Cannot override final method BaseClass::moreTesting()
?>
See also Final Keyword.
Final Methods Usage
[Since 0.8.4] - [ -P Classes/Finalmethod ] - [ Online docs ]
List of all final methods being used.
final may be applied to classes and methods.
<?php
class BaseClass {
public function test() {
echo 'BaseClass::test() called'.PHP_EOL;
}
final public function moreTesting() {
echo 'BaseClass::moreTesting() called'.PHP_EOL;
}
}
class ChildClass extends BaseClass {
public function moreTesting() {
echo 'ChildClass::moreTesting() called'.PHP_EOL;
}
}
// Results in Fatal error: Cannot override final method BaseClass::moreTesting()
?>
See also Final Keyword.
Bad Constants Names
[Since 0.8.4] - [ -P Constants/BadConstantnames ] - [ Online docs ]
PHP's manual recommends that developer do not use constants with the convention __NAME__ . Those are reserved for PHP future use.
For example, __TRAIT__ recently appeared in PHP, as a magic constant. In the future, other may appear.
<?php
const __MY_APP_CONST__ = 1;
const __MY_APP_CONST__ = 1;
define('__MY_OTHER_APP_CONST__', 2);
?>
The analyzer will report any constant which name is __.*.__ , or even _.*_ (only one underscore).
See also Constants.
Variable Constants
[Since 0.8.4] - [ -P Constants/VariableConstant ] - [ Online docs ]
Variable constants are actually constants whose value is accessed via the function constant(). Otherwise, there is no way to dynamically access a constant (aka, when the developer has the name of the constant as a incoming parameter, and it requires the value of it).
<?php
const A = 'constant_value';
$constant_name = 'A';
$variableConstant = constant($constant_name);
?>
See also `constant()
Empty Traits
[Since 0.8.4] - [ -P Traits/EmptyTrait ] - [ Online docs ]
List of all empty trait defined in the code.
<?php
// empty trait
trait t { }
// Another empty trait
trait t2 {
use t;
}
?>
Such traits may be reserved for future use. They may also be forgotten, and dead code.
Redefined PHP Traits
[Since 0.8.4] - [ -P Traits/Php ] - [ Online docs ]
List of all traits that bears name of a PHP trait. Although, at the moment, there are no PHP trait defined.
Traits Usage
[Since 0.8.4] - [ -P Traits/TraitUsage ] - [ Online docs ]
Usage of traits in the code.
<?php
trait t {
function t() {
echo 'I\'m in t';
}
}
class foo {
use t;
}
$x = new foo();
$x->t();
?>
See also Traits.
Trait Names
[Since 0.8.4] - [ -P Traits/Traitnames ] - [ Online docs ]
List all the traits names in the code.
<?php
// This trait is called 't'
trait t {}
?>
See also Traits.
Alternative Syntax
[Since 0.8.4] - [ -P Php/AlternativeSyntax ] - [ Online docs ]
Identify the usage of alternative syntax in the code, for If then, Switch, While, For and Foreach.
<?php
// Normal syntax
if ($a == 1) {
print $a;
}
// Alternative syntax : identical to the previous one.
if ($a == 1) :
print $a;
endif;
?>
See also Alternative syntax.
Short Syntax For Arrays
[Since 0.8.4] - [ -P Arrays/ArrayNSUsage ] - [ Online docs ]
Arrays written with the new short syntax.
PHP 5.4 introduced the new short syntax, with square brackets. The previous syntax, based on the array() keyword is still available.
<?php
// All PHP versions array
$a = array(1, 2, 3);
// PHP 5.4+ arrays
$a = [1, 2, 3];
?>
See also Array.
Inclusions
[Since 0.8.4] - [ -P Structures/IncludeUsage ] - [ Online docs ]
List of all inclusions. Inclusions are made with include(), include_once(), require() and require_once().
<?php
include 'library.php';
// display is a function defined in 'library.php';
display('Message');
?>
ext/file
[Since 0.8.4] - [ -P Extensions/Extfile ] - [ Online docs ]
Filesystem functions from standard.
Extension that handle access to file on the file system.
<?php
$row = 1;
if (($handle = fopen('test.csv', 'r')) !== FALSE) {
while (($data = fgetcsv($handle, 1000, ',')) !== FALSE) {
$num = count($data);
echo '<p> $num fields in line $row: <br /></p>'.PHP_EOL;
$row++;
for ($c=0; $c < $num; $c++) {
echo $data[$c] . '<br />'.PHP_EOL;
}
}
fclose($handle);
}
?>
See also filesystem.
Unused Use
[Since 0.8.4] - [ -P Namespaces/UnusedUse ] - [ Online docs ]
Unused use statements. They may be removed, as they clutter the code and slows PHP by forcing it to search in this list for nothing.
<?php
use A as B; // Used in a new call.
use Unused; // Never used. May be removed
$a = new B();
?>
Use With Fully Qualified Name
[Since 0.8.4] - [ -P Namespaces/UseWithFullyQualifiedNS ] - [ Online docs ]
Use statement doesn't require a fully qualified name.
PHP manual recommends not to use fully qualified name (starting with \) when using the 'use' statement : they are "the leading backslash is unnecessary and not recommended, as import names must be fully qualified, and are not processed relative to the current namespace".
<?php
// Recommended way to write a use statement.
use A\B\C\D as E;
// No need to use the initial \
use \A\B\C\D as F;
?>
ext/array
[Since 0.8.4] - [ -P Extensions/Extarray ] - [ Online docs ]
Core functions processing arrays.
These functions manipulate arrays in various ways. Arrays are essential for storing, managing, and operating on sets of variables.
This is not a real extension : it is a documentation section, that helps classifying the functions.
<?php
function odd($var)
{
// returns whether the input integer is odd
return($var & 1);
}
function even($var)
{
// returns whether the input integer is even
return(!($var & 1));
}
$array1 = array('a'=>1, 'b'=>2, 'c'=>3, 'd'=>4, 'e'=>5);
$array2 = array(6, 7, 8, 9, 10, 11, 12);
echo 'Odd :'.PHP_EOL;
print_r(array_filter($array1, 'odd'));
echo 'Even:'.PHP_EOL;
print_r(array_filter($array2, 'even'));
?>
See also Arrays.
ext/ffmpeg
[Since 0.8.4] - [ -P Extensions/Extffmpeg ] - [ Online docs ]
Extension ffmpeg for PHP.
ffmpeg-php is an extension for PHP that adds an easy to use, object-oriented API for accessing and retrieving information from video and audio files.
<?php
$movie = new ffmpeg_movie($path_to_media, $persistent);
echo 'The movie lasts '.$movie->getDuration().' seconds';
?>
See also ffmpeg-php and
FFMPEG.
ext/info
[Since 0.8.4] - [ -P Extensions/Extinfo ] - [ Online docs ]
PHP Options and Information.
These functions enable you to get a lot of information about PHP itself, e.g. runtime configuration, loaded extensions, version and much more.
<?php
/*
Our php.ini contains the following settings:
display_errors = On
register_globals = Off
post_max_size = 8M
*/
echo 'display_errors = ' . ini_get('display_errors') . "\n";
echo 'register_globals = ' . ini_get('register_globals') . "\n";
echo 'post_max_size = ' . ini_get('post_max_size') . "\n";
echo 'post_max_size+1 = ' . (ini_get('post_max_size')+1) . "\n";
echo 'post_max_size in bytes = ' . return_bytes(ini_get('post_max_size'));
function return_bytes($val) {
$val = trim($val);
$last = strtolower($val[strlen($val)-1]);
switch($last) {
// The 'G' modifier is available since PHP 5.1.0
case 'g':
$val *= 1024;
case 'm':
$val *= 1024;
case 'k':
$val *= 1024;
}
return $val;
}
?>
See also PHP Options And Information.
ext/math
[Since 0.8.4] - [ -P Extensions/Extmath ] - [ Online docs ]
Core functions that provides math standard functions.
This is not a real extension : it is a documentation section, that helps sorting the functions.
<?php
echo decbin(12) . PHP_EOL;
echo decbin(26);
?>
See also Mathematical Functions.
$HTTP_RAW_POST_DATA Usage
[Since 0.8.4] - [ -P Php/RawPostDataUsage ] - [ Online docs ]
$HTTP_RAW_POST_DATA is deprecated, and should be replaced by php://input .
$HTTP_RAW_POST_DATA is deprecated since PHP 5.6.
It is possible to prepare code to this lack of feature by setting always_populate_raw_post_data to -1.
<?php
// PHP 5.5 and older
$postdata = $HTTP_RAW_POST_DATA;
// PHP 5.6 and more recent
$postdata = file_get_contents(php://input);
?>
See also $HTTP_RAW_POST_DATA variable.
ext/yis
[Since 0.8.4] - [ -P Extensions/Extyis ] - [ Online docs ]
Yellow Pages extensions (NIS).
NIS (formerly called Yellow Pages) allows network management of important administrative files (e.g. the password file).
<?php
$entry = yp_first($domain, 'passwd.byname');
$key = key($entry);
$value = $entry[$key];
echo 'First entry in this map has key ' . $key . ' and value ' . $value;
?>
See also The Linux NIS(YP)/NYS/NIS+ HOWTO and YP/NIS.
New Functions In PHP 5.4
[Since 0.8.4] - [ -P Php/Php54NewFunctions ] - [ Online docs ] - [ PHP older than 5.3]
PHP introduced new functions in PHP 5.4. If there are defined functions with such names, there will be a conflict when upgrading. It is advised to change those functions' name.
New Functions In PHP 5.5
[Since 0.8.4] - [ -P Php/Php55NewFunctions ] - [ Online docs ] - [ PHP older than 5.5]
PHP introduced new functions in PHP 5.5. If you have already defined functions with such names, you will get a conflict when trying to upgrade. It is advised to change those functions' name.
Useless Instructions
[ -P Structures/UselessInstruction ] - [ Online docs ]
Those instructions are useless, or contains useless parts.
For example, an addition whose result is not stored in a variable, or immediately reused, does nothing : it is actually performed, and the result is lost. Just plain lost.
Here the useless instructions that are spotted :
// Concatenating with an empty string is useless.
$string = 'This part '.$is.' usefull but '.$not.'';
// This is a typo, that PHP turns into a constant, then a string, then nothing.
continue;
// Empty string in a concatenation
$a = 'abc' . '';
// Returning expression, whose result is not used (additions, comparisons, properties, closures, new without =, ...)
1 + 2;
// Returning post-incrementation
function foo($a) {
return $a++;
}
// array_replace() with only one argument
$replaced = array_replace($array);
// array_replace() is OK with ...
$replaced = array_replace(...$array);
// @ operator on source array, in foreach, or when assigning literals
$array = @array(1,2,3);
// Multiple comparisons in a for loop : only the last is actually used.
for($i = 0; $j = 0; $j < 10, $i < 20; ++$j, ++$i) {
print $i.' '.$j.PHP_EOL;
}
// Counting the keys and counting the array is the same.
$c = count(array_keys($array))
//array_keys already provides an array with only unique values, as they were keys in a previous array
$d = array_unique(array_keys($file['messages']))
// No need for assignation inside the ternary operator
$closeQuote = $openQuote[3] ===
Abstract Static Methods
[Since 0.8.4] - [ -P Classes/AbstractStatic ] - [ Online docs ] - [ PHP older than 7.0]
Methods cannot be both abstract and static. Static methods belong to a class, and will not be overridden by the child class. For normal methods, PHP will start at the object level, then go up the hierarchy to find the method. With static, it is necessary to mention the name, or use Late Static Binding, with self or static. Hence, it is useless to have an abstract static method : it should be a static method.
A child class is able to declare a method with the same name than a static method in the parent, but those two methods will stay independent.
This is not the case anymore in PHP 7.0+.
<?php
abstract class foo {
// This is not possible
static abstract function bar() ;
}
?>
See also Why does PHP 5.2+ disallow abstract static class methods?.
New Functions In PHP 5.6
[Since 0.8.4] - [ -P Php/Php56NewFunctions ] - [ Online docs ] - [ PHP older than 5.6]
PHP introduced new functions in PHP 5.6. If you have already defined functions with such names, you will get a conflict when trying to upgrade. It is advised to change those functions' name.
Invalid Constant Name
[Since 0.8.4] - [ -P Constants/InvalidName ] - [ Online docs ]
There is a naming convention for PHP constants names.
According to PHP's manual, constant names, ' A valid constant name starts with a letter or underscore, followed by any number of letters, numbers, or underscores.'.
Constant, must follow this regex : /[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*/ .
In particular when defined using define() function, no error is produced. When using const , on the other hand, the
<?php
define('+3', 1); // wrong constant!
echo constant('+3'); // invalid constant access
?>
See also Constants.
Multiple Constant Definition
[Since 0.8.4] - [ -P Constants/MultipleConstantDefinition ] - [ Online docs ]
Some constants are defined several times in your code. This will lead to a fatal error, if they are defined during the same execution.
Multiple definitions may happens at bootstrap, when the application code is collecting information about the current environment. It may also happen at inclusion time, which one set of constant being loaded, while other definition are not, avoiding conflict. Both are false positive.
<?php
// OS is defined twice.
if (PHP_OS == 'Windows') {
define('OS', 'Win');
} else {
define('OS', 'Other');
}
?>
Wrong Optional Parameter
[Since 0.8.4] - [ -P Functions/WrongOptionalParameter ] - [ Online docs ]
Wrong placement of optional parameters.
PHP parameters are optional when they defined with a default value, like this :
<?php
function x($arg = 1) {
// PHP code here
}
?>
When a function have both compulsory and optional parameters, the compulsory ones should appear first, and the optional should appear last :
<?php
function x($arg, $arg2 = 2) {
// PHP code here
}
?>
PHP solves this problem at runtime, assign values in the same other, but will miss some of the default values and emits warnings.
It is better to put all the optional parameters at the end of the method's signature.
Optional parameter wrongly placed are now a Notice in PHP 8.0. The only previous case that is allowed in PHP 8.0 and also in this analysis, is when the null value is used as default for typed arguments.
See also Function arguments.
Multiple Definition Of The Same Argument
[Since 0.8.4] - [ -P Functions/MultipleSameArguments ] - [ Online docs ] - [ PHP older than 7.0]
A method's signature is holding twice (or more) the same argument. For example, function x ($a, $a) { ... }.
This is accepted as is by PHP 5, and the last parameter's value will be assigned to the variable. PHP 7.0 and more recent has dropped this feature, and reports a fatal error when linting the code.
<?php
function x ($a, $a) { print $a; };
x(1,2); => display 2
// special case with a closure :
function ($a) use ($a) { print $a; };
x(1,2); => display 2?>
However, this is not common programming practise : all arguments should be named differently.
See also Prepare for PHP 7 error messages (part 3).
Echo Or Print
[Since 0.8.4] - [ -P Structures/EchoPrintConsistance ] - [ Online docs ]
Echo and print have the same functional use. printf() are also considered in this analysis.
There seems to be a choice that is not enforced : one form is dominant, (> 90%) while the others are rare.
The analyzed code has less than 10% of one of the three : for consistency reasons, it is recommended to make them all the same.
It happens that print, echo or
<?php
echo 'a';
echo 'b';
echo 'c';
echo 'd';
echo 'e';
echo 'f';
echo 'g';
echo 'h';
echo 'i';
echo 'j';
echo 'k';
// This should probably be written 'echo';
print 'l';
?>
Use === null
[Since 0.8.4] - [ -P Php/IsnullVsEqualNull ] - [ Online docs ]
It is faster to use === null instead of is_null().
<?php
// Operator === is fast
if ($a === null) {
}
// Function call is slow
if (is_null($a)) {
}
?>
Constant Comparison
[Since 0.8.4] - [ -P Structures/ConstantComparisonConsistance ] - [ Online docs ]
Constant to the left or right is a favorite.
Comparisons are commutative : they may be $a == B or B == $a. The analyzed code show less than 10% of one of the two : for consistency reasons, it is recommended to make them all the same.
Putting the constant on the left is also called 'Yoda Comparison', as it mimics the famous characters style of speech. It prevents errors like 'B = $a' where the comparison is turned into an assignation.
The natural way is to put the constant on the right. It is often less surprising.
Every comparison operator is used when finding the favorite.
<?php
//
if ($a === B) { doSomething(); }
if ($c > D) { doSomething(); }
if ($e !== G) { doSomething(); }
do { doSomething(); } while ($f === B);
while ($a === B) { doSomething(); }
// be consistent
if (B === $a) {}
// Compari
if (B <= $a) {}
?>
Assertions
[Since 0.8.4] - [ -P Php/AssertionUsage ] - [ Online docs ]
Usage of assertions, to add checks within PHP code.
Assertions should be used as a debugging feature only. You may use them for sanity-checks that test for conditions that should always be TRUE and that indicate some programming errors if not or to check for the presence of certain features like extension functions or certain system limits and features.
<?php
function foo($string) {
assert(!empty($string), 'An empty string was provided!');
echo '['.$string.']';
}
?>
See also assert.
$this Is Not An Array
[Since 0.8.4] - [ -P Classes/ThisIsNotAnArray ] - [ Online docs ]
$this variable represents the current object and it is not an array.
This is unless the class (or its parents) has the ArrayAccess interface, or extends ArrayObject or SimpleXMLElement .
<?php
// $this is an array
class Foo extends ArrayAccess {
function bar() {
++$this[3];
}
}
// $this is not an array
class Foo2 {
function bar() {
++$this[3];
}
}
?>
See also ArrayAccess,
ArrayObject and
The Basics.
One Variable String
[Since 0.8.4] - [ -P Type/OneVariableStrings ] - [ Online docs ]
These strings only contains one variable or property or array.
<?php
$a = 0;
$b = "$a"; // This is a one-variable string
// Better way to write the above
$b = (string) $a;
// Alternatives :
$b2 = "$a[1]"; // This is a one-variable string
$b3 = "$a->b"; // This is a one-variable string
$c = "d";
$d = "D";
$b4 = "{$$c}";
$b5 = "{$a->foo()}";
?>
When the goal is to convert a variable to a string, it is recommended to use the type casting (string) operator : it is then clearer to understand the conversion. It is also marginally faster, though very little.
See also Strings and
Type Juggling.
Cast Usage
[Since 0.8.4] - [ -P Php/CastingUsage ] - [ Online docs ]
List of all cast usage.
PHP does not require (or support) explicit type definition in variable declaration; a variable's type is determined by the context in which the variable is used.
<?php
if (is_int($_GET['x'])) {
$number = (int) $_GET['x'];
} else {
error_display('a wrong value was provided for "x"');
}
?>
Until PHP 7.2, a (unset) operator was available. It had the same role as unset()
See also Type Juggling and
unset.
Function Subscripting
[Since 0.8.4] - [ -P Structures/FunctionSubscripting ] - [ Online docs ] - [ PHP 5.4 and more recent ]
It is possible to use the result of a methodcall directly as an array, without storing the result in a temporary variable.
This works, given that the method actually returns an array.
This syntax was not possible until PHP 5.4. Until then, it was compulsory to store the result in a variable first. Although this is now superfluous, it has been a standard syntax in PHP, and is still being used.
<?php
function foo() {
return array(1 => 'a', 'b', 'c');
}
echo foo()[1]; // displays 'a';
// Function subscripting, the old way
function foo() {
return array(1 => 'a', 'b', 'c');
}
$x = foo();
echo $x[1]; // displays 'a';
?>
Storing the result in a variable is still useful if the result is actually used more than once.
Nested Loops
[Since 0.8.4] - [ -P Structures/NestedLoops ] - [ Online docs ]
Nested loops happens when a loop (while, do..while, for, foreach), is used inside another loop.
<?php
// Nested loops
foreach($array as $a) {
foreach ($letters as $b) {
// This is performed count($array) * count($letters) times.
doSomething();
}
}
?>
Such structure tends to require a lot of processing, as the size of both loops have to be multiplied to estimate the actual payload. They should be avoided as much as possible. This may no be always possible, though.
Nested loops are worth a check for performances reasons, as they will process a lot of times the same instructions.
[Since 0.8.4] - [ -P Php/EchoTagUsage ] - [ Online docs ]
Usage of the
?>
Static Methods Can't Contain $this
[Since 0.8.4] - [ -P Classes/StaticContainsThis ] - [ Online docs ]
Static methods are also called class methods : they may be called even if the class has no instantiated object. Thus, the local variable $this won't exist, PHP will set it to NULL as usual.
<?php
class foo {
// Static method may access other static methods, or property, or none.
static function staticBar() {
// This is not possible in a static method
return self::otherStaticBar() . static::$staticProperty;
}
static function bar() {
// This is not possible in a static method
return $this->property;
}
}
?>
Either this is not a static method, which is fixed by removing the static keyword, or replace all $this mention by static properties Class::$property .
See also Static Keyword
Closure May Use $this
[Since 0.8.4] - [ -P Php/ClosureThisSupport ] - [ Online docs ] - [ PHP older than 5.4]
$this is automatically accessible to closures.
When closures were introduced in PHP, they couldn't use the $this variable, making is cumbersome to access local properties when the closure was created within an object.
<?php
// Invalid code in PHP 5.4 and less
class Test
{
public function testing()
{
return function() {
var_dump($this);
};
}
}
$object = new Test;
$function = $object->testing();
$function();
?>
This is not the case anymore since PHP 5.4.
See also Anonymous functions.
While(List() = Each())
[Since 0.8.4] - [ -P Structures/WhileListEach ] - [ Online docs ]
This code structure is quite old : it should be replace by the more modern and efficient foreach.
This structure is deprecated since PHP 7.2. It may disappear in the future.
<?php
while(list($key, $value) = each($array)) {
doSomethingWith($key) and $value();
}
foreach($array as $key => $value) {
doSomethingWith($key) and $value();
}
?>
See also PHP RFC: Deprecations for PHP 7.2 : Each().
Several Instructions On The Same Line
[Since 0.8.4] - [ -P Structures/OneLineTwoInstructions ] - [ Online docs ]
Usually, instructions do not share their line : one instruction, one line.
This is good for readability, and help at understanding the code. This is especially important when fast-reading the code to find some special situation, where such double-meaning line way have an impact.
<?php
switch ($x) {
// Is it a fallthrough or not ?
case 1:
doSomething(); break;
// Easily spotted break.
case 1:
doSomethingElse();
break;
default :
doDefault();
break;
}
?>
See also Object Calisthenics, rule # 5.
Multiples Identical Case
[Since 0.8.4] - [ -P Structures/MultipleDefinedCase ] - [ Online docs ]
Some cases are defined multiple times, but only one will be processed. Check the list of cases, and remove the extra one.
Exakat tries to find the value of the case as much as possible, and ignore any dynamic cases (using variables).
<?php
const A = 1;
case ($x) {
case 1 :
break;
case true: // This is a duplicate of the previous
break;
case 1 + 0: // This is a duplicate of the previous
break;
case 1.0 : // This is a duplicate of the previous
break;
case A : // The A constant is actually 1
break;
case $y : // This is not reported.
break;
default:
}
?>
Switch Without Default
[Since 0.8.4] - [ -P Structures/SwitchWithoutDefault ] - [ Online docs ]
Always use a default statement in switch().
Switch statements hold a number of 'case' that cover all known situations, and a 'default' one which is executed when all other options are exhausted.
<?php
// Missing default
switch($format) {
case 'gif' :
processGif();
break 1;
case 'jpeg' :
processJpeg();
break 1;
case 'bmp' :
throw new UnsupportedFormat($format);
}
// In case $format is not known, then switch is ignored and no processing happens, leading to preparation errors
// switch with default
switch($format) {
case 'text' :
processText();
break 1;
case 'jpeg' :
processJpeg();
break 1;
case 'rtf' :
throw new UnsupportedFormat($format);
default :
throw new UnknownFileFormat($format);
}
// In case $format is not known, an exception is thrown for processing
?>
Most of the time, switch() do need a default case, so as to catch the odd situation where the 'value is not what it was expected'. This is a good place to catch unexpected values, to set a default behavior.
Function Subscripting, Old Style
[Since 0.8.4] - [ -P Structures/FunctionPreSubscripting ] - [ Online docs ] - [ PHP 5.4 and more recent ]
Since PHP 5.4, it is now possible use function results as an array, and access directly its element :
<?php
function foo() {
return array(1 => 'a', 'b', 'c');
}
echo foo()[1]; // displays 'a';
// Function subscripting, the old way
function foo() {
return array(1 => 'a', 'b', 'c');
}
$x = foo();
echo $x[1]; // displays 'a';
?>
$this Belongs To Classes Or Traits
[Since 0.8.4] - [ -P Classes/ThisIsForClasses ] - [ Online docs ]
$this variable represents only the current object.
It is a pseudo-variable, and should be used within class's or trait's methods (except for static) and not outside.
PHP 7.1 is stricter and check for $this at several positions. Some are found by static analysis, some are dynamic analysis.
<?php
// as an argument
function foo($this) {
// Using global
global $this;
// Using static (not a property)
static $this;
// Can't unset it
unset($this);
try {
// inside a foreach
foreach($a as $this) { }
foreach($a as $this => $b) { }
foreach($a as $b => $this) { }
} catch (Exception $this) {
// inside a catch
}
// with Variable Variable
$a = this;
$$a = 42;
}
class foo {
function bar() {
// Using references
$a =& $this;
$a = 42;
// Using `extract() <https://www.php.net/extract>`_, `parse_str() <https://www.php.net/parse_str>`_ or similar functions
extract([this => 42]); // throw new Error(Cannot re-assign $this)
var_dump($this);
}
static function __call($name, $args) {
// Using __call
var_dump($this); // prints object(C)#1 (0) {}, php-7.0 printed NULL
$this->test(); // prints ops
}
}
?>
Nested Ternary
[Since 0.8.4] - [ -P Structures/NestedTernary ] - [ Online docs ]
Ternary operators should not be nested too deep.
They are a convenient instruction to apply some condition, and avoid a if() structure. It works best when it is simple, like in a one liner.
However, ternary operators tends to make the syntax very difficult to read when they are nested. It is then recommended to use an if() structure, and make the whole code readable.
<?php
// Simple ternary expression
echo ($a == 1 ? $b : $c) ;
// Nested ternary expressions
echo ($a === 1 ? $d === 2 ? $b : $d : $d === 3 ? $e : $c) ;
echo ($a === 1 ? $d === 2 ? $f ===4 ? $g : $h : $d : $d === 3 ? $e : $i === 5 ? $j : $k) ;
//Previous expressions, written as a if / Then expression
if ($a === 1) {
if ($d === 2) {
echo $b;
} else {
echo $d;
}
} else {
if ($d === 3) {
echo $e;
} else {
echo $c;
}
}
if ($a === 1) {
if ($d === 2) {
if ($f === 4) {
echo $g;
} else {
echo $h;
}
} else {
echo $d;
}
} else {
if ($d === 3) {
echo $e;
} else {
if ($i === 5) {
echo $j;
} else {
echo $k;
}
}
}
?>
See also Nested Ternaries are Great.
Switch With Too Many Default
[Since 0.8.4] - [ -P Structures/SwitchWithMultipleDefault ] - [ Online docs ] - [ PHP older than 7.0]
Switch statements should only hold one default, not more. Check the code and remove the extra default.
PHP 7.0 won't compile a script that allows for several default cases.
Multiple default happens often with large switch().
<?php
switch($a) {
case 1 :
break;
default :
break;
case 2 :
break;
default : // This default is never reached
break;
}
?>
Non-constant Index In Array
[Since 0.8.4] - [ -P Arrays/NonConstantArray ] - [ Online docs ]
Undefined constants revert as strings in Arrays. They are also called barewords .
In $array[index] , PHP cannot find index as a constant, but, as a default behavior, turns it into the string index .
This default behavior raise concerns when a corresponding constant is defined, either using define() or the const keyword (outside a class). The definition of the index constant will modify the behavior of the index, as it will now use the constant definition, and not the 'index' string.
<?php
// assign 1 to the element index in $array
// index will fallback to string
$array[index] = 1;
//PHP Notice: Use of undefined constant index - assumed 'index'
echo $array[index]; // display 1 and the above error
echo "$array[index]"; // display 1
echo "$array['index']"; // Syntax error
define('index', 2);
// now 1 to the element 2 in $array
$array[index] = 1;
?>
It is recommended to make index a real string (with ' or "), or to define the corresponding constant to avoid any future surprise.
Note that PHP 7.2 removes the support for this feature.
See also PHP RFC: Deprecate and Remove Bareword (Unquoted) Strings and
Syntax.
Undefined Constants
[Since 0.8.4] - [ -P Constants/UndefinedConstants ] - [ Online docs ]
Constants definition can't be located.
Those constants are not defined in the code, and will raise errors, or use the fallback mechanism of being treated like a string.
<?php
const A = 1;
define('B', 2);
// here, C is not defined in the code and is reported
echo A.B.C;
?>
It is recommended to define them all, or to avoid using them.
See also Constants.
Instantiating Abstract Class
[Since 0.8.4] - [ -P Classes/InstantiatingAbstractClass ] - [ Online docs ]
PHP cannot instantiate an abstract class.
The classes are actually abstract classes, and should be derived into a concrete class to be instantiated.
<?php
abstract class Foo {
protected $a;
}
class Bar extends Foo {
protected $b;
}
// instantiating a concrete class.
new Bar();
// instantiating an abstract class.
// In real life, this is not possible also because the definition and the instantiation are in the same file
new Foo();
?>
See also Class Abstraction.
Classes Mutually Extending Each Other
[Since 0.8.4] - [ -P Classes/MutualExtension ] - [ Online docs ]
Those classes are extending each other, creating an extension loop. PHP will yield a fatal error at running time, even if it is compiling the code.
<?php
// This code is lintable but won't run
class Foo extends Bar { }
class Bar extends Foo { }
// The loop may be quite large
class Foo extends Bar { }
class Bar extends Bar2 { }
class Bar2 extends Foo { }
?>
Class, Interface Or Trait With Identical Names
[Since 0.8.4] - [ -P Classes/CitSameName ] - [ Online docs ]
The following names are used at the same time for classes, interfaces or traits. For example,
<?php
class a { /* some definitions */ }
interface a { /* some definitions */ }
trait a { /* some definitions */ }
?>
Even if they are in different namespaces, identical names makes classes easy to confuse. This is often solved by using alias at import time : this leads to more confusion, as a class suddenly changes its name.
Internally, PHP use the same list for all classes, interfaces and traits. As such, it is not allowed to have both a trait and a class with the same name.
In PHP 4, and PHP 5 before namespaces, it was not possible to have classes with the same name. They were simply included after a check.
Empty Try Catch
[Since 0.8.4] - [ -P Structures/EmptyTryCatch ] - [ Online docs ]
The code does try, then catch errors but do no act upon the error.
<?php
try {
doSomething();
} catch (Throwable $e) {
// ignore this
}
?>
At worst, the error should be logged, so as to measure the actual usage of the catch expression.
catch( Exception $e) (PHP 5) or catch(Throwable $e) with empty catch block should be banned. They ignore any error and proceed as if nothing happened. At worst, the event should be logged for future analysis.
See also Empty Catch Clause.
ext/pcntl
[Since 0.8.4] - [ -P Extensions/Extpcntl ] - [ Online docs ]
Extension for process control.
Process Control support in PHP implements the Unix style of process creation, program execution, signal handling and process termination. Process Control should not be enabled within a web server environment and unexpected results may happen if any Process Control functions are used within a web server environment.
<?php
declare(ticks=1);
$pid = pcntl_fork();
if ($pid == -1) {
die('could not fork');
} else if ($pid) {
exit(); // we are the parent
} else {
// we are the child
}
// detatch from the controlling terminal
if (posix_setsid() == -1) {
die('could not detach from terminal');
}
// setup signal handlers
pcntl_signal(SIGTERM, 'sig_handler');
pcntl_signal(SIGHUP, 'sig_handler');
// loop forever performing tasks
while (1) {
// do something interesting here
}
function sig_handler($signo)
{
switch ($signo) {
case SIGTERM:
// handle shutdown tasks
exit;
break;
case SIGHUP:
// handle restart tasks
break;
default:
// handle all other signals
}
}
?>
See also Process Control.
Undefined Classes
[Since 0.8.4] - [ -P Classes/UndefinedClasses ] - [ Online docs ]
Those classes are used in the code, but there are no definition for them.
This may happens under normal conditions, if the application makes use of an unsupported extension, that defines extra classes;
or if some external libraries, such as PEAR, are not provided during the analysis.
<?php
// FPDF is a classic PDF class, that is usually omitted by Exakat.
$o = new FPDF();
// Exakat reports undefined classes in instanceof
// PHP ignores them
if ($o instanceof SomeClass) {
// doSomething();
}
// Classes may be used in typehint too
function foo(TypeHintClass $x) {
// doSomething();
}
?>
ext/ming
[Since 0.8.4] - [ -P Extensions/Extming ] - [ Online docs ]
Extension ext/ming, to create swf files with PHP.
Ming is an open-source (LGPL) library which allows you to create SWF ('Flash') format movies.
<?php
$s = new SWFShape();
$f = $s->addFill(0xff, 0, 0);
$s->setRightFill($f);
$s->movePenTo(-500, -500);
$s->drawLineTo(500, -500);
$s->drawLineTo(500, 500);
$s->drawLineTo(-500, 500);
$s->drawLineTo(-500, -500);
$p = new SWFSprite();
$i = $p->add($s);
$i->setDepth(1);
$p->nextFrame();
for ($n=0; $n<5; ++$n) {
$i->rotate(-15);
$p->nextFrame();
}
$m = new SWFMovie();
$m->setBackground(0xff, 0xff, 0xff);
$m->setDimension(6000, 4000);
$i = $m->add($p);
$i->setDepth(1);
$i->moveTo(-500,2000);
$i->setName('box');
$m->add(new SWFAction('/box.x += 3;'));
$m->nextFrame();
$m->add(new SWFAction('gotoFrame(0); play();'));
$m->nextFrame();
header('Content-type: application/x-shockwave-flash');
$m->output();
?>
See also Ming (flash) and Ming.
ext/redis
[Since 0.8.4] - [ -P Extensions/Extredis ] - [ Online docs ]
Extension ext/redis.
The phpredis extension provides an API for communicating with the Redis key-value store.
<?php
$redis = new Redis();
$redis->connect('127.0.0.1', 6379);
$redis->setOption(Redis::OPT_SERIALIZER, Redis::SERIALIZER_NONE); // don't serialize data
$redis->setOption(Redis::OPT_SERIALIZER, Redis::SERIALIZER_PHP); // use built-in serialize/unserialize
$redis->setOption(Redis::OPT_SERIALIZER, Redis::SERIALIZER_IGBINARY); // use igBinary serialize/unserialize
$redis->setOption(Redis::OPT_PREFIX, 'myAppName:'); // use custom prefix on all keys
/* Options for the SCAN family of commands, indicating whether to abstract
empty results from the user. If set to SCAN_NORETRY (the default), phpredis
will just issue one SCAN command at a time, sometimes returning an empty
array of results. If set to SCAN_RETRY, phpredis will retry the scan command
until keys come back OR Redis returns an iterator of zero
*/
$redis->setOption(Redis::OPT_SCAN, Redis::SCAN_NORETRY);
$redis->setOption(Redis::OPT_SCAN, Redis::SCAN_RETRY);
?>
See also A PHP extension for Redis and Redis.
Htmlentities Calls
[Since 0.8.4] - [ -P Structures/Htmlentitiescall ] - [ Online docs ]
htmlentities() and htmlspecialchars() are used to prevent injecting special characters in HTML code. As a bare minimum, they take a string and encode it for HTML.
The second argument of the functions is the type of protection. The protection may apply to quotes or not, to HTML 4 or 5, etc. It is highly recommended to set it explicitly.
The third argument of the functions is the encoding of the string. In PHP 5.3, it is ISO-8859-1 , in 5.4, was UTF-8 , and in 5.6, it is now default_charset, a php.ini configuration that has the default value of UTF-8 . It is highly recommended to set this argument too, to avoid distortions from the configuration.
<?php
$str = 'A quote is <b>bold</b>';
// Outputs, without depending on the php.ini: A 'quote' is <b>bold</b>
echo htmlentities($str, ENT_QUOTES, 'UTF-8');
// Outputs, while depending on the php.ini: A quote is <b>bold</b>
echo htmlentities($str);
?>
Also, note that arguments 2 and 3 are constants and string, respectively, and should be issued from the list of values available in the manual. Other values than those will make PHP use the default values.
See also htmlentities and htmlspecialchars.
Undefined Class Constants
[Since 0.8.4] - [ -P Classes/UndefinedConstants ] - [ Online docs ]
Class constants that are used, but never defined. This should yield a fatal error upon execution, but no feedback at compile level.
<?php
class foo {
const A = 1;
define('B', 2);
}
// here, C is not defined in the code and is reported
echo foo::A.foo::B.foo::C;
?>
Unused Private Properties
[Since 0.8.4] - [ -P Classes/UnusedPrivateProperty ] - [ Online docs ]
Unused static properties should be removed.
Unused private properties are dead code. They are usually leftovers of development or refactorisation : they used to have a mission, but are now left.
Being private, those properties are only accessible to the current class or trait. As such, validating the
<?php
class foo {
// This is a used property (see bar method)
private $used = 1;
// This is an unused property
private $unused = 2;
function bar($a) {
$this->used += $a;
return $this->used;
}
}
?>
Unused Private Methods
[Since 0.8.4] - [ -P Classes/UnusedPrivateMethod ] - [ Online docs ]
Private methods that are not used are dead code.
Private methods are reserved for the defining class. Thus, they must be used with the current class, with $this or self:: .
<?php
class Foo {
// Those methods are used
private function method() {}
private static function staticMethod() {}
// Those methods are not used
private function unusedMethod() {}
private static function staticUnusedMethod() {}
public function bar() {
self::staticMethod();
$this->method();
}
}
?>
This analysis skips classes that makes self dynamic calls, such as $this->$method() .
Unused Functions
[Since 0.8.4] - [ -P Functions/UnusedFunctions ] - [ Online docs ]
The functions below are unused. They look like dead code.
Recursive functions, level 1, are detected : they are only reported when a call from outside the function is made. Recursive functions calls of higher level (A calls B calls A) are not handled.
<?php
function used() {}
// The 'unused' function is defined but never called
function unused() {}
// The 'used' function is called at least once
used();
?>
Used Once Variables (In Scope)
[Since 0.8.4] - [ -P Variables/VariableUsedOnceByContext ] - [ Online docs ]
This is the list of used once variables, scope by scope. Those variables are used once in a function, a method, a class or a namespace. In any case, this means the variable is read or written, while it should be used at least twice.
<?php
function foo() {
// The variables below never appear twice, inside foo()
$writtenOnce = 1;
foo($readOnce);
// They do appear again in other functions, or in global space.
}
function bar() {
$writtenOnce = 1;
foo($readOnce);
}
?>
Undefined Functions
[Since 0.8.4] - [ -P Functions/UndefinedFunctions ] - [ Online docs ]
Some functions are called, but not defined in the code. This means that the functions are probably defined in a missing library, or in an extension. If not, this will yield a Fatal error at execution.
<?php
// Undefined function
foo($a);
// valid function, as it belongs to the ext/yaml extension
$parsed = yaml_parse($yaml);
// This function is not defined in the a\b\c namespace, nor in the global namespace
a\b\c\foo();
?>
See also Functions.
Deprecated Functions
[Since 0.8.4] - [ -P Php/Deprecated ] - [ Online docs ]
The following functions are deprecated. It is recommended to stop using them now and replace them with a durable equivalent.
Note that these functions may be still usable : they generate warning that help tracking their usage in the log. To eradicate their usage, watch the logs, and update any deprecated warning. This way, the code won't be stuck when the function is actually removed from PHP.
<?php
// This is the current function
list($day, $month, $year) = explode('/', '08/06/1995');
// This is deprecated
list($day, $month, $year) = split('/', '08/06/1995');
?>
crypt() Without Salt
[Since 0.8.4] - [ -P Structures/CryptWithoutSalt ] - [ Online docs ] - [ PHP older than 5.6]
PHP requires a salt when calling crypt(). 5.5 and previous versions didn't require it. Salt is a simple string, that is usually only known by the application.
According to the manual : The salt parameter is optional. However, crypt() creates a weak hash without the salt. PHP 5.6 or later raise an E_NOTICE error without it. Make sure to specify a strong enough salt for better security.
<?php
// Set the password
$password = 'mypassword';
// salted crypt usage (always valid)
$hash = crypt($password, '123salt');
// Get the hash, letting the salt be automatically generated
// This generates a notice after PHP 5.6
$hash = crypt($password);
?>
See also crypt.
mcrypt_create_iv() With Default Values
[Since 0.8.4] - [ -P Structures/McryptcreateivWithoutOption ] - [ Online docs ] - [ PHP older than 5.6]
Avoid using mcrypt_create_iv() default values.
mcrypt_create_iv() used to have MCRYPT_DEV_RANDOM as default values, and in PHP 5.6, it now uses MCRYPT_DEV_URANDOM .
<?php
$size = mcrypt_get_iv_size(MCRYPT_CAST_256, MCRYPT_MODE_CFB);
// mcrypt_create_iv is missing the second argument
$iv = mcrypt_create_iv($size);
// Identical to the line below
// $iv = mcrypt_create_iv($size, MCRYPT_DEV_RANDOM);
?>
If the code doesn't have a second argument, it relies on the default value. It is recommended to set explicitly the value, so has to avoid problems while migrating.
See also mcrypt_create_iv().
Dangling Array References
[Since 0.8.4] - [ -P Structures/DanglingArrayReferences ] - [ Online docs ]
Always unset a referenced-variable used in a loop.
It is highly recommended to unset blind variables when they are set up as references after a loop.
<?php
$array = array(1,2,3,4);
foreach($array as &$a) {
$a += 1;
}
// This only unset the reference, not the value
unset($a);
// Dangling array problem
foreach($array as &$a) {
$a += 1;
}
//$array === array(3,4,5,6);
// This does nothing (apparently)
// $a is already a reference, even if it doesn't show here.
foreach($array as $a) {}
//$array === array(3,4,5,5);
?>
When omitting this step, the next loop that will also require this variable will deal with garbage values, and produce unexpected results.
See also : No Dangling Reference,
PHP foreach pass-by-reference: Do it right, or better not at all,
How does PHP 'foreach' actually work?,
References and foreach.
ext/cyrus
[Since 0.8.4] - [ -P Extensions/Extcyrus ] - [ Online docs ]
Extension ext/cyrus.
The Cyrus IMAP server is electronic mail server software developed by Carnegie Mellon University.
<?php
$connexion = cyrus_connect ('localhost');
?>
See also Cyrus and Cyrus IMAP server.
ext/sqlsrv
[Since 0.8.4] - [ -P Extensions/Extsqlsrv ] - [ Online docs ]
Extension for Microsoft SQL Server Driver.
The SQLSRV extension allows you to access Microsoft SQL Server and SQL Azure databases when running PHP on Windows.
<?php
$serverName = 'serverName\sqlexpress';
$connectionInfo = array( 'Database'=>'dbName', 'UID'=>'username', 'PWD'=>'password' );
$conn = sqlsrv_connect( $serverName, $connectionInfo);
if( $conn === false ) {
die( print_r( sqlsrv_errors(), true));
}
$sql = 'INSERT INTO Table_1 (id, data) VALUES (?, ?)';
$params = array(1, 'some data');
$stmt = sqlsrv_query( $conn, $sql, $params);
if( $stmt === false ) {
die( print_r( sqlsrv_errors(), true));
}
?>
See also Microsoft SQL Server Driver and PHP Driver for SQL Server Support for LocalDB.
Queries In Loops
[Since 0.8.4] - [ -P Structures/QueriesInLoop ] - [ Online docs ]
Avoid querying databases in a loop.
Querying an external database in a loop usually leads to performances problems. This is also called the 'n + 1 problem'.
This problem applies also to prepared statement : when such statement are called in a loop, they are slower than one-time large queries.
It is recommended to reduce the number of queries by making one query, and dispatching the results afterwards. This is true with SQL databases, graph queries, LDAP queries, etc.
<?php
// Typical N = 1 problem : there will be as many queries as there are elements in $array
$ids = array(1,2,3,5,6,10);
$db = new SQLite3('mysqlitedb.db');
// all the IDS are merged into the query at once
$results = $db->query('SELECT bar FROM foo WHERE id in ('.implode(',', $id).')');
while ($row = $results->fetchArray()) {
var_dump($row);
}
// Typical N = 1 problem : there will be as many queries as there are elements in $array
$ids = array(1,2,3,5,6,10);
$db = new SQLite3('mysqlitedb.db');
foreach($ids as $id) {
$results = $db->query('SELECT bar FROM foo WHERE id = '.$id);
while ($row = $results->fetchArray()) {
var_dump($row);
}
}
?>
This optimisation is not always possible : for example, some SQL queries may not be prepared, like DROP TABLE or DESC . UPDATE commands often update one row at a time, and grouping such queries may be counter-productive or unsafe.
Var Keyword
[Since 0.8.4] - [ -P Classes/OldStyleVar ] - [ Online docs ]
Var was used in PHP 4 to mark properties as public. Nowadays, new keywords are available : public, protected, private. Var is equivalent to public.
It is recommended to avoid using var, and explicitly use the new keywords.
<?php
class foo {
public $bar = 1;
// Avoid var
//var $bar = 1;
}
?>
See also Visibility.
Aliases Usage
[Since 0.8.4] - [ -P Functions/AliasesUsage ] - [ Online docs ]
PHP manual recommends to avoid function aliases.
Some functions have several names, and both may be used the same way. However, one of the names is the main name, and the others are aliases. Aliases may be removed or change or dropped in the future. Even if this is not forecast, it is good practice to use the main name, instead of the aliases.
<?php
// official way to count an array
$n = count($array);
// official way to count an array
$n = sizeof($array);
?>
Aliases are compiled in PHP, and do not provide any performances over the normal function.
Aliases are more likely to be removed later, but they have been around for a long time.
See documentation : List of function aliases.
Uses Default Values
[Since 0.8.4] - [ -P Functions/UsesDefaultArguments ] - [ Online docs ]
Default values are provided to methods so as to make it convenient to use. However, with new versions, those values may change. For example, in PHP 5.4, htmlentities() switched from Latin1 to UTF-8 default encoding.
<?php
$string = Eu não sou o pão;
echo htmlentities($string);
// PHP 5.3 : Eu não sou o pão
// PHP 5.4 : Eu não sou o pão
// Stable across versions
echo htmlentities($string, 'UTF8');
?>
As much as possible, it is recommended to use explicit values in those methods, so as to prevent from being surprise at a future PHP evolution.
This analyzer tend to report a lot of false positives, including usage of count(). Count() indeed has a second argument for recursive counts, and a default value. This may be ignored safely.
Wrong Number Of Arguments
[Since 0.8.4] - [ -P Functions/WrongNumberOfArguments ] - [ Online docs ]
Those functioncalls are made with too many or too few arguments.
When the number arguments is wrong for native functions, PHP emits a warning.
When the number arguments is too small for custom functions, PHP raises an exception.
When the number arguments is too high for custom functions, PHP ignores the arguments. Such arguments should be handled with the variadic operator, or with func_get_args() family of functions.
<?php
echo strtoupper('This function is', 'ignoring arguments');
//Warning: `strtoupper() <https://www.php.net/strtoupper>`_ expects exactly 1 parameter, 2 given in Command line code on line 1
echo `strtoupper() <https://www.php.net/strtoupper>`_;
//Warning: `strtoupper() <https://www.php.net/strtoupper>`_ expects exactly 1 parameter, 0 given in Command line code on line 1
function foo($argument) {}
echo foo();
//Fatal error: Uncaught ArgumentCountError: Too few arguments to function foo(), 0 passed in /Users/famille/Desktop/analyzeG3/test.php on line 10 and exactly 1 expected in /Users/famille/Desktop/analyzeG3/test.php:3
echo foo('This function is', 'ignoring arguments');
?>
It is recommended to check the signature of the methods, and fix the arguments.
Hardcoded Passwords
[Since 0.8.4] - [ -P Functions/HardcodedPasswords ] - [ Online docs ]
Hardcoded passwords in the code.
Hardcoding passwords is a bad idea. Not only it make the code difficult to change, but it is an information leak. It is better to hide this kind of information out of the code.
<?php
$ftp_server = '300.1.2.3'; // yes, this doesn't exists, it's an example
$conn_id = ftp_connect($ftp_server);
// login with username and password
$login_result = ftp_login($conn_id, 'login', 'password');
?>
See also 10 GitHub Security Best Practices and
Git How-To: Remove Your Password from a Repository.
Unresolved Classes
[Since 0.8.4] - [ -P Classes/UnresolvedClasses ] - [ Online docs ]
The following classes are instantiated in the code, but their definition couldn't be found.
<?php
class Foo extends Bar {
private function foobar() {
// here, parent is not resolved, as Bar is not defined in the code.
return parent::$prop;
}
}
?>
Ellipsis Usage
[Since 0.8.4] - [ -P Php/EllipsisUsage ] - [ Online docs ] - [ PHP 5.6 and more recent ]
Usage of the ellipsis keyword. The keyword is three dots : ... . It is also named variadic or splat operator.
It may be in function definitions, either in functioncalls.
... allows for packing or unpacking arguments into an array.
<?php
$args = [1, 2, 3];
foo(...$args);
// Identical to foo(1,2,3);
function bar(...$a) {
// Identical to : $a = `func_get_args() <https://www.php.net/func_get_args>`_;
}
?>
See also PHP RFC: Syntax for variadic functions,
PHP 5.6 and the Splat Operator, and
Variable-length argument lists.
Exponent Usage
[Since 0.8.4] - [ -P Php/ExponentUsage ] - [ Online docs ] - [ PHP 5.6 and more recent ]
Usage of the ** operator or **=, to make exponents.
<?php
$eight = 2 ** 3;
$sixteen = 4;
$sixteen **= 2;
?>
See also Arithmetic Operators.
** For Exponent
[Since 0.8.4] - [ -P Php/NewExponent ] - [ Online docs ] - [ PHP 5.6 and more recent ]
The operator ** calculates exponents, also known as power.
Use it instead of the slower function pow(). This operator was introduced in PHP 5.6.
<?php
$cube = pow(2, 3); // 8
$cubeInPHP56 = 2 ** 3; // 8
?>
If the code needs to be backward compatible to 5.5 or less, don't use the new operator.
Be aware the the '-' operator has lower priority than the ** operator : this leads to the following confusing result.
<?php
echo -3 ** 2;
// displays -9, instead of 9
?>
This is due to the parser that processes separately - and the following number. Since ** has priority, the power operation happens first.
Being an operator, ** is faster than pow(). This is a microoptimisation.
See also Arithmetic Operators.
Useless Constructor
[Since 0.8.4] - [ -P Classes/UselessConstructor ] - [ Online docs ]
Class constructor that have empty bodies are useless. They may be removed.
<?php
class X {
function __construct() {
// Do nothing
}
}
class Y extends X {
// Useful constructor, as it prevents usage of the parent
function __construct() {
// Do nothing
}
}
?>
Too Many Children
[Since 0.8.4] - [ -P Classes/TooManyChildren ] - [ Online docs ]
Classes that have more than 15 children. It is worth checking if they cannot be refactored in anyway.
The threshold of 15 children can be configured. There is no technical limitation of the number of children and grand-children for a class.
The analysis doesn't work recursively : only direct generations are counted. Only children that can be found in the code are counted.
<?php
// parent class
// calling it grandparent to avoid confusion with 'parent'
class grandparent {}
class children1 extends grandparent {}
class children2 extends grandparent {}
class children3 extends grandparent {}
class children4 extends grandparent {}
class children5 extends grandparent {}
class children6 extends grandparent {}
class children7 extends grandparent {}
class children8 extends grandparent {}
class children9 extends grandparent {}
class children11 extends grandparent {}
class children12 extends grandparent {}
class children13 extends grandparent {}
class children14 extends grandparent {}
class children15 extends grandparent {}
class children16 extends grandparent {}
class children17 extends grandparent {}
class children18 extends grandparent {}
class children19 extends grandparent {}
?>
See also Why is subclassing too much bad (and hence why should we use prototypes to do away with it)?.
Implement Is For Interface
[Since 0.8.4] - [ -P Classes/ImplementIsForInterface ] - [ Online docs ]
With class heritage, implements should be used for interfaces, and extends with classes.
PHP defers the implements check until execution : the code in example does lint, but won,t run.
<?php
class x {
function foo() {}
}
interface y {
function foo();
}
// Use implements with an interface
class z implements y {}
// Implements is for an interface, not a class
class z implements x {}
?>
Use const
[Since 0.8.4] - [ -P Constants/ConstRecommended ] - [ Online docs ]
The const keyword may be used to define constant, just like the define() function.
When defining a constant, it is recommended to use 'const' when the features of the constant are not dynamical (name or value are known at compile time).
This way, constant will be defined at compile time, and not at execution time.
<?php
//Do
const A = 1;
// Don't
define('A', 1);
?>
define() function is useful when the constant is not known at compile time, or when case sensitivity is necessary.
<?php
// Read $a in database or config file
define('A', $a);
// Read $a in database or config file
define('B', 1, true);
echo b;
?>
See also Syntax.
Unresolved Use
[Since 0.8.4] - [ -P Namespaces/UnresolvedUse ] - [ Online docs ]
The following use instructions cannot be resolved to a class or a namespace. They should be dropped or fixed.
<?php
namespace A {
// class B is defined
class B {}
// class C is not defined
}
namespace X/Y {
use A/B; // This use is valid
use A/C; // This use point to nothing.
new B();
new C();
}
?>
Use expression are options for the current namespace.
See also Using namespaces: Aliasing/Importing.
Unused Constants
[Since 0.8.4] - [ -P Constants/UnusedConstants ] - [ Online docs ]
Those constants are defined in the code but never used. Defining unused constants slow down the application, as they are executed and stored in PHP hashtables.
<?php
// const-defined constant
const USED_CONSTANT = 0;
const UNUSED_CONSTANT = 1 + USED_CONSTANT;
// define-defined constant
define('ANOTHER_UNUSED_CONSTANT', 3);
?>
It is recommended to comment them out, and only define them when it is necessary.
Undefined Parent
[Since 0.8.4] - [ -P Classes/UndefinedParentMP ] - [ Online docs ]
List of properties and methods that are accessed using parent keyword but are not defined in the parent classes.
This may compile but, eventually yields a fatal error during execution.
<?php
class theParent {
// No bar() method
// private bar() method is not accessible to theChild
}
class theChild extends theParent {
function foo() {
// bar is defined in theChild, but not theParent
parent::bar();
}
function bar() {
}
}
?>
Note that if the parent is defined using extends someClass but someClass is not available in the tested code, it will not be reported : it may be in composer, another dependency, or just missing.
See also parent.
Undefined static:: Or self::
[Since 0.8.4] - [ -P Classes/UndefinedStaticMP ] - [ Online docs ]
self and static refer to the current class, or one of its parent. The property or the method may be undefined.
<?php
class x {
static public function definedStatic() {}
private definedStatic = 1;
public function method() {
self::definedStatic();
self::undefinedStatic();
static::definedStatic;
static::undefinedStatic;
}
}
?>
See also Late Static Bindings.
Accessing Private
[Since 0.8.4] - [ -P Classes/AccessPrivate ] - [ Online docs ]
List of calls to private properties/methods that will compile but yield some fatal error upon execution.
<?php
class a {
private $a;
}
class b extends a {
function c() {
$this->a;
}
}
?>
Access Protected Structures
[Since 0.8.4] - [ -P Classes/AccessProtected ] - [ Online docs ]
It is not allowed to access protected properties or methods from outside the class or its relatives.
<?php
class foo {
protected $bar = 1;
}
$foo = new Foo();
$foo->bar = 2;
?>
Parent, Static Or Self Outside Class
[Since 0.8.4] - [ -P Classes/PssWithoutClass ] - [ Online docs ]
Parent, static and self keywords must be used within a class or a trait. They make no sens outside a class or trait scope, as self and static refers to the current class and parent refers to one of parent above.
PHP 7.0 and later detect their usage at compile time, and emits a fatal error.
<?php
class x {
const Y = 1;
function foo() {
// self is \x
echo self::Y;
}
}
const Z = 1;
// This doesn't compile anymore
echo self::Z;
?>
Static may be used in a function or a closure, but not globally.
ext/0mq
[Since 0.8.4] - [ -P Extensions/Extzmq ] - [ Online docs ]
Extension ext/zmq for 0mq.
ØMQ is a software library that lets you quickly design and implement a fast message-based application. --0MQ Website
<?php
// Example from https://github.com/kuying/ZeroMQ/blob/d80dcc3dc1c14a343ca90bbd656b98fd55366548/zguide/examples/PHP/msgqueue.php
/*
* Simple message queuing broker
* Same as request-reply broker but using QUEUE device
* @author Ian Barber <ian(dot)barber(at)gmail(dot)com>
*/
$context = new ZMQContext();
// Socket facing clients
$frontend = $context->getSocket(ZMQ::SOCKET_ROUTER);
$frontend->bind(tcp://*:5559);
// Socket facing services
$backend = $context->getSocket(ZMQ::SOCKET_DEALER);
$backend->bind(tcp://*:5560);
// Start built-in device
new ZMQDevice($frontend, $backend);
?>
See also ZeroMQ and ZMQ.
ext/memcache
[Since 0.8.4] - [ -P Extensions/Extmemcache ] - [ Online docs ]
Extension Memcache.
Memcache module provides handy procedural and object oriented interface to memcached, highly effective caching daemon, which was especially designed to decrease database load in dynamic web applications.
<?php
$memcache = new Memcache;
$memcache->connect('localhost', 11211) or die ('Could not connect');
$version = $memcache->getVersion();
echo 'Server\'s version: '.$version.'<br/>';
$tmp_object = new stdClass;
$tmp_object->str_attr = 'test';
$tmp_object->int_attr = 123;
$memcache->set('key', $tmp_object, false, 10) or die ('Failed to save data at the server');
echo 'Store data in the cache (data will expire in 10 seconds)<br/>';
$get_result = $memcache->get('key');
echo 'Data from the cache:<br/>';
var_dump($get_result);
?>
See also Memcache on PHP and memcached.
ext/memcached
[Since 0.8.4] - [ -P Extensions/Extmemcached ] - [ Online docs ]
Extension Memcached.
This extension uses the libmemcached library to provide an API for communicating with memcached servers. It also provides a session handler (memcached).
<?php
$m = new Memcached();
$m->addServer('localhost', 11211);
$m->set('foo', 100);
var_dump($m->get('foo'));
?>
See also ext/memcached manual and
memcached.
Dynamic Function Call
[Since 0.8.4] - [ -P Functions/Dynamiccall ] - [ Online docs ]
Mark a functioncall made with a variable name.
<?php
// function definition
function foo() {}
// function name is in a variable, as a string.
$var = 'foo';
// dynamic call of a function
$var();
call_user_func($var);
?>
Has Variable Arguments
[Since 0.8.4] - [ -P Functions/VariableArguments ] - [ Online docs ]
Indicates if this function or method accept an arbitrary number of arguments, based on ... or func_get_args() usage.
<?php
// Variables number of arguments
function fixedNumberOfArguments($a, $b, ...$c) {}
// Fixed number of arguments
function fixedNumberOfArguments($a, $b) {
if (`func_num_args() <https://www.php.net/func_num_args>`_ > 2) {
$c = `func_get_args() <https://www.php.net/func_get_args>`_;
array_shift($c); // $a
array_shift($c); // $b
}
// do something
}
// Fixed number of arguments
function fixedNumberOfArguments($a, $b, $c = 1) {}
?>
Multiple Catch
[Since 0.8.4] - [ -P Structures/MultipleCatch ] - [ Online docs ]
Indicates if a try structure have several catch statement.
<?php
// This try has several catch
try {
doSomething();
} catch (RuntimeException $e) {
processRuntimeException();
} catch (OtherException $e) {
processOtherException();
}
?>
Dynamically Called Classes
[Since 0.8.4] - [ -P Classes/VariableClasses ] - [ Online docs ]
Indicates if a class is called dynamically.
<?php
// This class is called dynamically
class X {
const CONSTANTE = 1;
}
$classe = 'X';
$x = new $classe();
echo $x::CONSTANTE;
?>
Conditioned Function
[Since 0.8.4] - [ -P Functions/ConditionedFunctions ] - [ Online docs ]
Indicates if a function is defined only if a condition is met.
// This is a conditioned function.
// it only exists if the PHP binary doesn't have it already.
if (!function_exists('join')) {
function join($glue, $array) {
return implode($glue, $array);
}
}
Conditioned Constants
[Since 0.8.4] - [ -P Constants/ConditionedConstants ] - [ Online docs ]
Indicates if a constant will be defined only if a condition is met.
<?php
if (time() > 1519629617) {
define('MY_CONST', false);
} else {
define('MY_CONST', time() - 1519629617);
}
?>
Is Generator
[Since 0.8.4] - [ -P Functions/IsGenerator ] - [ Online docs ]
Mark as such functions or methods that are using yield and yield from.
<?php
function generator() {
yield from generator2();
return 3;
}
function generator2() {
yield 1;
yield 2;
}
?>
Try With Finally
[Since 0.8.4] - [ -P Structures/TryFinally ] - [ Online docs ] - [ PHP 5.5 and more recent ]
Indicates if a try use a finally statement.
<?php
try {
$a = doSomething();
} catch (Throwable $e) {
// Fix the problem
} finally {
// remove $a anyway
unset($a);
}
?>
See also Exceptions, to learn about catching an exception.
Use password_hash()
[Since 0.8.4] - [ -P Php/Password55 ] - [ Online docs ] - [ PHP 5.5 and more recent ]
password_hash() and password_check() are a better choice to replace the use of crypt() to check password.
PHP 5.5 introduced these functions.
<?php
$password = 'rasmuslerdorf';
$hash = '$2y$10$YCFsG6elYca568hBi2pZ0.3LDL5wjgxct1N8w/oLR/jfHsiQwCqTS';
// The cost parameter can change over time as hardware improves
$options = array('cost' => 11);
// Verify stored hash against plain-text password
if (password_verify($password, $hash)) {
// Check if a newer hashing algorithm is available
// or the cost has changed
if (password_needs_rehash($hash, PASSWORD_DEFAULT, $options)) {
// If so, create a new hash, and replace the old one
$newHash = password_hash($password, PASSWORD_DEFAULT, $options);
}
// Log user in
}
?>
See also Password hashing.
Dereferencing String And Arrays
[Since 0.8.4] - [ -P Structures/DereferencingAS ] - [ Online docs ] - [ PHP older than 5.3]
PHP allows the direct dereferencing of strings and arrays.
This was added in PHP 5.5. There is no need anymore for an intermediate variable between a string and array (or any expression generating such value) and accessing an index.
<?php
$x = array(4,5,6);
$y = $x[2] ; // is 6
May be replaced by
$y = array(4,5,6)[2];
$y = [4,5,6][2];
?>
::class
[Since 0.8.4] - [ -P Php/StaticclassUsage ] - [ Online docs ] - [ PHP 5.5 and more recent ]
PHP has a special class constant to hold the name of the class : class keyword. It represents the class name that is used in the left part of the operator.
Using ::class is safer than relying on a string. It does adapt if the class's name or its namespace is changed'. It is also faster, though it is a micro-optimisation.
It is introduced in PHP 5.5.
<?php
use A\B\C as UsedName;
class foo {
public function bar( ) {
echo ClassName::class;
echo UsedName::class;
}
}
$f = new Foo( );
$f->bar( );
// displays ClassName
// displays A\B\C
?>
Be aware that ::class is a replacement for __CLASS__ magic constant.
See also Class Constant.
Foreach With list()
[Since 0.8.4] - [ -P Structures/ForeachWithList ] - [ Online docs ] - [ PHP 5.5 and more recent ]
Foreach loops have the ability to use list as blind variables. This syntax assign directly array elements to various variables.
PHP 5.5 introduced the usage of list in foreach() loops. Until PHP 7.1, it was not possible to use non-numerical arrays as list() wouldn't support string-indexed arrays.
<?php
// PHP 5.5 and later, with numerically-indexed arrays
foreach($array as list($a, $b)) {
// do something
}
// PHP 7.1 and later, with arrays
foreach($array as list('col1' => $a, 'col3' => $b)) { // 'col2 is ignored'
// do something
}
?>
Previously, it was compulsory to extract() the data from the blind array :
<?php
foreach($array as $c) {
list($a, $b) = $c;
// do something
}
?>
See also The list function & practical uses of array destructuring in PHP.
Empty With Expression
[Since 0.8.4] - [ -P Structures/EmptyWithExpression ] - [ Online docs ] - [ PHP 5.5 and more recent ]
empty() doesn't accept expressions until PHP 5.5. Until then, it is necessary to store the result of the expression in a variable and then, test it with empty().
<?php
// PHP 5.5+ `empty() <https://www.php.net/empty>`_ usage
if (empty(strtolower($b . $c))) {
doSomethingWithoutA();
}
// Compatible `empty() <https://www.php.net/empty>`_ usage
$a = strtolower($b . $c);
if (empty($a)) {
doSomethingWithoutA();
}
?>
See also empty.
list() May Omit Variables
[Since 0.8.4] - [ -P Structures/ListOmissions ] - [ Online docs ]
Simply omit any unused variable in a list() call.
list() is the only PHP function that accepts to have omitted arguments. If the following code makes no usage of a listed variable, just omit it.
<?php
// No need for '2', so no assignation
list ($a, , $b) = array(1, 2, 3);
// works with PHP 7.1 short syntax
[$a, , $b] = array(1, 2, 3);
// No need for '2', so no assignation
list ($a, $c, $b) = array(1, 2, 3);
?>
See also list.
Or Die
[Since 0.8.4] - [ -P Structures/OrDie ] - [ Online docs ]
Classic old style failed error management.
<?php
// In case the connexion fails, this kills the current script
mysql_connect('localhost', $user, $pass) or die();
?>
Interrupting a script will leave the application with a blank page, will make your life miserable for testing. Just don't do that.
See also pg_last_error or
PDO::exec.
Use Const And Functions
[Since 0.8.4] - [ -P Namespaces/UseFunctionsConstants ] - [ Online docs ] - [ PHP 5.6 and more recent ]
Since PHP 5.6 it is possible to import specific functions or constants from other namespaces.
<?php
namespace A {
const X = 1;
function foo() { echo __FUNCTION__; }
}
namespace My{
use function A\foo;
use constant A\X;
echo foo(X);
}
?>
See also Using namespaces: Aliasing/Importing.
Constant Scalar Expressions
[Since 0.8.4] - [ -P Structures/ConstantScalarExpression ] - [ Online docs ] - [ PHP 5.6 and more recent ]
Define constant with the result of static expressions. This means that constants may be defined with the const keyword, with the help of various operators but without any functioncalls.
This feature was introduced in PHP 5.6. It also supports array(), and expressions in arrays.
Those expressions (using simple operators) may only manipulate other constants, and all values must be known at compile time.
<?php
// simple definition
const A = 1;
// constant scalar expression
const B = A * 3;
// constant scalar expression
const C = [A ** 3, '3' => B];
?>
See also Constant Scalar Expressions.
Unreachable Code
[Since 0.8.4] - [ -P Structures/UnreachableCode ] - [ Online docs ]
Code may be unreachable, because other instructions prevent its reaching.
For example, it be located after throw, return, exit(), die(), goto, break or continue : this way, it cannot be reached, as the previous instruction will divert the engine to another part of the code.
<?php
function foo() {
$a++;
return $a;
$b++; // $b++ can't be reached;
}
function bar() {
if ($a) {
return $a;
} else {
return $b;
}
$b++; // $b++ can't be reached;
}
foreach($a as $b) {
$c += $b;
if ($c > 10) {
continue 1;
} else {
$c--;
continue;
}
$d += $e; // this can't be reached
}
$a = 1;
goto B;
class foo {} // Definitions are accessible, but not functioncalls
B:
echo $a;
?>
This is dead code, that may be removed.
Written Only Variables
[Since 0.8.4] - [ -P Variables/WrittenOnlyVariable ] - [ Online docs ]
Those variables are being written, but never read. This way, they are useless and should be removed, or read at some point.
<?php
// $a is used multiple times, but never read
$a = 'a';
$a .= 'b';
$b = 3;
//$b is actually read once
$a .= $b + 3;
?>
Must Return Methods
[Since 0.8.4] - [ -P Functions/MustReturn ] - [ Online docs ]
The following methods are expected to return a value that will be used later. Without return, they are useless.
Methods that must return are : __get(), __isset(), __sleep(), __toString(), __set_state(), __invoke(), __debugInfo().
Methods that may not return, but are often expected to : __call(), __callStatic().
<?php
class foo {
public function __isset($a) {
// returning something useful
return isset($this->$var[$a]);
}
public function __get($a) {
$this->$a++;
// not returning...
}
public function __call($name, $args) {
$this->$name(...$args);
// not returning anything, but that's OK
}
}
?>
__debugInfo() Usage
[Since 0.8.4] - [ -P Php/debugInfoUsage ] - [ Online docs ] - [ PHP 5.6 and more recent ]
The magic method __debugInfo() provides a custom way to dump an object.
It has been introduced in PHP 5.6. In the previous versions of PHP, this method is ignored and won't be called when debugging.
<?php
// PHP 5.6 or later
class foo {
private $bar = 1;
private $reallyHidden = 2;
function __debugInfo() {
return ['bar' => $this->bar,
'reallyHidden' => 'Secret'];
}
}
$f = new Foo();
var_dump($f);
/* Displays :
object(foo)#1 (2) {
[bar]=>
int(1)
[reallyHidden]=>
string(6) Secret
}
*/
?>
See also Magic methods.
Empty Instructions
[Since 0.8.4] - [ -P Structures/EmptyLines ] - [ Online docs ]
Empty instructions are part of the code that have no instructions.
This may be trailing semi-colon or empty blocks for if-then structures.
Comments that explains the reason of the situation are not taken into account.
<?php
$condition = 3;;;;
if ($condition) { }
?>
Mixed Keys Arrays
[Since 0.8.4] - [ -P Arrays/MixedKeys ] - [ Online docs ] - [ PHP 5.6 and more recent ]
Avoid mixing constants and literals in array keys.
When defining default values in arrays, it is recommended to avoid mixing constants and literals, as PHP may mistake them and overwrite the previous with the latter.
Either switch to a newer version of PHP (5.5 or newer), or make sure the resulting array hold the expected data. If not, reorder the definitions.
<?php
const ONE = 1;
$a = [ 1 => 2,
ONE => 3];
?>
ext/imagick
[Since 0.8.4] - [ -P Extensions/Extimagick ] - [ Online docs ]
Extension Imagick for PHP.
Imagick is a native php extension to create and modify images using the ImageMagick API.
<?php
header('Content-type: image/jpeg');
$image = new Imagick('image.jpg');
// If 0 is provided as a width or height parameter,
// aspect ratio is maintained
$image->thumbnailImage(100, 0);
echo $image;
?>
See also Imagick for PHP and Imagick.
Unused Methods
[Since 0.8.4] - [ -P Classes/UnusedMethods ] - [ Online docs ]
Those methods are never called.
They are probably dead code, unless they are called dynamically.
This analysis omits methods which are in a class that makes dynamical self calls : $this->$m() . That way, any method may be called.
This analysis omits methods which are overwritten by a child class. That way, they are considered to provide a default behavior.
<?php
class foo {
public function used() {
$this->used();
}
public function unused() {
$this->used();
}
}
class bar extends foo {
public function some() {
$this->used();
}
}
$a = new foo();
$a->used();
?>
See also Dead Code: Unused Method.
ext/oci8
[Since 0.8.4] - [ -P Extensions/Extoci8 ] - [ Online docs ]
Extension ext/oci8.
OCI8 gives access Oracle Database 12c, 11g, 10g, 9i and 8i.
<?php
$conn = oci_connect('hr', 'welcome', 'localhost/XE');
if (!$conn) {
$e = oci_error();
trigger_error(htmlentities($e['message'], ENT_QUOTES), E_USER_ERROR);
}
// Prepare the statement
$stid = oci_parse($conn, 'SELECT * FROM departments');
if (!$stid) {
$e = oci_error($conn);
trigger_error(htmlentities($e['message'], ENT_QUOTES), E_USER_ERROR);
}
// Perform the logic of the query
$r = oci_execute($stid);
if (!$r) {
$e = oci_error($stid);
trigger_error(htmlentities($e['message'], ENT_QUOTES), E_USER_ERROR);
}
// Fetch the results of the query
print '<table border='1'>' . PHP_EOL;
while ($row = oci_fetch_array($stid, OCI_ASSOC+OCI_RETURN_NULLS)) {
print '<tr>' . PHP_EOL;
foreach ($row as $item) {
print ' <td>' . ($item !== null ? htmlentities($item, ENT_QUOTES) : ' ') . '</td>' . PHP_EOL;
}
print '</tr>' . PHP_EOL;
}
print '</table>' . PHP_EOL;
oci_free_statement($stid);
oci_close($conn);
?>
See also Oracle OCI8 and Oracle.
Overwritten Exceptions
[Since 0.8.4] - [ -P Exceptions/OverwriteException ] - [ Online docs ]
In catch blocks, it is good practice not to overwrite the incoming exception, as information about the exception will be lost.
<?php
try {
doSomething();
} catch (SomeException $e) {
// $e is overwritten
$e = new anotherException($e->getMessage());
throw $e;
} catch (SomeOtherException $e) {
// $e is chained with the next exception
$e = new Exception($e->getMessage(), 0, $e);
throw $e;
}
?>
Foreach Reference Is Not Modified
[Since 0.8.4] - [ -P Structures/ForeachReferenceIsNotModified ] - [ Online docs ]
Foreach statement may loop using a reference, especially when the loop has to change values of the array it is looping on.
In the spotted loop, reference are used but never modified. They may be removed.
<?php
$letters = range('a', 'z');
// $letter is not used here
foreach($letters as &$letter) {
$alphabet .= $letter;
}
// $letter is actually used here
foreach($letters as &$letter) {
$letter = strtoupper($letter);
}
?>
ext/imap
[Since 0.8.4] - [ -P Extensions/Extimap ] - [ Online docs ]
Extension ext/imap.
This extension operate with the IMAP protocol, as well as the NNTP, POP3 and local mailbox access methods.
<?php
$mbox = imap_open('{imap.example.org}', 'username', 'password', OP_HALFOPEN)
or die('can't connect: ' . imap_last_error());
$list = imap_list($mbox, '{imap.example.org}', '*');
if (is_array($list)) {
foreach ($list as $val) {
echo imap_utf7_decode($val) . PHP_EOL;
}
} else {
echo 'imap_list failed: ' . imap_last_error() . PHP_EOL;
}
imap_close($mbox);?>
See also IMAP.
Overwritten Class Const
[Since 0.8.4] - [ -P Classes/OverwrittenConst ] - [ Online docs ]
Those class constants are overwritten in a parent class. This may lead to confusion, as the value of the constant may change depending on the way it is called.
<?php
class foo {
const C = 1;
}
class bar extends foo {
const C = 2;
function x() {
// depending on the access to C, value is different.
print self::C.' '.static::C.' '.parent::C;
}
}
?>
Direct Injection
[Since 0.8.4] - [ -P Security/DirectInjection ] - [ Online docs ]
The following code act directly upon PHP incoming variables like $_GET and $_POST . This makes those snippets very unsafe.
<?php
// Direct injection
echo Hello.$_GET['user']., welcome.;
// less direct injection
foo($_GET['user']);
function foo($user) {
echo Hello.$user., welcome.;
}
?>
See also Cross-Site Scripting (XSS)
Dynamic Class Constant
[Since 0.8.4] - [ -P Classes/DynamicConstantCall ] - [ Online docs ]
Dynamic calls to class constants.
Constant may be dynamically called with the constant() function.
<?php
// Dynamic access to 'E_ALL'
echo constant('E_ALL');
interface i {
const MY_CONSTANT = 1;
}
// Dynamic access to 'E_ALL'
echo constant('i::MY_CONSTANT');
?>
Dynamic Methodcall
[Since 0.8.4] - [ -P Classes/DynamicMethodCall ] - [ Online docs ]
Dynamic calls to class methods.
<?php
class x {
static public function foo() {}
public function bar() {}
}
$staticmethod = 'foo';
// dynamic static method call to x::foo()
x::$staticmethod();
$method = 'bar';
// dynamic method call to bar()
$object = new x();
$object->$method();
?>
Dynamic New
[Since 0.8.4] - [ -P Classes/DynamicNew ] - [ Online docs ]
Dynamic instantiation of classes.
<?php
$object = new $classname()
?>
.
Dynamic Property
[Since 0.8.4] - [ -P Classes/DynamicPropertyCall ] - [ Online docs ]
Dynamic access to class property.
<?php
class x {
static public $foo = 1;
public $bar = 2;
}
$staticproperty = 'foo';
// dynamic static property call to x::$foo
echo x::${$staticproperty};
$property = 'bar';
// dynamic property call to bar()
$object = new x();
$object->$property = 4;
?>
Don't Change Incomings
[Since 0.8.4] - [ -P Structures/NoChangeIncomingVariables ] - [ Online docs ]
PHP hands over a lot of information using special variables like $_GET, $_POST, etc... Modifying those variables and those values inside variables means that the original content is lost, while it will still look like raw data, and, as such, will be untrustworthy.
<?php
// filtering and keeping the incoming value.
$_DATA'id'] = (int) $_GET['id'];
// filtering and changing the incoming value.
$_GET['id'] = strtolower($_GET['id']);
?>
It is recommended to put the modified values in another variable, and keep the original one intact.
Dynamic Classes
[Since 0.8.4] - [ -P Classes/DynamicClass ] - [ Online docs ]
Dynamic calls of classes.
<?php
class x {
static function staticMethod() {}
}
$class = 'x';
$class::staticMethod();
?>
Compared Comparison
[Since 0.8.4] - [ -P Structures/ComparedComparison ] - [ Online docs ]
Usually, comparison are sufficient, and it is rare to have to compare the result of comparison. Check if this two-stage comparison is really needed.
<?php
if ($a === strpos($string, $needle) > 2) {}
// the expression above apply precedence :
// it is equivalent to :
if (($a === strpos($string, $needle)) > 2) {}
?>
See also Operators Precedence.
Useless Return
[Since 0.8.4] - [ -P Functions/UselessReturn ] - [ Online docs ]
The spotted functions or methods have a return statement, but this statement is useless. This is the case for constructor and destructors, whose return value are ignored or inaccessible.
When return is void, and the last element in a function, it is also useless.
<?php
class foo {
function __construct() {
// return is not used by PHP
return 2;
}
}
function bar(&$a) {
$a++;
// The last return, when empty, is useless
return;
}
?>
Multiple Classes In One File
[Since 0.8.4] - [ -P Classes/MultipleClassesInFile ] - [ Online docs ]
It is regarded as a bad practice to store several classes in the same file. This is usually done to make life of __autoload() easier.
It is often unexpected to find class foo in the bar.php file. This is also the case for interfaces and traits.
<?php
// three classes in the same file
class foo {}
class bar {}
class foobar{}
?>
One good reason to have multiple classes in one file is to reduce include time by providing everything into one nice include.
See also Is it a bad practice to have multiple classes in the same file?.
File Uploads
[Since 0.8.4] - [ -P Structures/FileUploadUsage ] - [ Online docs ]
This code makes usage of file upload features of PHP.
Upload file feature is detected through the usage of specific functions :
<?php
$uploaddir = '/var/www/uploads/';
$uploadfile = $uploaddir . basename($_FILES['userfile']['name']);
echo '<pre>';
if (move_uploaded_file($_FILES['userfile']['tmp_name'], $uploadfile)) {
echo 'File is valid, and was successfully uploaded.'.PHP_EOL;
} else {
echo 'Possible file upload attack!'.PHP_EOL;
}
echo 'Here is some more debugging info:';
print_r($_FILES);
print '</pre>';
?>
See also Handling file uploads.
Return With Parenthesis
[Since 0.8.4] - [ -P Php/ReturnWithParenthesis ] - [ Online docs ]
return statement doesn't need parenthesis. PHP tolerates them with return statement, but it is recommended not to use them.
From the PHP Manual : 'Note: Note that since return is a language construct and not a function, the parentheses surrounding its argument are not required and their use is discouraged.'.
<?php
function foo() {
$a = rand(0, 10);
// No need for parenthesis
return $a;
// Parenthesis are useless here
return ($a);
// Parenthesis are useful here: they are needed by the multplication.
return ($a + 1) * 3;
}
?>
See also PHP return(value); vs return value; and
return.
Unused Classes
[Since 0.8.4] - [ -P Classes/UnusedClass ] - [ Online docs ]
The following classes are never explicitly used in the code.
Note that this may be valid in case the current code is a library or framework, since it defines classes that are used by other (unprovided) codes.
Also, this analyzer may find classes that are, in fact, dynamically loaded.
<?php
class unusedClasss {}
class usedClass {}
$y = new usedClass();
?>
ext/intl
[Since 0.8.4] - [ -P Extensions/Extintl ] - [ Online docs ]
Extension international.
Internationalization extension (further is referred as Intl) is a wrapper for ICU library, enabling PHP programmers to perform various locale-aware operations including but not limited to formatting, transliteration, encoding conversion, calendar operations, UCA-conformant collation, locating text boundaries and working with locale identifiers, timezones and graphemes.
<?php
$coll = new Collator('en_US');
$al = $coll->getLocale(Locale::ACTUAL_LOCALE);
echo Actual locale: $al\n;
$formatter = new NumberFormatter('en_US', NumberFormatter::DECIMAL);
echo $formatter->format(1234567);
?>
See also Internationalization Functions.
ext/cairo
[Since 0.8.4] - [ -P Extensions/Extcairo ] - [ Online docs ]
Extension ext/cairo.
Cairo is a native PHP extension to create and modify graphics using the Cairo Graphics Library.
<?php
// Example from https://github.com/gtkforphp/cairo/blob/master/examples/big-line.php
$width = 100;
$height = 100;
$sur = new CairoPSSurface(temp.ps, $width, $height);
$con = new CairoContext($sur);
$con->setSourceRgb(0,0,1);
$con->moveTo(50,50);
$con->lineTo(50000,50000);
$con->stroke();
$con->setSourceRgb(0,1,0);
$con->moveTo(50,50);
$con->lineTo(-50000,50000);
$con->stroke();
$con->setSourceRgb(1,0,0);
$con->moveTo(50,50);
$con->lineTo(50000,-50000);
$con->stroke();
$con->setSourceRgb(1,1,0);
$con->moveTo(50,50);
$con->lineTo(-50000,-50000);
$con->stroke();
$sur->writeToPng(dirname(__FILE__) . /big-line-php.png);
?>
See also Cairo, gtkforphp/cairo.
Dynamic Code
[Since 0.8.4] - [ -P Structures/DynamicCode ] - [ Online docs ]
List of instructions that were left during analysis, as they rely on dynamic data.
<?php
// Dynamic call to 'method';
$name = 'method';
$object->$name();
// Hard coded call to 'method';
$object->method();
?>
Any further analysis will need to start from here.
See also Variable functions.
Unpreprocessed Values
[Since 0.8.4] - [ -P Structures/Unpreprocessed ] - [ Online docs ]
Preprocessing values is the preparation of values before PHP executes the code.
There is no macro language in PHP, that prepares the code before compilation, bringing some comfort and short syntax. Most of the time, one uses PHP itself to preprocess data.
For example :
<?php
$days_en = 'monday,tuesday,wednesday,thursday,friday,saturday,sunday';
$days_zh = '星期－,星期二,星期三,星期四,星期五,星期六,星期日';
$days = explode(',', $lang === 'en' ? $days_en : $days_zh);
?>
could be written
<?php
if ($lang === 'en') {
$days = ['monday', 'tuesday', 'wednesday', 'thursday', 'friday', 'saturday', 'sunday'];
} else {
$days = ['星期－', '星期二', '星期三', '星期四', '星期五', '星期六', '星期日'];
}
?>
and avoid preprocessing the string into an array first.
Preprocessing could be done anytime the script includes all the needed values to process the expression.
ext/pspell
[Since 0.8.4] - [ -P Extensions/Extpspell ] - [ Online docs ]
Extension pspell.
These functions allow you to check the spelling of a word and offer suggestions.
<?php
$pspell_link = pspell_new('en');
if (pspell_check($pspell_link, 'testt')) {
echo 'This is a valid spelling';
} else {
echo 'Sorry, wrong spelling';
}
?>
See also Pspell and pspell.
No Direct Access
[Since 0.8.4] - [ -P Structures/NoDirectAccess ] - [ Online docs ]
This expression protects files against direct access. It will kill the process if it realizes this is not supposed to be directly accessed.
Those expressions are used in applications and framework, to prevent direct access to definition files.
<?php
// CONSTANT_EXEC is defined in the main file of the application
defined('CONSTANT_EXEC') or die('Access not allowed'); : Constant used!
?>
ext/opcache
[Since 0.8.4] - [ -P Extensions/Extopcache ] - [ Online docs ]
Extension opcache.
OPcache improves PHP performance by storing precompiled script bytecode in shared memory, thereby removing the need for PHP to load and parse scripts on each request.
<?php
echo opcache_compile_file('/var/www/index.php');
print_r(opcache_get_status());
?>
See also OPcache functions.
ext/expect
[Since 0.8.4] - [ -P Extensions/Extexpect ] - [ Online docs ]
Extension Expect.
This extension allows to interact with processes through PTY . You may consider using the expect:// wrapper with the filesystem functions which provide a simpler and more intuitive interface.
<?php
ini_set('expect.loguser', 'Off');
$stream = fopen('expect://ssh root@remotehost uptime', 'r');
$cases = array (
array (0 => 'password:', 1 => PASSWORD)
);
switch (expect_expectl ($stream, $cases)) {
case PASSWORD:
fwrite ($stream, 'password'.PHP_EOL);
break;
default:
die ('Error was occurred while connecting to the remote host!'.PHP_EOL);
}
while ($line = fgets($stream)) {
print $line;
}
fclose ($stream);
?>
See also expect.
Undefined Properties
[Since 0.8.4] - [ -P Classes/UndefinedProperty ] - [ Online docs ]
List of properties that are not explicitly defined in the class, its parents or traits.
<?php
class foo {
// property definition
private bar = 2;
function foofoo() {
// $this->bar is defined in the class
// $this->barbar is NOT defined in the class
return $this->bar + $this->barbar;
}
}
?>
It is possible to spot unidentified properties by using the PHP's magic methods __get and __set . Even if the class doesn't use magic methods, any call to an undefined property will be directed to those methods, and they can be used as a canary, warning that the code is missing a definition.
<?php
trait NoUnefinedProperties {
function __get($name) {
assert(false, "Attempt to read the $name property, on the class ".__CLASS__;
}
function __set($name, $value) {
assert(false, "Attempt to read the $name property, on the class ".__CLASS__;
}
}
?>
See also Properties.
ext/recode
[Since 0.8.4] - [ -P Extensions/Extrecode ] - [ Online docs ]
Extension GNU Recode.
This module contains an interface to the GNU Recode library. The GNU Recode library converts files between various coded character sets and surface encodings.
<?php
echo recode_string('us..flat', 'The following character has a diacritical mark: á');
?>
This extension is not available on Windows.
See also ext/recode and Recode.
ext/parsekit
[Since 0.8.4] - [ -P Extensions/Extparsekit ] - [ Online docs ]
Extension Parsekit.
These functions allow runtime analysis of opcodes compiled from PHP scripts.
<?php
var_dump(parsekit_compile_file('hello_world.php', $errors, PARSEKIT_SIMPLE));
?>
See also Parsekit.
ext/runkit
[Since 0.8.4] - [ -P Extensions/Extrunkit ] - [ Online docs ]
Extension Runkit.
The runkit extension provides means to modify constants, user-defined functions, and user-defined classes. It also provides for custom superglobal variables and embeddable sub-interpreters via sandboxing.
<?php
class Example {
function foo() {
echo 'foo!'.PHP_EOL;
}
}
// create an Example object
$e = new Example();
// Add a new public method
runkit_method_add(
'Example',
'add',
'$num1, $num2',
'return $num1 + $num2;',
RUNKIT_ACC_PUBLIC
);
// add 12 + 4
echo $e->add(12, 4);
?>
See also runkit.
ext/gettext
[Since 0.8.4] - [ -P Extensions/Extgettext ] - [ Online docs ]
Extension Gettext.
The gettext functions implement an NLS (Native Language Support) API which can be used to internationalize your PHP applications.
<?php
// Set language to German
putenv('LC_ALL=de_DE');
setlocale(LC_ALL, 'de_DE');
// Specify location of translation tables
bindtextdomain('myPHPApp', './locale');
// Choose domain
textdomain('myPHPApp');
// Translation is looking for in ./locale/de_DE/LC_MESSAGES/myPHPApp.mo now
// Print a test message
echo gettext('Welcome to My PHP Application');
// Or use the alias _() for gettext()
echo _('Have a nice day');
?>
See also Gettext and ext/gettext
Short Open Tags
[Since 0.8.4] - [ -P Php/ShortOpenTagRequired ] - [ Online docs ]
Usage of short open tags is discouraged. The following files were found to be impacted by the short open tag directive at compilation time. They must be reviewed to ensure no <? tags are found in the code.
Strict Comparison With Booleans
[Since 0.8.4] - [ -P Structures/BooleanStrictComparison ] - [ Online docs ]
Strict comparisons prevent from mistaking an error with a false.
Boolean values may be easily mistaken with other values, especially when the function may return integer or boolean as a normal course of action.
It is encouraged to use strict comparison === or !== when booleans are involved in a comparison.
<?php
// distinguish between : $b isn't in $a, and, $b is at the beginning of $a
if (strpos($a, $b) === 0) {
doSomething();
}
// DOES NOT distinguish between : $b isn't in $a, and, $b is at the beginning of $a
if (strpos($a, $b)) {
doSomething();
}
// will NOT mistake 1 and true
$a = array(0, 1, 2, true);
if (in_array($a, true, true)) {
doSomething();
}
// will mistake 1 and true
$a = array(0, 1, 2, true);
if (in_array($a, true)) {
doSomething();
}
?>
switch() structures always uses == comparisons.
Native function in_array() has a third parameter to make it use strict comparisons.
Lone Blocks
[Since 0.8.4] - [ -P Structures/LoneBlock ] - [ Online docs ]
Any grouped code without a commanding structure is useless.
Blocks are compulsory when defining a structure, such as a class or a function. They are most often used with flow control instructions, like if then or switch.
Blocks are also valid syntax that group several instructions together, though they have no effect at all, except confuse the reader. Most often, it is a ruin from a previous flow control instruction, whose condition was removed or commented. They should be removed.
<?php
// Lone block
//foreach($a as $b)
{
$b++;
}
?>
$this Is Not For Static Methods
[Since 0.8.4] - [ -P Classes/ThisIsNotForStatic ] - [ Online docs ]
Static methods shouldn't use $this variable.
$this variable represents an object, the current object. It is not compatible with a static method, which may operate without any object.
While executing a static method, $this is actually set to NULL.
<?php
class foo {
static $staticProperty = 1;
// Static methods should use static properties
static public function `count() <https://www.php.net/count>`_ {
return self::$staticProperty++;
}
// Static methods can't use $this
static public function bar() {
return $this->a; // No $this usage in a static method
}
}
?>
See also Static Keyword.
Avoid sleep()/usleep()
[Since 0.8.4] - [ -P Security/NoSleep ] - [ Online docs ]
sleep() and usleep() help saturate the web server.
Pausing the script for a specific amount of time means that the Web server is also making all related resources sleep, such as database, sockets, session, etc. This may used to set up a DOS on the server.
<?php
$begin = microtime(true);
checkLogin($user, $password);
$end = microtime(true);
// Making all login checks looks the same
usleep(1000000 - ($end - $begin) * 1000000);
// Any hit on this page now uses 1 second, no matter if load is high or not
// Is it now possible to saturate the webserver in 1 s ?
?>
As much as possible, avoid delaying the end of the script.
sleep() and usleep() have less impact in commandline ( CLI ).
Super Global Usage
[Since 0.8.4] - [ -P Php/SuperGlobalUsage ] - [ Online docs ]
Spot usage of Super global variables, such as $_GET, $_POST or $_REQUEST.
<?php
echo htmlspecialchars($_GET['name'], UTF-8);
?>
See also Superglobals.
Global Usage
[Since 0.8.4] - [ -P Structures/GlobalUsage ] - [ Online docs ]
List usage of globals variables, with global keywords or direct access to $GLOBALS.
<?php
$a = 1; /* global scope */
function test()
{
echo $a; /* reference to local scope variable */
}
test();
?>
It is recommended to avoid using global variables, at it makes it very difficult to track changes in values across the whole application.
See also Variable scope.
PHP Keywords As Names
[Since 0.8.4] - [ -P Php/ReservedNames ] - [ Online docs ]
PHP has a set of reserved keywords. It is recommended not to use those keywords for names structures.
PHP does check that a number of structures, such as classes, methods, interfaces... can't be named or called using one of the keywords. However, in a few other situations, no check are enforced. Using keywords in such situation is confusing.
<?php
// This keyword is reserved since PHP 7.2
class object {
// _POST is used by PHP for the $_POST variable
// This methods name is probably confusing,
// and may attract more than its share of attention
function _POST() {
}
}
?>
See also List of Keywords,
Predefined Classes,
Predefined Constants,
List of other reserved words and
Predefined Variables.
Logical Should Use Symbolic Operators
[Since 0.8.4] - [ -P Php/LogicalInLetters ] - [ Online docs ]
Logical operators come in two flavors : and / &&, || / or, ^ / xor. However, they are not exchangeable, as && and and have different precedence.
<?php
// Avoid lettered operator, as they have lower priority than expected
$a = $b and $c;
// $a === 3 because equivalent to ($a = $b) and $c;
// safe way to write the above :
$a = ($b and $c);
$a = $b && $c;
// $a === 1
?>
It is recommended to use the symbol operators, rather than the letter ones.
See also Logical Operators.
Could Use self
[Since 0.8.4] - [ -P Classes/ShouldUseSelf ] - [ Online docs ]
self keyword refers to the current class, or any of its parents. Using it is just as fast as the full class name, it is as readable and it is will not be changed upon class or namespace change.
It is also routinely used in traits : there, self represents the class in which the trait is used, or the trait itself.
<?php
class x {
const FOO = 1;
public function bar() {
return self::FOO;
// same as return x::FOO;
}
}
?>
See also Scope Resolution Operator (::).
Const With Array
[Since 0.8.4] - [ -P Php/ConstWithArray ] - [ Online docs ] - [ PHP 5.5 and more recent ]
The const keyword supports array. This feature was added in PHP 5.6.
The array must be filled with other constants. It may also be build using the '+' operator.
<?php
const PRIMES = [2, 3, 5, 7];
class X {
const TWENTY_THREE = 23;
const MORE_PRIMES = PRIMES + [11, 13, 17, 19];
const EVEN_MORE_PRIMES = self::MORE_PRIMES + [self::TWENTY_THREE];
}
?>
See also Class Constants and
Constants Syntax.
Catch Overwrite Variable
[Since 0.8.4] - [ -P Structures/CatchShadowsVariable ] - [ Online docs ]
The try/catch structure uses some variables that are also in use in this scope. In case of a caught exception, the exception will be put in the catch variable, and overwrite the current value, loosing some data.
<?php
// variables and caught exceptions are distinct
$argument = 1;
try {
methodThatMayRaiseException($argument);
} (Exception $e) {
// here, $e has been changed to an exception.
}
// variables and caught exceptions are overlapping
$e = 1;
try {
methodThatMayRaiseException();
} (Exception $e) {
// here, $e has been changed to an exception.
}
?>
It is recommended to use another name for these catch variables.
Namespaces
[Since 0.8.4] - [ -P Namespaces/NamespaceUsage ] - [ Online docs ]
Inventory of all namespaces.
Avoid array_unique()
[Since 0.8.4] - [ -P Structures/NoArrayUnique ] - [ Online docs ]
The native function array_unique() is much slower than using other alternatives, such as array_count_values(), array_flip()/array_keys(), or even a foreach() loops.
<?php
// using `array_unique() <https://www.php.net/array_unique>`_
$uniques = array_unique($someValues);
// When values are strings or integers
$uniques = array_keys(array_count_values($someValues));
$uniques = array_flip(array_flip($someValues))
//even some loops are faster.
$uniques = [];
foreach($someValues as $s) {
if (!in_array($uniques, $s)) {
$uniques[] $s;
}
}
?>
See also array_unique.
Deep Definitions
[Since 0.8.4] - [ -P Functions/DeepDefinitions ] - [ Online docs ]
Structures, such as functions, classes, interfaces, traits, etc. may be defined anywhere in the code, including inside functions. This is legit code for PHP.
Since the availability of autoload, with spl_register_autoload(), there is no need for that kind of code. Structures should be defined, and accessible to the autoloading. Inclusions and deep definitions should be avoided, as they compel code to load some definitions, while autoloading will only load them if needed.
<?php
class X {
function init() {
// myFunction is defined when and only if X::init() is called.
if (!function_exists('myFunction'){
function myFunction($a) {
return $a + 1;
}
})
}
}
?>
Functions are excluded from autoload, but shall be gathered in libraries, and not hidden inside other code.
Constants definitions are tolerated inside functions : they may be used for avoiding repeat, or noting the usage of such function.
Definitions inside a if/then statement, that include PHP version check are accepted here.
See also Autoloading Classes.
Constant Class
[Since 0.8.4] - [ -P Classes/ConstantClass ] - [ Online docs ]
A class or an interface only made up of constants. Constants usually have to be used in conjunction of some behavior (methods, class...) and never alone.
<?php
class ConstantClass {
const KBIT = 1000;
const MBIT = self::KBIT * 1000;
const GBIT = self::MBIT * 1000;
const PBIT = self::GBIT * 1000;
}
?>
As such, they should be PHP constants (build with define or const), or included in a class with other methods and properties.
See also PHP Classes containing only constants.
Not Definitions Only
[Since 0.8.4] - [ -P Files/NotDefinitionsOnly ] - [ Online docs ]
Files should only include definitions (class, functions, traits, interfaces, constants), or global instructions, but not both.
<?php
// This whole script is a file
// It contains definitions and global code
class foo {
static public $foo = null;
}
//This can be a singleton creation
foo::$foo = new foo();
trait t {}
class bar {}
?>
Within this context, globals, use, and namespaces instructions are not considered a warning.
Preprocess Arrays
[Since 0.8.4] - [ -P Arrays/ShouldPreprocess ] - [ Online docs ]
Using long list of assignations for initializing arrays is significantly slower than the declaring them as an array.
<?php
// Slow way
$a = []; // also with $a = array();
$a[1] = 2;
$a[2] = 3;
$a[3] = 5;
$a[4] = 7;
$a[5] = 11;
// Faster way
$a = [1 => 2,
2 => 3,
3 => 5,
4 => 7,
5 => 11];
// Even faster way if indexing is implicit
$a = [2, 3, 5, 7, 11];
?>
If the array has to be completed rather than created, it is also faster to use += when there are more than ten elements to add.
<?php
// Slow way
$a = []; // also with $a = array();
$a[1] = 2;
$a[2] = 3;
$a[3] = 5;
// some expressions to get $seven and $eleven
$a[4] = $seven;
$a[5] = $eleven;
// Faster way
$a = [1 => 2,
2 => 3,
3 => 5];
// some expressions to get $seven and $eleven
$a += [4 => $seven,
5 => $eleven];
// Even faster way if indexing is implicit
$a = [2, 3, 5];
// some expressions to get $seven and $eleven
$a += [$seven, $eleven];
?>
Repeated print()
[Since 0.8.4] - [ -P Structures/RepeatedPrint ] - [ Online docs ]
Always merge several print or echo in one call.
It is recommended to use echo with multiple arguments, or a concatenation with print, instead of multiple calls to print echo, when outputting several blob of text.
<?php
//Write :
echo 'a', $b, 'c';
print 'a' . $b . 'c';
//Don't write :
print 'a';
print $b;
print 'c';
?>
Avoid Parenthesis
[Since 0.8.4] - [ -P Structures/PrintWithoutParenthesis ] - [ Online docs ]
Avoid Parenthesis for language construct. Languages constructs are a few PHP native elements, that looks like functions but are not.
Among other distinction, those elements cannot be directly used as variable function call, and they may be used with or without parenthesis.
<?php
// normal usage of include
include 'file.php';
// This looks like a function and is not
include('file2.php');
?>
The usage of parenthesis actually give some feeling of comfort, it won't prevent PHP from combining those argument with any later operators, leading to unexpected results.
Even if most of the time, usage of parenthesis is legit, it is recommended to avoid them.
Objects Don't Need References
[Since 0.8.4] - [ -P Structures/ObjectReferences ] - [ Online docs ]
There is no need to create references for objects, as those are always passed by reference when used as arguments.
Note that when the argument is assigned another value, including another object, then the reference is needed : PHP forgets about reference when they are replaced.
<?php
$object = new stdClass();
$object->name = 'a';
foo($object);
print $object->name; // Name is 'b'
// No need to make $o a reference
function foo(&$o) {
$o->name = 'b';
}
// $o is assigned inside the function : it must be called with a &, or the object won't make it out of the foo3 scope
function foo3(&$o) {
$o = new stdClass;
}
$array = array($object);
foreach($array as &$o) { // No need to make this a reference
$o->name = 'c';
}
?>
See also Passing by reference.
Redefined Property
[Since 0.8.4] - [ -P Classes/RedefinedProperty ] - [ Online docs ]
Property redefined in a parent class.
Using heritage, it is possible to define several times the same property, at different levels of the hierarchy.
<?php
class foo {
protected $aProperty = 1;
}
class bar extends foo {
// This property is redefined in the parent class, leading to potential confusion
protected $aProperty = 1;
}
?>
When this is the case, it is difficult to understand which class will actually handle the property.
In the case of a private property, the different instances will stay distinct. In the case of protected or public properties, they will all share the same value.
It is recommended to avoid redefining the same property in a hierarchy.
Locally Unused Property
[Since 0.8.4] - [ -P Classes/LocallyUnusedProperty ] - [ Online docs ]
Those properties are defined in a class, and this class doesn't have any method that makes use of them.
While this is syntactically correct, it is unusual that defined resources are used in a child class. It may be worth moving the definition to another class, or to move accessing methods to the class.
<?php
class foo {
public $unused, $used;// property $unused is never used in this class
function bar() {
$this->used++; // property $used is used in this method
}
}
class foofoo extends foo {
function bar() {
$this->unused++; // property $unused is used in this method, but defined in the parent class
}
}
?>
Lost References
[Since 0.8.4] - [ -P Variables/LostReferences ] - [ Online docs ]
Either avoid references, or propagate them correctly.
When assigning a referenced variable with another reference, the initial reference is lost, while the intend was to transfer the content.
<?php
function foo(&$lostReference, &$keptReference)
{
$c = 'c';
// $lostReference was a reference, but now, it is another
$lostReference =& $c;
// $keptReference was a reference : now it contains the actual value
$keptReference = $c;
}
$bar = 'bar';
$bar2 = 'bar';
foo($bar, $bar2);
//displays bar c, instead of bar bar
print $bar. ' '.$bar2;
?>
Do not reassign a reference with another reference. Assign new content to the reference to change its value.
Constants Created Outside Its Namespace
[Since 0.8.4] - [ -P Constants/CreatedOutsideItsNamespace ] - [ Online docs ]
Constants Created Outside Its Namespace.
Using the define() function, it is possible to create constant outside their namespace, but using the fully qualified namespace.
<?php
namespace A\B {
// define A\B\C as 1
define('C', 1);
}
namespace D\E {
// define A\B\C as 1, while outside the A\B namespace
define('A\B\C', 1);
}
?>
However, this makes the code confusing and difficult to debug. It is recommended to move the constant definition to its namespace.
Fully Qualified Constants
[Since 0.8.4] - [ -P Namespaces/ConstantFullyQualified ] - [ Online docs ]
Constants defined with their namespace.
When defining constants with define() function, it is possible to include the actual namespace :
<?php
define('a\b\c', 1);
?>
However, the name should be fully qualified without the initial \. Here, \a\b\c constant will never be accessible as a namespace constant, though it will be accessible via the constant() function.
Also, the namespace will be absolute, and not a relative namespace of the current one.
Never Used Properties
[Since 0.8.4] - [ -P Classes/PropertyNeverUsed ] - [ Online docs ]
Properties that are never used. They are defined in a class or a trait, but they never actually used.
Properties are considered used when they are used locally, in the same class as their definition, or in a parent class : a parent class is always included with the current class.
On the other hand, properties which are defined in a class, but only used in children classes is considered unused, since children may also avoid using it.
<?php
class foo {
public $usedProperty = 1;
// Never used anywhere
public $unusedProperty = 2;
function bar() {
// Used internally
++$this->usedProperty;
}
}
class foo2 extends foo {
function bar2() {
// Used in child class
++$this->usedProperty;
}
}
// Used externally
++$this->usedProperty;
?>
No Real Comparison
[Since 0.8.4] - [ -P Type/NoRealComparison ] - [ Online docs ]
Avoid comparing decimal numbers with ==, ===, !==, !=. Real numbers have an error margin which is random, and makes it very difficult to match even if the compared value is a literal.
PHP uses an internal representation in base 2 : any number difficult to represent with this base (like 0.1 or 0.7) will have a margin of error.
<?php
$a = 1/7;
$b = 2.0;
// 7 * $a is a real, not an integer
var_dump( 7 * $a === 1);
// rounding error leads to wrong comparison
var_dump( (0.1 + 0.7) * 10 == 8);
// although
var_dump( (0.1 + 0.7) * 10);
// displays 8
// precision formula to use with reals. Adapt 0.0001 to your precision needs
var_dump( abs(((0.1 + 0.7) * 10) - 8) < 0.0001);
?>
Use precision formulas with abs() to approximate values with a given precision, or avoid reals altogether.
See also Floating point numbers.
Should Use Local Class
[Since 0.8.4] - [ -P Classes/ShouldUseThis ] - [ Online docs ]
Methods should use the defining class, or be functions.
Methods should use $this with another method or a property, or call parent:: . Static methods should call another static method, or a static property.
Methods which are overwritten by a child class are omitted : the parent class act as a default value for the children class, and this is correct.
<?php
class foo {
public function __construct() {
// This method should do something locally, or be removed.
}
}
class bar extends foo {
private $a = 1;
public function __construct() {
// Calling parent:: is sufficient
parent::__construct();
}
public function barbar() {
// This is acting on the local object
$this->a++;
}
public function barfoo($b) {
// This has no action on the local object. It could be a function or a closure where needed
return 3 + $b;
}
}
?>
Note that a method using a class constant is not considered as using the local class, for this analyzer.
Usage Of class_alias()
[Since 0.8.4] - [ -P Classes/ClassAliasUsage ] - [ Online docs ]
class_alias creates dynamically an alias for classes.
<?php
class foo { }
class_alias('foo', 'bar');
$a = new foo;
$b = new bar;
// the objects are the same
var_dump($a == $b, $a === $b);
var_dump($a instanceof $b);
// the classes are the same
var_dump($a instanceof foo);
var_dump($a instanceof bar);
var_dump($b instanceof foo);
var_dump($b instanceof bar);
?>
See also class_alias.
Custom Class Usage
[Since 0.8.4] - [ -P Classes/AvoidUsing ] - [ Online docs ]
List of usage of custom classes throughout the code.
ext/apache
[Since 0.8.4] - [ -P Extensions/Extapache ] - [ Online docs ]
Extension Apache.
These functions are only available when running PHP as an Apache module.
<?php
$ret = apache_getenv(SERVER_ADDR);
echo $ret;
?>
See also Extension Apache and Apache server.
ext/eaccelerator
[Since 0.8.4] - [ -P Extensions/Exteaccelerator ] - [ Online docs ]
Extension Eaccelerator.
eAccelerator is a free open-source PHP accelerator & optimizer.
See also Eaccelerator and eaccelerator/eaccelerato.
ext/fpm
[Since 0.8.4] - [ -P Extensions/Extfpm ] - [ Online docs ]
Extension FPM, FastCGI Process Manager.
FPM (FastCGI Process Manager) is an alternative PHP FastCGI implementation with some additional features (mostly) useful for heavy-loaded sites.
<?php
echo $text;
fastcgi_finish_request( );
?>
See also FastCGI Process Manager.
ext/iis
[Since 0.8.4] - [ -P Extensions/Extiis ] - [ Online docs ]
Extension IIS Administration.
It provides functions to administrate Microsoft Internet Information Server (IIS).
<?php
$path = iis_get_server_by_path('/path/to/root/folder/')
?>
This extension is available for Windows only.
See also IIS Administration.
ext/xcache
[Since 0.8.4] - [ -P Extensions/Extxcache ] - [ Online docs ]
Extension Xcache.
XCache is a open-source opcode cacher, which means that it accelerates the performance of PHP on servers.
<?php
if (!xcache_isset(count)) {
xcache_set(count, load_count_from_mysql());
}
?>
This guest book has been visited
<?php
echo $count = xcache_inc(count); ?> times.
<?php
// save every 100 hits
if (($count % 100) == 0) {
save_count_to_mysql($count);
}
?>
See also xcache.
ext/wincache
[Since 0.8.4] - [ -P Extensions/Extwincache ] - [ Online docs ]
Extension Wincache.
The Wincache extension for PHP is a PHP accelerator that is used to increase the speed of PHP applications running on Windows and Windows Server.
<?php
$fp = fopen('/tmp/lock.txt', 'r+');
if (wincache_lock(“lock_txt_lock”)) { // do an exclusive lock
ftruncate($fp, 0); // truncate file
fwrite($fp, 'Write something here\n');
wincache_unlock(“lock_txt_lock”); // release the lock
} else {
echo 'Couldn't get the lock!';
}
fclose($fp);?>
See also WinCache Extension for PHP.
parse_str() Warning
[Since 0.8.4] - [ -P Security/parseUrlWithoutParameters ] - [ Online docs ]
The parse_str() function parses a query string and assigns the resulting variables to the local scope. This may create a unexpected number of variables, and even overwrite the existing one.
<?php
function foo( ) {
global $a;
echo $a;
}
parse_str('a=1'); // No second parameter
foo( );
// displays 1
?>
Always use an empty variable a second parameter to parse_str(), so as to collect the incoming values, and then, filter them in that array.
No Direct Call To Magic Method
[Since 0.8.4] - [ -P Classes/DirectCallToMagicMethod ] - [ Online docs ]
PHP features magic methods, which are methods related to operators.
Magic methods, such as __get(), related to =, or __clone(), related to clone , are supposed to be used in an object environment, and not with direct call.
It is recommended to use the magic method with its intended usage, and not to call it directly. For example, typecast to string instead of calling the __toString() method.
<?php
// Write
print $x->a;
// instead of
print $x->__get('a');
class Foo {
private $b = secret;
public function __toString() {
return strtoupper($this->b);
}
}
$bar = new Foo();
echo (string) $bar;
?>
Accessing those methods in a static way is also discouraged.
See also Magic Methods and
Magical PHP: __call.
String May Hold A Variable
[Since 0.8.4] - [ -P Type/StringHoldAVariable ] - [ Online docs ]
Those strings looks like holding a variable.
Single quotes and Nowdoc syntax may include $ signs that are treated as literals, and not replaced with a variable value.
However, there are some potential variables in those strings, making it possible for an error : the variable was forgotten and will be published as such. It is worth checking the content and make sure those strings are not variables.
<?php
$a = 2;
// Explicit variable, but literal effect is needed
echo '$a is '.$a;
// One of the variable has been forgotten
echo '$a is $a';
// $CAD is not a variable, rather a currency unit
$total = 12;
echo $total.' $CAD';
// $CAD is not a variable, rather a currency unit
$total = 12;
// Here, $total has been forgotten
echo <<<'TEXT'
$total $CAD
TEXT;
?>
Echo With Concat
[Since 0.8.4] - [ -P Structures/EchoWithConcat ] - [ Online docs ]
Optimize your echo 's by not concatenating at echo time, but serving all argument separated. This will save PHP a memory copy.
If values, literals and variables, are small enough, this won't have visible impact. Otherwise, this is less work and less memory waste.
<?php
echo $a, ' b ', $c;
?>
instead of
<?php
echo $a . ' b ' . $c;
echo $a b $c;
?>
Unused Global
[Since 0.8.4] - [ -P Structures/UnusedGlobal ] - [ Online docs ]
A global keyword is used in a method, yet the variable is not actually used. This makes PHP import values for nothing, or may create interference
<?php
function foo() {
global bar;
return 1;
}
?>
Useless Global
[Since 0.8.4] - [ -P Structures/UselessGlobal ] - [ Online docs ]
Global are useless in two cases. First, on super-globals, which are always globals, like $_GET; secondly, on variables that are not used.
<?php
// $_POST is already a global : it is in fact a global everywhere
global $_POST;
// $unused is useless
function foo() {
global $used, $unused;
++$used;
}
?>
Also, PHP has superglobals, a special team of variables that are always available, whatever the context.
They are : $GLOBALS, $_SERVER, $_GET, $_POST, $_FILES, $_COOKIE, $_SESSION, $_REQUEST and $_ENV.
Preprocessable
[Since 0.8.4] - [ -P Structures/ShouldPreprocess ] - [ Online docs ]
The following expression are made of literals or already known values : they may be fully calculated before running PHP.
<?php
// Building an array from a string
$name = 'PHP'.' '.'7.2';
// Building an array from a string
$list = explode(',', 'a,b,c,d,e,f');
// Calculating a power
$kbytes = $bytes / pow(2, 10);
// This will never change
$name = ucfirst(strtolower('PARIS'));
?>
By doing so, this will reduce the amount of work of PHP.
Slow Functions
[Since 0.8.4] - [ -P Performances/SlowFunctions ] - [ Online docs ]
Avoid using those slow native PHP functions, and replace them with alternatives.
<?php
$array = source();
// Slow extraction of distinct values
$array = array_unique($array);
// Much faster extraction of distinct values
$array = array_keys(array_count_values($array));
?>
| Slow Function | Faster | ||
| array_diff() | foreach() | ||
| array_intersect() | foreach() | ||
| array_key_exists() | isset() and array_key_exists() | ||
| array_map() | foreach() | ||
| array_search() | array_flip() and isset() | ||
| array_udiff() | Use another way | ||
| array_uintersect() | Use another way | ||
| array_unshift() | Use another way | ||
| array_walk() | foreach() | ||
| in_array() | isset() | ||
| preg_replace() | strpos() | ||
| strstr() | strpos() | ||
| uasort() | Use another way | ||
| uksort() | Use another way | ||
| usort() | Use another way | ||
| array_unique() | array_keys() and array_count_values() |
array_key_exists() has been accelerated in PHP 7.4 and may be used directly from this version on : Implement ZEND_ARRAY_KEY_EXISTS opcode to speed up `array_key_exists()
Useless Final
[Since 0.8.4] - [ -P Classes/UselessFinal ] - [ Online docs ]
When a class is declared final, all of its methods are also final by default.
There is no need to declare them individually final.
<?php
final class foo {
// Useless final, as the whole class is final
final function method() { }
}
class bar {
// Useful final, as the whole class is not final
final function method() { }
}
?>
See also Final Keyword, and When to declare final.
Use Constant
[Since 0.8.4] - [ -P Structures/UseConstant ] - [ Online docs ]
The following functioncall have a constant equivalent, that is faster to use than calling the functions.
This applies to the following functions :
- pi() : replace with `M_PI`
- phpversion() : replace with `PHP_VERSION`
- php_sapi_name() : replace with `PHP_SAPI_NAME`
<?php
// recommended way
echo PHP_VERSION;
// slow version
echo php_version();
?>
See also PHP why `pi() and M_PI
Resources Usage
[Since 0.8.4] - [ -P Structures/ResourcesUsage ] - [ Online docs ]
List of situations that are creating resources.
<?php
// This functioncall creates a resource to use
$fp = fopen('/tmp/file.txt', 'r');
if (!is_resource($fp)){
thrown new RuntimeException('Could not open file.txt');
}
?>
Useless Unset
[Since 0.8.4] - [ -P Structures/UselessUnset ] - [ Online docs ]
There are situations where trying to remove a variable is actually useless.
PHP ignores any command that tries to unset a global variable, a static variable, or a blind variable from a foreach loop.
This is different from the garbage collector, which is run on its own schedule. It is also different from an explicit unset, aimed at freeing memory early : those are useful.
<?php
function foo($a) {
// unsetting arguments is useless
unset($a);
global $b;
// unsetting global variable has no effect
unset($b);
static $c;
// unsetting static variable has no effect
unset($c);
foreach($d as &$e){
// unsetting a blind variable is useless
(unset) $e;
}
// Unsetting a blind variable AFTER the loop is good.
unset($e);
}
?>
See also unset.
Buried Assignation
[Since 0.8.4] - [ -P Structures/BuriedAssignation ] - [ Online docs ]
Those assignations are buried in the code, and placed in unexpected situations.
They are difficult to spot, and may be confusing. It is advised to place them in a more visible place.
<?php
// $b may be assigned before processing $a
$a = $c && ($b = 2);
// Display property p immeiately, but also, keeps the object for later
echo ($o = new x)->p;
// legit syntax, but the double assignation is not obvious.
for($i = 2, $j = 3; $j < 10; $j++) {
}
?>
No array_merge() In Loops
[Since 0.8.4] - [ -P Performances/ArrayMergeInLoops ] - [ Online docs ]
array_merge() is memory intensive : every call will duplicate the arguments in memory, before merging them.
To handle arrays that may be quite big, it is recommended to avoid using array_merge() in a loop. Instead, one should use array_merge() with as many arguments as possible, making the merge a on time call.
<?php
// A large multidimensional array
$source = ['a' => ['a', 'b', /*...*/],
'b' => ['b', 'c', 'd', /*...*/],
/*...*/
];
// Faster way
$b = array();
foreach($source as $key => $values) {
//Collect in an array
$b[] = $values;
}
// One call to array_merge
$b = call_user_func_array('array_merge', $b);
// or with variadic
$b = call_user_func('array_merge', ..$b);
// Fastest way (with above example, without checking nor data pulling)
$b = call_user_func_array('array_merge', array_values($source))
// or
$b = call_user_func('array_merge', ...array_values($source))
// Slow way to merge it all
$b = array();
foreach($source as $key => $values) {
$b = array_merge($b, $values);
}
?>
Note that array_merge_recursive() and file_put_contents() are affected and reported the same way.
Useless Parenthesis
[Since 0.8.4] - [ -P Structures/UselessParenthesis ] - [ Online docs ]
Situations where parenthesis are not necessary, and may be removed.
Parenthesis group several elements together, and allows for a more readable expression. They are used with logical and mathematical expressions. They are necessary when the precedence of the operators are not the intended execution order : for example, when an addition must be performed before the multiplication.
Sometimes, the parenthesis provide the same execution order than the default order : they are deemed useless.
<?php
if ( ($condition) ) {}
while( ($condition) ) {}
do $a++; while ( ($condition) );
switch ( ($a) ) {}
$y = (1);
($y) == (1);
f(($x));
// = has precedence over ==
($a = $b) == $c;
($a++);
// No need for parenthesis in default values
function foo($c = ( 1 + 2) ) {}
?>
See also Operators Precedence.
Shell Usage
[Since 0.8.4] - [ -P Structures/ShellUsage ] - [ Online docs ]
List of shell calls to system.
<?php
// Using backtick operator
$a = `ls -hla`;
// Using one of PHP native or extension functions
$a = shell_exec('ls -hla');
$b = \pcntl_exec('/path/to/command');
?>
See also shell_exec and
Execution Operators.
File Usage
[Since 0.8.4] - [ -P Structures/FileUsage ] - [ Online docs ]
The application makes usage of files on the system (read, write, delete, etc.).
Files usage is based on the usage of file functions.
<?php
$fp = fopen('/tmp/file.txt', 'w+');
// ....
?>
See also filesystem.
Mail Usage
[Since 0.8.4] - [ -P Structures/MailUsage ] - [ Online docs ]
Report usage of mail from PHP.
The analysis is based on mail() function and various classes used to send mail.
<?php
// The message
$message = Line 1\r\nLine 2\r\nLine 3;
// In case any of our lines are larger than 70 characters, we should use `wordwrap() <https://www.php.net/wordwrap>`_
$message = wordwrap($message, 70, \r\n);
// Send
mail('caffeinated@example.com', 'My Subject', $message);
?>
See also mail.
Dynamic Calls
[Since 0.8.4] - [ -P Structures/DynamicCalls ] - [ Online docs ]
List of dynamic calls. They will probably need to be review manually.
<?php
$a = 'b';
// Dynamic call of a constant
echo constant($a);
// Dynamic variables
$$a = 2;
echo $b;
// Dynamic call of a function
$a('b');
// Dynamic call of a method
$object->$a('b');
// Dynamic call of a static method
A::$a('b');
?>
See also Variable functions.
Unresolved Instanceof
[Since 0.8.4] - [ -P Classes/UnresolvedInstanceof ] - [ Online docs ]
The instanceof operator doesn't confirm if the compared class exists.
It checks if an variable is of a specific class. However, if the referenced class doesn't exist, because of a bug, a missed inclusion or a typo, the operator always fails, without a warning.
<?php
namespace X {
class C {}
// This is OK, as C is defined in X
if ($o instanceof C) { }
// This is not OK, as C is not defined in global
// instanceof respects namespaces and use expressions
if ($o instanceof \C) { }
// This is not OK, as undefinedClass
if ($o instanceof undefinedClass) { }
// This is not OK, as $class is now a full namespace. It actually refers to \c, which doesn't exist
$class = 'C';
if ($o instanceof $class) { }
}
?>
Make sure the following classes are well defined.
See also Instanceof.
Use PHP Object API
[Since 0.8.4] - [ -P Php/UseObjectApi ] - [ Online docs ]
OOP API is the modern version of the PHP API.
When PHP offers the alternative between procedural and OOP api for the same features, it is recommended to use the OOP API.
Often, this least to more compact code, as methods are shorter, and there is no need to bring the resource around. Lots of new extensions are directly written in OOP form too.
OOP / procedural alternatives are available for mysqli, tidy, cairo, finfo, and some others.
<?php
/// OOP version
$mysqli = new mysqli(localhost, my_user, my_password, world);
/* check connection */
if ($mysqli->connect_errno) {
printf(Connect failed: %s\n, $mysqli->connect_error);
exit();
}
/* Create table doesn't return a resultset */
if ($mysqli->query(CREATE TEMPORARY TABLE myCity LIKE City) === TRUE) {
printf(Table myCity successfully created.\n);
}
/* Select queries return a resultset */
if ($result = $mysqli->query(SELECT Name FROM City LIMIT 10)) {
printf(Select returned %d rows.\n, $result->num_rows);
/* free result set */
$result->close();
}
?>
<?php
/// Procedural version
$link = mysqli_connect(localhost, my_user, my_password, world);
/* check connection */
if (mysqli_connect_errno()) {
printf(Connect failed: %s\n, mysqli_connect_error());
exit();
}
/* Create table doesn't return a resultset */
if (mysqli_query($link, CREATE TEMPORARY TABLE myCity LIKE City) === TRUE) {
printf(Table myCity successfully created.\n);
}
?>
Unthrown Exception
[Since 0.8.4] - [ -P Exceptions/Unthrown ] - [ Online docs ]
These are exceptions that are defined in the code but never thrown.
<?php
//This exception is defined but never used in the code.
class myUnusedException extends \Exception {}
//This exception is defined and used in the code.
class myUsedException extends \Exception {}
throw new myUsedException('I was called');
?>
See also Exceptions.
Old Style __autoload()
[Since 0.8.4] - [ -P Php/oldAutoloadUsage ] - [ Online docs ]
Avoid __autoload(), only use spl_register_autoload().
__autoload() is deprecated since PHP 7.2 and possibly removed in later versions. spl_register_autoload() was introduced in PHP 5.1.0.
__autoload() may only be declared once, and cannot be modified later. This creates potential conflicts between libraries that try to set up their own autoloading schema.
On the other hand, spl_register_autoload() allows registering and de-registering multiple autoloading functions or methods.
<?php
// Modern autoloading.
function myAutoload($class){}
spl_register_autoload('myAutoload');
// Old style autoloading.
function __autoload($class){}
?>
Do not use the old __autoload() function, but rather the new spl_register_autoload() function.
See also Autoloading Classe.
Altering Foreach Without Reference
[Since 0.8.4] - [ -P Structures/AlteringForeachWithoutReference ] - [ Online docs ]
Foreach() loop that should use a reference.
When using a foreach loop that modifies the original source, it is recommended to use referenced variables, rather than access the original value with $source[$index].
Using references is then must faster, and easier to read.
<?php
// Using references in foreach
foreach($source as $key => &$value) {
$value = newValue($value, $key);
}
// Avoid foreach : use array_map
$source = array_walk($source, 'newValue');
// Here, $key MUST be the second argument or newValue
// Slow version to update the array
foreach($source as $key => &$value) {
$source[$key] = newValue($value, $key);
}
?>
You may also use array_walk() or array_map() (when $key is not used) to avoid the use of foreach.
See also foreach.
Test Class
[Since 0.8.4] - [ -P Classes/TestClass ] - [ Online docs ]
Those are test classes, based on popular UT frameworks.
Mark Callable
[Since 0.8.4] - [ -P Functions/MarkCallable ] - [ Online docs ]
Create an attribute that guess what are the called function or methods, when possible.
Magic Visibility
[Since 0.8.4] - [ -P Classes/toStringPss ] - [ Online docs ] - [ PHP older than 5.4]
The class magic methods must have public visibility and cannot be static.
<?php
class foo{
// magic method must bt public and non-static
public static function __clone($name) { }
// magic method can't be private
private function __get($name) { }
// magic method can't be protected
private function __set($name, $value) { }
// magic method can't be static
public static function __isset($name) { }
}
?>
See also Magic methods.
Use Pathinfo
[Since 0.8.4] - [ -P Php/UsePathinfo ] - [ Online docs ]
Use pathinfo() function instead of string manipulations.
pathinfo() is more efficient and readable and string functions.
<?php
$filename = '/path/to/file.php';
// With `pathinfo() <https://www.php.net/pathinfo>`_;
$details = pathinfo($filename);
print $details['extension']; // also capture php
// With string functions (other solutions possible)
$ext = substr($filename, - strpos(strreverse($filename), '.')); // Capture php
?>
When the path contains UTF-8 characters, pathinfo() may strip them. There, string functions are necessary.
Should Use Constants
[Since 0.8.4] - [ -P Functions/ShouldUseConstants ] - [ Online docs ]
The following functions have related constants that should be used as arguments, instead of scalar literals, such as integers or strings.
<?php
// The file is read and new lines are ignored.
$lines = file('file.txt', FILE_IGNORE_NEW_LINES)
// What is this doing, with 2 ?
$lines = file('file.txt', 2);
?>
See also Bitmask Constant Arguments in PHP.
Hash Algorithms
[Since 0.8.4] - [ -P Php/HashAlgos ] - [ Online docs ]
There is a long but limited list of hashing algorithm available to PHP. The one found doesn't seem to be existing.
<?php
// This hash has existed in PHP. Check with hash_algos() if it is available on your system.
echo hash('ripmed160', 'The quick brown fox jumped over the lazy dog.');
// This hash doesn't exist
echo hash('ripemd160', 'The quick brown fox jumped over the lazy dog.');
?>
See also hash_algos.
Avoid Those Hash Functions
[Since 0.8.4] - [ -P Security/AvoidThoseCrypto ] - [ Online docs ]
The following cryptographic algorithms are considered insecure, and should be replaced with new and more performent algorithms.
MD2 , MD4 , MD5 , SHA0 , SHA1 , CRC , DES , 3DES , RC2 , RC4 .
When possible, avoid using them, may it be as PHP functions, or hashing function configurations (mcrypt, hash...).
<?php
// Weak cryptographic algorithm
echo md5('The quick brown fox jumped over the lazy dog.');
// Weak crypotgraphic algorthim, used with a modern PHP extension (easier to update)
echo hash('md5', 'The quick brown fox jumped over the lazy dog.');
// Strong crypotgraphic algorthim, used with a modern PHP extension
echo hash('sha156', 'The quick brown fox jumped over the lazy dog.');
?>
Weak cryptography is commonly used for hashing values when caching them. In such cases, security is not a primary concern. However, it may later become such, when hackers get access to the cache folders, or if the cached identifier is published. As a preventive protection, it is recommended to always use a secure hashing function.
See also Secure Hash Algorithms.
ext/dio
[Since 0.8.4] - [ -P Extensions/Extdio ] - [ Online docs ]
Extension DIO : Direct Input Output.
PHP supports the direct io functions as described in the Posix Standard (Section 6) for performing I/O functions at a lower level than the C-Language stream I/O functions
<?php
$fd = dio_open('/dev/ttyS0', O_RDWR | O_NOCTTY | O_NONBLOCK);
dio_close($fd);
?>
See also DIO.
No Parenthesis For Language Construct
[Since 0.8.4] - [ -P Structures/NoParenthesisForLanguageConstruct ] - [ Online docs ]
Some PHP language constructs, such are include , print , echo don't need parenthesis. They accept parenthesis, but it is may lead to strange situations.
<?php
// This is an attempt to load 'foo.inc', or kill the script
include('foo.inc') or die();
// in fact, this is read by PHP as : include 1
// include 'foo.inc' or die();
?>
It it better to avoid using parenthesis with echo , print , return , throw , yield , yield from , include , require , include_once , require_once .
See also include.
Unused Label
[Since 0.8.4] - [ -P Structures/UnusedLabel ] - [ Online docs ]
Some labels have been defined in the code, but they are not used. They may be removed as they are dead code.
<?php
$a = 0;
A:
++$a;
// A loop. A: is used
if ($a < 10) { goto A; }
// B is never called explicitely. This is useless.
B:
?>
There is no analysis for undefined goto call, as PHP checks that goto has a destination label at compile time :
See also Goto.
No Hardcoded Path
[Since 0.8.4] - [ -P Structures/NoHardcodedPath ] - [ Online docs ]
It is not recommended to use hardcoded literals when designating files. Full paths are usually tied to one file system organization. As soon as the organisation changes or must be adapted to any external constraint, the path is not valid anymore.
Either use __FILE__ and __DIR__ to make the path relative to the current file; use a DOC_ROOT as a configuration constant that will allow the moving of the script to another folder; finally functions like sys_get_temp_dir() produce a viable temporary folder.
Relative paths are relative to the current execution directory, and not the current file. This means they may differ depending on the location of the start of the application, and are sensitive to chdir() and chroot() usage.
<?php
// This depends on the current executed script
file_get_contents('token.txt');
// Exotic protocols are ignored
file_get_contents('jackalope://file.txt');
// Some protocols are ignored : http, https, ftp, ssh2, php (with memory)
file_get_contents('http://www.php.net/');
file_get_contents('php://memory/');
// `glob() <https://www.php.net/glob>`_ with special chars * and ? are not reported
glob('./*/foo/bar?.txt');
// `glob() <https://www.php.net/glob>`_ without special chars * and ? are reported
glob('/foo/bar/');
?>
Methodcall On New
[Since 0.8.4] - [ -P Php/MethodCallOnNew ] - [ Online docs ] - [ PHP 5.4 and more recent ]
It is possible to call a method right at object instantiation.
This syntax was added in PHP 5.4+. Before, this was not possible : the object had to be stored in a variable first.
<?php
// Data is collected
$data = data_source();
// Data is saved, but won't be reused from this databaseRow object. It may be ignored.
$result = (new databaseRow($data))->save();
// The actual result of the save() is collected and tested.
if ($result !== true) {
processSaveError($data);
}
?>
This syntax is interesting when the object is not reused, and may be discarded
No Hardcoded Port
[Since 0.8.4] - [ -P Structures/NoHardcodedPort ] - [ Online docs ]
When connecting to a remove server, port is an important information. It is recommended to make this configurable (with constant or configuration), to as to be able to change this value without changing the code.
<?php
// Both configurable IP and hostname
$connection = ssh2_connect($_ENV['SSH_HOST'], $_ENV['SSH_PORT'], $methods, $callbacks);
// Both hardcoded IP and hostname
$connection = ssh2_connect('shell.example.com', 22, $methods, $callbacks);
if (!$connection) die('Connection failed');
?>
ext/phalcon
[Since 0.8.4] - [ -P Extensions/Extphalcon ] - [ Online docs ]
Extension Phalcon : High Performance PHP Framework.
Phalcon's autoload examples from the docs : Tutorial 1: Let’s learn by example
<?php
use Phalcon\Loader;
// ...
$loader = new Loader();
$loader->registerDirs(
[
../app/controllers/,
../app/models/,
]
);
$loader->register();
?>
See also PhalconPHP.
Use Constant As Arguments
[Since 0.8.4] - [ -P Functions/UseConstantAsArguments ] - [ Online docs ]
Some methods and functions are defined to be used with constants as arguments. Those constants are made to be meaningful and readable, keeping the code maintenable. It is recommended to use such constants as soon as they are documented.
<?php
// Turn off all error reporting
// 0 and -1 are accepted
error_reporting(0);
// Report simple running errors
error_reporting(E_ERROR | E_WARNING | E_PARSE);
// The first argument can be one of INPUT_GET, INPUT_POST, INPUT_COOKIE, INPUT_SERVER, or INPUT_ENV.
$search_html = filter_input(INPUT_GET, 'search', FILTER_SANITIZE_SPECIAL_CHARS);
// sort accepts one of SORT_REGULAR, SORT_NUMERIC, SORT_STRING, SORT_LOCALE_STRING, SORT_NATURAL
// SORT_FLAG_CASE may be added, and combined with SORT_STRING or SORT_NATURAL
sort($fruits);
?>
Here is the list of function that use a unique PHP constant as argument :
+ array_change_key_case()
+ array_multisort()
+ array_unique()
+ count()
+ dns_get_record()
+ easter_days()
+ extract()
+ filter_input()
+ filter_var()
+ fseek()
+ get_html_translation_table()
+ gmp_div_q()
+ gmp_div_qr()
+ gmp_div_r()
+ html_entity_decode()
+ htmlspecialchars_decode()
+ http_build_query()
+ http_parse_cookie()
+ http_parse_params()
+ http_redirect()
+ http_support()
+ parse_ini_file()
+ parse_ini_string()
+ parse_url()
+ pathinfo()
+ pg_select()
+ posix_access()
+ round()
+ scandir()
+ socket_read()
+ str_pad()
+ trigger_error()
Here is the list of functions that use a combination of PHP native functions as argument.
+ arsort()
+ asort()
+ error_reporting()
+ filter_input()
+ filter_var()
+ get_html_translation_table()
+ htmlentities()
+ htmlspecialchars()
+ http_build_url()
+ jdtojewish()
+ krsort()
+ ksort()
+ pg_result_status()
+ phpcredits()
+ phpinfo()
+ preg_grep()
+ preg_match()
+ preg_split()
+ rsort()
+ runkit_import()
+ sort()
+ stream_socket_client()
+ stream_socket_server()
Implied If
[Since 0.8.4] - [ -P Structures/ImpliedIf ] - [ Online docs ]
It is confusing to emulate if/then with boolean operators.
It is possible to emulate a if/then structure by using the operators 'and' and 'or'. Since optimizations will be applied to them :
when the left operand of 'and' is false, the right one is not executed, as its result is useless;
when the left operand of 'or' is true, the right one is not executed, as its result is useless;
However, such structures are confusing. It is easy to misread them as conditions, and ignore an important logic step.
<?php
// Either connect, or die
mysql_connect('localhost', $user, $pass) or die();
// Defines a constant if not found.
defined('SOME_CONSTANT') and define('SOME_CONSTANT', 1);
// Defines a default value if provided is empty-ish
// Warning : this is
$user = $_GET['user'] || 'anonymous';
?>
It is recommended to use a real 'if then' structures, to make the condition readable.
Overwritten Literals
[Since 0.8.4] - [ -P Variables/OverwrittenLiterals ] - [ Online docs ]
The same variable is assigned a literal twice. It is possible that one of the assignation is too much.
This analysis doesn't take into account the distance between two assignations : it may report false positives when the variable is actually used for several purposes, and, as such, assigned twice with different values.
<?php
function foo() {
// Two assignations in a short sequence : one is too many.
$a = 1;
$a = 2;
for($i = 0; $i < 10; $i++) {
$a += $i;
}
$b = $a;
// New assignation. $a is now used as an array.
$a = array(0);
}
?>
Assign Default To Properties
[Since 0.8.4] - [ -P Classes/MakeDefault ] - [ Online docs ]
Properties may be assigned default values at declaration time. Such values may be later modified, if needed.
<?php
class foo {
private $propertyWithDefault = 1;
private $propertyWithoutDefault;
private $propertyThatCantHaveDefault;
public function __construct() {
// Skip this extra line, and give the default value above
$this->propertyWithoutDefault = 1;
// Static expressions are available to set up simple computation at definition time.
$this->propertyWithoutDefault = OtherClass::CONSTANT + 1;
// Arrays, just like scalars, may be set at definition time
$this->propertyWithoutDefault = [1,2,3];
// Objects or resources can't be made default. That is OK.
$this->propertyThatCantHaveDefault = fopen('/path/to/file.txt');
$this->propertyThatCantHaveDefault = new Fileinfo();
}
}
?>
Default values will save some instructions in the constructor, and makes the value obvious in the code.
No Public Access
[Since 0.8.4] - [ -P Classes/NoPublicAccess ] - [ Online docs ]
The properties below are declared with public access, but are never used publicly. They can be made protected or private.
<?php
class foo {
public $bar = 1; // Public, and used in public space
public $neverInPublic = 3; // Public, but never used in outside the class
function bar() {
$neverInPublic++;
}
}
$x = new foo();
$x->bar = 3;
$x->bar();
?>
Composer Usage
[Since 0.8.4] - [ -P Composer/UseComposer ] - [ Online docs ]
Mark the usage of composer, mostly by having a composer.json file.
Composer's autoload
[Since 0.8.4] - [ -P Composer/Autoload ] - [ Online docs ]
Is this code using the autoload from Composer.
Composer Namespace
[Since 0.8.4] - [ -P Composer/IsComposerNsname ] - [ Online docs ]
Mark this namespace as a Composer namespace.
When the namespace is found in the composer database, it is marked as such.
<?php
namespace Monolog;
use Monolog\Processor\WebProcessor;
use Monolog\Handler\TestHandler;
class MyLogger extends WebProcessor {
/**/
}
?>
See also Packagist.
Should Chain Exception
[Since 0.8.4] - [ -P Structures/ShouldChainException ] - [ Online docs ]
Chain exception to provide more context.
When catching an exception and rethrowing another one, it is recommended to chain the exception : this means providing the original exception, so that the final recipient has a chance to track the origin of the problem. This doesn't change the thrown message, but provides more information.
Note : Chaining requires PHP > 5.3.0.
<?php
try {
throw new Exception('Exception 1', 1);
} catch (\Exception $e) {
throw new Exception('Exception 2', 2, $e);
// Chaining here.
}
?>
See also Exception::__construct and
What are the best practices for catching and re-throwing exceptions?.
Unused Interfaces
[Since 0.8.4] - [ -P Interfaces/UnusedInterfaces ] - [ Online docs ]
Those interfaces are defined and never used. They should be removed, as they are dead code.
Interfaces may be use as parent for other interfaces, as typehint (argument, return and property), in instance of.
<?php
interface used {}
interface unused {}
// Used by implementation
class c implements used {}
// Used by extension
interface j implements used {}
$x = new c;
// Used in a instanceof
var_dump($x instanceof used);
// Used in a typehint
function foo(Used $x) {}
?>
Useless Interfaces
[Since 0.8.4] - [ -P Interfaces/UselessInterfaces ] - [ Online docs ]
The interfaces below are defined and are implemented by some classes.
However, they are never used to enforce an object's class in the code, using instanceof or in a typehint.
As they are currently used, those interfaces may be removed without change in behavior.
<?php
// only defined interface but never enforced
interface i {};
class c implements i {}
?>
Interfaces should be used in Typehint or with the instanceof operator.
<?php
interface i {};
function foo(i $arg) {
// Now, $arg is always an 'i'
}
function bar($arg) {
if (!($arg instanceof i)) {
// Now, $arg is always an 'i'
}
}
?>
Undefined Interfaces
[Since 0.8.4] - [ -P Interfaces/UndefinedInterfaces ] - [ Online docs ]
Some typehints or instanceof that are relying on undefined interfaces or classes. They will always return false. Any condition based upon them are dead code.
<?php
class var implements undefinedInterface {
// If undefinedInterface is undefined, this code lints but doesn't run
}
if ($o instanceof undefinedInterface) {
// This is silent dead code
}
function foo(undefinedInterface $a) {
// This is dead code
// it will probably be discovered at execution
}
?>
See also Object interfaces,
Type declarations, and
Instanceof.
Concrete Visibility
[Since 0.8.4] - [ -P Interfaces/ConcreteVisibility ] - [ Online docs ]
Methods that implements an interface in a class must be public.
PHP does lint this, unless the interface and the class are in the same file. At execution, it stops immediately with a Fatal error : 'Access level to c::iPrivate() must be public (as in class i) ';
<?php
interface i {
function iPrivate() ;
function iProtected() ;
function iPublic() ;
}
class c implements i {
// Methods that implements an interface in a class must be public.
private function iPrivate() {}
protected function iProtected() {}
public function iPublic() {}
}
?>
See also Interfaces.
ext/apcu
[Since 0.8.4] - [ -P Extensions/Extapcu ] - [ Online docs ]
Extension APCU .
APCu is APC stripped of opcode caching. The Alternative PHP Cache (APC) is a free and open opcode cache for PHP. Its goal is to provide a free, open, and robust framework for caching and optimizing PHP intermediate code.
<?php
$bar = 'BAR';
apcu_add('foo', $bar);
var_dump(apcu_fetch('foo'));
echo \n;
$bar = 'NEVER GETS SET';
apcu_add('foo', $bar);
var_dump(apcu_fetch('foo'));
echo \n;
?>
See also APCU,
ext/apcu and
krakjoe/apcu.
Double Instructions
[Since 0.8.4] - [ -P Structures/DoubleInstruction ] - [ Online docs ]
Twice the same call in a row. This is worth a check.
<?php
// repetition of the same command, with the same effect each time.
$a = array_merge($b, $c);
$a = array_merge($b, $c);
// false positive : commands are identical, but the effect is compounded
$a = array_merge($a, $c);
$a = array_merge($a, $c);
?>
Should Use Prepared Statement
[Since 0.8.4] - [ -P Security/ShouldUsePreparedStatement ] - [ Online docs ]
Modern databases provides support for prepared statement : it separates the query from the processed data and raise significantly the security.
Building queries with concatenations is not recommended, though not always avoidable. When possible, use prepared statements.
<?php
/* Execute a prepared statement by passing an array of values */
$sql = 'SELECT name, colour, calories
FROM fruit
WHERE calories < :calories AND colour = :colour';
$sth = $conn->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
$sth->execute(array(':calories' => 150, ':colour' => 'red'));
$red = $sth->fetchAll();
?>
Same code, without preparation :
<?php
$sql = 'SELECT name, color, calories FROM fruit WHERE calories < '.$conn-quote(150).' AND colour = '.$conn->quotes('red').' ORDER BY name';
$sth = $conn->query($sql) as $row);
}
?>
See also Prepared Statements,
PHP MySQLi Prepared Statements Tutorial to Prevent SQL Injection,
The Best Way to Perform MYSQLI Prepared Statements in PHP.
Hash Algorithms Incompatible With PHP 5.3
[Since 0.8.4] - [ -P Php/HashAlgos53 ] - [ Online docs ]
List of hash algorithms incompatible with PHP 5.3.
<?php
// Compatible only with 5.3 and more recent
echo hash('md2', 'The quick brown fox jumped over the lazy dog.');
// Always compatible
echo hash('ripemd320', 'The quick brown fox jumped over the lazy dog.');
?>
See also hash_algos.
Hash Algorithms Incompatible With PHP 5.4/5.5
[Since 0.8.4] - [ -P Php/HashAlgos54 ] - [ Online docs ] - [ PHP older than 5.4]
List of hash algorithms incompatible with PHP 5.4 and 5.5.
<?php
// Compatible only with 5.4 and more recent
echo hash('fnv132', 'The quick brown fox jumped over the lazy dog.');
// Always compatible
echo hash('ripemd320', 'The quick brown fox jumped over the lazy dog.');
?>
See also hash_algos.
Print And Die
[Since 0.8.4] - [ -P Structures/PrintAndDie ] - [ Online docs ]
Die() also prints.
When stopping a script with die(), it is possible to provide a message as first argument, that will be displayed at execution. There is no need to make a specific call to print or echo.
<?php
// die may do both print and die.
echo 'Error message';
die();
// exit may do both print and die.
print 'Error message';
exit;
// exit cannot print integers only : they will be used as status report to the system.
print 'Error message';
exit 1;
?>
Unchecked Resources
[Since 0.8.4] - [ -P Structures/UncheckedResources ] - [ Online docs ]
Resources are created, but never checked before being used. This is not safe.
Always check that resources are correctly created before using them.
<?php
// always check that the resource is created correctly
$fp = fopen($d,'r');
if ($fp === false) {
throw new Exception('File not found');
}
$firstLine = fread($fp);
// This directory is not checked : the path may not exist and return false
$uncheckedDir = opendir($pathToDir);
while(readdir($uncheckedDir)) {
// do something()
}
// This file is not checked : the path may not exist or be unreadable and return false
$fp = fopen($pathToFile);
while($line = freads($fp)) {
$text .= $line;
}
// unsafe one-liner : using bzclose on an unchecked resource
bzclose(bzopen('file'));
?>
See also resources.
Class Const With Array
[Since 0.8.4] - [ -P Php/ClassConstWithArray ] - [ Online docs ] - [ PHP 5.5 and more recent ]
Constant defined with const keyword may be arrays but only stating with PHP 5.6. Define never accept arrays : it only accepts scalar values.
ext/trader
[Since 0.8.4] - [ -P Extensions/Exttrader ] - [ Online docs ]
Extension trader.
The trader extension is a free open source stock library based on TA-Lib. It's dedicated to trading software developers requiring to perform technical analysis of financial market data.
<?php
// get_data() reads the data from a source
var_dump(trader_avgprice(
get_data(open, $data0),
get_data(high, $data0),
get_data(low, $data0),
get_data(close, $data0)
));
?>
See also trader, 'TA-lib
ext/mailparse
[Since 0.8.4] - [ -P Extensions/Extmailparse ] - [ Online docs ]
Extension mailparse.
Mailparse is an extension for parsing and working with email messages. It can deal with RFC 822 (MIME) and RFC 2045 (MIME) compliant messages.
<?php
$mail = mailparse_msg_create();
mailparse_msg_parse($mail, $mailInString);
$parts = mailparse_msg_get_structure($mail);
foreach($parts as $part) {
$section = mailparse_msg_get_part($mail, $part);
$info = mailparse_msg_get_part_data($section);
}
?>
See also Mailparse.
ext/mail
[Since 0.8.4] - [ -P Extensions/Extmail ] - [ Online docs ]
Extension for mail.
The mail() function allows you to send mail.
<?php
// The message
$message = "Line 1\r\nLine 2\r\nLine 3";
// In case any of our lines are larger than 70 characters, we should use `wordwrap() <https://www.php.net/wordwrap>`_
$message = wordwrap($message, 70, "\r\n");
// Send
mail('caffeinated@example.com', 'My Subject', $message);
?>
See also Mail related functions.
Unresolved Catch
[Since 0.8.4] - [ -P Classes/UnresolvedCatch ] - [ Online docs ]
Catch clauses do not check for Exception existence.
Catch clauses check that the emitted expression is of the requested Class, but if that class doesn't exist in the code, the catch clause is always false. This is dead code.
<?php
try {
// doSomething()
} catch {TypoedExxeption $e) { // Do not exist Exception
// Fix this exception
} catch {Stdclass $e) { // Exists, but is not an exception
// Fix this exception
} catch {Exception $e) { // Actual and effective catch
// Fix this exception
}
?>
No Hardcoded Ip
[Since 0.8.4] - [ -P Structures/NoHardcodedIp ] - [ Online docs ]
Do not leave hard coded IP in your code.
It is recommended to move such configuration in external files or databases, for each update.
This may also come handy when testing.
<?php
// This IPv4 is hardcoded.
$ip = '183.207.224.50';
// This IPv6 is hardcoded.
$ip = '2001:0db8:85a3:0000:0000:8a2e:0370:7334';
// This looks like an IP
$thisIsNotAnIP = '213.187.99.50';
$thisIsNotAnIP = '2133:1387:9393:5330';
?>
127.0.0.1 , ::1 and ::0 are omitted, and not considered as a violation.
See also Use of Hardcoded IPv4 Addresses and
Never hard code sensitive information.
Variable Global
[Since 0.8.3] - [ -P Structures/VariableGlobal ] - [ Online docs ] - [ PHP older than 7.0]
Variable global such are valid in PHP 5.6, but no in PHP 7.0. They should be replaced with ${$foo->bar}.
<?php
// Forbidden in PHP 7
global $normalGlobal;
// Forbidden in PHP 7
global $$variable->global ;
// Tolerated in PHP 7
global ${$variable->global};
?>
Else If Versus Elseif
[Since 0.8.4] - [ -P Structures/ElseIfElseif ] - [ Online docs ]
Always use elseif instead of else and if.
"The keyword elseif SHOULD be used instead of else if so that all control keywords look like single words". Quoted from the PHP-FIG documentation
<?php
// Using elseif
if ($a == 1) { doSomething(); }
elseif ($a == 2) { doSomethingElseIf(); }
else { doSomethingElse(); }
// Using else if
if ($a == 1) { doSomething(); }
else if ($a == 2) { doSomethingElseIf(); }
else { doSomethingElse(); }
// Using else if, no {}
if ($a == 1) doSomething();
else if ($a == 2) doSomethingElseIf();
else doSomethingElse();
?>
See also elseif/else if.
Reserved Keywords In PHP 7
[Since 0.8.4] - [ -P Php/ReservedKeywords7 ] - [ Online docs ] - [ PHP older than 7.0]
PHP reserved names for class/trait/interface. They won't be available anymore in user space starting with PHP 7.
For example, string, float, false, true, null, resource,... are not acceptable as class name.
<?php
// This doesn't compile in PHP 7.0 and more recent
class null { }
?>
See also List of other reserved words.
Unset In Foreach
[Since 0.8.4] - [ -P Structures/UnsetInForeach ] - [ Online docs ]
Unset applied to the variables of a foreach loop are useless. Those variables are copies and not the actual value. Even if the value is a reference, unsetting it has no effect on the original array : the only effect may be indirect, on elements inside an array, or on properties inside an object.
<?php
// When unset is useless
$array = [1, 2, 3];
foreach($array as $a) {
unset($a);
}
print_r($array); // still [1, 2, 3]
foreach($array as $b => &$a) {
unset($a);
}
print_r($array); // still [1, 2, 3]
// When unset is useful
$array = [ [ 'c' => 1] ]; // Array in array
foreach($array as &$a) {
unset(&$a['c']);
}
print_r($array); // now [ ['c' => null] ]
?>
See also foreach.
Could Be Class Constant
[Since 0.8.4] - [ -P Classes/CouldBeClassConstant ] - [ Online docs ]
When a property is defined and read, but never modified, it may be a constant.
<?php
class foo {
// $this->bar is never modified.
private $bar = 1;
// $this->foofoo is modified, at least once
private $foofoo = 2;
function method($a) {
$this->foofoo = $this->bar + $a + $this->foofoo;
return $this->foofoo;
}
}
?>
Starting with PHP 5.6, even array() may be defined as constants.
Could Be Static
[Since 0.8.4] - [ -P Structures/CouldBeStatic ] - [ Online docs ]
This global is only used in one function or method. It may be called 'static', instead of global. This allows you to keep the value between call to the function, but will not be accessible outside this function.
<?php
function foo( ) {
static $variableIsReservedForX; // only accessible within foo( ), even between calls.
global $variableIsGlobal; // accessible everywhere in the application
}
?>
Multiple Class Declarations
[Since 0.8.4] - [ -P Classes/MultipleDeclarations ] - [ Online docs ]
It is possible to declare several times the same class in the code. PHP will not mention it until execution time, since declarations may be conditional.
<?php
$a = 1;
// Conditional declaration
if ($a == 1) {
class foo {
function method() { echo 'class 1';}
}
} else {
class foo {
function method() { echo 'class 2';}
}
}
(new foo())->method();
?>
It is recommended to avoid declaring several times the same class in the code. The best practice is to separate them with namespaces, they are for here for that purpose. In case those two classes are to be used interchangeably, the best is to use an abstract class or an interface.
Compare Hash
[Since 0.8.4] - [ -P Security/CompareHash ] - [ Online docs ]
When comparing hash values, it is important to use the strict comparison : hash_equals(), === or !== .
In a number of situations, the hash value will start with 0e , and PHP will understand that the comparison involves integers : it will then convert the strings into numbers, and it may end up converting them to 0.
Here is an example :
<?php
// The two following passwords hashes matches, while they are not the same.
$hashed_password = 0e462097431906509000000000000;
if (hash('md5','240610708',false) == $hashed_password) {
print 'Matched.'.PHP_EOL;
}
// hash returns a string, that is mistaken with 0 by PHP
// The strength of the hashing algorithm is not a problem
if (hash('ripemd160','20583002034',false) == '0') {
print 'Matched.'.PHP_EOL;
}
if (hash('md5','240610708',false) !== $hashed_password) {
print 'NOT Matched.'.PHP_EOL;
}
// Display true
var_dump(md5('240610708') == md5('QNKCDZO') );
?>
You may also use password_hash() and password_verify() : they work together without integer conversion problems, and they can't be confused with a number.
See also Magic Hashes
What is the best way to compare hashed strings? (PHP) and
md5('240610708') == md5('QNKCDZO').
Empty Namespace
[Since 0.8.4] - [ -P Namespaces/EmptyNamespace ] - [ Online docs ]
Declaring a namespace in the code and not using it for structure declarations or global instructions is useless.
Using simple style :
<?php
namespace Y;
class foo {}
namespace X;
// This is useless
?>
Using bracket-style syntax :
<?php
namespace X {
// This is useless
}
namespace Y {
class foo {}
}
?>
Could Use Short Assignation
[Since 0.8.4] - [ -P Structures/CouldUseShortAssignation ] - [ Online docs ]
Use short assignment operator, to speed up code, and keep syntax clear.
Some operators, like * or +, have a compact and fast 'do-and-assign' version. They looks like a compacted version for = and the operator. This syntax is good for readability, and saves some memory in the process.
Depending on the operator, not all permutations of arguments are possible.
Addition and short assignation of addition have a different set of features when applied to arrays. Do not exchange one another in that case.
<?php
$a = 10 + $a;
$a += 10;
$b = $b - 1;
$b -= 1;
$c = $c * 2;
$c *= 2;
$d = $d / 3;
$d /= 3;
$e = $e % 4;
$e %= 4;
$f = $f | 5;
$f |= 5;
$g = $g & 6;
$g &= 6;
$h = $h ^ 7;
$h ^= 7;
$i = $i >> 8;
$i >>= 8;
$j = $j << 9;
$j <<= 9;
// PHP 7.4 and more recent
$l = $l ?? 'value';
$l ??= 'value';
?>
Short operators are faster than the extended version, though it is a micro-optimization.
See also Assignation Operators.
Useless Abstract Class
[Since 0.8.4] - [ -P Classes/UselessAbstract ] - [ Online docs ]
Those classes are marked 'abstract' and they are never extended. This way, they won't be instantiated nor used.
Abstract classes that have only static methods are omitted here : one usage of such classes are Utilities classes, which only offer static methods.
<?php
// Never extended class : this is useless
abstract class foo {}
// Extended class
abstract class bar {
public function barbar() {}
}
class bar2 extends bar {}
// Utility class : omitted here
abstract class bar {
public static function barbar() {}
}
?>
Null On New
[Since 0.8.4] - [ -P Classes/NullOnNew ] - [ Online docs ] - [ PHP older than 7.0]
Until PHP 7, some classes instantiation could yield null, instead of throwing an exception.
After issuing a 'new' with those classes, it was important to check if the returned object were null or not. No exception were thrown.
<?php
// Example extracted from the wiki below
$mf = new MessageFormatter('en_US', '{this was made intentionally incorrect}');
if ($mf === null) {
echo 'Surprise!';
}
?>
This inconsistency has been cleaned in PHP 7 : see See Internal Constructor Behavior
See also PHP RFC: Constructor behaviour of internal classes.
Scalar Typehint Usage
[Since 0.8.4] - [ -P Php/ScalarTypehintUsage ] - [ Online docs ] - [ PHP 7.0 and more recent ]
Spot usage of scalar type hint : int , float , boolean and string .
Scalar typehint are PHP 7.0 and more recent. Some, like object , is 7.2.
Scalar typehint were not supported in PHP 5 and older. Then, the typehint is treated as a class name.
<?php
function withScalarTypehint(string $x) {}
function withoutScalarTypehint(someClass $x) {}
?>
See also PHP RFC: Scalar Type Hints and Type declarations.
Return Typehint Usage
[Since 0.8.4] - [ -P Php/ReturnTypehintUsage ] - [ Online docs ] - [ PHP 7.0 and more recent ]
Spot usage of return typehint. It is a PHP 7.0 feature.
Return typehint were introduced in PHP 7.0, and are backward incompatible with PHP 5.x.
<?php
function foo($a) : stdClass {
return new \stdClass();
}
?>
See also RFC: Return Type Declarations and
Return Type Declarations.
ext/ob
[Since 0.8.4] - [ -P Extensions/Extob ] - [ Online docs ]
Extension Output Buffering Control.
The Output Control functions allow you to control when output is sent from the script.
<?php
`ob_start() <https://www.php.net/ob_start>`_;
echo Hello\n;
setcookie(cookiename, cookiedata);
`ob_end_flush() <https://www.php.net/ob_end_flush>`_;
?>
See also Output Buffering Control.
Static Loop
[Since 0.8.4] - [ -P Structures/StaticLoop ] - [ Online docs ]
Static loop may be preprocessed.
It looks like the following loops are static : the same code is executed each time, without taking into account loop variables.
<?php
// Static loop
$total = 0;
for($i = 0; $i < 10; $i++) {
$total += $i;
}
// The above loop may be replaced by (with some math help)
$total = 10 * (10 + 1) / 2;
// Non-Static loop (the loop depends on the size of the array)
$n = count($array);
for($i = 0; $i < $n; $i++) {
$total += $i;
}
?>
It is possible to create loops that don't use any blind variables, though this is fairly rare. In particular, calling a method may update an internal pointer, like next() or SimpleXMLIterator::next() .
It is recommended to turn a static loop into an expression that avoid the loop. For example, replacing the sum of all integers by the function $n * ($n + 1) / 2 , or using array_sum().
This analysis doesn't detect usage of variables with compact .
Pre-increment
[Since 0.8.4] - [ -P Performances/PrePostIncrement ] - [ Online docs ]
When possible, use the pre-increment operator ( ++$i or --$i ) instead of the post-increment operator ( $i++ or $i-- ).
The latter needs an extra memory allocation that costs about 10% of performances.
<?php
// ++$i should be preferred over $i++, as current value is not important
for($i = 0; $i <10; ++$i) {
// do Something
}
// ++$b and $b++ have different impact here, since $a will collect $b + 1 or $b, respectively.
$a = $b++;
?>
This is a micro-optimisation. However, its usage is so widespread, including within loops, that it may eventually have an significant impact on execution time. As such, it is recommended to adopt this rule, and only consider changing legacy code as they are refactored for other reasons.
Only Variable Returned By Reference
[Since 0.8.4] - [ -P Structures/OnlyVariableReturnedByReference ] - [ Online docs ]
Function can't return literals by reference.
When a function returns a reference, it is only possible to return variables, properties or static properties.
Anything else, like literals or static expressions, yield a warning at execution time.
<?php
// Can't return a literal number
function &foo() {
return 3 + `rand() <https://www.php.net/rand>`_;
}
// bar must return values that are stored in a
function &bar() {
$a = 3 + `rand() <https://www.php.net/rand>`_;
return $a;
}
?>
ext/geoip
[Since 0.8.4] - [ -P Extensions/Extgeoip ] - [ Online docs ]
Extension geoip for PHP.
The GeoIP extension allows the localisation of an IP address.
<?php
$org = geoip_org_by_name('www.example.com');
if ($org) {
echo 'This host IP is allocated to: ' . $org;
}
?>
See also GeoIP.
ext/event
[Since 0.8.4] - [ -P Extensions/Extevent ] - [ Online docs ]
Extension event.
This is an extension to efficiently schedule I/O, time and signal based events using the best I/O notification mechanism available for specific platform. This is a port of libevent to the PHP infrastructure.
<?php
// Read callback
function readcb($bev, $base) {
//$input = $bev->input; //$bev->getInput();
//$pos = $input->search('TTP');
$pos = $bev->input->search('TTP');
while (($n = $bev->input->remove($buf, 1024)) > 0) {
echo $buf;
}
}
// Event callback
function eventcb($bev, $events, $base) {
if ($events & EventBufferEvent::CONNECTED) {
echo 'Connected.';
} elseif ($events & (EventBufferEvent::ERROR | EventBufferEvent::EOF)) {
if ($events & EventBufferEvent::ERROR) {
echo 'DNS error: ', $bev->getDnsErrorString(), PHP_EOL;
}
echo 'Closing'.PHP_EOL;
$base->exit();
exit('Done'.PHP_EOL);
}
}
if ($argc != 3) {
echo <<<EOS
Trivial HTTP 0.x client
Syntax: php {$argv[0]} [hostname] [resource]
Example: php {$argv[0]} www.google.com /
EOS;
exit();
}
$base = new EventBase();
$dns_base = new EventDnsBase($base, TRUE); // We'll use async DNS resolving
if (!$dns_base) {
exit('Failed to init DNS Base'.PHP_EOL);
}
$bev = new EventBufferEvent($base, /* use internal socket */ NULL,
EventBufferEvent::OPT_CLOSE_ON_FREE | EventBufferEvent::OPT_DEFER_CALLBACKS,
'readcb', /* writecb */ NULL, 'eventcb'
);
if (!$bev) {
exit('Failed creating bufferevent socket'.PHP_EOL);
}
//$bev->setCallbacks('readcb', /* writecb */ NULL, 'eventcb', $base);
$bev->enable(Event::READ | Event::WRITE);
$output = $bev->output; //$bev->getOutput();
if (!$output->add(
'GET '.$argv[2].' HTTP/1.0'."\r\n".
?>
See also Event and libevent.
ext/amqp
[Since 0.8.4] - [ -P Extensions/Extamqp ] - [ Online docs ]
Extension amqp .
PHP AMQP Binding Library. This is an interface with the RabbitMQ AMQP client library. It is a C-language AMQP client library for use with v2.0+ of the RabbitMQ broker.
<?php
$cnn = new AMQPConnection();
$cnn->connect();
echo 'Used channels: ', $cnn->getUsedChannels(), PHP_EOL;
$ch = new AMQPChannel($cnn);
echo 'Used channels: ', $cnn->getUsedChannels(), PHP_EOL;
$ch = new AMQPChannel($cnn);
echo 'Used channels: ', $cnn->getUsedChannels(), PHP_EOL;
$ch = null;
echo 'Used channels: ', $cnn->getUsedChannels(), PHP_EOL;
?>
See also PHP AMQP Binding Library.
ext/gearman
[Since 0.8.4] - [ -P Extensions/Extgearman ] - [ Online docs ]
Extension Gearman.
Gearman is a generic application framework for farming out work to multiple machines or processes.
<?php
# Create our client object.
$gmclient= new GearmanClient();
# Add default server (localhost).
$gmclient->addServer();
echo 'Sending job'.PHP_EOL;
# Send reverse job
do
{
$result = $gmclient->doNormal('reverse', 'Hello!');
# Check for various return packets and errors.
switch($gmclient->returnCode())
{
case GEARMAN_WORK_DATA:
echo 'Data: '.$result . PHP_EOL;;
break;
case GEARMAN_WORK_STATUS:
list($numerator, $denominator)= $gmclient->doStatus();
echo 'Status: '.$numerator.'/'.$denominator.' complete'. PHP_EOL;
break;
case GEARMAN_WORK_FAIL:
echo 'Failed\n';
exit;
case GEARMAN_SUCCESS:
echo 'Success: $result\n';
break;
default:
echo 'RET: ' . $gmclient->returnCode() . PHP_EOL;
exit;
}
}
while($gmclient->returnCode() != GEARMAN_SUCCESS);
?>
See also Gearman on PHP and Gearman.
ext/com
[Since 0.8.4] - [ -P Extensions/Extcom ] - [ Online docs ]
Extension COM and .Net (Windows).
COM is an acronym for 'Component Object Model'; it is an object orientated layer (and associated services) on top of DCE RPC (an open standard) and defines a common calling convention that enables code written in any language to call and interoperate with code written in any other language (provided those languages are COM aware).
<?php
$domainObject = new COM(WinNT://Domain);
foreach ($domainObject as $obj) {
echo $obj->Name . <br />;
}
?>
See also COM and .Net (Windows).
ext/gmagick
[Since 0.8.4] - [ -P Extensions/Extgmagick ] - [ Online docs ]
Extension gmagick.
Gmagick is a php extension to create, modify and obtain meta information of images using the GraphicsMagick API.
<?php
//Instantiate a new Gmagick object
$image = new Gmagick('example.jpg');
//Make thumbnail from image loaded. 0 for either axes preserves aspect ratio
$image->thumbnailImage(100, 0);
//Create a border around the image, then simulate how the image will look like as an oil painting
//Note the chaining of mutator methods which is supported in gmagick
$image->borderImage(yellow, 8, 8)->oilPaintImage(0.3);
//Write the current image at the current state to a file
$image->write('example_thumbnail.jpg');
?>
See also PHP gmagick and
gmagick.
ext/ibase
[Since 0.8.4] - [ -P Extensions/Extibase ] - [ Online docs ]
Extensions Interbase and Firebird .
Firebird is a relational database offering many ISO SQL-2003 features that runs on Linux, Windows, and a variety of Unix platforms.
<?php
$host = 'localhost:/path/to/your.gdb';
$dbh = ibase_connect($host, $username, $password);
$stmt = 'SELECT * FROM tblname';
$sth = ibase_query($dbh, $stmt) or die(ibase_errmsg());
?>
See also Firebase / Interbase and Firebird.
ext/inotify
[Since 0.8.4] - [ -P Extensions/Extinotify ] - [ Online docs ]
Extension inotify.
The Inotify extension gives access to the Linux kernel subsystem that acts to extend filesystems to notice changes to the filesystem, and report those changes to applications.
<?php
// Open an inotify instance
$fd = inotify_init();
// Watch __FILE__ for metadata changes (e.g. mtime)
$watch_descriptor = inotify_add_watch($fd, __FILE__, IN_ATTRIB);
// generate an event
touch(__FILE__);
// Read events
$events = inotify_read($fd);
print_r($events);
// The following methods allows to use inotify functions without blocking on inotify_read():
// - Using `stream_select() <https://www.php.net/stream_select>`_ on $fd:
$read = array($fd);
$write = null;
$except = null;
stream_select($read,$write,$except,0);
// - Using `stream_set_blocking() <https://www.php.net/stream_set_blocking>`_ on $fd
stream_set_blocking($fd, 0);
inotify_read($fd); // Does no block, and return false if no events are pending
// - Using inotify_queue_len() to check if event queue is not empty
$queue_len = inotify_queue_len($fd); // If > 0, inotify_read() will not block
// Stop watching __FILE__ for metadata changes
inotify_rm_watch($fd, $watch_descriptor);
// Close the inotify instance
// This may have closed all watches if this was not already done
fclose($fd);
?>
See also ext/inotify manual and
inotify.
ext/proctitle
[Since 0.8.4] - [ -P Extensions/Extproctitle ] - [ Online docs ]
Extension proctitle.
This extension allows changing the current process', and thread, name on Linux and *BSD systems. This is useful when using pcntl_fork() to identify running processes in process list
<?php
setproctitle('myscript');
?>
See also proctitle.
ext/wikidiff2
[Since 0.8.4] - [ -P Extensions/Extwikidiff2 ] - [ Online docs ]
Extension wikidiff2.
Wikidiff2 is a PHP and HHVM module that provides the external diff engine for MediaWiki.
<?php
$x = <<<EOT
foo bar
baz
quux
bang
EOT;
$y = <<<EOT
foo test
baz
test
bang
EOT;
print wikidiff2_inline_diff( $x, $y, 2 );
?>
See also wikidiff2 and wikidiff2 (C ext).
ext/xdiff
[Since 0.8.4] - [ -P Extensions/Extxdiff ] - [ Online docs ]
Extension xdiff.
xdiff extension enables you to create and apply patch files containing differences between different revisions of files.
<?php
$old_version = 'my_script-1.0.php';
$patch = 'my_script.patch';
$errors = xdiff_file_patch($old_version, $patch, 'my_script-1.1.php');
if (is_string($errors)) {
echo 'Rejects:'.PHP_EOL;
echo $errors;
}
?>
See also xdiff and libxdiff.
ext/libevent
[Since 0.8.4] - [ -P Extensions/Extlibevent ] - [ Online docs ]
Extension libevent.
Libevent is a library that provides a mechanism to execute a callback function when a specific event occurs on a file descriptor or after a timeout has been reached.
<?php
function print_line($fd, $events, $arg)
{
static $max_requests = 0;
$max_requests++;
if ($max_requests == 10) {
// exit loop after 10 writes
event_base_loopexit($arg[1]);
}
// print the line
echo fgets($fd);
}
// create base and event
$base = event_base_new();
$event = event_new();
$fd = STDIN;
// set event flags
event_set($event, $fd, EV_READ | EV_PERSIST, 'print_line', array($event, $base));
// set event base
event_base_set($event, $base);
// enable event
event_add($event);
// start event loop
event_base_loop($base);
?>
See also libevent and Libevent.
ext/ev
[Since 0.8.4] - [ -P Extensions/Extev ] - [ Online docs ]
Extension ev.
ext/ev is a high performance full-featured event loop written in C.
<?php
// Create and start timer firing after 2 seconds
$w1 = new EvTimer(2, 0, function () {
echo '2 seconds elapsed'.PHP_EOL;
});
// Create and launch timer firing after 2 seconds repeating each second
// until we manually stop it
$w2 = new EvTimer(2, 1, function ($w) {
echo 'is called every second, is launched after 2 seconds'.PHP_EOL;
echo 'iteration = ', Ev::iteration(), PHP_EOL;
// Stop the watcher after 5 iterations
Ev::iteration() == 5 and $w->stop();
// Stop the watcher if further calls cause more than 10 iterations
Ev::iteration() >= 10 and $w->stop();
});
// Create stopped timer. It will be inactive until we start it ourselves
$w_stopped = EvTimer::createStopped(10, 5, function($w) {
echo 'Callback of a timer created as stopped'.PHP_EOL;
// Stop the watcher after 2 iterations
Ev::iteration() >= 2 and $w->stop();
});
// Loop until Ev::stop() is called or all of watchers stop
Ev::run();
// Start and look if it works
$w_stopped->start();
echo 'Run single iteration'.PHP_EOL;
Ev::run(Ev::RUN_ONCE);
echo 'Restart the second watcher and try to handle the same events, but don\'t block'.PHP_EOL;
$w2->again();
Ev::run(Ev::RUN_NOWAIT);
$w = new EvTimer(10, 0, function() {});
echo 'Running a blocking loop'.PHP_EOL;
Ev::run();
echo 'END'.PHP_EOL;
?>
See also Ev and libev.
ext/php-ast
[Since 0.8.4] - [ -P Extensions/Extast ] - [ Online docs ] - [ PHP 7.0 and more recent ]
PHP-AST extension (PHP 7.0 +).
<?php
$code = <<<'EOC'
<?php
$var = 42;
EOC;
var_dump(ast\parse_code($code, $version=50));
?>
See also ext/ast and Extension exposing PHP 7 abstract syntax tree.
ext/xml
[Since 0.8.4] - [ -P Extensions/Extxml ] - [ Online docs ]
Extension xml (Parser).
This PHP extension implements support for James Clark's expat in PHP. This toolkit lets you parse, but not validate, XML documents.
<?php
$file = data.xml;
$depth = array();
function startElement($parser, $name, $attrs)
{
global $depth;
if (!isset($depth[$parser])) {
$depth[$parser] = 0;
}
for ($i = 0; $i < $depth[$parser]; $i++) {
echo ;
}
echo $name\n;
$depth[$parser]++;
}
function endElement($parser, $name)
{
global $depth;
$depth[$parser]--;
}
$xml_parser = xml_parser_create();
xml_set_element_handler($xml_parser, startElement, endElement);
if (!($fp = fopen($file, r))) {
die(could not open XML input);
}
while ($data = fread($fp, 4096)) {
if (!xml_parse($xml_parser, $data, feof($fp))) {
die(sprintf(XML error: %s at line %d,
xml_error_string(xml_get_error_code($xml_parser)),
xml_get_current_line_number($xml_parser)));
}
}
xml_parser_free($xml_parser);
?>
See also XML Parser.
ext/xhprof
[Since 0.8.4] - [ -P Extensions/Extxhprof ] - [ Online docs ]
Extension xhprof.
XHProf is a light-weight hierarchical and instrumentation based profiler.
<?php
xhprof_enable(XHPROF_FLAGS_CPU + XHPROF_FLAGS_MEMORY);
for ($i = 0; $i <= 1000; $i++) {
$a = $i * $i;
}
$xhprof_data = xhprof_disable();
$XHPROF_ROOT = '/tools/xhprof/';
include_once $XHPROF_ROOT . '/xhprof_lib/utils/xhprof_lib.php';
include_once $XHPROF_ROOT . '/xhprof_lib/utils/xhprof_runs.php';
$xhprof_runs = new XHProfRuns_Default();
$run_id = $xhprof_runs->save_run($xhprof_data, 'xhprof_testing');
echo 'http://localhost/xhprof/xhprof_html/index.php?run={$run_id}&source=xhprof_testing'.PHP_EOL;
?>
See also XHprof Documentation.
Indices Are Int Or String
[Since 0.8.4] - [ -P Structures/IndicesAreIntOrString ] - [ Online docs ]
Indices in an array notation such as $array['indice'] may only be integers or string.
Boolean, Null or float will be converted to their integer or string equivalent.
<?php
$a = [true => 1,
1.0 => 2,
1.2 => 3,
1 => 4,
'1' => 5,
0.8 => 6,
0x1 => 7,
01 => 8,
null => 1,
'' => 2,
false => 1,
0 => 2,
'0.8' => 3,
'01' => 4,
'2a' => 5
];
print_r($a);
/*
The above displays
Array
(
[1] => 8
[0] => 2
[] => 2
[0.8] => 3
[01] => 4
[2a] => 5
)
*/
?>
Decimal numbers are rounded to the closest integer; Null is transtyped to '' (empty string); true is 1 and false is 0; Integers in strings are transtyped, while partial numbers or decimals are not analyzed in strings.
As a general rule of thumb, only use integers or strings that don\'t look like integers.
This analyzer may find constant definitions, when available.
Note also that PHP detects integer inside strings, and silently turn them into integers. Partial and octal numbers are not transformed.
<?php
$a = [1 => 1,
'2' => 2,
'011' => 9, // octal number
'11d' => 11, // partial number
];
var_dump($a);
/*
The above displays
array(4) {
[1]=>
int(1)
[2]=>
int(2)
[011]=>
int(9)
[11d]=>
int(11)
}*/
?>
See also Arrays syntax.
Should Typecast
[Since 0.8.4] - [ -P Type/ShouldTypecast ] - [ Online docs ]
When typecasting, it is better to use the casting operator, such as (int) or (bool) .
Functions such as intval() or settype() are always slower.
<?php
// Fast version
$int = (int) $X;
// Slow version
$int = intval($X);
// Convert to base 8 : can't use (int) for that
$int = intval($X, 8);
?>
This is a micro-optimisation, although such conversion may be use multiple time, leading to a larger performance increase.
Note that intval() may also be used to convert an integer to another base.
No Self Referencing Constant
[Since 0.8.4] - [ -P Classes/NoSelfReferencingConstant ] - [ Online docs ]
It is not possible to use a constant to define itself in a class. It yields a fatal error at runtime.
The PHP error reads : Cannot declare self-referencing constant 'self::C2' . Unlike PHP which is self-referencing, self referencing variables can't have a value : just don't use that.
<?php
class a {
const C1 = 1; // fully defined constant
const C2 = self::C2; // self referencing constant
const C3 = a::C3 + 2; // self referencing constant
}
?>
The code may access an already declared constant with self or with its class name.
<?php
class a {
const C1 = 1;
const C2 = a::C1;
}
?>
This error is not detected by linting. It is only detected at instantiation time : if the class is not used, it won't appear.
No Direct Usage
[Since 0.8.4] - [ -P Structures/NoDirectUsage ] - [ Online docs ]
The results of the following functions shouldn't be used directly, but checked first.
For example, glob() returns an array, unless some error happens, in which case it returns a boolean (false). In such case, however rare it is, plugging glob() directly in a foreach() loops will yield errors.
<?php
// Used without check :
foreach(glob('.') as $file) { /* do Something */ }.
// Used without check :
$files = glob('.');
if (!is_array($files)) {
foreach($files as $file) { /* do Something */ }.
}
?>
Break Outside Loop
[Since 0.8.4] - [ -P Structures/BreakOutsideLoop ] - [ Online docs ] - [ PHP older than 7.0]
Starting with PHP 7, break or continue that are outside a loop (for, foreach(), do...while(), while()) or a switch() statement won't compile anymore.
It is not possible anymore to include a piece of code inside a loop that will then break.
<?php
// outside a loop : This won't compile
break 1;
foreach($array as $a) {
break 1; // Compile OK
break 2; // This won't compile, as this break is in one loop, and not 2
}
foreach($array as $a) {
foreach($array2 as $a2) {
break 2; // OK in PHP 5 and 7
}
}
?>
Else Usage
[Since 0.8.4] - [ -P Structures/ElseUsage ] - [ Online docs ]
Else should be avoided by various means. For example, defaulting values before, or short-circuiting the method as soon as the condition is not met.
<?php
// $a is always set
$a = 'default';
if ($condition) {
$a = foo($condition);
}
// Don't use else for default : set default before
if ($condition) {
$a = foo($condition);
} else {
$a = 'default';
}
// Use then to exit
if ( ! $condition) {
return;
}
$a = foo($condition);
// don't use else to return
if ($condition) {
$a = foo($condition);
} else {
return;
}
?>
See also Avoid Else, Return Early and
Why does clean code forbid else expression.
isset() With Constant
[Since 0.8.4] - [ -P Structures/IssetWithConstant ] - [ Online docs ] - [ PHP 7.0 and more recent ]
Until PHP 7, it was possible to use arrays as constants, but it was not possible to test them with isset.
<?php
const X = [1,2,3];
if (isset(X[4])) {}
?>
This would yield an error : Cannot use isset() on the result of an expression (you can use "null !== expression" instead) . This is a backward incompatibility.
Avoid Substr() One
[Since 0.8.4] - [ -P Structures/NoSubstrOne ] - [ Online docs ]
Use array notation $string[$position] to reach a single byte in a string.
There are two ways to access a byte in a string : substr() and $v[$pos] .
The second style is more readable. It may be up to four times faster, though it is a micro-optimization. It is recommended to use it.
PHP 7.1 also introduces the support of negative offsets as string index : negative offset are also reported.
<?php
$string = 'ab人cde';
echo substr($string, $pos, 1);
echo $string[$pos];
echo mb_substr($string, $pos, 1);
// when $pos = 1
// displays bbb
// when $pos = 2
// displays ??人
?>
Beware that substr() and $v[$pos] are similar, while mb_substr() is not. The first function works on bytes, while the latter works on characters.
Global Inside Loop
[Since 0.8.4] - [ -P Structures/GlobalOutsideLoop ] - [ Online docs ]
The global keyword must be used out of loops. Otherwise, it is evaluated each loop, slowing the whole process.
<?php
// Here, global is used once
global $total;
foreach($a as $b) {
$total += $b;
}
// Global is called each time : this is slow.
foreach($a as $b) {
global $total;
$total += $b;
}
?>
Anonymous Classes
[Since 0.8.4] - [ -P Classes/Anonymous ] - [ Online docs ] - [ PHP 7.0 and more recent ]
Anonymous classes.
<?php
// Anonymous class, available since PHP 7.0
$object = new class { function __construct() { echo __METHOD__; } };
?>
Coalesce
[Since 0.8.4] - [ -P Php/Coalesce ] - [ Online docs ] - [ PHP 7.0 and more recent ]
Usage of coalesce operator, in PHP since PHP 5.3.
Note that the coalesce operator is a special case of the ternary operator.
<?php
// Coalesce operator, since PHP 5.3
$a = $b ?: 'default value';
// Equivalent to $a = $b ? $b : 'default value';
?>
See also Ternary Operator.
Double Assignation
[Since 0.8.4] - [ -P Structures/DoubleAssignation ] - [ Online docs ]
This happens when a container (variable, property, array index) is assigned with values twice in a row. One of them is probably a debug instruction, that was forgotten.
<?php
// Normal assignation
$a = 1;
// Double assignation
$b = 2;
$b = 3;
?>
Unicode Escape Syntax
[Since 0.8.4] - [ -P Php/UnicodeEscapeSyntax ] - [ Online docs ] - [ PHP 7.0 and more recent ]
Usage of the Unicode Escape syntax, with the \u{xxxxx} format, available since PHP 7.0.
<?php
// Produce an elephant icon in PHP 7.0+
echo \u{1F418};
// Produce the raw sequence in PHP 5.0
echo \u{1F418};
?>
See also PHP RFC: Unicode Codepoint Escape Syntax,
Code point and
Unicode.
New Functions In PHP 7.0
[Since 0.8.4] - [ -P Php/Php70NewFunctions ] - [ Online docs ] - [ PHP older than 7.0]
The following functions are now native functions in PHP 7.0. It is advised to change them before moving to this new version.
- get_resources()
- gc_mem_caches()
- preg_replace_callback_array()
- posix_setrlimit()
- random_bytes()
- random_int()
- intdiv()
- error_clear_last()
PHP 7.0 Removed Functions
[Since 0.8.4] - [ -P Php/Php70RemovedFunctions ] - [ Online docs ] - [ PHP older than 7.0]
The following PHP native functions were removed in PHP 7.0.
- ereg()
- ereg_replace()
- eregi()
- eregi_replace()
- split()
- spliti()
- sql_regcase()
- magic_quotes_runtime()
- set_magic_quotes_runtime()
- call_user_method()
- call_user_method_array()
- set_socket_blocking()
- mcrypt_ecb()
- mcrypt_cbc()
- mcrypt_cfb()
- mcrypt_ofb()
- datefmt_set_timezone_id()
- imagepsbbox()
- imagepsencodefont()
- imagepsextendfont()
- imagepsfreefont()
- imagepsloadfont()
- imagepsslantfont()
- imagepstext()
This analysis skips redefined PHP functions : when a replacement for a removed PHP function was created, with condition on the PHP version, then its usage is considered valid.
See also PHP 7.0 Removed Functions.
PHP 7.0 New Classes
[Since 0.8.4] - [ -P Php/Php70NewClasses ] - [ Online docs ] - [ PHP older than 7.0]
Those classes are now declared natively in PHP 7.0 and should not be declared in custom code.
There are 8 new classes :
- Error
- ParseError
- TypeError
- ArithmeticError
- DivisionByZeroError
- ClosedGeneratorException
- ReflectionGenerator
- ReflectionType
- AssertionError
<?php
namespace {
// Global namespace
class Error {
// Move to a namespace
// or, remove this class
}
}
namespace B {
class Error {
// This is OK : in a namespace
}
}
?>
See also New Classes and Interfaces.
PHP 7.0 New Interfaces
[Since 0.8.4] - [ -P Php/Php70NewInterfaces ] - [ Online docs ] - [ PHP older than 7.0]
The following interfaces are introduced in PHP 7.0. They shouldn't be defined in custom code.
Empty List
[Since 0.8.4] - [ -P Php/EmptyList ] - [ Online docs ] - [ PHP older than 7.0]
Empty list() are not allowed anymore in PHP 7. There must be at least one variable in the list call.
<?php
//Not accepted since PHP 7.0
list() = array(1,2,3);
//Still valid PHP code
list(,$x) = array(1,2,3);
?>
List With Appends
[Since 0.8.4] - [ -P Php/ListWithAppends ] - [ Online docs ]
List() behavior has changed in PHP 7.0 and it has impact on the indexing when list is used with the [] operator.
<?php
$x = array();
list($x[], $x[], $x[]) = [1, 2, 3];
print_r($x);
?>
In PHP 7.0, results are :
<?php
Array
(
[0] => 1
[1] => 2
[2] => 3
)?>In PHP 5.6, results are :
<?php
Array
(
[0] => 3
[1] => 2
[2] => 1
)?>Simple Global Variable
[Since 0.8.4] - [ -P Php/GlobalWithoutSimpleVariable ] - [ Online docs ] - [ PHP older than 7.0]
The global keyword should only be used with simple variables. Since PHP 7, it cannot be used with complex or dynamic structures.
<?php
// Forbidden in PHP 7
global $normalGlobal;
// Forbidden in PHP 7
global $$variable->global ;
// Tolerated in PHP 7
global ${$variable->global};
?>
Parenthesis As Parameter
[Since 0.8.4] - [ -P Php/ParenthesisAsParameter ] - [ Online docs ]
Using parenthesis around parameters used to silent some internal check. This is not the case anymore in PHP 7, and should be fixed by removing the parenthesis and making the value a real reference.
<?php
// PHP 7 sees through parenthesis
$d = foo(1, 2, $c);
// Avoid parenthesis in arguments
$d = foo(1, 2, ($c));
?>
Foreach Don't Change Pointer
[Since 0.8.4] - [ -P Php/ForeachDontChangePointer ] - [ Online docs ] - [ PHP older than 7.0]
foreach loops use their own internal cursor.
A foreach loop won't change the internal pointer of the array, as it works on a copy of the source. Hence, applying array pointer's functions such as current() or next() to the source array won't have the same behavior in PHP 5 than PHP 7.
This only applies when a foreach() by reference is used.
<?php
$numbers = range(1, 10);
next($numbers);
foreach($numbers as &$number){
print $number;
print current($numbers).\n; // Always
}
?>
See also foreach no longer changes the internal array pointer and
foreach.
PHP5 Indirect Variable Expression
[Since 0.8.4] - [ -P Variables/Php5IndirectExpression ] - [ Online docs ] - [ PHP older than 7.0]
Indirect variable expressions changes between PHP 5 an 7.
The following structures are evaluated differently in PHP 5 and 7. It is recommended to review them or switch to a less ambiguous syntax.
<?php
// PHP 7
$foo = 'bar';
$bar['bar']['baz'] = 'foobarbarbaz';
echo $$foo['bar']['baz'];
echo ($$foo)['bar']['baz'];
// PHP 5
$foo['bar']['baz'] = 'bar';
$bar = 'foobarbazbar';
echo $$foo['bar']['baz'];
echo ${$foo['bar']['baz']};
?>
See Backward incompatible changes PHP 7.0
| Expression | PHP 5 interpretation | PHP 7 interpretation | ||
| $$foo['bar']['baz'] | ${$foo['bar']['baz']} | ($$foo)['bar']['baz'] | ||
| $foo->$bar['baz'] | $foo->{$bar['baz']} | ($foo->$bar)['baz'] | ||
| $foo->$bar['baz']() | $foo->{$bar['baz']}() | ($foo->$bar)['baz']() | ||
| Foo::$bar['baz']() | Foo::{$bar['baz']}() | (Foo::$bar)['baz']() |
Php 7 Indirect Expression
[Since 0.8.4] - [ -P Variables/Php7IndirectExpression ] - [ Online docs ] - [ PHP 7.0 and more recent ]
Those are variable indirect expressions that are interpreted differently in PHP 5 and PHP 7.
You should check them so they don't behave strangely.
<?php
// Ambiguous expression :
$b = $$foo['bar']['baz'];
echo $b;
$foo = array('bar' => array('baz' => 'bat'));
$bat = 'PHP 5.6';
// In PHP 5, the expression above means :
$b = $\{$foo['bar']['baz']};
$b = 'PHP 5.6';
$foo = 'a';
$a = array('bar' => array('baz' => 'bat'));
// In PHP 7, the expression above means :
$b = ($$foo)['bar']['baz'];
$b = 'bat';
?>
See also Changes to variable handling.
Unicode Escape Partial
[Since 0.8.4] - [ -P Php/UnicodeEscapePartial ] - [ Online docs ] - [ PHP older than 7.0]
PHP 7 introduces a new escape sequence for strings : \u{hex}. It is backward incompatible with previous PHP versions for two reasons :
PHP 7 will recognize en replace those sequences, while PHP 5 keep them intact.
PHP 7 will halt on partial Unicode Sequences, as it tries to understand them, but may fail.
<?php
echo \u{1F418}\n;
// PHP 5 displays the same string
// PHP 7 displays : an elephant
echo \u{NOT A UNICODE CODEPOINT}\n;
// PHP 5 displays the same string
// PHP 7 emits a fatal error
?>
Is is recommended to check all those strings, and make sure they will behave correctly in PHP 7.
Define With Array
[Since 0.8.4] - [ -P Php/DefineWithArray ] - [ Online docs ] - [ PHP 7.0 and more recent ]
PHP 7.0 has the ability to define an array as a constant, using the define() native call. This was not possible until that version, only with the const keyword.
<?php
//Defining an array as a constant
define('MY_PRIMES', [2, 3, 5, 7, 11]);
?>
PHP 7.0 Removed Directives
[Since 0.8.4] - [ -P Php/Php70RemovedDirective ] - [ Online docs ] - [ PHP 7.0 and more recent ]
List of directives that are removed in PHP 7.0.
Directives Usage
[Since 0.8.4] - [ -P Php/DirectivesUsage ] - [ Online docs ]
List of the directives mentioned in the code.
<?php
//accessing the configuration to change it
ini_set('timelimit', -1);
//accessing the configuration to check it
ini_get('safe_mode');
?>
Useless Brackets
[Since 0.8.4] - [ -P Structures/UselessBrackets ] - [ Online docs ]
Standalone brackets have no use. Brackets are used to delimit a block of code, and are used by control statements. They may also be used to protect variables in strings.
Standalone brackets may be a left over of an old instruction, or a misunderstanding of the alternative syntax.
<?php
// The following brackets are useless : they are a leftover from an older instruction
// if (DEBUG)
{
$a = 1;
}
// Here, the extra brackets are useless
for($a = 2; $a < 5; $a++) : {
$b++;
} endfor;
?>
preg_replace With Option e
[Since 0.8.4] - [ -P Structures/pregOptionE ] - [ Online docs ]
preg_replace() supported the /e option until PHP 7.0. It allowed the use of eval()'ed expression as replacement. This has been dropped in PHP 7.0, for security reasons.
preg_replace() with /e option may be replaced with preg_replace_callback() and a closure, or preg_replace_callback_array() and an array of closures.
<?php
// preg_replace with /e
$string = 'abcde';
// PHP 5.6 and older usage of /e
$replaced = preg_replace('/c/e', 'strtoupper($0)', $string);
// PHP 7.0 and more recent
// With one replacement
$replaced = preg_replace_callback('/c/', function ($x) { return strtoupper($x[0]); }, $string);
// With several replacements, preventing multiple calls to preg_replace_callback
$replaced = preg_replace_callback_array(array('/c/' => function ($x) { return strtoupper($x[0]); },
'/[a-b]/' => function ($x) { return strtolower($x[0]); }), $string);
?>
eval() Without Try
[Since 0.8.4] - [ -P Structures/EvalWithoutTry ] - [ Online docs ] - [ PHP 7.0 and more recent ]
eval()
<?php
$code = 'This is no PHP code.';
//PHP 5 style
eval($code);
// Ends up with a Fatal error, at execution time
//PHP 7 style
try {
eval($code);
} catch (ParseError $e) {
cleanUpAfterEval();
}
?>
Note that it will catch situations where eval()
No List With String
[Since 0.8.4] - [ -P Php/NoListWithString ] - [ Online docs ] - [ PHP older than 7.0]
list() can't be used anymore to access particular offset in a string. This should be done with substr() or $string[$offset] syntax.
<?php
$x = 'abc';
list($a, $b, $c) = $x;
//list($a, $b, $c) = 'abc'; Never works
print $c;
// PHP 5.6- displays 'c'
// PHP 7.0+ displays nothing
?>
See also PHP 7.0 Backward incompatible changes : list() can no longer unpack string variables .
Setlocale() Uses Constants
[Since 0.8.4] - [ -P Structures/SetlocaleNeedsConstants ] - [ Online docs ]
setlocal() don't use strings but constants.
The first argument of setlocale() must be one of the valid constants, LC_ALL , LC_COLLATE , LC_CTYPE , LC_MONETARY , LC_NUMERIC , LC_TIME, LC_MESSAGES .
<?php
// Use constantes for setlocale first argument
setlocale(LC_ALL, 'nl_NL');
setlocale(\LC_ALL, 'nl_NL');
// Don't use string for setlocale first argument
setlocale('LC_ALL', 'nl_NL');
setlocale('LC_'.'ALL', 'nl_NL');
?>
The PHP 5 usage of strings (same name as above, enclosed in ' or ") is not legit anymore in PHP 7 and later.
See also setlocale.
Global In Global
[Since 0.8.4] - [ -P Structures/GlobalInGlobal ] - [ Online docs ]
List of global variables. There are the global variables, defined with the global keyword, and the implicit global variables, defined in the global scope.
<?php
global $explicitGlobal; // in global namespace
$implicitGlobal = 1; // in global namespace, variables are automatically global
function foo() {
global $explicitGlobalInFoo; // in functions, globals must be declared with global
}
?>
See also Variable Scope.
Usort Sorting In PHP 7.0
[Since 0.8.4] - [ -P Php/UsortSorting ] - [ Online docs ]
Usort(), uksort() and uasort() behavior has changed in PHP 7. Values that are equals (based on the user-provided method) may be sorted differently than in PHP 5.
If this sorting is important, it is advised to add extra comparison in the user-function and avoid returning 0 (thus, depending on default implementation).
<?php
$a = [ 2, 4, 3, 6];
function noSort($a) { return $a > 5; }
usort($a, 'noSort');
print_r($a);
?>
In PHP 5, the results is :
<?php
Array
(
[0] => 3
[1] => 4
[2] => 2
[3] => 6
)?>in PHP 7, the result is :
<?php
Array
(
[0] => 2
[1] => 4
[2] => 3
[3] => 6
)?>Hexadecimal In String
[Since 0.8.4] - [ -P Type/HexadecimalString ] - [ Online docs ]
Mark strings that may be confused with hexadecimal.
Until PHP 7.0, PHP recognizes hexadecimal numbers inside strings, and converts them accordingly.
PHP 7.0 and until 7.1, converts the string to 0, silently.
PHP 7.1 and later, emits a 'A non-numeric value encountered' warning, and convert the string to 0.
<?php
$a = '0x0030';
print $a + 1;
// Print 49
$c = '0x0030zyc';
print $c + 1;
// Print 49
$b = 'b0x0030';
print $b + 1;
// Print 0
?>
ext/fann
[Since 0.8.4] - [ -P Extensions/Extfann ] - [ Online docs ]
Extension FANN : Fast Artificial Neural Network.
PHP binding for FANN library which implements multilayer artificial neural networks with support for both fully connected and sparsely connected networks.
<?php
$num_input = 2;
$num_output = 1;
$num_layers = 3;
$num_neurons_hidden = 3;
$desired_error = 0.001;
$max_epochs = 500000;
$epochs_between_reports = 1000;
$ann = fann_create_standard($num_layers, $num_input, $num_neurons_hidden, $num_output);
if ($ann) {
fann_set_activation_function_hidden($ann, FANN_SIGMOID_SYMMETRIC);
fann_set_activation_function_output($ann, FANN_SIGMOID_SYMMETRIC);
$filename = dirname(__FILE__) . '/xor.data';
if (fann_train_on_file($ann, $filename, $max_epochs, $epochs_between_reports, $desired_error))
fann_save($ann, dirname(__FILE__) . '/xor_float.net');
fann_destroy($ann);
}
?>
See also extension FANN and lib FANN.
Relay Function
[Since 0.8.4] - [ -P Functions/RelayFunction ] - [ Online docs ]
Relay function only delegate workload to another one.
Relay functions and methods are delegating the actual work to another function or method. They do not have any impact on the results, besides exposing another name for the same feature.
<?php
function myStrtolower($string) {
return \strtolower($string);
}
?>
Relay functions are typical of transition API, where an old API have to be preserved until it is fully migrated. Then, they may be removed, so as to reduce confusion, and simplify the API.
func_get_arg() Modified
[Since 0.8.4] - [ -P Functions/funcGetArgModified ] - [ Online docs ]
func_get_arg() and func_get_args() used to report the calling value of the argument until PHP 7. Since PHP 7, it is reporting the value of the argument at calling time, which may have been modified by a previous instruction.
<?php
function x($a) {
$a++;
print func_get_arg(0);
}
x(0);
?>
This code will display 1 in PHP 7, and 0 in PHP 5.
Use Web
[Since 0.8.4] - [ -P Php/UseWeb ] - [ Online docs ]
The code is used in web environment.
The web usage is identified through the usage of the superglobals.
<?php
// Accessing $_GET is possible when PHP is used in a web server.
$x = filter_validate($_GET['x'], FILTER_EMAIL);
?>
Use Cli
[Since 0.8.4] - [ -P Php/UseCli ] - [ Online docs ]
Signal the usage of code in CLI mode, through the usage of `$argv` and `$argc` variables.
<?php
// Characteristics of CLI usage
getopt(abcd);
?>
Register Globals
[Since 0.8.4] - [ -P Security/RegisterGlobals ] - [ Online docs ]
register_globals was a PHP directive that dumped all incoming variables from GET, POST, COOKIE and FILES as global variables in the called scripts.
This lead to security failures, as the variables were often used but not filtered.
Though it is less often found in more recent code, register_globals is sometimes needed in legacy code, that haven't made the move to eradicate this style of coding.
Backward compatible pieces of code that mimic the register_globals features usually create even greater security risks by being run after scripts startup. At that point, some important variables are already set, and may be overwritten by the incoming call, creating confusion in the script.
Mimicking register_globals is achieved with variables variables, extract(), parse_str() and import_request_variables() (Up to PHP 5.4).
<?php
// Security warning ! This overwrites existing variables.
extract($_POST);
// Security warning ! This overwrites existing variables.
foreach($_REQUEST as $var => $value) {
$$var = $value;
}
?>
Avoid get_class()
[Since 0.8.4] - [ -P Structures/UseInstanceof ] - [ Online docs ]
get_class() should be replaced with the instanceof operator to check the class of an object.
get_class() only compares the full namespace name of the object's class, while instanceof actually resolves the name, using the local namespace and aliases.
<?php
use Stdclass as baseClass;
function foo($arg) {
// Slow and prone to namespace errors
if (get_class($arg) === 'Stdclass') {
// doSomething()
}
}
function bar($arg) {
// Faster, and uses aliases.
if ($arg instanceof baseClass) {
// doSomething()
}
}
?>
See also get_class and
Instanceof.
Silently Cast Integer
[Since 0.8.4] - [ -P Type/SilentlyCastInteger ] - [ Online docs ]
Those are integer literals that are cast to a float when running PHP. They are too big for the current PHP version, and PHP resorts to cast them into a float, which has a much larger capacity but a lower precision.
Compare your literals to PHP_MAX_INT (typically 9223372036854775807 ) and PHP_MIN_INT (typically -9223372036854775808 ).
This applies to binary ( 0b10101 ...), octal ( 0123123 ...) and hexadecimal ( 0xfffff ...) too.
<?php
echo 0b1010101101010110101011010101011010101011010101011010101011010111;
//6173123008118052203
echo 0b10101011010101101010110101010110101010110101010110101010110101111;
//1.2346246016236E+19
echo 0123123123123123123123;
//1498121094048818771
echo 01231231231231231231231;
//1.1984968752391E+19
echo 0x12309812311230;
//5119979279159856
echo 0x12309812311230fed;
//2.0971435127439E+19
echo 9223372036854775807; //PHP_MAX_INT
//9223372036854775807
echo 9223372036854775808;
9.2233720368548E+18?>
See also Integer overflow.
PHP7 Dirname
[Since 0.8.4] - [ -P Structures/PHP7Dirname ] - [ Online docs ]
With PHP 7, dirname() has a second argument that represents the number of parent folder to follow. This prevent us from using nested dirname() calls to reach an grand-parent direct.
<?php
$path = '/a/b/c/d/e/f';
// PHP 7 syntax
$threeFoldersUp = dirname($path, 3);
// PHP 5 syntax
$threeFoldersUp = dirname(dirname(dirname($path)));
?>
See also dirname.
Error Messages
[Since 0.8.4] - [ -P Structures/ErrorMessages ] - [ Online docs ]
Error message when an error is reported in the code. Those messages will be read by whoever is triggering the error, and it has to be helpful.
It is a good exercise to read the messages out of context, and try to understand what is about.
<?php
// Not so helpful messages
die('Here be monsters');
exit('An error happened');
throw new Exception('Exception thrown at runtime');
?>
Error messages are spotted via die, exit or throw.
Timestamp Difference
[Since 0.8.4] - [ -P Structures/TimestampDifference ] - [ Online docs ]
time() and microtime()
time() and microtime()
<?php
// Calculating tomorow, same hour, the wrong way
// tomorrow is not always in 86400s, especially in countries with daylight saving
$tomorrow = time() + 86400;
// Good way to calculate tomorrow
$datetime = new DateTime('tomorrow');
?>
When the difference may be rounded to a larger time unit (rounding the difference to days, or several hours), the variation may be ignored safely.
When the difference is very small, it requires a better way to measure time difference, such as `Ticks
`ext/hrtime
See also PHP DateTime difference – it’s a trap! and
PHP Daylight savings bug?.
Php7 Relaxed Keyword
[Since 0.8.4] - [ -P Php/Php7RelaxedKeyword ] - [ Online docs ] - [ PHP 7.0 and more recent ]
Most of the traditional PHP keywords may be used inside classes, trait or interfaces.
<?php
// Compatible with PHP 7.0 +
class foo {
// as is a PHP 5 keyword
public function as() {
}
}
?>
This was not the case in PHP 5, and will yield parse errors.
See also Loosening Reserved Word Restrictions.
ext/pecl_http
[Since 0.8.4] - [ -P Extensions/Exthttp ] - [ Online docs ]
Extension HTTP.
This HTTP extension aims to provide a convenient and powerful set of functionalities for one of PHP major applications.
It eases handling of HTTP URL, headers and messages, provides means for negotiation of a client's preferred content type, language and charset, as well as a convenient way to send any arbitrary data with caching and resuming capabilities.
It provides powerful request functionality with support for parallel requests.
<?php
$client = new http\Client;
$client->setSslOptions(array("verifypeer" => true));
$client->addSslOptions(array("verifyhost" => 2));
$client->enqueue($req = new http\Client\Request("GET", "https://twitter.com/"));
$client->s`end() <https://www.php.net/end>`_;
$ti = (array) $client->getTransferInfo($req);
var_dump($ti);
?>
See also ext-http and
pecl_http.
Joining file()
[Since 0.8.4] - [ -P Performances/JoinFile ] - [ Online docs ]
Use file() to read lines separately.
Applying join('', ) or implode('', ) to the result of file() provides the same results than using file_get_contents(), but at a higher cost of memory and processing.
If the delimiter is not '', then implode() and file() are a better solution than file_get_contents() and str_replace() or nl2br().
<?php
// memory intensive
$content = file_get_contents('path/to/file.txt');
// memory and CPU intensive
$content = join('', file('path/to/file.txt'));
// Consider reading the data line by line and processing it along the way,
// to save memory
$fp = fopen('path/to/file.txt', 'r');
while($line = fget($fp)) {
// process a line
}
fclose($fp);
?>
Always use file_get_contents() to get the content of a file as a string. Consider using readfile() to echo the content directly to the output.
See also file_get_contents and
file.
Real Variables
[Since 0.8.4] - [ -P Variables/RealVariables ] - [ Online docs ]
Inventory of real variables. Global, Static and property declarations are skipped here.
<?php
$realVariable = 1;
class foo {
private $property; // not a variable
private function bar() {
global $global; // not a variable
static $static; // not a variable
}
}
?>
This is a refined version of a search on T_VARIABLE token.
Real Functions
[Since 0.8.4] - [ -P Functions/RealFunctions ] - [ Online docs ]
Real functions, not methods.
Function keywords, that are not in a class, trait, interface, nor a closure.
<?php
// a real Function
function realFunction () {}
// Those are not real functions
function ($closure) { }
class foo {
function isAClassMethod() {}
}
interface fooi {
function isAnInterfaceMethod() {}
}
trait foot {
function isATraitMethod() {}
}
?>
Normal Methods
[Since 0.8.4] - [ -P Classes/NormalMethods ] - [ Online docs ]
Spot normal Methods.
<?php
class foo{
// Normal method
private function bar() {}
// Static method
private static function barbar() {}
}
?>
Unused Arguments
[Since 0.8.4] - [ -P Functions/UnusedArguments ] - [ Online docs ]
Those arguments are not used in the method or function.
Unused arguments should be removed in functions : they are just dead code.
Unused argument may have to stay in methods, as the signature is actually defined in the parent class.
<?php
// $unused is in the signature, but not used.
function foo($unused, $b, $c) {
return $b + $c;
}
?>
Uses Environment
[Since 0.8.4] - [ -P Php/UsesEnv ] - [ Online docs ]
Spot usage of $_ENV and getenv() putenv() functions that will fetch data from the environment.
<?php
// Take some configuration from the environment
$secret_key = getenv('secret_key');
?>
Switch To Switch
[Since 0.8.4] - [ -P Structures/SwitchToSwitch ] - [ Online docs ]
The following structures are based on if / elseif / else. Since they have more than three conditions (not withstanding the final else), it is recommended to use the switch structure, so as to make this more readable.
On the other hand, switch() structures with less than 3 elements should be expressed as a if / else structure.
Note that if condition that uses strict typing (=== or !==) can't be converted to switch() as the latter only performs == or != comparisons.
<?php
if ($a == 1) {
} elseif ($a == 2) {
} elseif ($a == 3) {
} elseif ($a == 4) {
} else {
}
// Better way to write long if/else lists
switch ($a) {
case 1 :
doSomething(1);
break 1;
case 2 :
doSomething(2);
break 1;
case 3 :
doSomething(3);
break 1;
case 4 :
doSomething(4);
break 1;
default :
doSomething();
break 1;
}
?>
Note that simple switch statement, which compare a variable to a literal are optimised in PHP 7.2 and more recent. This gives a nice performance boost, and keep code readable.
See also PHP 7.2's switch optimisations and
Is Your Code Readable By Humans? Cognitive Complexity Tells You.
Wrong Parameter Type
[Since 0.8.4] - [ -P Php/InternalParameterType ] - [ Online docs ]
The expected parameter is not of the correct type. Check PHP documentation to know which is the right format to be used.
<?php
// substr() shouldn't work on integers.
// the first argument is first converted to string, and it is 123456.
echo substr(123456, 0, 4); // display 1234
// substr() shouldn't work on boolean
// the first argument is first converted to string, and it is 1, and not t
echo substr(true, 0, 1); // displays 1
// substr() works correctly on strings.
echo substr(123456, 0, 4);
?>
Property Could Be Private Property
[Since 0.8.4] - [ -P Classes/CouldBePrivate ] - [ Online docs ]
The following properties are never used outside their class of definition Given the analyzed code, they could be set as private.
<?php
class foo {
public $couldBePrivate = 1;
public $cantdBePrivate = 1;
function bar() {
// couldBePrivate is used internally.
$this->couldBePrivate = 3;
}
}
class foo2 extends foo {
function bar2() {
// cantdBePrivate is used in a child class.
$this->cantdBePrivate = 3;
}
}
//$couldBePrivate is not used outside
$foo = new foo();
//$cantdBePrivate is used outside the class
$foo->cantdBePrivate = 2;
?>
Note that dynamic properties (such as $x->$y) are not taken into account.
Redefined Methods
[Since 0.8.4] - [ -P Classes/RedefinedMethods ] - [ Online docs ]
Redefined methods are overwritten methods. Those methods are defined in different classes that are part of the same classes hierarchy.
Protected and public redefined methods replace each other. Private methods are kept separated, and depends on the caller to be distinguished.
<?php
class foo {
function method() {
return 1;
}
}
class bar extends foo {
function method() {
return 2;
}
}
?>
See also Object Inheritance.
Redefined Class Constants
[Since 0.8.4] - [ -P Classes/RedefinedConstants ] - [ Online docs ]
Redefined class constants.
Class constants may be redefined, though it is prone to errors when using them, as it is now crucial to use the right class name to access the right value.
<?php
class a {
const A = 1;
}
class b extends a {
const A = 2;
}
class c extends c { }
echo a::A, ' ', b::A, ' ', c::A;
// 1 2 2
?>
It is recommended to use distinct names.
Redefined Default
[Since 0.8.4] - [ -P Classes/RedefinedDefault ] - [ Online docs ]
Classes allows properties to be set with a default value. When those properties get, unconditionally, another value at constructor time, then one of the default value are useless. One of those definition should go : it is better to define properties outside the constructor.
<?php
class foo {
public $redefined = 1;
public function __construct( ) {
$this->redefined = 2;
}
}
?>
Wrong fopen() Mode
[Since 0.8.4] - [ -P Php/FopenMode ] - [ Online docs ]
Wrong file opening for fopen().
fopen() has a few modes, as described in the documentation : 'r', 'r+', for reading; 'w', 'w+' for writing; 'a', 'a+' for appending; 'x', 'x+' for modifying; 'c', 'c+' for writing and locking, 't' for text files and windows only.
An optional 'b' may be used to make the fopen() call more portable and binary safe. Another optional 't' may be used to make the fopen() call process automatically text input : this one should be avoided.
<?php
// open the file for reading, in binary mode
$fp = fopen('/tmp/php.txt', 'rb');
// New option e in PHP 7.0.16 and 7.1.2 (beware of compatibility)
$fp = fopen('/tmp/php.txt', 'rbe');
// Unknown option x
$fp = fopen('/tmp/php.txt', 'rbx');
?>
Any other values are not understood by PHP.
Is CLI Script
[Since 0.8.4] - [ -P Files/IsCliScript ] - [ Online docs ]
Mark a file as a CLI script, based on the usage of #!.
PHP Bugfixes
[Since 0.8.4] - [ -P Php/MiddleVersion ] - [ Online docs ]
This is the list of features, used in the code, that also received a bug fix in recent PHP versions.
preg_match_all() Flag
[Since 0.8.4] - [ -P Php/PregMatchAllFlag ] - [ Online docs ]
preg_match_all() has an option to configure the structure of the results : it is either by capturing parenthesis (by default), or by result sets.
The second option is the most interesting when the following foreach() loop has to manipulate several captured strings at the same time. No need to use an index in the first array and use it in the other arrays.
<?php
$string = 'ababab';
// default behavior
preg_match_all('/(a)(b)/', $string, $r);
$found = '';
foreach($r[1] as $id => $s) {
$found .= $s.$r[2][$id];
}
// better behavior
preg_match_all('/(a)(b)/', $string, $r, PREG_SET_ORDER);
$found = '';
foreach($r as $s) {
$found .= $s[1].$s[2];
}
?>
The second syntax is easier to read and may be marginally faster to execute (preg_match_all() and foreach()).
Safe Curl Options
[Since 0.8.4] - [ -P Security/CurlOptions ] - [ Online docs ]
It is advised to always use CURLOPT_SSL_VERIFYPEER and CURLOPT_SSL_VERIFYHOST when requesting a SSL connection.
With those tests, the certificate is verified, and if it isn't valid, the connection fails : this is a safe behavior.
<?php
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, https://www.php.net/);
// To be safe, always set this to true
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
curl_exec($ch);
curl_close($ch);
?>
See also Don’t turn off CURLOPT_SSL_VERIFYPEER, fix your PHP configuration,
Certainty: Automated CACert.pem Management for PHP Software and
Server-Side HTTPS Requests.
Negative Power
[Since 0.8.4] - [ -P Structures/NegativePow ] - [ Online docs ]
The power operator ** has higher precedence than the sign operators + and -.
This means that -2 ** 2 == -4. It is in fact, -(2 ** 2).
When using negative power, it is clearer to add parenthesis or to use the pow() function, which has no such ambiguity :
<?php
// -2 to the power of 2 (a square)
pow(-2, 2) == 4;
// minus 2 to the power of 2 (a negative square)
-2 ** 2 == -(2 ** 2) == 4;
?>
Already Parents Interface
[Since 0.8.4] - [ -P Interfaces/AlreadyParentsInterface ] - [ Online docs ]
The same interface is implemented by a class and one of its children.
That way, the child doesn't need to implement the interface, nor define its methods to be an instance of the interface.
<?php
interface i {
function i();
}
class A implements i {
function i() {
return __METHOD__;
}
}
// This implements is useless.
class AB extends A implements i {
// No definition for function i()
}
// Implements i is understated
class AB extends A {
// redefinition of the i method
function i() {
return __METHOD__.' ';
}
}
$x = new AB;
var_dump($x instanceof i);
// true
$x = new AC;
var_dump($x instanceof i);
// true
?>
Use random_int()
[Since 0.8.4] - [ -P Php/BetterRand ] - [ Online docs ]
rand() and mt_rand() should be replaced with random_int().
At worse, rand() should be replaced with mt_rand(), which is a drop-in replacement and srand() by mt_srand().
random_int() replaces rand(), and has no seeding function like srand().
Other sources of entropy that should be replaced by random_int() : microtime(), uniqid(), time(). Those a often combined with hashing functions and mixed with other sources of entropy, such as a salt.
<?php
// Avoid using this
$random = rand(0, 10);
// Drop-in replacement
$random = mt_rand(0, 10);
// Even better but different :
// valid with PHP 7.0+
try {
$random = random_int(0, 10);
} catch (\Exception $e) {
// process case of not enoug random values
}
// This is also a source of entropy, based on `srand() <https://www.php.net/srand>`_
// random_int() is a drop-in replacement here
$a = sha256(`uniqid() <https://www.php.net/uniqid>`_);
?>
Since PHP 7, random_int() along with random_bytes(), provides cryptographically secure pseudo-random bytes, which are good to be used
when security is involved. openssl_random_pseudo_bytes() may be used when the OpenSSL extension is available.
See also CSPRNG and OpenSSL.
Cant Use Return Value In Write Context
[Since 0.8.4] - [ -P Php/CantUseReturnValueInWriteContext ] - [ Online docs ] - [ PHP 5.5 and more recent ]
empty() used to work only on data containers, such as variables. Until PHP 5.5, it was not possible to use directly expressions, such as functioncalls, inside an empty() function call : they were met with a 'Can't use function return value in write context' fatal error.
<?php
function foo($boolean) {
return $boolean;
}
// Valid since PHP 5.5
echo empty(foo(true)) : 'true' : 'false';
?>
This also applies to methodcalls, static or not.
See also Cant Use Return Value In Write Context.
set_exception_handler() Warning
[Since 0.8.4] - [ -P Php/SetExceptionHandlerPHP7 ] - [ Online docs ]
The set_exception_handler() callable function has to be adapted to PHP 7 : Exception is not the right typehint, it is now Throwable .
When in doubt about backward compatibility, just drop the typehint. Otherwise, use Throwable .
<?php
// PHP 5.6- typehint
class foo { function bar(\Exception $e) {} }
// PHP 7+ typehint
class foo { function bar(Throwable $e) {} }
// PHP 5 and PHP 7 compatible typehint (note : there is none)
class foo { function bar($e) {} }
set_exception_handler(foo);
?>
Can't Extend Final
[Since 0.8.4] - [ -P Classes/CantExtendFinal ] - [ Online docs ]
It is not possible to extend final classes.
Since PHP fails with a fatal error, this means that the extending class is probably not used in the rest of the code. Check for dead code.
<?php
// File Foo
final class foo {
public final function bar() {
// doSomething
}
}
?>
In a separate file :
<?php
// File Bar
class bar extends foo {
}
?>
See also Final Keyword.
Ternary In Concat
[Since 0.8.4] - [ -P Structures/TernaryInConcat ] - [ Online docs ]
Ternary and coalesce operator have higher priority than dot '.' for concatenation. This means that :
<?php
// print B0CE as expected
print 'B'.$b.'C'. ($b > 1 ? 'D') : 'E';
// print E, instead of B0CE
print 'B'.$b.'C'. $b > 1 ? 'D' : 'E';
print 'B'.$b.'C'. $b > 1 ? 'D' : 'E';
?>
prints actually 'E', instead of the awaited 'B0CE'.
To be safe, always add parenthesis when using ternary operator with concatenation.
See also Operator Precedence.
Using $this Outside A Class
[Since 0.8.4] - [ -P Classes/UsingThisOutsideAClass ] - [ Online docs ] - [ PHP older than 7.0]
$this is a special variable, that should only be used in a class context.
Until PHP 7.1, $this may be used as an argument in a function or a method, a global, a static : while this is legit, it sounds confusing enough to avoid it.
<?php
function foo($this) {
echo $this;
}
// A closure can be bound to an object at later time. It is valid usage.
$closure = function ($x) {
echo $this->foo($x);
}
?>
Starting with PHP 7.1, the PHP engine check thoroughly that $this is used in an appropriate manner, and raise fatal errors in case it isn't.
Yet, it is possible to find $this outside a class : if the file is included inside a class, then $this will be recognized and validated. If the file is included outside a class context, it will yield a fatal error : Using $this when not in object context .
See also Closure::bind and
The Basics.
Simplify Regex
[Since 0.8.4] - [ -P Structures/SimplePreg ] - [ Online docs ]
Avoid using regex when the searched string or the replacement are simple enough.
PRCE regex are a powerful way to search inside strings, but they also come at the price of performance. When the query is simple enough, try using strpos() or stripos() instead.
<?php
// simple preg calls
if (preg_match('/a/', $string)) {}
if (preg_match('/b/i', $string)) {} // case insensitive
// light replacements
if( strpos('a', $string)) {}
if( stripos('b', $string)) {} // case insensitive
?>
ext/tokyotyrant
[Since 0.8.4] - [ -P Extensions/Exttokyotyrant ] - [ Online docs ]
Extension for Tokyo Tyrant.
tokyo_tyrant extension provides a wrapper for Tokyo Tyrant client libraries.
<?php
$tt = new TokyoTyrant("localhost");
$tt->put("key", "value");
echo $tt->get("key");
?>
See also tokyo_tyrant and
Tokyo cabinet.
ext/v8js
[Since 0.8.4] - [ -P Extensions/Extv8js ] - [ Online docs ]
Extension v8js.
This extension embeds the V8 Javascript Engine into PHP.
<?php
$v8 = new V8Js();
/* basic.js */
$JS = <<< EOT
len = print('Hello' + ' ' + 'World!' + '\n');
len;
EOT;
try {
var_dump($v8->executeString($JS, 'basic.js'));
} catch (V8JsException $e) {
var_dump($e);
}
?>
See also V8 Javascript Engine Integration,
V8 Javascript Engine for PHP and
pecl v8js.
Yield Usage
[Since 0.8.4] - [ -P Php/YieldUsage ] - [ Online docs ] - [ PHP 5.5 and more recent ]
Usage of generators, with yield keyword.
Yield was introduced in PHP 5.5, and is backward incompatible.
<?php
function prime() {
$primes = [2, 3, 5, 7, 11, 13, 17, 19];
foreach($primes as $prime) {
yield $prime;
}
}
?>
See also Generator Syntax,
Deal with Memory Gently using Yield in PHP and
Understanding PHP Generators.
Yield From Usage
[Since 0.8.4] - [ -P Php/YieldFromUsage ] - [ Online docs ] - [ PHP 7.0 and more recent ]
Usage of generator delegation, with yield from keyword.
In PHP 7, generator delegation allows you to yield values from another Generator , Traversable object, or array by using the yield from .
Yield from was introduced in PHP 7.1, and is backward incompatible.
<?php
// Yield delegation
function foo() {
yield from bar();
}
function bar() {
yield 1;
}
?>
See also Generator Syntax and
Understanding PHP Generators.
Pear Usage
[Since 0.8.4] - [ -P Php/PearUsage ] - [ Online docs ]
Pear Usage : list of Pear packages in use.
<?php
require_once('MDB2.php');
$dsn = 'mysql://user:pass@host';
$mdb2 = &MDB2::factory($dsn);
$mdb2->setFetchMode(MDB2_FETCHMODE_ASSOC);
?>
See also PEAR.
Undefined Trait
[Since 0.8.4] - [ -P Traits/UndefinedTrait ] - [ Online docs ]
Those traits are undefined.
When the using class or trait is instantiated, PHP emits a a fatal error.
<?php
use Composer/Component/someTrait as externalTrait;
trait t {
function foo() {}
}
// This class uses trait that are all known
class hasOnlyDefinedTrait {
use t, externalTrait;
}
// This class uses trait that are unknown
class hasUndefinedTrait {
use unknownTrait, t, externalTrait;
}
?>
No Hardcoded Hash
[Since 0.8.4] - [ -P Structures/NoHardcodedHash ] - [ Online docs ]
Hash should never be hardcoded.
Hashes may be MD5, SHA1, SHA512, Bcrypt or any other. Such values must be easily changed, for security reasons, and the source code is not the safest place to hide it.
<?php
// Those strings may be sha512 hashes.
// it is recomemdned to check if they are static or should be put into configuration
$init512 = array( // initial values for SHA512
'6a09e667f3bcc908', 'bb67ae8584caa73b', '3c6ef372fe94f82b', 'a54ff53a5f1d36f1',
);
// strings which are obvious conversion are ignored
$decimal = intval('87878877', 12);
?>
See also Salted Password Hashing - Doing it Right and
Hash-Buster.
Identical Conditions
[Since 0.8.4] - [ -P Structures/IdenticalConditions ] - [ Online docs ]
These logical expressions contain members that are identical.
This means those expressions may be simplified.
<?php
// twice $a
if ($a || $b || $c || $a) { }
// Hiding in parenthesis is bad
if (($a) ^ ($a)) {}
// expressions may be large
if ($a === 1 && 1 === $a) {}
?>
Unkown Regex Options
[Since 0.8.4] - [ -P Structures/UnknownPregOption ] - [ Online docs ]
Regex support in PHP accepts the following list of options : eimsuxADJSUX .
All other letter used as option are not supported : depending on the situation, they may be ignored or raise an error.
<?php
// all options are available
if (preg_match('/\d+/isA', $string, $results)) { }
// p and h are not regex options, p is double
if (preg_match('/\d+/php', $string, $results)) { }
?>
See also Pattern Modifiers
Random Without Try
[Since 0.8.4] - [ -P Structures/RandomWithoutTry ] - [ Online docs ] - [ PHP 7.0 and more recent ]
random_int() and random_bytes() require a try/catch structure around them.
random_int() and random_bytes() emit Exceptions if they meet a problem. This way, failure can't be mistaken with returning an empty value, which leads to lower security.
<?php
try {
$salt = random_bytes($length);
} catch (TypeError $e) {
// Error while reading the provided parameter
} catch (Exception $e) {
// Insufficient random data generated
} catch (Error $e) {
// Error with the provided parameter : <= 0
}
?>
Since PHP 7.4, openssl_random_pseudo_bytes() has adopted the same behavior. It is included in this analysis : check your PHP version for actual application.
No Choice
[Since 0.8.4] - [ -P Structures/NoChoice ] - [ Online docs ]
A conditional structure is being used, but both alternatives are the same, leading to the illusion of choice.
Either the condition is useless, and may be removed, or the alternatives need to be distinguished.
<?php
if ($condition == 2) {
doSomething();
} else {
doSomething();
}
$condition == 2 ? doSomething() : doSomething();
?>
Common Alternatives
[Since 0.8.4] - [ -P Structures/CommonAlternatives ] - [ Online docs ]
In the following conditional structures, expressions were found that are common to both 'then' and 'else'. It may be interesting, though not always possible, to put them both out of the conditional, and reduce line count.
<?php
if ($c == 5) {
$b = strtolower($b[2]);
$a++;
} else {
$b = strtolower($b[2]);
$b++;
}
?>
may be rewritten in :
<?php
$b = strtolower($b[2]);
if ($c == 5) {
$a++;
} else {
$b++;
}
?>
Logical Mistakes
[Since 0.8.4] - [ -P Structures/LogicalMistakes ] - [ Online docs ]
Avoid logical mistakes within long expressions.
Sometimes, the logic is not what it seems. It is important to check the actual impact of every part of the logical expression. Do not hesitate to make a table with all possible cases. If those cases are too numerous, it may be time to rethink the whole expression.
<?php
// Always true
if ($a != 1 || $a != 2) { }
// $a == 1 is useless
if ($a == 1 || $a != 2) {}
// Always false
if ($a == 1 && $a == 2) {}
// $a != 2 is useless
if ($a == 1 && $a != 2) {}
?>
Based on article from Andrey Karpov Logical Expressions in C/C++. Mistakes Made by Professionals
Exception Order
[Since 0.8.4] - [ -P Exceptions/AlreadyCaught ] - [ Online docs ]
When catching exception, the most specialized exceptions must be in the early catch, and the most general exceptions must be in the later catch. Otherwise, the general catches intercept the exception, and the more specialized will not be read.
<?php
class A extends \Exception {}
class B extends A {}
try {
throw new A();
}
catch(A $a1) { }
catch(B $b2 ) {
// Never reached, as previous Catch is catching the early worm
}
?>
ext/lua
[Since 0.8.4] - [ -P Extensions/Extlua ] - [ Online docs ]
Extension Lua.
'Lua is a powerful, fast, light-weight, embeddable scripting language.' This extension embeds the lua interpreter and offers an OO-API to lua variables and functions.
<?php
$lua = new Lua();
$lua->eval(<<<CODE
print(2);
CODE
);
?>
See also ext/lua manual and
LUA
Uncaught Exceptions
[Since 0.8.4] - [ -P Exceptions/UncaughtExceptions ] - [ Online docs ]
The following exceptions are thrown in the code, but are never caught.
<?php
// This exception is throw, but not caught. It will lead to a fatal error.
if ($message = check_for_error()) {
throw new My\Exception($message);
}
// This exception is throw, and caught.
try {
if ($message = check_for_error()) {
throw new My\Exception($message);
}
} catch (\Exception $e) {
doSomething();
}
?>
Either they will lead to a Fatal Error, or they have to be caught by an including application. This is a valid behavior for libraries, but is not for a final application.
See also Structuring PHP Exceptions.
Undefined Caught Exceptions
[Since 0.8.4] - [ -P Exceptions/CaughtButNotThrown ] - [ Online docs ]
Those are exceptions that are caught in the code, but are not defined in the application.
They may be externally defined, such as in core PHP, extensions or libraries. Make sure those exceptions are useful to your application : otherwise, they are dead code.
<?php
try {
library_function($some, $args);
} catch (LibraryException $e) {
// This exception is not defined, and probably belongs to Library
print Library failed\n;
} catch (OtherLibraryException $e) {
// This exception is not defined, and probably do not belongs to this code
print Library failed\n;
} catch (\Exception $e) {
// This exception is a PHP standard exception
print Something went wrong, but not at Libary level\n;
}
?>
Same Conditions In Condition
[Since 0.8.4] - [ -P Structures/SameConditions ] - [ Online docs ]
At least two consecutive if/then structures use identical conditions. The latter will probably be ignored.
This analysis returns false positive when there are attempt to fix a situation, or to call an alternative solution.
<?php
if ($a == 1) { doSomething(); }
elseif ($b == 1) { doSomething(); }
elseif ($c == 1) { doSomething(); }
elseif ($a == 1) { doSomething(); }
else {}
// Also works on if then else if chains
if ($a == 1) { doSomething(); }
else if ($b == 1) { doSomething(); }
else if ($c == 1) { doSomething(); }
else if ($a == 1) { doSomething(); }
else {}
// This sort of situation generate false postive.
$config = load_config_from_commandline();
if (empty($config)) {
$config = load_config_from_`file() <https://www.php.net/file>`_;
if (empty($config)) {
$config = load_default_config();
}
}
?>
Php 7.1 New Class
[Since 0.8.4] - [ -P Php/Php71NewClasses ] - [ Online docs ] - [ PHP older than 7.1]
New classes, introduced in PHP 7.1. If classes where created with the same name, in current code, they have to be moved in a namespace, or removed from code to migrate safely to PHP 7.1.
The new class is : ReflectionClassConstant. The other class is 'Void' : this is forbidden as a class name, as Void is used for return type hint.
<?php
class ReflectionClassConstant {
// Move to a namespace, do not leave in global
// or, remove this class
}
?>
Return True False
[Since 0.8.4] - [ -P Structures/ReturnTrueFalse ] - [ Online docs ]
These conditional expressions return true/false, depending on the condition. This may be simplified by dropping the control structure altogether.
<?php
if (version_compare($a, $b) >= 0) {
return true;
} else {
return false;
}
?>
This may be simplified with :
<?php
return version_compare($a, $b) >= 0;
?>
This may be applied to assignations and ternary operators too.
<?php
if (version_compare($a, $b) >= 0) {
$a = true;
} else {
$a = false;
}
$a = version_compare($a, $b) >= 0 ? false : true;
?>
Indirect Injection
[Since 0.8.4] - [ -P Security/IndirectInjection ] - [ Online docs ]
Look for injections through indirect usage for GPRC values ($_GET, $_POST, $_REQUEST, $_COOKIE).
<?php
$a = $_GET['a'];
echo $a;
function foo($b) {
echo $b;
}
foo($_POST['c']);
?>
Useless Switch
[Since 0.8.4] - [ -P Structures/UselessSwitch ] - [ Online docs ]
This switch has only one case. It may very well be replaced by a ifthen structure.
<?php
switch($a) {
case 1:
doSomething();
break;
}
// Same as
if ($a == 1) {
doSomething();
}
?>
Could Use __DIR__
[Since 0.8.4] - [ -P Structures/CouldUseDir ] - [ Online docs ]
Use __DIR__ constant to access the current file's parent directory.
Avoid using dirname() on __FILE__.
<?php
// Better way
$fp = fopen(__DIR__.'/myfile.txt', 'r');
// compatible, but slow way
$fp = fopen(dirname(__FILE__).'/myfile.txt', 'r');
// Since PHP 5.3
assert(dirname(__FILE__) == __DIR__);
?>
__DIR__ has been introduced in PHP 5.3.0.
See also Magic Constants.
Should Use Coalesce
[Since 0.8.4] - [ -P Php/ShouldUseCoalesce ] - [ Online docs ] - [ PHP 7.0 and more recent ]
PHP 7 introduced the ?? operator, that replaces longer structures to set default values when a variable is not set.
<?php
// Fetches the request parameter user and results in 'nobody' if it doesn't exist
$username = $_GET['user'] ?? 'nobody';
// equivalent to: $username = isset($_GET['user']) ? $_GET['user'] : 'nobody';
// Calls a hypothetical model-getting function, and uses the provided default if it fails
$model = Model::get($id) ?? $default_model;
// equivalent to: if (($model = Model::get($id)) === NULL) { $model = $default_model; }
?>
Sample extracted from PHP docs Isset Ternary.
See also New in PHP 7: null coalesce operator.
Make Global A Property
[Since 0.8.4] - [ -P Classes/MakeGlobalAProperty ] - [ Online docs ]
Calling global (or $GLOBALS) in methods is slower and less testable than setting the global to a property, and using this property.
Using properties is slightly faster than calling global or $GLOBALS, though the gain is not important.
Setting the property in the constructor (or in a factory), makes the class easier to test, as there is now a single point of configuration.
<?php
// Wrong way
class fooBad {
function x() {
global $a;
$a->do();
// Or $GLOBALS['a']->do();
}
}
class fooGood {
private $bar = null;
function __construct() {
global $bar;
$this->bar = $bar;
// Even better, do this via arguments
}
function x() {
$this->a->do();
}
}
?>
List With Keys
[Since 0.8.4] - [ -P Php/ListWithKeys ] - [ Online docs ] - [ PHP 7.1 and more recent ]
Setting keys when using list() is a PHP 7.1 feature.
<?php
// PHP 7.1 and later only
list('a' => $a, 'b' => $b) = ['b' => 1, 'c' => 2, 'a' => 3];
?>
If With Same Conditions
[Since 0.8.4] - [ -P Structures/IfWithSameConditions ] - [ Online docs ]
Successive If / then structures that have the same condition may be either merged or have one of the condition changed.
<?php
if ($a == 1) {
doSomething();
}
if ($a == 1) {
doSomethingElse();
}
// May be replaced by
if ($a == 1) {
doSomething();
doSomethingElse();
}
?>
Note that if the values used in the condition have been modified in the first if/then structure, the two distinct conditions may be needed.
<?php
// May not be merged
if ($a == 1) {
// Check that this is really the situation
$a = checkSomething();
}
if ($a == 1) {
doSomethingElse();
}
?>
ext/suhosin
[Since 0.8.4] - [ -P Extensions/Extsuhosin ] - [ Online docs ]
Suhosin extension.
Suhosin (pronounced 'su-ho-shin') is an advanced protection system for PHP installations. It was designed to protect servers and users from known and unknown flaws in PHP applications and the PHP core.
<?php
// sha256 is a ext/suhosin specific function
$sha256 = sha256($string);
?>
See also Suhosin.org
Unserialize Second Arg
[Since 0.8.4] - [ -P Security/UnserializeSecondArg ] - [ Online docs ] - [ PHP 7.0 and more recent ]
Since PHP 7, unserialize() function has a second argument that limits the classes that may be unserialized. In case of a breach, this is limiting the classes accessible from unserialize().
One way to exploit unserialize, is to make PHP unserialized the data to an available class, may be one that may be auto-loaded.
<?php
// safe unserialization : only the expected class will be extracted
$serialized = 'O:7:dbClass:0:{}';
$var = unserialize($serialized, ['dbClass']);
$var->connect();
// unsafe unserialization : $var may be of any type that was in the serialized string
// although, here, this is working well.
$serialized = 'O:7:dbClass:0:{}';
$var = unserialize($serialized);
$var->connect();
// unsafe unserialization : $var is not of the expected type.
// and, here, this will lead to disaster.
$serialized = 'O:10:debugClass:0:{}';
$var = unserialize($serialized);
$var->connect();
?>
See also `unserialize()
Securely Implementing (De)Serialization in PHP, and
Remote code execution via PHP [Unserialize].
Throw Functioncall
[Since 0.8.4] - [ -P Exceptions/ThrowFunctioncall ] - [ Online docs ]
The throw keyword expects to use an exception. Calling a function to prepare that exception before throwing it is possible, but forgetting the new keyword is also possible.
<?php
// Forgotten new
throw \RuntimeException('error!');
// Code is OK, function returns an exception
throw getException(ERROR_TYPE, 'error!');
function getException(ERROR_TYPE, $message) {
return new \RuntimeException($messsage);
}
?>
When the new keyword is forgotten, then the class constructor is used as a function name, and now exception is emitted, but an Undefined function fatal error is emitted.
See also Exceptions.
Can't Disable Function
[Since 0.8.4] - [ -P Security/CantDisableFunction ] - [ Online docs ]
This is the list of potentially dangerous PHP functions being used in the code, such as exec() or fsockopen().
eval() is not reported here, as it is not a PHP function, but a language construct : it can't be disabled.
<?php
// This script uses ftp_connect(), therefore, this function shouldn't be disabled.
$ftp = ftp_connect($host, 21);
// This script doesn't use imap_open(), therefore, this function may be disabled.
?>
This analysis is the base for suggesting values for the disable_functions directive.
Functions Using Reference
[Since 0.8.4] - [ -P Functions/FunctionsUsingReference ] - [ Online docs ]
Functions and methods using references in their signature.
<?php
function usingReferences( &$a) {}
class foo {
public function methodUsingReferences($b, &$c = 1) {}
}
?>
Use Instanceof
[Since 0.8.4] - [ -P Classes/UseInstanceof ] - [ Online docs ]
The instanceof operator is a more precise alternative to is_object()
instanceof checks for an variable to be of a class or its parents or the interfaces it implements.
Once instanceof has been used, the actual attributes available (properties, constants, methods) are known, unlike with is_object()
Last, instanceof may be upgraded to Typehint, by moving it to the method signature.
<?php
class Foo {
// Don't use is_object
public function bar($o) {
if (!is_object($o)) { return false; } // Classic argument check
return $o->method();
}
// use instanceof
public function bar($o) {
if ($o instanceof myClass) { // Now, we know which methods are available
return $o->method();
}
return false; } // Default behavior
}
// use of typehinting
// in case $o is not of the right type, exception is raised automatically
public function bar(myClass $o) {
return $o->method();
}
}
?>
instanceof and is_object()
The instanceof operator is also faster than the is_object()
See also Type Operators and
is_object.
Make One Call With Array
[Since 0.8.4] - [ -P Performances/MakeOneCall ] - [ Online docs ]
Avoid calling the same function several times by batching the calls with arrays.
Calling the same function to chain modifications tends to be slower than calling the same function with all the transformations at the same time. Some PHP functions accept scalars or arrays, and using the later is more efficient.
<?php
$string = 'abcdef';
//`str_replace() <https://www.php.net/str_replace>`_ accepts arrays as arguments
$string = str_replace( ['a', 'b', 'c'],
['A', 'B', 'C'],
$string);
// Too many calls to str_replace
$string = str_replace( 'a', 'A', $string);
$string = str_replace( 'b', 'B', $string);
$string = str_replace( 'c', 'C', $string);
// Too many nested calls to str_replace
$string = str_replace( 'a', 'A', str_replace( 'b', 'B', str_replace( 'c', 'C', $string)));
?>
Potential replacements :
| Function | Replacement | ||
| str_replace() | str_replace() | ||
| str_ireplace() | str_replace() | ||
| substr_replace() | substr_replace() | ||
| preg_replace() | preg_replace() | ||
| preg_replace_callback() | preg_replace_callback_array() |
<?php
$subject = 'Aaaaaa Bbb';
//`preg_replace_callback_array() <https://www.php.net/preg_replace_callback_array>`_ is better than multiple preg_replace_callback :
preg_replace_callback_array(
[
'~[a]+~i' => function ($match) {
echo strlen($match[0]), ' matches for a found', PHP_EOL;
},
'~[b]+~i' => function ($match) {
echo strlen($match[0]), ' matches for b found', PHP_EOL;
}
],
$subject
);
$result = preg_replace_callback('~[a]+~i', function ($match) {
echo strlen($match[0]), ' matches for a found', PHP_EOL;
}, $subject);
$result = preg_replace_callback('~[b]+~i', function ($match) {
echo strlen($match[0]), ' matches for b found', PHP_EOL;
}, $subject);
//`str_replace() <https://www.php.net/str_replace>`_ accepts arrays as arguments
$string = str_replace( ['a', 'b', 'c'],
['A', 'B', 'C'],
$string);
// Too many calls to str_replace
$string = str_replace( 'a', 'A');
$string = str_replace( 'b', 'B');
$string = str_replace( 'c', 'C');
?>
List Short Syntax
[Since 0.8.4] - [ -P Php/ListShortSyntax ] - [ Online docs ] - [ PHP 7.1 and more recent ]
Usage of short syntax version of list().
<?php
// PHP 7.1 short list syntax
// PHP 7.1 may also use key => value structures with list
[$a, $b, $c] = ['2', 3, '4'];
// PHP 7.0 list syntax
list($a, $b, $c) = ['2', 3, '4'];
?>
Results May Be Missing
[Since 0.8.4] - [ -P Structures/ResultMayBeMissing ] - [ Online docs ]
preg_match() may return empty values, if the search fails. It is important to check for the existence of results before assigning them to another variable, or using it.
<?php
preg_match('/PHP ([0-9\.]+) /', $res, $r);
$s = $r[1];
// $s may end up null if preg_match fails.
?>
Use Nullable Type
[Since 0.8.4] - [ -P Php/UseNullableType ] - [ Online docs ] - [ PHP 7.1 and more recent ]
The code uses nullable type, available since PHP 7.1.
Nullable Types are an option to type hint : they allow the passing value to be null, or another type.
According to the authors of the feature : 'It is common in many programming languages including PHP to allow a variable to be of some type or null. This null often indicates an error or lack of something to return.'
<?php
function foo(?string $a = 'abc') : ?string {
return $a.b;
}
?>
See also Type declarations and
PHP RFC: Nullable Types.
Always Positive Comparison
[Since 0.8.4] - [ -P Structures/NeverNegative ] - [ Online docs ]
Some PHP native functions, such as count(), strlen(), or abs() only returns positive or null values.
When comparing them to 0, the following expressions are always true and should be avoided.
<?php
$a = [1, 2, 3];
var_dump(count($a) >= 0);
var_dump(count($a) < 0);
?>
PHP 7.1 Removed Directives
[Since 0.8.4] - [ -P Php/Php71RemovedDirective ] - [ Online docs ] - [ PHP 7.1 and more recent ]
List of directives that are removed in PHP 7.1.
New Functions In PHP 7.1
[Since 0.8.4] - [ -P Php/Php71NewFunctions ] - [ Online docs ] - [ PHP older than 7.1]
The following functions are now native functions in PHP 7.1. It is advised to change them before moving to this new version.
- curl_share_strerror()
- curl_multi_errno()
- curl_share_errno()
- mb_ord()
- mb_chr()
- mb_scrub()
- is_iterable()
Multiple Exceptions Catch()
[Since 0.8.4] - [ -P Exceptions/MultipleCatch ] - [ Online docs ]
It is possible to have several distinct exceptions class caught by the same catch, preventing code repetition.
This is a new feature since PHP 7.1.
<?php
// PHP 7.1 and more recent
try {
throw new someException();
} catch (Single $s) {
doSomething();
} catch (oneType | anotherType $s) {
processIdentically();
} finally {
}
// PHP 7.0 and older
try {
throw new someException();
} catch (Single $s) {
doSomething();
} catch (oneType $s) {
processIdentically();
} catch (anotherType $s) {
processIdentically();
} finally {
}
?>
This is a backward incompatible feature of PHP 7.1.
Empty Blocks
[Since 0.8.4] - [ -P Structures/EmptyBlocks ] - [ Online docs ]
Full empty block, part of a control structures.
It is recommended to remove those blocks, so as to reduce confusion in the code.
<?php
foreach($foo as $bar) ; // This block seems erroneous
$foobar++;
if ($a === $b) {
doSomething();
} else {
// Empty block. Remove this
}
// Blocks containing only empty expressions are also detected
for($i = 0; $i < 10; $i++) {
;
}
// Although namespaces are not control structures, they are reported here
namespace A;
namespace B;
?>
Throw In Destruct
[Since 0.8.4] - [ -P Classes/ThrowInDestruct ] - [ Online docs ]
According to the manual, Attempting to throw an exception from a destructor (called in the time of script termination) causes a fatal error.
The destructor may be called during the lifespan of the script, but it is not certain. If the exception is thrown later, the script may end up with a fatal error.
Thus, it is recommended to avoid throwing exceptions within the __destruct method of a class.
<?php
// No exception thrown
class Bar {
function __construct() {
throw new Exception('__construct');
}
function __destruct() {
$this->cleanObject();
}
}
// Potential crash
class Foo {
function __destruct() {
throw new Exception('__destruct');
}
}
?>
See also Constructors and Destructors.
Unused Protected Methods
[Since 0.8.4] - [ -P Classes/UnusedProtectedMethods ] - [ Online docs ]
The following protected methods are unused in children class. As such, they may be considered for being private.
Methods reported by this analysis are not used by children, yet they are protected.
<?php
class Foo {
// This method is not used
protected function unusedBar() {}
protected function usedInFoo() {}
protected function usedInFooFoo() {}
public function bar2() {
// some code
$this->usedInFoo();
}
}
class FooFoo extends Foo {
protected function bar() {}
public function bar2() {
// some code
$this->usedInFooFoo();
}
}
class someOtherClass {
protected function bar() {
// This is not related to foo.
$this->unusedbar();
}
}
?>
No usage of those methods were found.
This analysis is impacted by dynamic method calls.
Use System Tmp
[Since 0.8.4] - [ -P Structures/UseSystemTmp ] - [ Online docs ]
It is recommended to avoid hardcoding the temporary file. It is better to rely on the system's temporary folder, which is accessible with sys_get_temp_dir().
<?php
// Where the tmp is :
file_put_contents(`sys_get_temp_dir() <https://www.php.net/sys_get_temp_dir>`_.'/tempFile.txt', $content);
// Avoid hard-coding tmp folder :
// On Linux-like systems
file_put_contents('/tmp/tempFile.txt', $content);
// On Windows systems
file_put_contents('C:\WINDOWS\TEMP\tempFile.txt', $content);
?>
See also PHP: When is /tmp not /tmp?.
No Count With 0
[Since 0.8.4] - [ -P Performances/NotCountNull ] - [ Online docs ]
Comparing count(), strlen() or mb_strlen() to 0 is a waste of resources. There are three distinct situations.
When comparing count() with 0, with ===, ==, !==, !=, it is more efficient to use empty(). empty() is a language construct that checks if a value is present, while count() actually load the number of element.
<?php
// Checking if an array is empty
if (count($array) == 0) {
// doSomething();
}
// This may be replaced with
if (empty($array)) {
// doSomething();
}
?>
When comparing count() strictly with 0 and > , it is more efficient to use !(empty( ))
<?php
// Checking if an array is empty
if (count($array) > 0) {
// doSomething();
}
// This may be replaced with
if (!empty($array)) {
// doSomething();
}
Of course comparing `count() <https://www.php.net/count>`_ with negative values, or with >= is useless.
<?php
// Checking if an array is empty
if (count($array) < 0) {
// This never happens
// doSomething();
}
?>
Comparing count(), strlen() or mb_strlen() with other values than 0 cannot be replaced with a comparison with empty().
Note that this is a micro-optimisation : since PHP keeps track of the number of elements in arrays (or number of chars in strings), the total computing time of both operations is often lower than a ms. However, both functions tends to be heavily used, and may even be used inside loops.
See also count,
strlen and
mb_strlen.
Dependant Trait
[Since 0.8.4] - [ -P Traits/DependantTrait ] - [ Online docs ]
Traits should be autonomous. It is recommended to avoid depending on methods or properties that should be in the using class.
The following traits make usage of methods and properties, static or not, that are not defined in the trait. This means the host class must provide those methods and properties, but there is no way to enforce this.
This may also lead to dead code : when the trait is removed, the host class have unused properties and methods.
<?php
// autonomous trait : all it needs is within the trait
trait t {
private $p = 0;
function foo() {
return ++$this->p;
}
}
// dependant trait : the host class needs to provide some properties or methods
trait t2 {
function foo() {
return ++$this->p;
}
}
class x {
use t2;
private $p = 0;
}
?>
See also Classes/DependantAbstractClass.
[Since 0.8.4] - [ -P Namespaces/HiddenUse ] - [ Online docs ]
The use expression for namespaces should always be at the beginning of the namespace block.
It is where everyone expect them, and it is less confusing than having them at various levels.
<?php
// This is visible
use A;
class B {}
// This is hidden
use C as D;
class E extends D {
use traitT; // This is a use for a trait
function foo() {
// This is a use for a closure
return function ($a) use ($b) {}
}
}
?>
Could Use Alias
[Since 0.8.4] - [ -P Namespaces/CouldUseAlias ] - [ Online docs ]
This long name may be reduced by using an available alias.
This applies to classes (as full name or prefix), and to constants and functions.
<?php
use a\b\c;
use function a\b\c\foo;
use const a\b\c\D;
// This may be reduced with the above alias to c\d()
new a\b\c\d();
// This may be reduced to c\d\e\f
new a\b\c\d\e\f();
// This may be reduced to c()
new a\b\c();
// This may be reduced to D
echo a\b\c\D;
// This may be reduced to D
a\b\c\foo();
// This can't be reduced : it is an absolute name
\a\b\c\foo();
// This can't be reduced : it is no an alias nor a prefix
a\b\d\foo();
?>
Should Make Alias
[Since 0.8.4] - [ -P Namespaces/ShouldMakeAlias ] - [ Online docs ]
Long names should be aliased.
Aliased names are easy to read at the beginning of the script; they may be changed at one point, and update the whole code at the same time.
Finally, short names makes the rest of the code readable.
<?php
namespace x\y\z;
use a\b\c\d\e\f\g as Object;
// long name, difficult to read, prone to change.
new a\b\c\d\e\f\g();
// long name, difficult to read, prone to silent dead code if namespace change.
if ($o instanceof a\b\c\d\e\f\g) {
}
// short names Easy to update all at once.
new Object();
if ($o instanceof Object) {
}
?>
Multiple Identical Trait Or Interface
[Since 0.8.4] - [ -P Classes/MultipleTraitOrInterface ] - [ Online docs ]
There is no need to use the same trait, or implements the same interface more than once.
Up to PHP 7.1 (at least), this doesn't raise any warning. Traits are only imported once, and interfaces may be implemented as many times as wanted.
<?php
class foo {
use t3,t3,t3;
}
class bar implements i,i,i {
}
?>
Multiple Alias Definitions
[Since 0.8.4] - [ -P Namespaces/MultipleAliasDefinitions ] - [ Online docs ]
Some aliases are representing different classes across the repository. This leads to potential confusion.
Across an application, it is recommended to use the same namespace for one alias. Failing to do this lead to the same keyword to represent different values in different files, with different behavior. Those are hard to find bugs.
<?php
namespace A {
use d\d; // aka D
}
// Those are usually in different files, rather than just different namespaces.
namespace B {
use b\c as D; // also D. This could be named something else
}
?>
Nested Ifthen
[Since 0.8.4] - [ -P Structures/NestedIfthen ] - [ Online docs ]
Three levels of ifthen is too much. The method should be split into smaller functions.
<?php
function foo($a, $b) {
if ($a == 1) {
// Second level, possibly too much already
if ($b == 2) {
}
}
}
function bar($a, $b, $c) {
if ($a == 1) {
// Second level.
if ($b == 2) {
// Third level level.
if ($c == 3) {
// Too much
}
}
}
}
?>
Cast To Boolean
[Since 0.8.4] - [ -P Structures/CastToBoolean ] - [ Online docs ]
This expression may be reduced by casting to boolean type.
<?php
$variable = $condition == 'met' ? 1 : 0;
// Same as
$variable = (bool) $condition == 'met';
$variable = $condition == 'met' ? 0 : 1;
// Same as (Note the condition inversion)
$variable = (bool) $condition != 'met';
// also, with an indentical condition
$variable = !(bool) $condition == 'met';
// This also works with straight booleans expressions
$variable = $condition == 'met' ? true : false;
// Same as
$variable = $condition == 'met';
?>
Failed Substr Comparison
[Since 0.8.4] - [ -P Structures/FailingSubstrComparison ] - [ Online docs ]
The extracted string must be of the size of the compared string.
This is also true for negative lengths.
<?php
// Possible comparison
if (substr($a, 0, 3) === 'abc') { }
if (substr($b, 4, 3) === 'abc') { }
// Always failing
if (substr($a, 0, 3) === 'ab') { }
if (substr($a, 3, -3) === 'ab') { }
// Omitted in this analysis
if (substr($a, 0, 3) !== 'ab') { }
?>
Should Make Ternary
[Since 0.8.5] - [ -P Structures/ShouldMakeTernary ] - [ Online docs ]
Ternary operators are the best when assigning values to a variable.
This way, they are less verbose, compatible with assignation and easier to read.
<?php
// verbose if then structure
if ($a == 3) {
$b = 2;
} else {
$b = 3;
}
// compact ternary call
$b = ($a == 3) ? 2 : 3;
// verbose if then structure
// Works with short assignations and simple expressions
if ($a != 3) {
$b += 2 - $a * 4;
} else {
$b += 3;
}
// compact ternary call
$b += ($a != 3) ? 2 - $a * 4 : 3;
?>
Unused Returned Value
[Since 0.8.5] - [ -P Functions/UnusedReturnedValue ] - [ Online docs ]
The function called returns a value, which is ignored.
Usually, this is a sign of dead code, or a missed check on the results of the functioncall. At times, it may be a valid call if the function has voluntarily no return value.
It is recommended to add a check on the return value, or remove the call.
<?php
// simplest form
function foo() {
return 1;
}
foo();
// In case of multiple return, any one that returns something means that return value is meaningful
function bar() {
if (rand(0, 1)) {
return 1;
} else {
return ;
}
}
bar();
?>
Note that this analysis ignores functions that return void (same meaning that PHP 7.1 : return ; or no return in the function body).
Modernize Empty With Expression
[Since 0.8.6] - [ -P Structures/ModernEmpty ] - [ Online docs ] - [ PHP 5.5 and more recent ]
empty() accepts expressions as argument. This feature was added in PHP 5.5.
There is no need to store the expression in a variable before testing, unless it is reused later.
<?php
// PHP 5.5+ `empty() <https://www.php.net/empty>`_ usage
if (empty(foo($b . $c))) {
doSomethingWithoutA();
}
// Compatible `empty() <https://www.php.net/empty>`_ usage
$a = foo($b . $c);
if (empty($a)) {
doSomethingWithoutA();
}
// $a2 is reused, storage is legit
$a2 = strtolower($b . $c);
if (empty($a2)) {
doSomething();
} else {
echo $a2;
}
?>
See also empty()
Use Positive Condition
[Since 0.8.6] - [ -P Structures/UsePositiveCondition ] - [ Online docs ]
Whenever possible, use a positive condition.
Positive conditions are easier to understand, and lead to less understanding problems.
Negative conditions are not reported when else is not present.
<?php
// This is a positive condition
if ($a == 'b') {
doSomething();
} else {
doSomethingElse();
}
if (!empty($a)) {
doSomething();
} else {
doSomethingElse();
}
// This is a negative condition
if ($a == 'b') {
doSomethingElse();
} else {
doSomething();
}
// No need to force $a == 'b' with empty else
if ($a != 'b') {
doSomethingElse();
}
?>
Drop Else After Return
[Since 0.8.6] - [ -P Structures/DropElseAfterReturn ] - [ Online docs ]
Avoid else clause when the then clause returns, but not the else. And vice-versa.
This way, the else block disappears, and is now the main sequence of the function.
This is also true if else has a return, and then not. When doing so, don't forget to reverse the condition.
<?php
// drop the else
if ($a) {
return $a;
} else {
doSomething();
}
// drop the then
if ($b) {
doSomething();
} else {
return $a;
}
// return in else and then
if ($a3) {
return $a;
} else {
$b = doSomething();
return $b;
}
?>
Use Class Operator
[Since 0.8.7] - [ -P Classes/UseClassOperator ] - [ Online docs ]
Use ::class to hardcode class names, instead of strings.
This is actually faster than strings, which are parsed at execution time, while ::class is compiled, making it faster to execute.
It is also capable to handle aliases, making the code easier to maintain.
<?php
namespace foo\bar;
use foo\bar\X as B;
class X {}
$className = '\foo\bar\X';
$className = foo\bar\X::class;
$className = B\X;
$object = new $className;
?>
This is not possible when building the name of the class with concatenation.
This is a micro-optimization. This also helps static analysis, as it gives more information at compile time to analyse.
ext/rar
[Since 0.8.7] - [ -P Extensions/Extrar ] - [ Online docs ]
Extension RAR.
Rar is a powerful and effective archiver created by Eugene Roshal. This extension gives you possibility to read Rar archives but doesn't support writing Rar archives, because this is not supported by the UnRar library and is directly prohibited by its license.
<?php
$arch = RarArchive::open(example.rar);
if ($arch === FALSE)
die(Cannot open example.rar);
$entries = $arch->getEntries();
if ($entries === FALSE)
die(Cannot retrieve entries);
?>
See also Rar archiving and rarlabs.
Don't Echo Error
[Since 0.8.7] - [ -P Security/DontEchoError ] - [ Online docs ]
It is recommended to avoid displaying error messages directly to the browser.
PHP's uses the display_errors directive to control display of errors to the browser. This must be kept to off when in production.
<?php
// Inside a 'or' test
mysql_connect('localhost', $user, $pass) or die(mysql_error());
// Inside a if test
$result = pg_query( $db, $query );
if( !$result )
{
echo Erreur SQL: . pg_error();
exit;
}
// Changing PHP configuration
ini_set('display_errors', 1);
// This is also a security error : 'false' means actually true.
ini_set('display_errors', 'false');
?>
Error messages should be logged, but not displayed.
See also Error reporting and
List of php.ini directives.
Useless Casting
[Since 0.8.7] - [ -P Structures/UselessCasting ] - [ Online docs ]
There is no need to overcast returned values.
<?php
// trim always returns a string : cast is useless
$a = (string) trim($b);
// strpos doesn't always returns an integer : cast is useful
$a = (boolean) strpos($b, $c);
// comparison don't need casting, nor parenthesis
$c = (bool) ($b > 2);
?>
See also Type juggling.
No isset() With empty()
[Since 0.8.7] - [ -P Structures/NoIssetWithEmpty ] - [ Online docs ]
empty() actually does the job of isset() too.
From the manual : No warning is generated if the variable does not exist. That means empty() is essentially the concise equivalent to !isset($var) || $var == false. The main difference is that isset() only works with variables, while empty() works with other structures, such as constants.
<?php
// Enough validation
if (!empty($a)) {
doSomething();
}
// Too many tests
if (isset($a) && !empty($a)) {
doSomething();
}
?>
See also Isset and
empty.
time() Vs strtotime()
[Since 0.8.7] - [ -P Performances/timeVsstrtotime ] - [ Online docs ]
time() is actually faster than strtotime() with 'now' key string.
<?php
// Faster version
$a = time();
// Slower version
$b = strtotime('now');
?>
This is a micro-optimisation. Relative gain is real, but small unless the function is used many times.
Useless Check
[Since 0.8.9] - [ -P Structures/UselessCheck ] - [ Online docs ]
Situation where the condition is useless. Foreach() will apply a test on the source, and skip all the loops if no element was found.
<?php
// Checking for type is good.
if (is_array($array)) {
foreach($array as $a) {
doSomething($a);
}
}
// Foreach on empty arrays doesn't start. Checking is useless
if (!empty($array)) {
foreach($array as $a) {
doSomething($a);
}
}
?>
See also foreach.
Unitialized Properties
[Since 0.8.9] - [ -P Classes/UnitializedProperties ] - [ Online docs ]
Properties that are not initialized in the constructor, nor at definition.
<?php
class X {
private $i1 = 1, $i2;
protected $u1, $u2;
function __construct() {
$this->i2 = 1 + $this->u2;
}
function m() {
echo $this->i1, $this->i2, $this->u1, $this->u2;
}
}
?>
With the above class, when m() is accessed right after instantiation, there will be a missing property.
Using default values at property definition, or setting default values in the constructor ensures that the created object is consistent.
Bail Out Early
[Since 0.8.9] - [ -P Structures/BailOutEarly ] - [ Online docs ]
When using conditions, it is recommended to quit in the current context, and avoid else clause altogether.
The main benefit is to make clear the method applies a condition, and stop immediately when it is not satisfied.
The main sequence is then focused on the actual code.
This works with the break , continue , throw and goto keywords too, depending on situations.
<?php
// Bailing out early, low level of indentation
function foo1($a) {
if ($a > 0) {
return false;
}
$a++;
return $a;
}
// Works with continue too
foreach($array as $a => $b) {
if ($a > 0) {
continue false;
}
$a++;
return $a;
}
// No need for else
function foo2($a) {
if ($a > 0) {
return false;
} else {
$a++;
}
return $a;
}
// No need for else : return goes into then.
function foo3($a) {
if ($a < 0) {
$a++;
} else {
return false;
}
return $a;
}
// Make a return early, and make the condition visible.
function foo3($a) {
if ($a < 0) {
$a++;
methodcall();
functioncall();
}
}
?>
See also Avoid nesting too deeply and return early (part 1) and
Avoid nesting too deeply and return early (part 2).
Die Exit Consistence
[Since 0.8.9] - [ -P Structures/DieExitConsistance ] - [ Online docs ]
Die and Exit have the same functional use.
The analyzed code has less than 10% of one of them : for consistency reasons, it is recommended to make them all the same.
It happens that die or exit are used depending on coding style and files. One file may be consistently using exit, while the others are all using exit.
<?php
// be consistent
switch ($a) {
case 1 :
exit;
case 2 :
exit;
case 3 :
exit;
case 4 :
exit;
case 5 :
exit;
case 6 :
exit;
case 7 :
exit;
case 8 :
exit;
case 9 :
exit;
case 10 :
exit;
default :
die(); // Be consistent, always use the same.
}
?>
Using die or exit is also the target of other analysis.
Array() / [ ] Consistence
[Since 0.8.9] - [ -P Arrays/ArrayBracketConsistence ] - [ Online docs ]
array() or [ ] is the favorite.
array() and [ ] have the same functional use.
The analyzed code has less than 10% of one of them : for consistency reasons, it is recommended to make them all the same.
It happens that array() or [] are used depending on coding style and files. One file may be consistently using array(), while the others are all using [].
<?php
$a = array(1, 2);
$b = array(array(3, 4), array(5, 6));
$c = array(array(array(7, 8), array(9, 10)), array(11, 12), array(13, 14)));
// be consistent
$d = [1, 3];
?>
The only drawback to use [] over array() is backward incompatibility.
PHP 7.1 Microseconds
[Since 0.8.9] - [ -P Php/Php71microseconds ] - [ Online docs ]
PHP supports microseconds in DateTime class and date_create() function. This was introduced in PHP 7.1.
In previous PHP versions, those dates only used seconds, leading to lazy comparisons :
<?php
$now = date_create();
usleep(10); // wait for 0.001 ms
var_dump($now == date_create());
?>
This code displays true in PHP 7.0 and older, (unless the code was run too close from the next second). In PHP 7.1, this is always false.
This is also true with DateTime :
<?php
$now = new DateTime();
usleep(10); // wait for 0.001 ms
var_dump((new DateTime())->format('u') == $now->format('u'));
?>
This evolution impacts mostly exact comparisons (== and ===). Non-equality (!= and !==) will probably be always true, and should be reviewed.
See also Backward incompatible changes.
Dont Change The Blind Var
[Since 0.8.9] - [ -P Structures/DontChangeBlindKey ] - [ Online docs ]
When using a foreach(), the blind variables hold a copy of the original value. It is confusing to modify them, as it seems that the original value may be changed.
When actually changing the original value, use the reference in the foreach definition to make it obvious, and save the final reassignation.
When the value has to be prepared before usage, then save the filtered value in a separate variable. This makes the clean value obvious, and preserve the original value for a future usage.
<?php
// $bar is duplicated and kept
$foo = [1, 2, 3];
foreach($foo as $bar) {
// $bar is updated but its original value is kept
$nextBar = $bar + 1;
print $bar . ' => ' . ($nextBar) . PHP_EOL;
foobar($nextBar);
}
// $bar is updated and lost
$foo = [1, 2, 3];
foreach($foo as $bar) {
// $bar is updated but its final value is lost
print $bar . ' => ' . (++$bar) . PHP_EOL;
// Now that $bar is reused, it is easy to confuse its value
foobar($bar);
}
// $bar is updated and kept
$foo = [1, 2, 3];
foreach($foo as &$bar) {
// $bar is updated and keept
print $bar . ' => ' . (++$bar) . PHP_EOL;
foobar($bar);
}
?>
Getting Last Element
[Since 0.9.0] - [ -P Arrays/GettingLastElement ] - [ Online docs ]
Getting the last element of an array relies on array_key_last().
array_key_last() was added in PHP 7.3. Before that,
<?php
$array = ['a' => 1, 'b' => 2, 'c' => 3];
// Best solutions, by far
$last = $array[array_key_last($array)];
// Best solutions, just as fast as each other
$last = $array[count($array) - 1];
$last = end($array);
// Bad solutions
// popping, but restoring the value.
$last = array_pop($array);
$array[] = $last;
// array_unshift would be even worse
// reversing array
$last = array_reverse($array)[0];
// slicing the array
$last = array_slice($array, -1)[0]',
$last = current(array_slice($array, -1));
);?>
Rethrown Exceptions
[Since 0.9.0] - [ -P Exceptions/Rethrown ] - [ Online docs ]
Throwing a caught exception is usually useless and dead code.
When exceptions are caught, they should be processed or transformed, but not rethrown as is.
Those issues often happen when a catch structure was positioned for debug purposes, but lost its usage later.
<?php
try {
doSomething();
} catch (Exception $e) {
throw $e;
}
?>
See also What are the best practices for catching and re-throwing exceptions? and
Exception chaining.
Avoid Using stdClass
[Since 0.9.1] - [ -P Php/UseStdclass ] - [ Online docs ]
stdClass is the default class for PHP. It is instantiated when PHP needs to return a object, but no class is specifically available.
It is recommended to avoid instantiating this class, nor use it is any way.
<?php
$json = '{a:1,b:2,c:3}';
$object = json_decode($json);
// $object is a stdClass, as returned by json_decode
// Fast building of $o
$a = [];
$a['a'] = 1;
$a['b'] = 2;
$a['c'] = 3;
json_encode( (object) $a);
// Slow building of $o
$o = new stdClass();
$o->a = 1;
$o->b = 2;
$o->c = 3;
json_encode($o);
?>
If you need a stdClass object, it is faster to build it as an array, then cast it, than instantiate stdClass . This is a micro-optimisation.
Could Return Void
[Since 0.9.1] - [ -P Functions/CouldReturnVoid ] - [ Online docs ]
The following functions may bear the void return typehint.
<?php
// This can be Void
function foo(&$a) {
++$a;
return;
}
// This can't be Void
function bar($a) {
++$a;
return $a;
}
?>
See also Returning values and
Void Return Type.
Invalid Octal In String
[Since 0.9.1] - [ -P Type/OctalInString ] - [ Online docs ] - [ PHP older than 7.1]
Any octal sequence inside a string can't be go \377. Those will be a fatal error at parsing time.
The check is applied to the string, starting with PHP 7.1. In PHP 7.0 and older, those sequences were silently adapted (modulo/% \400).
<?php
// A valid octal in a PHP string
echo \100; // @
// Emit a warning in PHP 7.1
//Octal escape sequence overflow \500 is greater than \377
echo \500; // @
// Silent conversion
echo \478; // 8
?>
See also Integers.
Avoid array_push()
[Since 0.9.1] - [ -P Performances/AvoidArrayPush ] - [ Online docs ]
array_push() is slower than the [] operator.
This is also true if the [] operator is called several times, while array_push() may be called only once.
And using count after the push is also faster than collecting array_push() return value.
<?php
$a = [1,2,3];
// Fast version
$a[] = 4;
$a[] = 5;
$a[] = 6;
$a[] = 7;
$count = count($a);
// Slow version
array_push($a, 4);
$count = array_push($a, 5,6,7);
// Multiple version :
$a[] = 1;
$a[] = 2;
$a[] = 3;
array_push($a, 1, 2, 3);
?>
This is a micro-optimisation.
ext/nsapi
[Since 0.9.2] - [ -P Extensions/Extnsapi ] - [ Online docs ]
NSAPI specific functions calls.
These functions are only available when running PHP as a NSAPI module in Netscape/iPlanet/Sun webservers.
<?php
// This scripts depends on ext/nsapi
if (ini_get('nsapi.read_timeout') < 60) {
doSomething();
}
?>
See also Sun, iPlanet and Netscape servers on Sun Solaris.
ext/newt
[Since 0.9.2] - [ -P Extensions/Extnewt ] - [ Online docs ]
Newt PHP CLI extension.
This is a PHP language extension for RedHat Newt library, a terminal-based window and widget library for writing applications with user friendly interface.
<?php
newt_init ();
newt_cls ();
newt_draw_root_text (0, 0, Test Mode Setup Utility 1.12);
newt_push_help_line (null);
newt_get_screen_size ($rows, $cols);
newt_open_window ($rows/2-17, $cols/2-10, 34, 17, Choose a Tool);
$form = newt_form ();
$list = newt_listbox (3, 2, 10);
foreach (array (
Authentication configuration,
Firewall configuration,
Mouse configuration,
Network configuration,
Printer configuration,
System services) as $l_item)
{
newt_listbox_add_entry ($list, $l_item, $l_item);
}
$b1 = newt_button (5, 12, Run Tool);
$b2 = newt_button (21, 12, Quit);
newt_form_add_component ($form, $list);
newt_form_add_components ($form, array($b1, $b2));
newt_refresh ();
newt_run_form ($form);
newt_pop_window ();
newt_pop_help_line ();
newt_finished ();
newt_form_destroy ($form);
?>
See also Newt.
ext/ncurses
[Since 0.9.2] - [ -P Extensions/Extncurses ] - [ Online docs ]
Extension ncurses (CLI).
ncurses (new curses) is a free software emulation of curses in System V Rel 4.0 (and above).
<?php
ncurses_init();
ncurses_start_color();
ncurses_init_pair(1, NCURSES_COLOR_GREEN, NCURSES_COLOR_BLACK);
ncurses_init_pair(2, NCURSES_COLOR_RED, NCURSES_COLOR_BLACK);
ncurses_init_pair(3, NCURSES_COLOR_WHITE, NCURSES_COLOR_BLACK);
ncurses_color_set(1);
ncurses_addstr('OK ');
ncurses_color_set(3);
ncurses_addstr('Success!'.PHP_EOL);
ncurses_color_set(2);
ncurses_addstr('FAIL ');
ncurses_color_set(3);
ncurses_addstr('Success!'.PHP_EOL);
?>
See also Ncurses Terminal Screen Control and Ncurses.
Use Composer Lock
[Since 0.9.2] - [ -P Composer/UseComposerLock ] - [ Online docs ]
Reports if composer.lock was committed to the archive.
Too Many Local Variables
[Since 0.9.2] - [ -P Functions/TooManyLocalVariables ] - [ Online docs ]
Too many local variables were found in the methods. When over 15 variables are found in such a method, a violation is reported.
Local variables exclude globals (imported with global) and arguments. Local variable include static variables.
When too many variables are used in a function, it is a code smells. The function is trying to do too much and needs extra space for juggling.
Beyond 15 variables, it becomes difficult to keep track of their name and usage, leading to confusion, overwriting or hijacking.
<?php
// This function is OK : 3 vars are arguments, 3 others are globals.
function a20a3g3($a1, $a2, $a3) {
global $a4, $a5, $a6;
$a1 = 1;
$a2 = 2;
$a3 = 3 ;
$a4 = 4 ;
$a5 = 5 ;
$a6 = 6 ;
$a7 = 7 ;
$a8 = 8 ;
$a9 = 9 ;
$a10 = 10;
$a11 = 11;
$a12 = 12;
$a13 = 13 ;
$a14 = 14 ;
$a15 = 15 ;
$a16 = 16 ;
$a17 = 17 ;
$a18 = 18 ;
$a19 = 19 ;
$a20 = 20;
}
// This function has too many variables
function a20() {
$a1 = 1;
$a2 = 2;
$a3 = 3 ;
$a4 = 4 ;
$a5 = 5 ;
$a6 = 6 ;
$a7 = 7 ;
$a8 = 8 ;
$a9 = 9 ;
$a10 = 10;
$a11 = 11;
$a12 = 12;
$a13 = 13 ;
$a14 = 14 ;
$a15 = 15 ;
$a16 = 16 ;
$a17 = 17 ;
$a18 = 18 ;
$a19 = 19 ;
$a20 = 20;
}
?>
$GLOBALS Or global
[Since 0.9.2] - [ -P Php/GlobalsVsGlobal ] - [ Online docs ]
Usually, PHP projects make a choice between the global keyword, and the $GLOBALS variable. Sometimes, the project has no recommendations.
When your project use a vast majority of one of the convention, then the analyzer will report all remaining inconsistently cased constant.
<?php
global $a, $b, $c, $d, $e, $f, $g, $h, $i, $j, $k, $l, $m;
// This access is inconsistent with the previous usage
$GLOBALS['a'] = 2;
?>
Illegal Name For Method
[Since 0.9.2] - [ -P Classes/WrongName ] - [ Online docs ]
PHP has reserved usage of methods starting with __ for magic methods. It is recommended to avoid using this prefix, to prevent confusions.
<?php
class foo{
// Constructor
function __construct() {}
// Constructor's typo
function __constructor() {}
// Illegal function name, even as private
private function __bar() {}
}
?>
See also Magic Methods.
Unset() Or (unset)
[Since 0.9.3] - [ -P Php/UnsetOrCast ] - [ Online docs ]
Unset() and (unset) have the same functional use.
The analyzed code has less than 10% of one of them : for consistency reasons, it is recommended to make them all the same.
It happens that unset() or (unset) are used depending on coding style and files. One file may be consistently using unset(), while the others are all using (unset).
<?php
// be consistent
(unset) $a1;
(unset) $a2;
(unset) $a3;
(unset) $a4;
(unset) $a5;
(unset) $a6;
(unset) $a7;
(unset) $a8;
(unset) $a9;
(unset) $a10;
(unset) $a11;
(unset) $a12;
unset($b);
?>
Close Tags Consistency
[Since 0.9.3] - [ -P Php/CloseTagsConsistency ] - [ Online docs ]
PHP scripts may omit the final closing tag.
This is a convention, used to avoid the infamous 'headers already sent' error message, that appears when a script with extra invisible spaces is included before actually emitting the headers.
The PHP manual recommends : If a file is pure PHP code, it is preferable to omit the PHP closing tag at the end of the file.. (See PHP Tags)
<?php
class foo {
}
?>
String
[Since 0.9.4] - [ -P Extensions/Extstring ] - [ Online docs ]
Strings in PHP. Strings are part of the core of PHP, and are not a separate extension.
<?php
$str = Mary Had A Little Lamb and She LOVED It So;
$str = strtolower($str);
echo $str; // Prints mary had a little lamb and she loved it so
?>
See also String functions.
Class Should Be Final By Ocramius
[Since 0.9.4] - [ -P Classes/FinalByOcramius ] - [ Online docs ]
'Make your classes always final, if they implement an interface, and no other public methods are defined'.
When a class should be final, as explained by Ocramius ( Marco Pivetta ).
<?php
interface i1 {
function i1() ;
}
// Class should final, as its public methods are in an interface
class finalClass implements i1 {
// public interface
function i1 () {}
// private method
private function a1 () {}
}
?>
See also When to declare classes final.
ext/mhash
[Since 0.9.4] - [ -P Extensions/Extmhash ] - [ Online docs ]
Extension mhash (obsolete since PHP 5.3.0).
This extension provides functions, intended to work with mhash.
<?php
$input = 'what do ya want for nothing?';
$hash = mhash(MHASH_MD5, $input);
echo 'The hash is ' . bin2hex($hash) . '<br />'.PHP_EOL;
$hash = mhash(MHASH_MD5, $input, 'Jefe');
echo 'The hmac is ' . bin2hex($hash) . '<br />'.PHP_EOL;
?>
See also Extension mhash.
ext/zbarcode
[Since 0.9.5] - [ -P Extensions/Extzbarcode ] - [ Online docs ] - [ PHP 7.0 and more recent ]
Extension Zbarcode.
PHP extension for reading barcodes.
<?php
/* Create new image object */
$image = new ZBarCodeImage('test.jpg');
/* Create a barcode scanner */
$scanner = new ZBarCodeScanner();
/* Scan the image */
$barcode = $scanner->scan($image);
/* Loop through possible barcodes */
if (!empty($barcode)) {
foreach ($barcode as $code) {
printf('Found type %s barcode with data %s\n', $code['type'], $code['data']);
}
}
?>
See also php-zbarcode.
ext/mongodb
[Since 0.9.5] - [ -P Extensions/Extmongodb ] - [ Online docs ] - [ PHP 7.0 and more recent ]
Extension MongoDb.
Do not mistake with extension Mongo, the previous version.
Mongodb driver supports both PHP and HHVM and is developed atop the libmongoc and libbson libraries.
<?php
require 'vendor/autoload.php'; // include Composer's autoloader
$client = new MongoDB\Client(mongodb://localhost:27017);
$collection = $client->demo->beers;
$result = $collection->insertOne( [ 'name' => 'Hinterland', 'brewery' => 'BrewDog' ] );
echo Inserted with Object ID {$result->getInsertedId()};
?>
See also MongoDB driver.
Should Use Function
[Since 0.9.5] - [ -P Php/ShouldUseFunction ] - [ Online docs ]
Functioncalls that fall back to global scope should be using 'use function' or be fully namespaced.
PHP searches for functions in the local namespaces, and in case it fails, makes the same search in the global scope. Anytime a native function is referenced this way, the search (and fail) happens. This slows down the scripts.
The speed bump range from 2 to 8 %, depending on the availability of functions in the local scope. The overall bump is about 1 µs per functioncall, which makes it a micro optimisation until a lot of function calls are made.
Based on one of Marco Pivetta tweet.
<?php
namespace X {
use function strtolower as strtolower_aliased;
// PHP searches for strtolower in X, fails, then falls back to global scope, succeeds.
$a = strtolower($b);
// PHP searches for strtolower in global scope, succeeds.
$a = \strtolower($b);
// PHP searches for strtolower_aliased in global scope, succeeds.
$a = \strtolower_aliased($b);
}
?>
This analysis is a related to Performances/Php74ArrayKeyExists, and is a more general version.
See also blog post.
One Expression Brackets Consistency
[Since 0.9.5] - [ -P Structures/OneExpressionBracketsConsistency ] - [ Online docs ]
Brackets around one-line expressions are not consistent.
PHP makes bracket optional when a control structure pilot only one expression. Both are semantically identical.
This analysis reports code that uses brackets while the vast majority of other expressions uses none. Or the contrary.
<?php
// One expression with brackets
for($i = 0; $i < 10; $i++) { $c++; }
// One expression without bracket
for($i2 = 0; $i2 < 10; $i2++) $c++;
?>
Another analysis, [Structures/Bracketless], reports the absence of brackets as an error.
Fetch One Row Format
[Since 0.9.6] - [ -P Performances/FetchOneRowFormat ] - [ Online docs ]
When reading results with ext/Sqlite3, it is recommended to explicitly request SQLITE3_NUM or SQLITE3_ASSOC, while avoiding the default value and SQLITE3_BOTH.
<?php
$res = $database->query($query);
// Fastest version, but less readable
$row = $res->fetchArray(\SQLITE3_NUM);
// Almost the fastest version, and more readable
$row = $res->fetchArray(\SQLITE3_ASSOC);
// Default version. Quite slow
$row = $res->fetchArray();
// Worse case
$row = $res->fetchArray(\SQLITE3_BOTH);
?>
This is a micro-optimisation. The difference may be visible with 200k rows fetches, and measurable with 10k.
No String With Append
[Since 0.8.4] - [ -P Php/NoStringWithAppend ] - [ Online docs ] - [ PHP 7.0 and more recent ]
PHP 7 doesn't allow the usage of [] with strings. [] is an array-only operator.
<?php
$string = 'abc';
// Not possible in PHP 7
$string[] = 'd';
?>
This was possible in PHP 5, but is now forbidden in PHP 7.
Avoid glob() Usage
[Since 0.9.6] - [ -P Performances/NoGlob ] - [ Online docs ]
glob() and scandir() sorts results by default. When that kind of sorting is not needed, save some time by requesting NOSORT with those functions.
Besides, whenever possible, use scandir() instead of glob().
<?php
// Scandir without sorting is the fastest.
scandir('docs/', SCANDIR_SORT_NONE);
// Scandir sorts files by default. Same as above, but with sorting
scandir('docs/');
// glob sorts files by default. Same as below, but no sorting
glob('docs/*', GLOB_NOSORT);
// glob sorts files by default. This is the slowest version
glob('docs/*');
?>
Using opendir() and a while loop may be even faster.
This analysis skips scandir() and glob() if they are expliciely configured with flags (aka, sorting is explicitly needed).
glob() accepts wildchar, such as * , that may not easily replaced with scandir() or opendir().
See also Putting glob to the test and
glob://.
Avoid Large Array Assignation
[Since 0.9.7] - [ -P Structures/NoAssignationInFunction ] - [ Online docs ]
Avoid setting large arrays to local variables. This is done every time the function is called.
There are different ways to avoid this : inject the array, build the array once. Using an constant or even a global variable is faster.
The effect on small arrays (less than 10 elements) is not significant. Arrays with 10 elements or more are reported here. The effect is also more important on functions that are called often, or within loops.
<?php
// with constants, for functions
const ARRAY = array(1,2,3,4,5,6,7,8,9,10,11);
function foo() {
$array = ARRAY;
//more code
}
// with class constants, for methods
class x {
const ARRAY = array(1,2,3,4,5,6,7,8,9,10,11);
function foo() {
$array = self::ARRAY;
//more code
}
}
// with properties, for methods
class x {
private $array = array(1,2,3,4,5,6,7,8,9,10,11);
function foo() {
$array = $this->array;
//more code
}
}
// injection, leveraging default values
function foo($array = array(1,2,3,4,5,6,7,8,9,10,11)) {
//more code
}
// local cache with static
function foo() {
static $array;
if ($array === null) {
$array = array(1,2,3,4,5,6,7,8,9,10,11);
}
//more code
}
// Avoid creating the same array all the time in a function
class x {
function foo() {
// assign to non local variable is OK.
// Here, to a property, though it may be better in a __construct or as default values
$this->s = array(1,2,3,4,5,6,7,8,9,10,11);
// This is wasting resources, as it is done each time.
$a?>
Could Be Protected Property
[Since 0.9.7] - [ -P Classes/CouldBeProtectedProperty ] - [ Online docs ]
Those properties are declared public, but are never used publicly. They may be made protected.
<?php
class foo {
// Public, and used publicly
public $publicProperty;
// Public, but never used outside the class or its children
public $protectedProperty;
function bar() {
$this->protectedProperty = 1;
}
}
$foo = new Foo();
$foo->publicProperty = 3;
?>
This property may even be made private.
Long Arguments
[Since 0.9.7] - [ -P Structures/LongArguments ] - [ Online docs ]
Long arguments should be put in variable, to preserve readability.
When literal arguments are too long, they break the hosting structure by moving the next argument too far on the right. Whenever possible, long arguments should be set in a local variable to keep the readability.
<?php
// Now the call to foo() is easier to read.
$reallyBigNumber = <<<BIGNUMBER
123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890
BIGNUMBER
foo($reallyBigNumber, 2, '12345678901234567890123456789012345678901234567890');
// where are the next arguments ?
foo('123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890', 2, '123456789012345678901234567890123456789012345678901234567890');
// This is still difficult to read
foo(<<<BIGNUMBER
123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890
BIGNUMBER
, 2, '123456789012345678901234567890123456789012345678901234567890');
?>
Literal strings and heredoc strings, including variables, that are over 50 chars longs are reported here.
New On Functioncall Or Identifier
[Since 0.9.8] - [ -P Classes/NewOnFunctioncallOrIdentifier ] - [ Online docs ]
Object instantiation with new works with or without arguments. Both are valid in PHP.
The analyzed code has less than 10% of one of the two forms : for consistency reasons, it is recommended to make them all the same.
<?php
$a = new stdClass();
// Parenthesis are used when arguments are compulsory
$mysql = new MySQLI($host, $user, $pass);
// Parenthesis are omitted when no arguments are available
// That also makes the instantiation look different
$b = new stdClass;
?>
Assigned Twice
[Since 0.9.8] - [ -P Variables/AssignedTwiceOrMore ] - [ Online docs ]
The same variable is assigned twice in the same function.
While this is possible and quite common, it is also a good practice to avoid changing a value from one literal to another. It is far better to assign the new value to
Incremental changes to a variables are not reported here.
<?php
function foo() {
// incremental changes of $a;
$a = 'a';
$a++;
$a = uppercase($a);
$b = 1;
$c = bar($b);
// B changed its purpose. Why not call it $d?
$b = array(1,2,3);
// This is some forgotten debug
$e = $config->getSomeList();
$e = array('OneElement');
}
?>
New Line Style
[Since 0.9.8] - [ -P Structures/NewLineStyle ] - [ Online docs ]
New lines may be written with the sequence \n or with the constant PHP_EOL.
When one of those alternatives is used over 90% of the time, it is considered as standard : the remaining are reported.
\n are only located when used alone, in \n (including the double quotes). When \n is used inside a double-quoted string, its replacement with PHP_EOL would be cumbersome : as such, they are ignored by this analyzer.
<?php
// This may be repeated over 10 times
$a = PHP is a great language\n;
$a .= \n;
// This only appears once in the code : this line is reported.
$b = $a.PHP_EOL.$c;
?>
PHP 7.2 Deprecations
[Since 0.9.9] - [ -P Php/Php72Deprecation ] - [ Online docs ] - [ PHP older than 7.2]
Several functions are deprecated in PHP 7.2.
- parse_str() with no second argument
- assert() on strings
- Usage of gmp_random(), create_function(), each()
- Usage of (unset)
- Usage of $php_errormsg
- directive mbstring.func_overload (not supported yet)
Deprecated functions and extensions are reported in a separate analysis.
See also Deprecations for PHP 7.2.
PHP 7.2 Removed Functions
[Since 0.9.9] - [ -P Php/Php72RemovedFunctions ] - [ Online docs ] - [ PHP older than 7.2]
The following PHP native functions were removed in PHP 7.2.
- png2wbmp()
- jpeg2wbmp()
- create_function()
- gmp_random()
- each()
This analysis skips redefined PHP functions : when a replacement for a removed PHP function was created, with condition on the PHP version, then its usage is considered valid.
See also Deprecated features in PHP 7.2.x.
Error_Log() Usage
[Since 0.10.0] - [ -P Php/ErrorLogUsage ] - [ Online docs ]
Usage of error_log() function. This leads to checking the configuration of error_log in the PHP configuration directives.
<?php
error_log(logging message\n);
?>
Raised Access Level
[Since 0.10.0] - [ -P Classes/RaisedAccessLevel ] - [ Online docs ]
A property's visibility may be lowered, but not raised.
This error may be detected when the classes are all in the same file : then, PHP reports the problem. However, when the classes are separated in different files, as it is customary, PHP won't check this at linting time, yielding a fatal error at execution time.
First file.
<?php
class Foo {
public $publicProperty;
protected $protectedProperty;
private $privateProperty;
}
?>
Second file.
<?php
class Bar extends Foo {
private $publicProperty;
private $protectedProperty;
private $privateProperty; // This one is OK
}
?>
See also Visibility and
Understanding the concept of visibility in object oriented php.
No Boolean As Default
[Since 0.10.0] - [ -P Functions/NoBooleanAsDefault ] - [ Online docs ]
Default values should always be set up with a constant name.
Class constants and constants improve readability when calling the methods or comparing values and statuses.
<?php
const CASE_INSENSITIVE = true;
const CASE_SENSITIVE = false;
function foo($case_insensitive = true) {
// doSomething()
}
// Readable code
foo(CASE_INSENSITIVE);
foo(CASE_SENSITIVE);
// unreadable code : is true case insensitive or case sensitive ?
foo(true);
foo(false);
?>
See also FlagArgument and
Clean code: The curse of a boolean parameter.
SQL queries
[Since 0.10.1] - [ -P Type/Sql ] - [ Online docs ]
SQL queries, detected in literal strings.
SQL queries are detected with keywords, inside literals or concatenations.
<?php
// SQL in a string
$query = 'SELECT name FROM users WHERE id = 1';
// SQL in a concatenation
$query = 'SELECT name FROM '.$table_users.' WHERE id = 1';
// SQL in a Heredoc
$query = <<<SQL
SELECT name FROM $table_users WHERE id = 1
SQL;
?>
ext/libsodium
[Since 0.10.2] - [ -P Extensions/Extlibsodium ] - [ Online docs ]
Extension for libsodium : in PECL until PHP 7.2, and in core ever since.
The Sodium crypto library (libsodium) is a modern, easy-to-use software library for encryption, decryption, signatures, password hashing and more.
Sodium supports a variety of compilers and operating systems, including Windows (with MinGW or Visual Studio, x86 and x64), iOS and Android.
The design choices emphasize security, and "magic constants" have clear rationales.
<?php
// Example from the docs : https://paragonie.com/book/pecl-libsodium/read/06-hashing.md#crypto-generichash
// Fast, unkeyed hash function.
// Can be used as a secure replacement for MD5
$h = \Sodium\crypto_generichash('msg');
// Fast, keyed hash function.
// The key can be of any length between \Sodium\CRYPTO_GENERICHASH_KEYBYTES_MIN
// and \Sodium\CRYPTO_GENERICHASH_KEYBYTES_MAX, in bytes.
// \Sodium\CRYPTO_GENERICHASH_KEYBYTES is the recommended length.
$h = \Sodium\crypto_generichash('msg', $key);
// Fast, keyed hash function, with user-chosen output length, in bytes.
// Output length can be between \Sodium\CRYPTO_GENERICHASH_BYTES_MIN and
// \Sodium\CRYPTO_GENERICHASH_BYTES_MAX.
// \Sodium\CRYPTO_GENERICHASH_BYTES is the default length.
$h = \Sodium\crypto_generichash('msg', $key, 64);
?>
See also PHP extension for libsodium and
Using Libsodium in PHP Projects.
Forgotten Thrown
[Since 0.10.2] - [ -P Exceptions/ForgottenThrown ] - [ Online docs ]
An exception is instantiated, but not thrown.
<?php
class MyException extends \Exception { }
if ($error !== false) {
// This looks like 'throw' was omitted
new MyException();
}
?>
Should Use array_column()
[Since 0.10.2] - [ -P Php/ShouldUseArrayColumn ] - [ Online docs ]
Avoid writing a whole slow loop, and use the native array_column().
array_column() is a native PHP function, that extract a property or a index from a array of object, or a multidimensional array. This prevents the usage of foreach to collect those values.
<?php
$a = array(array('b' => 1),
array('b' => 2, 'c' => 3),
array( 'c' => 4)); // b doesn't always exists
$bColumn = array_column($a, 'b');
// Slow and cumbersome code
$bColumn = array();
foreach($a as $k => $v) {
if (isset($v['b'])) {
$bColumn[] = $v['b'];
}
}
?>
array_column() is faster than foreach() (with or without the isset() test) with 3 elements or more, and it is significantly faster beyond 5 elements. Memory consumption is the same.
See also [blog] `array_column()
Multiple Alias Definitions Per File
[Since 0.10.3] - [ -P Namespaces/MultipleAliasDefinitionPerFile ] - [ Online docs ]
Avoid aliasing the same name with different aliases. This leads to confusion.
<?php
// first occurrence
use name\space\ClasseName;
// when this happens, several other uses are mentionned
// name\space\ClasseName has now two names
use name\space\ClasseName as anotherName;
?>
See also Namespaces/MultipleAliasDefinition.
__DIR__ Then Slash
[Since 0.10.3] - [ -P Structures/DirThenSlash ] - [ Online docs ]
__DIR__ must be concatenated with a string starting with /.
The magic constant __DIR__ holds the name of the current directory, without final /. When it is used to build path, then the following path fragment must start with /. Otherwise, two directories names will be merged together.
<?php
// __DIR__ = /a/b/c
// $filePath = /a/b/c/g.php
// /a/b/c/d/e/f.txt : correct path
echo __DIR__.'/d/e/f.txt';
echo dirname($filePath).'/d/e/f.txt';
// /a/b/cd/e/f.txt : most probably incorrect path
echo __DIR__.'d/e/f.txt';
echo dirname($filePath).'d/e/f.txt';
?>
self, parent, static Outside Class
[Since 0.10.3] - [ -P Classes/NoPSSOutsideClass ] - [ Online docs ]
self, parent and static should be called inside a class or trait. PHP lint won't report those situations.
self, parent and static may be used in a trait : their actual value will be only known at execution time, when the trait is used.
<?php
// In the examples, self, parent and static may be used interchangeably
// This raises a Fatal error
//Fatal error: Uncaught Error: Cannot access static:: when no class scope is active
new static();
// static calls
echo self::CONSTANTE;
echo self::$property;
echo self::method();
// as a type hint
function foo(static $x) {
doSomething();
}
// as a instanceof
if ($x instanceof static) {
doSomething();
}
?>
Such syntax problem is only revealed at execution time : PHP raises a Fatal error.
The origin of the problem is usually a method that was moved outside a class, at least temporarily.
See also Scope Resolution Operator (::).
Used Once Property
[Since 0.10.3] - [ -P Classes/UsedOnceProperty ] - [ Online docs ]
Property used once in their defining class.
Properties used in one method only may be used several times, and read only. This may be a class constant. Such properties are meant to be overwritten by an extending class, and that's possible with class constants.
Setting properties with default values is a good way to avoid littering the code with literal values, and provide a single point of update (by extension, or by hardcoding) for all those situations. A constant is definitely better suited for this task.
<?php
class foo {
private $defaultCols = '*';
cont DEFAULT_COLUMNS = '*';
// $this->defaultCols holds a default value. Should be a constant.
function bar($table, $cols) {
// This is necessary to activate usage of default values
if (empty($cols)) {
$cols = $this->defaultCols;
}
$res = $this->query('SELECT '.$cols.' FROM '.$table);
// ....
}
// Upgraded version of bar, with default values
function bar2($table, $cols = self::DEFAULT_COLUMNS) {
$res = $this->query('SELECT '.$cols.' FROM '.$table);
// .....
}
}
?>
Property Used In One Method Only
[Since 0.10.3] - [ -P Classes/PropertyUsedInOneMethodOnly ] - [ Online docs ]
Properties should be used in several methods. When a property is used in only one method, this should have be of another shape.
Properties used in one method only may be used several times, and read only. This may be a class constant. Such properties are meant to be overwritten by an extending class, and that's possible with class constants.
Properties that read and written may be converted into a variable, static to the method. This way, they are kept close to the method, and do not pollute the object's properties.
<?php
class foo {
private $once = 1;
const ONCE = 1;
private $counter = 0;
function bar() {
// $this->once is never used anywhere else.
someFunction($this->once);
someFunction(self::ONCE); // Make clear that it is a
}
function bar2() {
static $localCounter = 0;
$this->counter++;
// $this->once is only used here, for distinguising calls to someFunction2
if ($this->counter > 10) { // $this->counter is used only in bar2, but it may be used several times
return false;
}
someFunction2($this->counter);
// $localCounter keeps track for all the calls
if ($localCounter > 10) {
return false;
}
someFunction2($localCounter);
}
}
?>
Note : properties used only once are not returned by this analysis. They are omitted, and are available in the analysis `Used Once Property`_.
ext/ds
[Since 0.10.4] - [ -P Extensions/Extds ] - [ Online docs ]
Extension Data Structures : Data structures.
See also : Efficient data structures for PHP 7.
<?php
$vector = new \Ds\Vector();
$vector->push('a');
$vector->push('b', 'c');
$vector[] = 'd';
print_r($vector);
?>
No Need For Else
[Since 0.10.4] - [ -P Structures/NoNeedForElse ] - [ Online docs ]
Else is not needed when the Then ends with a break. A break may be the following keywords : break, continue, return, goto. Any of these send the execution somewhere in the code. The else block is then executed as the main sequence, only if the condition fails.
<?php
function foo() {
// Else may be in the main sequence.
if ($a1) {
return $a1;
} else {
$a++;
}
// Same as above, but negate the condition : if (!$a2) { return $a2; }
if ($a2) {
$a++;
} else {
return $a2;
}
// This is OK
if ($a3) {
return;
}
// This has no break
if ($a4) {
$a++;
} else {
$b++;
}
// This has no else
if ($a5) {
$a++;
}
}
?>
See also Object Calisthenics, rule # 2.
Should Use session_regenerateid()
[Since 0.10.4] - [ -P Security/ShouldUseSessionRegenerateId ] - [ Online docs ]
session_regenerateid() should be used when sessions are used.
When using sessions, a session ID is assigned to the user. It is a random number, used to connect the user and its data on the server. Actually, anyone with the session ID may have access to the data. This is why those session ID are so long and complex.
A good approach to protect the session ID is to reduce its lifespan : the shorter the time of use, the better. While changing the session ID at every hit on the page may no be possible, a more reasonable approach is to change the session id when an important action is about to take place. What important means is left to the application to decide.
Based on this philosophy, a code source that uses Zend\Session but never uses Zend\Session::regenerateId() has to be updated.
<?php
session_start();
$id = (int) $_SESSION['id'];
// no usage of session_regenerateid() anywhere triggers the analysis
// basic regeneration every 20 hits on the page.
if (++$_SESSION['count'] > 20) {
session_regenerateid();
}
?>
See session_regenerateid() and PHP Security Guide: Sessions.
Strange Name For Variables
[Since 0.10.5] - [ -P Variables/StrangeName ] - [ Online docs ]
Variables with strange names. They might be a typo, or bear strange patterns.
Any variable with three identical letter in a row are considered as strange. 2 letters in a row is classic, and while three letters may happen, it is rare enough.
A list of classic typo is also used to find such variables.
This analysis is case-sensitive.
<?php
class foo {
function bar() {
// Strange name $tihs
return $tihs;
}
function barbar() {
// variables with blocks of 3 times the same character are reported
// Based on Alexandre Joly's tweet
$aaa = $bab + $www;
}
}
?>
See also #QuandLeDevALaFleme.
Strange Name For Constants
[Since 0.10.5] - [ -P Constants/StrangeName ] - [ Online docs ]
Those constants looks like a typo from other names.
<?php
// This code looks OK : DIRECTORY_SEPARATOR is a native PHP constant
$path = $path . DIRECTORY_SEPARATOR . $file;
// Strange name DIRECOTRY_SEPARATOR
$path = $path . DIRECOTRY_SEPARATOR . $file;
?>
Regex Delimiter
[Since 0.10.5] - [ -P Structures/RegexDelimiter ] - [ Online docs ]
PCRE regular expressions may use a variety of delimiters.
There seems to be a standard delimiter in the code, and some exceptions : one or several forms are dominant (> 90%), while the others are rare.
The analyzed code has less than 10% of the rare delimiters. For consistency reasons, it is recommended to make them all the same.
Generally, one or two delimiters are used, depending on the expected special chars in the scanned strings : for example, / tends to be avoided when parsing HTML.
Regex are literals, or partial literals, used in preg_match(), preg_match_all(), preg_replace(), preg_replace_callback(), preg_replace_callback_array().
<?php
echo 'a';
echo 'b';
echo 'c';
echo 'd';
echo 'e';
echo 'f';
echo 'g';
echo 'h';
echo 'i';
echo 'j';
echo 'k';
// This should probably be written 'echo';
print 'l';
?>
See also Ideal regex delimiters in PHP.
Could Be Typehinted Callable
[Since 0.10.5] - [ -P Functions/CouldBeCallable ] - [ Online docs ]
Those arguments may use the callable Typehint.
'callable' is a PHP keyword that represents callback functions. Those may be used in dynamic function call, like $function(); or as callback functions, like with array_map();
callable may be a string representing a function name or a static call (including ::), an array with two elements, (a class or object, and a method), or a closure.
When arguments are used to call a function, but are not marked with 'callable', they are reported by this analysis.
<?php
function foo(callable $callable) {
// very simple callback
return $callable();
}
function foo2($array, $callable) {
// very simple callback
return array_map($array, $callable);
}
?>
See also Callback / callable.
Encoded Simple Letters
[Since 0.10.5] - [ -P Security/EncodedLetters ] - [ Online docs ]
Some simple letters are written in escape sequence.
Usually, escape sequences are made to encode unusual characters. Using escape sequences for simple characters, like letters or numbers is suspicious.
This analysis also detects Unicode codepoint with superfluous leading zeros.
<?php
// This escape sequence makes eval hard to spot
$a = ev\101l;
$a('php_info();');
// With a PHP 7.0 unicode code point sequence
$a = ev\u{000041}l;
$a('php_info();');
// With a PHP 5.0+ hexadecimal sequence
$a = ev\x41l;
$a('php_info();');
?>
Too Many Finds
[Since 0.10.5] - [ -P Classes/TooManyFinds ] - [ Online docs ]
Too many methods called 'find*' in this class. It is may be time to consider the Specification pattern.
<?php
// quite a fishy interface
interface UserInterface {
public function findByEmail($email);
public function findByUsername($username);
public function findByFirstName($firstname);
public function findByLastName($lastname);
public function findByName($name);
public function findById($id);
public function insert($user);
public function update($user);
}
?>
See also On Taming Repository Classes in Doctrine ,
On Taming Repository Classes in Doctrine… Among other things.,
specifications.
Use Cookies
[Since 0.10.6] - [ -P Php/UseCookies ] - [ Online docs ]
This code source uses cookies.
Cookie usage is spotted with the usage of setcookie(), setawcookie() and header() with the 'Set-Cookie' header.
<?php
header('Set-Cookie: '.$name.'='.$value.'; EXPIRES'.$date.';');
// From the PHP Manual :
setcookie('TestCookie3', $value, time()+3600, '/~rasmus/', 'example.com', 1);
?>
See also : Cookies.
Should Use SetCookie()
[Since 0.10.6] - [ -P Php/UseSetCookie ] - [ Online docs ]
Use setcookie() or setrawcookie(). Avoid using header() to do so, as the PHP native functions are more convenient and easier to spot during a refactoring.
setcookie() applies some encoding internally, for the value of the cookie and the date of expiration. Rarely, this encoding has to be skipped : then, use setrawencoding().
Both functions help by giving a checklist of important attributes to be used with the cookie.
<?php
// same as below
setcookie(myCookie, 'chocolate', time()+3600, /, , true, true);
// same as above. Slots for path and domain are omitted, but should be used whenever possible
header('Set-Cookie: myCookie=chocolate; Expires='.date('r', (time()+3600)).'; Secure; HttpOnly');
?>
See also Set-Cookie,
setcookie.
Set Cookie Safe Arguments
[Since 0.10.6] - [ -P Security/SetCookieArgs ] - [ Online docs ]
The last five arguments of setcookie() and setrawcookie() are for security. Use them anytime you can.
setcookie ( string $name [, string $value = [, int $expire = 0 [, string $path = [, string $domain = [, bool $secure = false [, bool $httponly = false ]]]]]] )
The $expire argument sets the date of expiration of the cookie. It is recommended to make it as low as possible, to reduce its chances to be captured. Sometimes, low expiration date may be several days (for preferences), and other times, low expiration date means a few minutes.
The $path argument limits the transmission of the cookie to URL whose path matches the one mentioned here. By default, it is '/' , which means the whole server. If a cookie usage is limited to a part of the application, use it here.
The $domain argument limits the transmission of the cookie to URL whose domain matches the one mentioned here. By default, it is '' , which means any server on the internet. At worse, you may use mydomain.com to cover your whole domain, or better, refine it with the actual subdomain of usage.
The $secure argument limits the transmission of the cookie over HTTP (by default) or HTTPS. The second is better, as the transmission of the cookie is crypted. In case HTTPS is still at the planned stage, use '$_SERVER[HTTPS]'. This environment variable is false on HTTP, and true on HTTPS.
The $httponly argument limits the access of the cookie to JavaScript. It is only transmitted to the browser, and retransmitted. This helps reducing XSS and CSRF attacks, though it is disputed.
The $samesite argument limits the sending of the cookie to the domain that initiated the request. It is by default Lax but should be upgraded to Strict whenever possible. This feature is available as PHP 7.3.
<?php
//admin cookie, available only on https://admin.my-domain.com/system/, for the next minute, and not readable by javascript
setcookie(admin, $login, time()+60, /system/, admin.my-domain.com, $_SERVER['HTTPS'], 1);
//login cookie, available until the browser is closed, over http or https
setcookie(login, $login);
//removing the login cookie : Those situations are omitted by the analysis
setcookie(login, '');
?>
See also setcookie and
'SameSite' cookie attribute.
Check All Types
[Since 0.10.6] - [ -P Structures/CheckAllTypes ] - [ Online docs ]
When checking for time, avoid using else. Mention explicitly all tested type, and raise an exception when reaching else.
PHP has a short list of scalar types : null, boolean, integer, real, strings, object, resource and array. When a variable is not holding one the the type, then it may be of any other type.
Most of the time, when using a simple is_string() / else test, this is relying on the conception of the code. By construction, the arguments may be one of two types : array or string.
What happens often is that in case of failure in the code (database not working, another class not checking its results), a third type is pushed to the structure, and it ends up breaking the execution.
The safe way is to check the various types all the time, and use the default case (here, the else) to throw exception() or test an assertion and handle the special case.
<?php
// hasty version
if (is_array($argument)) {
$out = $argument;
} else {
// Here, $argument is NOT an array. What if it is an object ? or a NULL ?
$out = array($argument);
}
// Safe type checking : do not assume that 'not an array' means that it is the other expected type.
if (is_array($argument)) {
$out = $argument;
} elseif (is_string($argument)) {
$out = array($argument);
} else {
assert(false, '$argument is not an array nor a string, as expected!');
}
?>
Using is_callable(), is_iterable() with this structure is fine : when variable is callable or not, while a variable is an integer or else.
Using a type test without else is also accepted here. This is a special treatment for this test, and all others are ignored. This aspect may vary depending on situations and projects.
Missing Cases In Switch
[Since 0.10.7] - [ -P Structures/MissingCases ] - [ Online docs ]
It seems that some cases are missing in this switch structure.
When comparing two different switch() structures, it appears that some cases are missing in one of them. The set of cases are almost identical, but one of the values are missing.
Switch() structures using strings as literals are compared in this analysis. When the discrepancy between two lists is below 25%, both switches are reported.
<?php
// This switch operates on a, b, c, d and default
switch($a) {
case 'a': doSomethingA(); break 1;
case 'b': doSomethingB(); break 1;
case 'c': doSomethingC(); break 1;
case 'd': doSomethingD(); break 1;
default: doNothing();
}
// This switch operates on a, b, d and default
switch($o->p) {
case 'a': doSomethingA(); break 1;
case 'b': doSomethingB(); break 1;
case 'd': doSomethingD(); break 1;
default: doNothing();
}
?>
In the example, one may argue that the 'c' case is actually handled by the 'default' case. Otherwise, business logic may request that omission.
New Functions In PHP 7.2
[Since 0.10.7] - [ -P Php/Php72NewFunctions ] - [ Online docs ] - [ PHP older than 7.2]
The following functions are now native functions in PHP 7.2. It is advised to change custom functions that are currently created, and using those names, before moving to this new version.
- mb_ord()
- mb_chr()
- mb_scrub()
- stream_isatty()
- proc_nice() (Windows only)
New Constants In PHP 7.2
[Since 0.10.7] - [ -P Php/Php72NewConstants ] - [ Online docs ] - [ PHP older than 7.2]
The following constants are now native in PHP 7.2. It is advised to avoid using such names for constant before moving to this new version.
- PHP_OS_FAMILY
- PHP_FLOAT_DIG
- PHP_FLOAT_EPSILON
- PHP_FLOAT_MAX
- PHP_FLOAT_MIN
- SQLITE3_DETERMINISTIC
- CURLSSLOPT_NO_REVOKE
- CURLOPT_DEFAULT_PROTOCOL
- CURLOPT_STREAM_WEIGHT
- CURLMOPT_PUSHFUNCTION
- CURL_PUSH_OK
- CURL_PUSH_DENY
- CURL_HTTP_VERSION_2TLS
- CURLOPT_TFTP_NO_OPTIONS
- CURL_HTTP_VERSION_2_PRIOR_KNOWLEDGE
- CURLOPT_CONNECT_TO
- CURLOPT_TCP_FASTOPEN
- DNS_CAA
See also New global constants in 7.2.
Group Use Declaration
[Since 0.10.7] - [ -P Php/GroupUseDeclaration ] - [ Online docs ]
The group use declaration is used in the code.
<?php
// Adapted from the RFC documentation
// Pre PHP 7 code
use some\name_space\ClassA;
use some\name_space\ClassB;
use some\name_space\ClassC as C;
use function some\name_space\fn_a;
use function some\name_space\fn_b;
use function some\name_space\fn_c;
use const some\name_space\ConstA;
use const some\name_space\ConstB;
use const some\name_space\ConstC;
// PHP 7+ code
use some\name_space\{ClassA, ClassB, ClassC as C};
use function some\name_space\{fn_a, fn_b, fn_c};
use const some\name_space\{ConstA, ConstB, ConstC};
?>
See also Group Use Declaration RFC and Using namespaces: Aliasing/Importing.
Repeated Regex
[Since 0.10.9] - [ -P Structures/RepeatedRegex ] - [ Online docs ]
Repeated regex should be centralized.
When a regex is repeatedly used in the code, it is getting harder to update.
<?php
// Regex used several times, at least twice.
preg_match('/^abc_|^square$/i', $_GET['x']);
//.......
preg_match('/^abc_|^square$/i', $row['name']);
// This regex is dynamically built, so it is not reported.
preg_match('/^circle|^'.$x.'$/i', $string);
// This regex is used once, so it is not reported.
preg_match('/^circle|^square$/i', $string);
?>
Regex that are repeated at least once (aka, used twice or more) are reported. Regex that are dynamically build are not reported.
No Class In Global
[Since 0.10.9] - [ -P Php/NoClassInGlobal ] - [ Online docs ]
Avoid defining structures in Global namespace. Always prefer using a namespace. This will come handy later, either when publishing the code, or when importing a library, or even if PHP reclaims that name.
<?php
// Code prepared for later
namespace Foo {
class Bar {}
}
// Code that may conflict with other names.
namespace {
class Bar {}
}
?>
Crc32() Might Be Negative
[Since 0.11.0] - [ -P Php/Crc32MightBeNegative ] - [ Online docs ]
crc32() may return a negative number, on 32 bits platforms.
According to the manual : Because PHP\'s integer type is signed many CRC32 checksums will result in negative integers on 32 bits platforms. On 64 bits installations, all crc32() results will be positive integers though.
<?php
// display the checksum with %u, to make it unsigned
echo sprintf('%u', crc32($str));
// turn the checksum into an unsigned hexadecimal
echo dechex(crc32($str));
// avoid concatenating crc32 to a string, as it may be negative on 32bits platforms
echo 'prefix'.crc32($str);
?>
See also `crc32()
Could Use str_repeat()
[Since 0.11.0] - [ -P Structures/CouldUseStrrepeat ] - [ Online docs ]
Use str_repeat() or str_pad() instead of making a loop.
Making a loop to repeat the same concatenation is actually much longer than using str_repeat(). As soon as the loop repeats more than twice, str_repeat() is much faster. With arrays of 30, the difference is significant, though the whole operation is short by itself.
<?php
// This adds 7 'e' to $x
$x .= str_repeat('e', 7);
// This is the same as above,
for($a = 3; $a < 10; ++$a) {
$x .= 'e';
}
// here, $default must contains 7 elements to be equivalent to the previous code
foreach($default as $c) {
$x .= 'e';
}
?>
Suspicious Comparison
[Since 0.11.0] - [ -P Structures/SuspiciousComparison ] - [ Online docs ]
The comparison seems to be misplaced.
A comparison happens in the last argument, while the actual function expect another type : this may be the case of a badly placed parenthesis.
<?php
// trim expect a string, a boolean is given.
if (trim($str === '')){
}
// Just move the first closing parenthesis to give back its actual meaning
if (trim($str) === ''){
}
?>
Original idea by Vladimir Reznichenko.
Empty Final Element
[Since 0.11.0] - [ -P Arrays/EmptyFinal ] - [ Online docs ]
The array() construct allows for the empty last element.
By putting an element on each line, and adding the final comma, it is possible to reduce the size of the diff when comparing code with the previous version.
<?php
// Array definition with final empty element
$array = [1,
2,
3,
];
// This array definition has only one line of diff with the previous array : the line with '4,'
$array = [1,
2,
3,
4,
];
// This array definition is totally different from the first array :
$array = [1, 2, 3, 4];
?>
See also Array,
Zend Framework Coding Standard and
How clean is your code? How clean are your diffs?.
Strings With Strange Space
[Since 0.11.0] - [ -P Type/StringWithStrangeSpace ] - [ Online docs ]
An invisible space may be mistaken for a normal space.
However, PHP does straight comparisons, and may fail at recognizing. This analysis reports when it finds such strange spaces inside strings.
PHP doesn't mistake space and tables for whitespace when tokenizing the code.
This analysis doesn't report Unicode Codepoint Notation : those are visible in the code.
<?php
// PHP 7 notation,
$a = \u{3000};
$b = ;
// Displays false
var_dump($a === $b);
?>
See also Unicode spaces, and
disallow irregular whitespace (no-irregular-whitespace).
Difference Consistence
[Since 0.11.1] - [ -P Structures/DifferencePreference ] - [ Online docs ]
There are two operators to check a difference : <> and !=.
The analyzed code has less than 10% of one of them : for consistency reasons, it is recommended to make them all the same.
It happens that != and <> are used depending on coding style and files. One file may be consistently using <>, while the others are all using !=.
<?php
// Both != and <> are used in the code
// When one of them is used less than 10%, it is reported as a consistence issue.
if ($a != $b) {
} elseif ($c <> $d) {
}
?>
<> and != are the two only comparison operators that are identical.
See also Comparison Operators.
No Empty Regex
[Since 0.11.1] - [ -P Structures/NoEmptyRegex ] - [ Online docs ]
PHP regex don't accept empty regex, nor regex with alphanumeric delimiter.
Most of those errors happen at execution time, when the regex is build dynamically, but still may end empty. At compile time, such error are made when the code is not tested before commit.
<?php
// No empty regex
preg_match('', $string, $r);
// Delimiter must be non-alphanumerical
preg_replace('1abc1', $string, $r);
// Delimiter must be non-alphanumerical
preg_replace('1'.$regex.'1', $string, $r);
?>
See also PCRE and Delimiters.
Alternative Syntax Consistence
[Since 0.11.2] - [ -P Structures/AlternativeConsistenceByFile ] - [ Online docs ]
PHP allows for two syntax : the alternative syntax, and the classic syntax.
The classic syntax is almost always used. When used, the alternative syntax is used in templates.
This analysis reports files that are using both syntax at the same time. This is confusing.
<?php
// Mixing both syntax is confusing.
foreach($array as $item) :
if ($item > 1) {
print $item elements\n;
} else {
print $item element\n;
}
endforeach;
?>
Randomly Sorted Arrays
[Since 0.11.2] - [ -P Arrays/RandomlySortedLiterals ] - [ Online docs ]
Those literal arrays are written in several places, but their items are in various orders.
This may reduce the reading and proofing of the arrays, and induce confusion. The random order may also be a residue of development : both arrays started with different values, but they grew overtime to handle the same items. The way they were written lead to the current order.
Unless order is important, it is recommended to always use the same order when defining literal arrays. This makes it easier to match different part of the code by recognizing one of its literal.
<?php
// an array
$set = [1,3,5,9,10];
function foo() {
// an array, with the same values but different order, in a different context
$list = [1,3,5,10,9,];
}
// an array, with the same order than the initial one
$inits = [1,3,5,9,10];
?>
ext/sphinx
[Since 0.11.3] - [ -P Extensions/Extsphinx ] - [ Online docs ]
Extension for the Sphinx search server.
This extension provides bindings for Sphinx search client library.
<?php
$s = new SphinxClient;
$s->setServer(localhost, 6712);
$s->setMatchMode(SPH_MATCH_ANY);
$s->setMaxQueryTime(3);
$result = $s->query(test);
var_dump($result);
?>
See also Sphinx Client and Sphinx Search.
Try With Multiple Catch
[Since 0.11.3] - [ -P Php/TryMultipleCatch ] - [ Online docs ]
Try may be used with multiple catch clauses.
<?php
try {
OneCatch();
} catch (FirstException $e) {
}
try {
TwoCatches();
} catch (FirstException $e) {
} catch (SecondException $e) {
}
?>
See also Exceptions.
ext/grpc
[Since 0.11.3] - [ -P Extensions/Extgrpc ] - [ Online docs ]
Extension for GRPC : A high performance, open-source universal RPC framework.
<?php
//https://github.com/grpc/grpc/blob/master/examples/php/greeter_client.php
require dirname(__FILE__).'/vendor/autoload.php';
// The following includes are needed when using protobuf 3.1.0
// and will suppress warnings when using protobuf 3.2.0+
@include_once dirname(__FILE__).'/helloworld.pb.php';
@include_once dirname(__FILE__).'/helloworld_grpc_pb.php';
function greet($name)
{
$client = new Helloworld\GreeterClient('localhost:50051', [
'credentials' => Grpc\ChannelCredentials::createInsecure(),
]);
$request = new Helloworld\HelloRequest();
$request->setName($name);
list($reply, $status) = $client->SayHello($request)->wait();
$message = $reply->getMessage();
return $message;
}
$name = !empty($argv[1]) ? $argv[1] : 'world';
echo greet($name).\n;
?>
See also GRPC and GRPC on PECL.
Only Variable Passed By Reference
[Since 0.11.3] - [ -P Functions/OnlyVariablePassedByReference ] - [ Online docs ]
When an argument is expected by reference, it is compulsory to provide a container. A container may be a variable, an array, a property or a static property.
This may be linted by PHP, when the function definition is in the same file as the function usage. This is silently linted if definition and usage are separated, if the call is dynamical or made as a method.
<?php
function foo(&$bar) { /**/ }
function &bar() { /**/ }
// This is not possible : `strtolower() <https://www.php.net/strtolower>`_ returns a value
foo(strtolower($string));
// This is valid : bar() returns a reference
foo(bar($string));
?>
This analysis currently covers functioncalls and static methodcalls, but omits methodcalls.
No Return Used
[Since 0.11.3] - [ -P Functions/NoReturnUsed ] - [ Online docs ]
The return value of the following functions are never used. The return argument may be dropped from the code, as it is dead code.
This analysis supports functions and static methods, when a definition may be found. It doesn't support method calls.
<?php
function foo($a = 1;) { return 1; }
foo();
foo();
foo();
foo();
foo();
foo();
// This function doesn't return anything.
function foo2() { }
// The following function are used in an expression, thus the return is important
function foo3() { return 1;}
function foo4() { return 1;}
function foo5() { return 1;}
foo3() + 1;
$a = foo4();
foo(foo5());
?>
Use Browscap
[Since 0.11.4] - [ -P Php/UseBrowscap ] - [ Online docs ]
Browscap is a browser database, accessible via get_browser().
Browscap is the 'Browser Capabilities Project'.
<?php
echo $_SERVER['HTTP_USER_AGENT'] . \n\n;
$browser = get_browser(null, true);
print_r($browser);
?>
See also browscap.
Use Debug
[Since 0.11.4] - [ -P Structures/UseDebug ] - [ Online docs ]
The code source includes calls to debug functions.
The following debug functions and libraries are reported :
- Aronduby Dump
- Cakephp Debug Toolbar
- Kint
- Krumo
- Nette tracy
- php-debugbar
- PHP native functions : print_r(), var_dump(), debug_backtrace(), debug_print_backtrace(), debug_zval_dump()
- Symfony debug
- Wordpress debug
- Xdebug
- Zend debug
<?php
// Example with Zend Debug
Zend\Debug\Debug::dump($var, $label = null, $echo = true);
?>
No Reference On Left Side
[Since 0.11.5] - [ -P Structures/NoReferenceOnLeft ] - [ Online docs ]
Do not use references as the right element in an assignation.
<?php
$b = 2;
$c = 3;
$a = &$b + $c;
// $a === 2 === $b;
$a = $b + $c;
// $a === 5
?>
This is the case for most situations : addition, multiplication, bitshift, logical, power, concatenation.
Note that PHP won't compile the code if the operator is a short operator (+=, .=, etc.), nor if the & is on the right side of the operator.
Implemented Methods Are Public
[Since 0.11.5] - [ -P Classes/ImplementedMethodsArePublic ] - [ Online docs ]
Class methods that are defined in an interface must be public. They cannot be either private, nor protected.
This error is not reported by lint, but is reported at execution time.
<?php
interface i {
function foo();
}
class X {
// This method is defined in the interface : it must be public
protected function foo() {}
// other methods may be private
private function bar() {}
}
?>
See also Interfaces and
Interfaces - the next level of abstraction.
PSR-16 Usage
[Since 0.11.6] - [ -P Psr/Psr16Usage ] - [ Online docs ]
PSR-16 describes a simple yet extensible interface for a cache item and a cache driver. It is supported by an set of interfaces, that one may use in the code.
<?php
namespace My\SimpleCache;
// MyCache implements the PSR-16 Simple cache.
// MyCache is more of a black hole than a real cache.
class MyCache implements Psr\SimpleCache\CacheInterface {
public function get($key, $default = null) {}
public function set($key, $value, $ttl = null) {}
public function delete($key) {}
public function clear() {}
public function getMultiple($keys, $default = null) {}
public function setMultiple($values, $ttl = null) {}
public function deleteMultiple($keys) {}
public function has($key) {}
}
?>
See also PSR-16 : Common Interface for Caching Libraries.
PSR-7 Usage
[Since 0.11.6] - [ -P Psr/Psr7Usage ] - [ Online docs ]
PSR-7 describes common interfaces for representing HTTP messages as described in RFC 7230 and RFC 7231, and URIs for use with HTTP messages as described in RFC 3986.
It is supported by an set of interfaces, that one may use in the code.
<?php
namespace MyNamespace;
// MyServerRequest implements the PSR-7 ServerRequestInterface.
// MyServerRequest is more of a black hole than a real Server.
class MyServerRequest extends \Psr\Http\Message\ServerRequestInterface {
public function getServerParams() {}
public function getCookieParams() {}
public function withCookieParams(array $cookies) {}
public function getQueryParams() {}
public function withQueryParams(array $query) {}
public function getUploadedFiles() {}
public function withUploadedFiles(array $uploadedFiles) {}
public function getParsedBody() {}
public function withParsedBody($data) {}
public function getAttributes() {}
public function getAttribute($name, $default = null) {}
public function withAttribute($name, $value) {}
public function withoutAttribute($name) {}
}
?>
See also PSR-7 : HTTP message interfaces.
PSR-6 Usage
[Since 0.11.6] - [ -P Psr/Psr6Usage ] - [ Online docs ]
PSR-6 is the cache standard for PHP.
The goal of PSR-6 is to allow developers to create cache-aware libraries that can be integrated into existing frameworks and systems without the need for custom development.
It is supported by an set of interfaces, that one may use in the code.
<?php
namespace MyNamespace;
// MyCacheItem implements the PSR-7 CacheItemInterface.
// This MyCacheItem is more of a black hole than a real CacheItem.
class MyCacheItem implements \Psr\Cache\CacheItemInterface {
public function getKey() {}
public function get() {}
public function isHit() {}
public function set($value) {}
public function expiresAt($expiration) {}
public function expiresAfter($time) {}
}
?>
See also PSR-6 : Caching.
PSR-3 Usage
[Since 0.11.6] - [ -P Psr/Psr3Usage ] - [ Online docs ]
PSR-3 describes a common interface for logging libraries.
It is supported by an set of interfaces, that one may use in the code.
<?php
namespace MyNamespace;
// MyLog implements the PSR-3 LoggerInterface.
// MyLog is more of a black hole than a real Log.
namespace ;
class MyLog implements \Psr\Log\LoggerInterface {
public function emergency($message, array $context = array()) {}
public function alert($message, array $context = array()) {}
public function critical($message, array $context = array()) {}
public function error($message, array $context = array()) {}
public function warning($message, array $context = array()) {}
public function notice($message, array $context = array()) {}
public function info($message, array $context = array()) {}
public function debug($message, array $context = array()) {}
public function log($level, $message, array $context = array()) {}
}
?>
See also PSR-3 : Logger Interface.
PSR-11 Usage
[Since 0.11.5] - [ -P Psr/Psr11Usage ] - [ Online docs ]
PSR-11 describes a common interface for dependency injection containers.
It is supported by an set of interfaces, that one may use in the code.
<?php
namespace MyNamespace;
// MyContainerInterface implements the PSR-7 ServerRequestInterface.
// MyContainerInterface is more of a black hole than a real Container.
class MyContainerInterface implements \Psr\Container\ContainerInterface {
public function get($id) {}
public function has($id) {}
}
?>
See also PSR-11 : Dependency injection container.
PSR-13 Usage
[Since 0.11.6] - [ -P Psr/Psr13Usage ] - [ Online docs ]
PSR-13 describes a common interface for dependency injection containers.
It is supported by an set of interfaces, that one may use in the code.
<?php
namespace MyNamespace;
// MyLink implements the PSR-13 LinkInterface.
// MyLink is more of a black hole than a real Container.
class MyLink implements LinkInterface {
public function getHref() {}
public function isTemplated() {}
public function getRels() {}
public function getAttributes() {}
}
?>
See also PSR-13 : Link definition interface.
Mixed Concat And Interpolation
[Since 0.11.5] - [ -P Structures/MixedConcatInterpolation ] - [ Online docs ]
Mixed usage of concatenation and string interpolation is error prone. It is harder to read, and leads to overlooking the concatenation or the interpolation.
<?php
// Concatenation string
$a = $b . 'c' . $d;
// Interpolation strings
$a = {$b}c{$d}; // regular form
$a = {$b}c$d; // irregular form
// Mixed Concatenation and Interpolation string
$a = {$b}c . $d;
$a = $b . c$d;
$a = $b . c{$d};
// Mixed Concatenation and Interpolation string with constant
$a = {$b}c . CONSTANT;
?>
Fixing this issue has no impact on the output. It makes code less error prone.
There are some situations where using concatenation are compulsory : when using a constant, calling a function, running a complex expression or make use of the escape sequence. You may also consider pushing the storing of such expression in a local variable.
ext/stats
[Since 0.11.5] - [ -P Extensions/Extstats ] - [ Online docs ]
Statistics extension.
This extension contains few dozens of functions useful for statistical computations. It is a wrapper around 2 scientific libraries, namely DCDFLIB (Library of C routines for Cumulative Distributions Functions, Inverses, and Other parameters) by B. Brown & J. Lavato and RANDLIB by Barry Brown, James Lavato & Kathy Russell.
<?php
$x = [ 15, 16, 8, 6, 15, 12, 12, 18, 12, 20, 12, 14, ];
$y = [ 17.24, 15, 14.91, 4.5, 18, 6.29, 19.23, 18.69, 7.21, 42.06, 7.5, 8,];
sprintf(%2.9f, stats_covariance($a_1, $a_2));
?>
See also Statistics and ext/stats.
Concatenation Interpolation Consistence
[Since 0.11.6] - [ -P Structures/ConcatenationInterpolationFavorite ] - [ Online docs ]
Concatenations are done with the . operator or by interpolation inside a string.
Interpolation is a clean way to write concatenation, though it gets messy with long dereferences or with constants. Concatenations are longer to write.
The analyzed code has less than 10% of one of them : for consistency reasons, it is recommended to make them all the same.
<?php
// be consistent
$a = $b $c;
$d = $b $e;
$e = $b $e;
$d = $b $f;
$f = $b $z;
$h = $b $e;
$y = $b $e;
$d = $b $x;
$j = $b $c;
$d = $b $g;
$d = $b $h;
// Be consistent, always use the same.
$z = $w.' '.$e;
?>
New Functions In PHP 7.3
[Since 0.10.7] - [ -P Php/Php73NewFunctions ] - [ Online docs ] - [ PHP older than 7.3]
New functions are added to new PHP version.
The following functions are now native functions in PHP 7.3. It is compulsory to rename any custom function that was created in older versions. One alternative is to move the function to a custom namespace, and update the use list at the beginning of the script.
- net_get_interfaces
- gmp_binomial
- gmp_lcm
- gmp_perfect_power
- gmp_kronecker
- openssl_pkey_derive
- is_countable
- ldap_exop_refresh
Note : At the moment of writing, all links to the manual are not working.
Too Many Injections
[Since 0.11.6] - [ -P Classes/TooManyInjections ] - [ Online docs ]
When a class is constructed with more than four dependencies, it should be split into smaller classes.
<?php
// This class relies on 5 other instances.
// It is probably doing too much.
class Foo {
public function __construct(
A $a,
B $b,
C $c,
D $d
E $e ) {
$this->a = $a;
$this->b = $b;
$this->d = $d;
$this->d = $d;
$this->e = $e;
}
}
?>
See also Dependency Injection Smells.
Dependency Injection
[Since 0.11.6] - [ -P Patterns/DependencyInjection ] - [ Online docs ]
A dependency injection is a typehinted argument, that is stored in a property by the constructor.
<?php
// Classic dependency injection
class foo {
private $bar;
public function __construct(Bar $bar) {
$this->bar = $bar;
}
public function doSomething($args) {
return $this->bar->barbar($args);
}
}
// Without typehint, this is not a dependency injection
class foo {
private $bar;
public function __construct($bar) {
$this->bar = $bar;
}
}
?>
See also Understanding Dependency Injection.
Courier Anti-Pattern
[Since 0.11.6] - [ -P Patterns/CourrierAntiPattern ] - [ Online docs ]
The courier anti-pattern is the storage of a dependency by a class, in order to create an instance that requires this dependency.
The class itself doesn't actually need this dependency, but has a dependency to a class that requires it.
<?php
// The foo class requires bar
class Foo {
public function __construct(Bar $b) {
}
}
// Class A doesn't depends on Bar, but depends on Foo
// Class A never uses Bar, but only uses Foo.
class A {
private $courier;
public function __construct(Bar $courier) {
$this->courier = $courier;
}
public function Afoo() {
$b = new Foo($this->courier);
}
}
?>
The alternative here is to inject Foo instead of Bar.
See also Courier Anti-pattern.
ext/gender
[Since 0.11.6] - [ -P Extensions/Extgender ] - [ Online docs ]
Gender extension.
The Gender PHP extension is a port of the gender.c program originally written by Joerg Michael. Its main purpose is to find out the gender of firstnames, based on a database of over 40000 firstnames from 54 countries.
<?php
namespace Gender;
$gender = new Gender;
$name = 'Milene';
$country = Gender::FRANCE;
$result = $gender->get($name, $country);
$data = $gender->country($country);
switch($result) {
case Gender::IS_FEMALE:
printf('The name %s is female in %s\n', $name, $data['country']);
break;
case Gender::IS_MOSTLY_FEMALE:
printf('The name %s is mostly female in %s\n', $name, $data['country']);
break;
case Gender::IS_MALE:
printf('The name %s is male in %s\n', $name, $data['country']);
break;
case Gender::IS_MOSTLY_MALE:
printf('The name %s is mostly male in %s\n', $name, $data['country']);
break;
case Gender::IS_UNISEX_NAME:
printf('The name %s is unisex in %s\n', $name, $data['country']);
break;
case Gender::IS_A_COUPLE:
printf('The name %s is both male and female in %s\n', $name, $data['country']);
break;
case Gender::NAME_NOT_FOUND:
printf('The name %s was not found for %s\n', $name, $data['country']);
break;
case Gender::ERROR_IN_NAME:
echo 'There is an error in the given name!'.PHP_EOL;
break;
default:
echo 'An error occurred!'.PHP_EOL;
break;
}
?>
See also ext/gender manual and
genderReader.
ext/judy
[Since 0.11.6] - [ -P Extensions/Extjudy ] - [ Online docs ]
The Judy extension.
PHP Judy is a PECL extension for the Judy C library implementing dynamic sparse arrays.
<?php
$judy = new Judy(Judy::BITSET);
if ($judy->getType() === judy_type($judy) &&
$judy->getType() === Judy::BITSET) {
echo 'Judy BITSET type OK'.PHP_EOL;
} else {
echo 'Judy BITSET type check fail'.PHP_EOL;
}
unset($judy);
?>
See also php-judy.
Could Make A Function
[Since 0.11.6] - [ -P Functions/CouldCentralize ] - [ Online docs ]
When a function is called across the code with the same arguments often enough, it should be turned into a local API.
This approach is similar to turning literals into constants : it centralize the value, it helps refactoring by updating it. It also makes the code more readable. Moreover, it often highlight common grounds between remote code locations.
The analysis looks for functions calls, and checks the arguments. When the calls occurs more than 4 times, it is reported.
<?php
// str_replace is used to clean '&' from strings.
// It should be upgraded to a central function
function foo($arg ) {
$arg = str_replace('&', '', $arg);
// do something with $arg
}
class y {
function bar($database ) {
$value = $database->queryName();
$value = str_replace('&', '', $value);
// $value = removeAmpersand($value);
// do something with $arg2
}
}
// helper function
function removeAmpersand($string) {
return str_replace('&', '', $string);
}
?>
See also Don't repeat yourself (DRY).
Forgotten Interface
[Since 0.11.7] - [ -P Interfaces/CouldUseInterface ] - [ Online docs ]
The following classes have been found implementing an interface's methods, though it doesn't explicitly implements this interface. This may have been forgotten.
<?php
interface i {
function i();
}
// i is not implemented and declared
class foo {
function i() {}
function j() {}
}
// i is implemented and declared
class foo implements i {
function i() {}
function j() {}
}
?>
See also Traits/CouldUseTrait.
Yii usage
[Since 0.11.8] - [ -P Vendors/Yii ] - [ Online docs ]
This analysis reports usage of the Yii framework.
<?php
// A Yii controller
class SiteController extends CController
{
public function actionIndex()
{
// ...
}
public function actionContact()
{
// ...
}
}
?>
See also Yii.
Codeigniter usage
[Since 0.11.8] - [ -P Vendors/Codeigniter ] - [ Online docs ]
This analysis reports usage of the Codeigniter framework.
<?php
// A code igniter controller
class Blog extends CI_Controller {
public function index()
{
echo 'Hello World!';
}
}
?>
See also Codeigniter.
Laravel usage
[Since 0.11.8] - [ -P Vendors/Laravel ] - [ Online docs ]
This analysis reports usage of the Laravel framework.
<?php
namespace App\Http\Controllers;
use App\User;
use App\Http\Controllers\Controller;
class UserController extends Controller
{
/**
* Show the profile for the given user.
*
* @param int $id
* @return Response
*/
public function show($id)
{
return view('user.profile', ['user' => User::findOrFail($id)]);
}
}
?>
See also Laravel.
Symfony usage
[Since 0.11.8] - [ -P Vendors/Symfony ] - [ Online docs ]
This analysis reports usage of the Symfony framework.
<?php
// src/AppBundle/Controller/LuckyController.php
namespace AppBundle\Controller;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
use Symfony\Component\HttpFoundation\Response;
class LuckyController
{
/**
* @Route(/lucky/number)
*/
public function numberAction()
{
$number = mt_rand(0, 100);
return new Response(
'<html><body>Lucky number: '.$number.'</body></html>'
);
}
}
?>
See also Symfony.
Wordpress usage
[Since 0.11.8] - [ -P Vendors/Wordpress ] - [ Online docs ]
This analysis reports usage of the Wordress platform.
<?php
//Usage of the WP_http class from Wordpress
$rags = array(
'x' => '1',
'y' => '2'
);
$url = 'http://www.example.com/';
$request = new WP_Http();
$result = $request->request( $url, array( 'method' => 'POST', 'body' => $body) );
?>
See also Wordpress.
Ez cms usage
[Since 0.11.8] - [ -P Vendors/Ez ] - [ Online docs ]
This analysis reports usage of the Ez cms.
<?php
namespace My\Bundle\With\Controller;
use eZ\Bundle\EzPublishCoreBundle\Controller;
use Symfony\Component\HttpFoundation\Request;
class DemoController extends Controller {
public function demoCreateContentAction(Request $request) {
//
}
}
?>
See also Ez.
Use session_start() Options
[Since 0.11.8] - [ -P Php/UseSessionStartOptions ] - [ Online docs ] - [ PHP 7.0 and more recent ]
It is possible to set the session's option at session_start() call, skipping the usage of session_option().
This way, session's options are set in one call, saving several hits.
This is available since PHP 7.0. It is recommended to set those values in the php.ini file, whenever possible.
<?php
// PHP 7.0
session_start(['session.name' => 'mySession',
'session.cookie_httponly' => 1,
'session.gc_maxlifetime' => 60 * 60);
// PHP 5.6- old way
ini_set ('session.name', 'mySession');
ini_set(session.cookie_httponly, 1);
ini_set('session.gc_maxlifetime', 60 * 60);
session_start();
?>
Cant Inherit Abstract Method
[Since 0.11.8] - [ -P Classes/CantInheritAbstractMethod ] - [ Online docs ] - [ PHP 7.2 and more recent ]
Inheriting abstract methods was made available in PHP 7.2. In previous versions, it emitted a fatal error.
<?php
abstract class A { abstract function bar(stdClass $x); }
abstract class B extends A { abstract function bar($x): stdClass; }
// Fatal error: Can't inherit abstract function A::bar()
?>
See also PHP RFC: Allow abstract function override.
Joomla usage
[Since 0.11.8] - [ -P Vendors/Joomla ] - [ Online docs ]
This analysis reports usage of the Joomla CMS.
<?php
// no direct access
defined('_JEXEC') or die('Restricted access');
jimport('joomla.application.component.controller');
JLoader::import('KBIntegrator', JPATH_PLUGINS . DS . 'kbi');
class MyController extends JController {
function display($message) {
echo $message;
}
}
?>
See also Joomla.
Non Breakable Space In Names
[Since 0.12.0] - [ -P Structures/NonBreakableSpaceInNames ] - [ Online docs ]
PHP allows non-breakable spaces in structures names, such as class, interfaces, traits, and variables.
This may be a nice trick to make names more readable outside code context, like long-named methods for tests.
<?php
class class with non breakable spaces {}
class ClassWithoutNonBreakableSpaces {}
?>
See also the original post by Matthieu Napoli : Using non-breakable spaces in test method names and
PHP Variable Names.
Multiple Functions Declarations
[Since 0.12.0] - [ -P Functions/MultipleDeclarations ] - [ Online docs ]
Some functions are declared multiple times in the code.
PHP accepts multiple definitions for the same functions, as long as they are not in the same file (linting error), or not included simultaneously during the execution.
This creates to several situations in which the same functions are defined multiple times : the function may be compatible with various PHP version, but their implementation may not. Or the function is part of a larger library, and sometimes only need without the rest of the library.
It is recommended to avoid having several functions with the same name in one repository. Turn those functions into methods and load them when needed.
<?php
namespace a {
function foo() {}
}
// Other file
namespace a {
function foo() {}
function bar() {}
}
?>
Avoid Optional Properties
[Since 0.12.0] - [ -P Classes/AvoidOptionalProperties ] - [ Online docs ]
Avoid optional properties, to prevent littering the code with existence checks.
When a property has to be checked once for existence, it is safer to check it each time. This leads to a decrease in readability and a lot of checks added to the code.
Either make sure the property is set with an actual object rather than with null, or use a null object. A null object offers the same interface than the expected object, but does nothing. It allows calling its methods, without running into a Fatal error, nor testing it.
<?php
// Example is courtesy 'The Coding Machine' : it has been adapted from its original form. See link below.
class MyMailer {
private $logger;
public function __construct(LoggerInterface $logger = null) {
$this->logger = $logger;
}
private function sendMail(Mail $mail) {
// Since $this->logger may be null, it must be tested anytime it is used.
if ($this->logger) {
$this->logger->info('Mail successfully sent.');
}
}
}
?>
See also Avoid optional services as much as possible,
The Null Object Pattern – Polymorphism in Domain Models, and
Practical PHP Refactoring: Introduce Null Object.
ext/swoole
[Since 0.12.0] - [ -P Extensions/Extswoole ] - [ Online docs ]
Swoole : Production-Grade Async programming Framework for PHP.
Swoole is an event-driven asynchronous & concurrent networking communication framework with high performance written only in C for PHP.
<?php
for($i = 0; $i < 100; $i++) {
Swoole\Coroutine::create(function() use ($i) {
$redis = new Swoole\Coroutine\Redis();
$res = $redis->connect('127.0.0.1', 6379);
$ret = $redis->incr('coroutine');
$redis->close();
if ($i == 50) {
Swoole\Coroutine::create(function() use ($i) {
$redis = new Swoole\Coroutine\Redis();
$res = $redis->connect('127.0.0.1', 6379);
$ret = $redis->set('coroutine_i', 50);
$redis->close();
});
}
});
}
?>
See also Swoole and
Swoole src.
Manipulates NaN
[Since 0.10.6] - [ -P Php/IsNAN ] - [ Online docs ]
This code handles Not-a-Number situations. Not-a-Number , also called NaN , happens when a calculation can't return an actual float.
<?php
// acos returns a float, unless it is not possible.
$a = acos(8);
var_dump(is_nan($a));
?>
See also Floats.
Manipulates INF
[Since 0.10.6] - [ -P Php/IsINF ] - [ Online docs ]
This code handles INF situations. INF represents the infinity, when used in a float context. It happens when a calculation returns a number that is much larger than the maximum allowed float (not integer), or a number that is not a Division by 0.
<?php
// pow returns INF, as it is equivalent to 1 / 0 ^ 2
$a = pow(0,-2); //
// exp returns an actual value, but won't be able to represent it as a float
$a = exp(PHP_INT_MAX);
// 0 ^ -1 is like 1 / 0 but returns INF.
$a = pow(0, -1);
var_dump(is_infinite($a));
// This yields a Division by zero exception
$a = 1 / 0;
?>
See also Math predefined constants.
No Return Or Throw In Finally
[Since 0.12.1] - [ -P Structures/NoReturnInFinally ] - [ Online docs ]
Avoid using return and throw in a finally block. Both command will interrupt the processing of the try catch block, and any exception that was emitted will not be processed. This leads to unprocessed exceptions, leaving the application in an unstable state.
Note that PHP prevents the usage of goto, break and continue within the finally block at linting phase. This is categorized as a Security problem.
<?php
function foo() {
try {
// Exception is thrown here
throw new \Exception();
} catch (Exception $e) {
// This is executed AFTER finally
return 'Exception';
} finally {
// This is executed BEFORE catch
return 'Finally';
}
}
}
// Displays 'Finally'. No exception
echo foo();
function bar() {
try {
// Exception is thrown here
throw new \Exception();
} catch (Exception $e) {
// Process the exception.
return 'Exception';
} finally {
// clean the current situation
// Keep running the current function
}
return 'Finally';
}
}
// Displays 'Exception', with processed Exception
echo bar();
?>
See also Return Inside Finally Block.
Const Or Define
[Since 0.12.1] - [ -P Structures/ConstDefineFavorite ] - [ Online docs ]
const and define()
The analyzed code has less than 10% of one of them : for consistency reasons, it is recommended to make them all the same.
They are almost interchangeable, though not totally : define()
<?php
// be consistent
const A1 = 1 ;
const A2 = 2 ;
const A3 = 3 ;
const A4 = 4 ;
const A5 = 5 ;
const A6 = 6 ;
const A7 = 7 ;
const A8 = 8 ;
const A9 = 9 ;
const A10 = 10;
const A11 = 11;
define('A12', 12); // Be consistent, always use the same.
?>
See also define and
const.
Mkdir Default
[Since 0.12.2] - [ -P Security/MkdirDefault ] - [ Online docs ]
mkdir() gives universal access to created folders, by default. It is recommended to gives limited set of rights (0755, 0700), or to explicitly set the rights to 0777.
<?php
// By default, this dir is 777
mkdir('/path/to/dir');
// Explicitely, this is wanted. It may also be audited easily
mkdir('/path/to/dir', 0777);
// This dir is limited to the current user.
mkdir('/path/to/dir', 0700);
?>
See also Why 777 Folder Permissions are a Security Risk.
strict_types Preference
[Since 0.12.2] - [ -P Php/DeclareStrict ] - [ Online docs ] - [ PHP 7.0 and more recent ]
strict_types is a PHP mode where typehint are enforced strictly or weakly. By default, it is weak typing, allowing backward compatibility with previous versions.
This analysis reports if strict_types are used systematically or not. strict_types affects the calling file, not the definition file.
<?php
// define strict_types
declare(strict_types = 1);
foo(1);
?>
See also Strict typing.
Declare strict_types Usage
[Since 0.12.1] - [ -P Php/DeclareStrictType ] - [ Online docs ] - [ PHP 7.0 and more recent ]
Usage of strict_types . By default, PHP attempts to change the original type to match the type specified by the type-declaration. With an explicit strict_types declaration, PHP ensures that the incoming argument has the exact type.
strict_types were introduced in PHP 7.0.
<?php
// Setting strict_types;
declare(strict_types = 1);
function foo(int $i) {
echo $i;
}
// Always valid : displays 1
foo(1);
// with strict types, this emits an error
// without strict types, this displays 1
foo(1.7);
?>
See also declare.
Encoding Usage
[Since 0.12.1] - [ -P Php/DeclareEncoding ] - [ Online docs ]
Usage of declare(encoding = );.
<?php
// Setting encoding for the file;
declare(encoding = 'UTF-8');
?>
See also declare.
Ticks Usage
[Since 0.12.1] - [ -P Php/DeclareTicks ] - [ Online docs ]
Usage of declare(ticks = );.
<?php
// Setting ticks value
declare(ticks = 'UTF-8');
?>
See also declare.
Mismatched Ternary Alternatives
[Since 0.12.1] - [ -P Structures/MismatchedTernary ] - [ Online docs ]
A ternary operator should yield the same type on both branches.
Ternary operator applies a condition, and yield two different results. Those results will then be processed by code that expects the same types. It is recommended to match the types on both branches of the ternary operator.
<?php
// $object may end up in a very unstable state
$object = ($type == 'Type') ? new $type() : null;
//same result are provided by both alternative, though process is very different
$result = ($type == 'Addition') ? $a + $b : $a * $b;
//Currently, this is omitted
$a = 1;
$result = empty($condition) ? $a : 'default value';
$result = empty($condition) ? $a : getDefaultValue();
?>
ext/lapack
[Since 0.12.2] - [ -P Extensions/Extlapack ] - [ Online docs ]
Extension Lapack. LAPACK provides routines for solving systems of simultaneous linear equations, least-squares solutions of linear systems of equations, eigenvalue problems, and singular value problems.
$a = array(
array( 1.44, -7.84, -4.39, 4.53),
array(-9.96, -0.28, -3.24, 3.83),
array(-7.55, 3.24, 6.27, -6.64),
array( 8.34, 8.09, 5.28, 2.06),
array( 7.08, 2.52, 0.74, -2.47),
array(-5.45, -5.70, -1.19, 4.70),
);
$b = array(
array( 8.58, 9.35),
array( 8.26, -4.43),
array( 8.48, -0.70),
array(-5.28, -0.26),
array( 5.72, -7.36),
array( 8.93, -2.52),
);
$result = Lapack::leastSquaresByFactorisation($a, $b);
?>
See also Lapack and php-lapack.
Mismatched Default Arguments
[Since 0.12.3] - [ -P Functions/MismatchedDefaultArguments ] - [ Online docs ]
Arguments are relayed from one method to the other, and the arguments have different default values.
Although it is possible to have different default values, it is worth checking why this is actually the case.
<?php
function foo($a = null, $b = array() ) {
// foo method calls directly bar.
// When argument are provided, it's OK
// When argument are omited, the default value is not the same as the next method
bar($a, $b);
}
function bar($c = 1, $d = array() ) {
}
?>
Mismatched Typehint
[Since 0.12.3] - [ -P Functions/MismatchedTypehint ] - [ Online docs ]
Relayed arguments don't have the same typehint.
Typehint acts as a filter method. When an object is checked with a first class, and then checked again with a second distinct class, the whole process is always false : $a can't be of two different classes at the same time.
<?php
// Foo() calls bar()
function foo(A $a, B $b) {
bar($a, $b);
}
// $a is of A typehint in both methods, but
// $b is of B then BB typehing
function bar(A $a, BB $b) {
}
?>
Note : This analysis currently doesn't check generalisation of classes : for example, when B is a child of BB, it is still reported as a mismatch.
Scalar Or Object Property
[Since 0.12.3] - [ -P Classes/ScalarOrObjectProperty ] - [ Online docs ]
Property shouldn't use both object and scalar syntaxes. When a property may be an object, it is recommended to implement the Null Object pattern : instead of checking if the property is scalar, make it always object.
<?php
class x {
public $display = 'echo';
function foo($string) {
if (is_string($this->display)) {
echo $this->string;
} elseif ($this->display instanceof myDisplayInterface) {
$display->display();
} else {
print Error when displaying\n;
}
}
}
interface myDisplayInterface {
public function display($string); // does the display in its own way
}
class nullDisplay implements myDisplayInterface {
// implements myDisplayInterface but does nothing
public function display($string) {}
}
class x2 {
public $display = null;
public function __construct() {
$this->display = new nullDisplay();
}
function foo($string) {
// Keep the check, as $display is public, and may get wrong values
if ($this->display instanceof myDisplayInterface) {
$display->display();
} else {
print Error when displaying\n;
}
}
}
// Simple class for echo
class echoDisplay implements myDisplayInterface {
// implements myDisplayInterface but does nothing
public function display($string) {
echo $string;
}
}
?>
See also Null Object Pattern. and The Null Object Pattern.
Group Use Trailing Comma
[Since 0.12.3] - [ -P Php/GroupUseTrailingComma ] - [ Online docs ] - [ PHP 7.2 and more recent ]
The usage of a final empty slot in array() was allowed with use statements. This works in PHP 7.2 and more recent.
Although this empty instruction is ignored at execution, this allows for clean presentation of code, and short diff when committing in a VCS.
<?php
// Valid in PHP 7.2 and more recent.
use a\b\{c,
d,
e,
f,
};
// This won't compile in 7.1 and older.
?>
See also Trailing Commas In List Syntax and Revisit trailing commas in function arguments.
Assign With And
[Since 0.12.4] - [ -P Php/AssignAnd ] - [ Online docs ]
The lettered logical operators yield to assignation. It may collect less information than expected.
It is recommended to use the &&, ^ and || operators, instead of and, or and xor, to prevent confusion.
<?php
// The expected behavior is
// The following are equivalent
$a = $b && $c;
$a = ($b && $c);
// The unexpected behavior is
// The following are equivalent
$a = $b and $c;
($a = $b) and $c;
?>
See also Operator Precedence.
Logical Operators Favorite
[Since 0.12.4] - [ -P Php/LetterCharsLogicalFavorite ] - [ Online docs ]
PHP has two sets of logical operators : letters (and, or, xor) and chars (&&, ||, ^).
The analyzed code has less than 10% of one of the two sets : for consistency reasons, it is recommended to make them all the same.
Warning : the two sets of operators have different precedence levels. Using and or && is not exactly the same, especially and not only, when assigning the results to a variable.
<?php
$a1 = $b and $c;
$a1 = $b and $c;
$a1 = $b and $c;
$a1 = $b or $c;
$a1 = $b OR $c;
$a1 = $b and $c;
$a1 = $b and $c;
$a1 = $b and $c;
$a1 = $b or $c;
$a1 = $b OR $c;
$a1 = $b ^ $c;
?>
Using and or && are also the target of other analysis.
See also Logical Operators and Operators Precedence.
Isset Multiple Arguments
[Since 0.12.4] - [ -P Php/IssetMultipleArgs ] - [ Online docs ]
isset() may be used with multiple arguments and acts as a AND.
<?php
// isset without and
if (isset($a, $b, $c)) {
// doSomething()
}
// isset with and
if (isset($a) && isset($b) && isset($c)) {
// doSomething()
}
?>
See also Isset.
No Magic With Array
[Since 0.12.4] - [ -P Classes/NoMagicWithArray ] - [ Online docs ]
Magic method __set() doesn't work for array syntax.
When overloading properties, they can only be used for scalar values, excluding arrays. Under the hood, PHP uses __get() to reach for the name of the property, and doesn't recognize the following index as an array. It yields an error : Indirect modification of overloaded property.
<?php
class c {
private $a;
private $o = array();
function __get($name) {
return $this->o[$name];
}
function foo() {
// property b doesn't exists
$this->b['a'] = 3;
print_r($this);
}
// This method has no impact on the issue
function __set($name, $value) {
$this->o[$name] = $value;
}
}
$c = new c();
$c->foo();
?>
It is possible to use the array syntax with a magic property : by making the __get returns an array, the syntax will actually extract the expected item in the array.
This is not reported by linting.
In this analysis, only properties that are found to be magic are reported. For example, using the b property outside the class scope is not reported, as it would yield too many false-positives.
See also Overload.
PHP 7.2 Object Keyword
[Since 0.12.4] - [ -P Php/Php72ObjectKeyword ] - [ Online docs ] - [ PHP older than 7.2]
'object' is a PHP keyword. It can't be used for class, interface or trait name.
This is the case since PHP 7.2.
<?php
// Valid until PHP 7.2
class object {}
// Altough it is really weird anyway...
?>
See also List of Keywords.
Child Class Removes Typehint
[Since 0.12.4] - [ -P Classes/ChildRemoveTypehint ] - [ Online docs ] - [ PHP 7.2 and more recent ]
PHP 7.2 introduced the ability to remove a typehint when overloading a method. This is not valid code for older versions.
<?php
class foo {
function foobar(foo $a) {}
}
class bar extends foo {
function foobar($a) {}
}
?>
ext/xattr
[Since 0.12.4] - [ -P Extensions/Extxattr ] - [ Online docs ]
Extensions xattr.
The xattr extension allows for the manipulation of extended attributes on a filesystem.
<?php
$file = 'my_favourite_song.wav';
xattr_set($file, 'Artist', 'Someone');
xattr_set($file, 'My ranking', 'Good');
xattr_set($file, 'Listen count', '34');
/* ... other code ... */
printf('You\'ve played this song %d times', xattr_get($file, 'Listen count'));
?>
See also xattr and Extended attributres.
Avoid Concat In Loop
[Since 0.12.4] - [ -P Performances/NoConcatInLoop ] - [ Online docs ]
Concatenations inside a loop generate a lot of temporary variables. They are accumulated and tend to raise the memory usage, leading to slower performances.
It is recommended to store the values in an array, and then use implode() on that array to make the concatenation at once. The effect is positive when the source array has at least 50 elements.
<?php
// Concatenation in one operation
$tmp = array();
foreach(data_source() as $data) {
$tmp[] = $data;
}
$final = implode('', $tmp);
// Concatenation in many operations
foreach(data_source() as $data) {
$final .= $data;
}
?>
The same doesn't apply to addition and multiplication, with array_sum() and array_multiply(), as those operations work on the current memory allocation, and don't need to allocate new memory at each step.
See also PHP 7 performance improvements (3/5): Encapsed strings optimization.
No Substr Minus One
[Since 0.12.5] - [ -P Php/NoSubstrMinusOne ] - [ Online docs ] - [ PHP 7.1 and more recent ]
Negative index were introduced in PHP 7.1. This syntax is not compatible with PHP 7.0 and older.
<?php
$string = 'abc';
echo $string[-1]; // c
echo $string[1]; // a
?>
See also Generalize support of negative string offsets.
Logical To in_array
[Since 0.12.5] - [ -P Performances/LogicalToInArray ] - [ Online docs ]
Multiples exclusive comparisons may be replaced by in_array().
in_array() makes the alternatives more readable, especially when the number of alternatives is large. In fact, the list of alternative may even be set in a variable, and centralized for easier management.
Even two 'or' comparisons are slower than using a in_array() call. More calls are even slower than just two. This is a micro-optimisation : speed gain is low, and marginal. Code centralisation is a more significant advantage.
<?php
// Set the list of alternative in a variable, property or constant.
$valid_values = array(1, 2, 3, 4);
if (in_array($a, $valid_values) ) {
// doSomething()
}
if ($a == 1 || $a == 2 || $a == 3 || $a == 4) {
// doSomething()
}
// in_array also works with strict comparisons
if (in_array($a, $valid_values, true) ) {
// doSomething()
}
if ($a === 1 || $a === 2 || $a === 3 || $a === 4) {
// doSomething()
}
?>
See also `in_array()
Should Use Foreach
[Since 0.12.7] - [ -P Structures/ShouldUseForeach ] - [ Online docs ]
Use foreach instead of for when traversing an array.
Foreach() is the modern loop : it maps automatically every element of the array to a blind variable, and loop over it. This is faster and safer.
<?php
// Foreach version
foreach($array as $element) {
doSomething($element);
}
// The above case may even be upgraded with array_map and a callback,
// for the simplest one of them
$array = array_map('doSomething', $array);
// For version (one of various alternatives)
for($i = 0; $i < count($array); $i++) {
$element = $array[$i];
doSomething($element);
}
// Based on array_pop or `array_shift() <https://www.php.net/array_shift>`_
while($value = array_pop($array)) {
doSomething($array);
}
?>
See also foreach and
5 Ways To Loop Through An Array In PHP.
ext/rdkafka
[Since 0.12.8] - [ -P Extensions/Extrdkafka ] - [ Online docs ]
Extension for RDkafka.
PHP-rdkafka is a thin librdkafka binding providing a working PHP 5 / PHP 7 Kafka 0.8 / 0.9 / 0.10 client.
<?php
$rk = new RdKafka\Producer();
$rk->setLogLevel(LOG_DEBUG);
$rk->addBrokers(10.0.0.1,10.0.0.2);
?>
See also Kafka client for PHP.
ext/fam
[Since 0.12.8] - [ -P Extensions/Extfam ] - [ Online docs ]
File Alteration Monitor extension.
FAM monitors files and directories, notifying interested applications of changes.
ext/FAM is not available for Windows
<?php
$fam = fam_open('myApplication');
fam_monitor_directory($fam, '/tmp');
fam_close($fam);
?>
See also File Alteration Monitor.
Shell Favorite
[Since 0.12.9] - [ -P Php/ShellFavorite ] - [ Online docs ]
PHP has several syntax to make system calls. shell_exec(), exec() and back-ticks, ` are the common ones.
It was found that one of those three is actually being used over 90% of the time. The remaining cases should be uniformed, so has to make this code consistent.
<?php
// back-ticks ` are only used once.
`back-tick`;
shell_exec('exec1');
shell_exec('exec2');
shell_exec('exec3');
shell_exec('exec4');
shell_exec('exec5');
shell_exec('exec6');
shell_exec('exec7');
shell_exec('exec8');
shell_exec('exec9');
shell_exec('exec10');
shell_exec('exec11');
shell_exec('exec12');
?>
See also Execution Operators and
`shell_exec()
Could Be Private Class Constant
[Since 0.12.10] - [ -P Classes/CouldBePrivateConstante ] - [ Online docs ]
Class constant may use private visibility.
Since PHP 7.1, constants may also have a public/protected/private visibility. This restrict their usage to anywhere, class and children or class.
As a general rule, it is recommended to make constant private by default, and to relax this restriction as needed. PHP makes them public by default.
<?php
class foo {
// pre-7.1 style
const PRE_71_CONSTANT = 1;
// post-7.1 style
private const PRIVATE_CONSTANT = 2;
public const PUBLIC_CONSTANT = 3;
function bar() {
// PRIVATE CONSTANT may only be used in its class
echo self::PRIVATE_CONSTANT;
}
}
// Other constants may be used anywhere
function x($a = foo::PUBLIC_CONSTANT) {
echo $a.' '.foo:PRE_71_CONSTANT;
}
?>
Constant shall stay public when the code has to be compatible with PHP 7.0 and older.
They also have to be public in the case of component : some of those constants have to be used by external actors, in order to configure the component.
See also Class Constants.
Could Be Protected Class Constant
[Since 0.12.11] - [ -P Classes/CouldBeProtectedConstant ] - [ Online docs ]
Class constant may use 'protected' visibility.
Since PHP 7.1, constants may also have a public/protected/private visibility. This restrict their usage to anywhere, class and children or class.
As a general rule, it is recommended to make constant 'private' by default, and to relax this restriction as needed. PHP makes them public by default.
<?php
class foo {
// pre-7.1 style
const PRE_71_CONSTANT = 1;
// post-7.1 style
protected const PROTECTED_CONSTANT = 2;
public const PUBLIC_CONSTANT = 3;
}
class foo2 extends foo {
function bar() {
// PROTECTED_CONSTANT may only be used in its class or its children
echo self::PROTECTED_CONSTANT;
}
}
class foo3 extends foo {
function bar() {
// PROTECTED_CONSTANT may only be used in its class or any of its children
echo self::PROTECTED_CONSTANT;
}
}
// Other constants may be used anywhere
function x($a = foo::PUBLIC_CONSTANT) {
echo $a.' '.foo:PRE_71_CONSTANT;
}
?>
Method Could Be Private Method
[Since 0.12.11] - [ -P Classes/CouldBePrivateMethod ] - [ Online docs ]
The following methods are never used outside their class of definition. Given the analyzed code, they could be set as private.
<?php
class foo {
public function couldBePrivate() {}
public function cantdBePrivate() {}
function bar() {
// couldBePrivate is used internally.
$this->couldBePrivate();
}
}
class foo2 extends foo {
function bar2() {
// cantdBePrivate is used in a child class.
$this->cantdBePrivate();
}
}
//couldBePrivate() is not used outside
$foo = new foo();
//cantdBePrivate is used outside the class
$foo->cantdBePrivate();
?>
Note that dynamic properties (such as $x->$y) are not taken into account.
Could Be Protected Method
[Since 0.12.11] - [ -P Classes/CouldBeProtectedMethod ] - [ Online docs ]
Those methods are declared public, but are never used publicly. They may be made protected.
<?php
class foo {
// Public, and used publicly
public publicMethod() {}
// Public, but never used outside the class or its children
public protectedMethod() {}
private function bar() {
$this->protectedMethod();
}
}
$foo = new Foo();
$foo->publicMethod();
?>
These properties may even be made private.
Pathinfo() Returns May Vary
[Since 0.12.11] - [ -P Php/PathinfoReturns ] - [ Online docs ]
pathinfo() function returns an array whose content may vary. It is recommended to collect the values after check, rather than directly.
<?php
$file = '/a/b/.c';
//$extension may be missing, leading to empty $filename and filename in $extension
list( $dirname, $basename, $extension, $filename ) = array_values( pathinfo($file) );
//Use PHP 7.1 list() syntax to assign correctly the values, and skip `array_values() <https://www.php.net/array_values>`_
//This emits a warning in case of missing index
['dirname' => $dirname,
'basename' => $basename,
'extension' => $extension,
'filename' => $filename ] = pathinfo($file);
//This works without warning
$details = pathinfo($file);
$dirname = $details['dirname'] ?? getpwd();
$basename = $details['basename'] ?? '';
$extension = $details['extension'] ?? '';
$filename = $details['filename'] ?? '';
?>
The same applies to parse_url(), which returns an array with various index.
Use pathinfo() Arguments
[Since 0.12.12] - [ -P Php/UsePathinfoArgs ] - [ Online docs ]
pathinfo() has a second argument to select only useful data.
It is twice faster to get only one element from pathinfo() than get the four of them, and use only one.
This analysis reports pathinfo() usage, without second argument, where only one or two indices are used, after the call.
<?php
// This could use only PATHINFO_BASENAME
function foo_db() {
$a = pathinfo($file2);
return $a['basename'];
}
// This could be 2 calls, with PATHINFO_BASENAME and PATHINFO_DIRNAME.
function foo_de() {
$a = pathinfo($file3);
return $a['dirname'].'/'.$a['basename'];
}
// This is OK : 3 calls to `pathinfo() <https://www.php.net/pathinfo>`_ is slower than array access.
function foo_deb() {
$a = pathinfo($file4);
return $a['dirname'].'/'.$a['filename'].'.'.$a['extension'];
}
?>
Depending on the situation, the functions dirname() and basename() may also be used. They are even faster, when only fetching those data.
See also list.
ext/parle
[Since 0.12.12] - [ -P Extensions/Extparle ] - [ Online docs ]
Extension Parser and Lexer.
The parle extension provides lexing and parsing facilities. The implementation is based on » Ben Hanson's libraries and requires a » C++14 capable compiler.
<?php
use Parle\{Token, Lexer, LexerException};
/* name => id */
$token = array(
'EOI' => 0,
'COMMA' => 1,
'CRLF' => 2,
'DECIMAL' => 3,
);
/* id => name */
$token_rev = array_flip($token);
$lex = new Lexer;
$lex->push("[\x2c]", $token['COMMA']);
$lex->push("[\r][\n]", $token['CRLF']);
$lex->push("[\d]+", $token['DECIMAL']);
$lex->build();
$in = 0,1,2\r\n3,42,5\r\n6,77,8\r\n;
$lex->consume($in);
do {
$lex->advance();
$tok = $lex->getToken();
if (Token::UNKNOWN == $tok->id) {
throw new LexerException('Unknown token "'.$tok->value.'" at offset '.$tok->offset.'.');
}
echo 'TOKEN: ', $token_rev[$tok->id], PHP_EOL;
} while (Token::EOI != $tok->id);
?>
See also Parsing and Lexing.
Regex Inventory
[Since 0.12.14] - [ -P Type/Regex ] - [ Online docs ]
All regex used in the code. PHP has the PCRE extension that handles all regex : preg_match(), preg_replace(), etc.
<?php
// PCRE regex used with preg_match
preg_match('/[abc]+/', $string);
// Mbstring regex, in the arabic range
if(mb_ereg('[\x{0600}-\x{06FF}]', $text))
?>
mbstring regexes are also collected. Pre-PHP 7.0 POSIX regex are not listed.
See also `ext/mbstring
`ext/pcre
Switch Fallthrough
[Since 0.12.14] - [ -P Structures/Fallthrough ] - [ Online docs ]
A switch with fallthrough is prone to errors.
A fallthrough happens when a case or default clause in a switch statement is not finished by a break (or equivalent);
CWE report this as a security concern, unless well documented.
A fallthrough may be used as a feature. Then, it is indistinguishable from an error.
When the case block is empty, this analysis doesn't report it : the case is then used as an alias.
<?php
switch($variable) {
case 1 : // case 1 is not reported, as it actually shares the same body as case 33
case 33 :
break ;
case 2 :
break ;
default:
++$a;
case 4 :
break ;
}
?>
This analysis doesn't take into account comments about the fallthrough.
See also CWE-484: Omitted Break Statement in Switch and
Rule: no-switch-case-fall-through.
Upload Filename Injection
[Since 0.12.14] - [ -P Security/UploadFilenameInjection ] - [ Online docs ]
When receiving a file via Upload, it is recommended to store it under a self-generated name. Any storage that uses the original filename, or even a part of it may be vulnerable to injections.
<?php
// Security error ! the $_FILES['upload']['filename'] is provided by the sender.
// 'a.<script>alert(\'a\')</script>'; may lead to a HTML injection.
$extension = substr( strrchr($_FILES['upload']['name'], '.') ,1);
if (!in_array($extension, array('gif', 'jpeg', 'jpg')) {
// process error
continue;
}
// Md5 provides a name without special characters
$name = md5($_FILES['upload']['filename']);
if(@move_uploaded_file($_FILES['upload']['tmp_name'], '/var/no-www/upload/'.$name.'.'.$extension)) {
safeStoring($name.'.'.$extension, $_FILES['upload']['filename']);
}
// Security error ! the $_FILES['upload']['filename'] is provided by the sender.
if(@move_uploaded_file($_FILES['upload']['tmp_name'], $_FILES['upload']['filename'])) {
safeStoring($_FILES['upload']['filename']);
}
// Security error ! the $_FILES['upload']['filename'] is provided by the sender.
// 'a.<script>alert('a')</script>'; may lead to a HTML injection.
$extension = substr( strrchr($_FILES['upload']['name'], '.') ,1);
$name = md5($_FILES['upload']['filename']);
if(@move_uploaded_file($_FILES['upload']['tmp_name'], $name.'.'.$extension)) {
safeStoring($name.'.'.$extension, $_FILES['upload']['filename']);
}
?>
It is highly recommended to validate any incoming file, generate a name for it, and store the result in a folder outside the web folder. Also, avoid accepting PHP scripts, if possible.
See also [CVE-2017-6090],
CWE-616: Incomplete Identification of Uploaded File Variables,
Why File Upload Forms are a Major Security Threat.
Always Anchor Regex
[Since 0.12.15] - [ -P Security/AnchorRegex ] - [ Online docs ]
Unanchored regex finds the requested pattern, and leaves room for malicious content.
Without ^ and $ , the regex searches for any pattern that satisfies the criteria, leaving any unused part of the string available for arbitrary content. It is recommended to use both anchor
<?php
$birthday = getSomeDate($_GET);
// Permissive version : $birthday = '1970-01-01<script>xss();</script>';
if (!preg_match('/\d{4}-\d{2}-\d{2}/', $birthday) {
error('Wrong data format for your birthday!');
}
// Restrictive version : $birthday = '1970-01-01';
if (!preg_match('/^\d{4}-\d{2}-\d{2}$/', $birthday) {
error('Wrong data format for your birthday!');
}
echo 'Your birthday is on '.$birthday;
?>
Note that $ may be a line ending, still leaving room after it for injection.
<?php
$birthday = '1970-01-01'.PHP_EOL.'<script>xss();</script>';
?>
This analysis reports false positive when the regex is used to search a pattern in a much larger string. Check if this rule doesn't apply, though.
See also CWE-625: Permissive Regular Expression.
Multiple Type Variable
[Since 0.12.15] - [ -P Structures/MultipleTypeVariable ] - [ Online docs ]
Avoid using the same variable with different types of data.
It is recommended to use different names for differently typed data, while processing them. This prevents errors where one believe the variable holds the former type, while it has already been cast to the later.
Incrementing variables, with math operations or concatenation, is OK : the content changes, but not the type. And casting the variable without storing it in itself is OK.
<?php
// $x is an array
$x = range('a', 'z');
// $x is now a string
$x = join('', $x);
$c = count($x); // $x is not an array anymore
// $letters is an array
$letters = range('a', 'z');
// $alphabet is a string
$alphabet = join('', $letters);
// Here, $letters is cast by PHP, but the variable is changed.
if ($letters) {
$count = count($letters); // $letters is still an array
}
?>
Is Actually Zero
[Since 0.12.15] - [ -P Structures/IsZero ] - [ Online docs ]
This addition actually may be simplified because one term is actually negated by another.
This kind of error happens when the expression is very large : the more terms are included, the more chances are that some auto-annihilation happens.
This error may also be a simple typo : for example, calculating the difference between two consecutive terms.
<?php
// This is quite obvious
$a = 2 - 2;
// This is obvious too. This may be a typo-ed difference between two consecutive terms.
// Could have been $c = $fx[3][4] - $fx[3][3] or $c = $fx[3][5] - $fx[3][4];
$c = $fx[3][4] - $fx[3][4];
// This is less obvious
$a = $b[3] - $c + $d->foo(1,2,3) + $c + $b[3];
?>
Unconditional Break In Loop
[Since 0.12.16] - [ -P Structures/UnconditionLoopBreak ] - [ Online docs ]
An unconditional break in a loop creates dead code. Since the break is directly in the body of the loop, it is always executed, creating a strange loop that can only run once.
Here, break may also be a return, a goto or a continue. They all branch out of the loop. Such statement are valid, but should be moderated with a condition.
<?php
// return in loop should be in
function summAll($array) {
$sum = 0;
foreach($array as $a) {
// Stop at the first error
if (is_string($a)) {
return $sum;
}
$sum += $a;
}
return $sum;
}
// foreach loop used to collect first element in array
function getFirst($array) {
foreach($array as $a) {
return $a;
}
}
?>
Session Lazy Write
[Since 0.12.15] - [ -P Security/SessionLazyWrite ] - [ Online docs ]
Classes that implements SessionHandlerInterface must also implements SessionUpdateTimestampHandlerInterface.
The two extra methods are used to help lazy loading : the first actually checks if a sessionId is available, and the seconds updates the time of last usage of the session data in the session storage.
This was spotted by Nicolas Grekas , and fixed in Symfony [HttpFoundation] Make sessions secure and lazy #24523.
<?php
interface SessionUpdateTimestampHandlerInterface {
// returns a boolean to indicate that valid data is available for this sessionId, or not.
function validateId($sessionId);
//called to change the last time of usage for the session data.
//It may be a file's touch or full write, or a simple update on the database
function updateTimestamp($sessionId, $sessionData);
}
?>
See also Sessions: Improve original RFC about lazy_write and
the Sessions.
Session Variables
[Since 0.12.16] - [ -P Php/SessionVariables ] - [ Online docs ]
Sessions names, used across the application.
<?php
if (isset($_SESSION['mySessionVariable'])) {
$_SESSION['mySessionVariable']['counter']++;
} else {
$_SESSION['mySessionVariable'] = array('counter' => 1,
'creation' => time());
}
?>
See also Sessions.
Incoming Variables
[Since 0.12.16] - [ -P Php/IncomingVariables ] - [ Online docs ]
Incoming names, used across the application.
Incoming variables are first-level index in $_POST , $_GET , $_COOKIE , $_REQUEST and $_FILE ;
$_SESSION and $_ENV are not reported as incoming data, as they are not supposed to be manipulated by normal user.
Dynamic names are not reported too.
<?php
$name = $_GET['name'];
$cookie = $_COOKIE['cookie'];
// 'archive' is the incoming variable, not 'file_name'
$file_name = $_FILE['archive']['file_name'];
// This is not reported, because it is from $_ENV.
$db_pass = $_ENV['DB_PASS'];
// This is not reported, because it is dynamic
$x = 'userId';
$userId = $_GET[$x];
?>
Cookies Variables
[Since 0.12.16] - [ -P Php/CookiesVariables ] - [ Online docs ]
Cookies names, used across the application.
<?php
if (isset($_COOKIE['myCookie'])) {
// Usual method for reading and setting cookies
$_COOKIE['myCookie']++;
}
// Usual method for writing cookies
setcookie('myCookie', $value);
?>
See also setcookie.
Too Complex Expression
[Since 0.12.16] - [ -P Structures/ComplexExpression ] - [ Online docs ]
Long expressions should be broken in small chunks, to limit complexity.
Really long expressions tends to be error prone : either by typo, or by missing details. They are even harder to review, once the initially build of the expression is gone.
As a general rule, it is recommended to keep expressions short. The analysis include any expression that is more than 15 tokens large : variable and operators counts as one, properties, arrays count as two. Parenthesis are also counted.
PHP has no specific limit to expression size, so long expression are legal and valid. It is possible that the business logic requires a complex equation.
<?php
// Why not calculate wordwrap size separatedly ?
$a = explode("\n", wordwrap($this->message, floor($this->width / imagefontwidth($this->fontsize)), "\n"));
// Longer but easier to read
$width = floor($this->width / imagefontwidth($this->fontsize)), "\n");
$a = explode("\n", wordwrap($this->message, $width);
// Here, some string building, including error management with @, is making the data quite complex.
fwrite($fp, 'HEAD ' . @$url['path'] . @$url['query'] . ' HTTP/1.0' . "\r\n" . 'Host: ' . @$url['host'] . "\r\n\r\n")
// Better validation of data.
$http_header = 'HEAD ';
if (isset($url['path'])) {
$http_header .= $url['path'];
}
if (isset($url['query'])) {
$http_header .= $url['query'];
}
$http_header .= "\r\n";
if (isset($url['host'])) {
$http_header .= 'Host: ' . $url['host'] . "\r\n\r\n";
}
fwrite($fp, $http_header);
?>
Date Formats
[Since 0.12.16] - [ -P Php/DateFormats ] - [ Online docs ]
Inventory of date formats used in the code.
<?php
$time = time();
// This is a formated date
echo date('r', $time);
?>
See also Date and Time.
Could Be Else
[Since 1.0.1] - [ -P Structures/CouldBeElse ] - [ Online docs ]
Merge opposition conditions into one if/then structure.
When two if/then structures follow each other, using a condition and its opposite, they may be merged into one.
<?php
// Short version
if ($a == 1) {
$b = 2;
} else {
$b = 1;
}
// Long version
if ($a == 1) {
$b = 2;
}
if ($a != 1) {
$b = 3;
}
?>
Simple Switch
[Since 1.0.1] - [ -P Performances/SimpleSwitch ] - [ Online docs ] - [ PHP 7.2 and more recent ]
Switches are faster when relying only on integers or strings.
Since PHP 7.2, simple switches that use only strings or integers are optimized. The gain is as great as the switch is big.
<?php
// Optimized switch.
switch($b) {
case "a":
break;
case "b":
break;
case "c":
break;
case "d":
break;
default :
break;
}
// Unoptimized switch.
// Try moving the foo() call in the default, to keep the rest of the switch optimized.
switch($c) {
case "a":
break;
case foo($b):
break;
case "c":
break;
case "d":
break;
default :
break;
}
?>
See also PHP 7.2's "switch" optimisations.
Next Month Trap
[Since 1.0.1] - [ -P Structures/NextMonthTrap ] - [ Online docs ]
Avoid using +1 month with strtotime().
strtotime() calculates the next month by incrementing the month number. For day number that do not exist from one month to the next, strtotime() fixes them by setting them in the next-next month.
This happens to January, March, May, July, August and October. January is also vulnerable for 29 (not every year), 30 and 31.
Avoid using '+1 month', and rely on 'first day of next month' or 'last day of next month' to extract the next month's name.
<?php
// Base date is October 31 => 10/31
// +1 month adds +1 to 10 => 11/31
// Since November 31rst doesn't exists, it is corrected to 12/01.
echo date('F', strtotime('+1 month',mktime(0,0,0,$i,31,2017))).PHP_EOL;
// Base date is October 31 => 10/31
echo date('F', strtotime('first day of next month',mktime(0,0,0,$i,31,2017))).PHP_EOL;
?>
See also It is the 31st again.
Printf Number Of Arguments
[Since 1.0.1] - [ -P Structures/PrintfArguments ] - [ Online docs ]
The number of arguments provided to printf() or vprintf() doesn't match the format string.
Extra arguments are ignored, and are dead code as such. Missing arguments are reported with a warning, and nothing is displayed.
Omitted arguments produce an error.
<?php
// not enough
printf(' a %s ', $a1);
// OK
printf(' a %s ', $a1, $a2);
// too many
printf(' a %s ', $a1, $a2, $a3);
// not enough
sprintf(' a %s ', $a1);
// OK
\sprintf(' a %s ', $a1, $a2);
// too many
sprintf(' a %s ', $a1, $a2, $a3);
?>
See also printf and sprintf.
Substring First
[Since 1.0.1] - [ -P Performances/SubstrFirst ] - [ Online docs ]
Always start by reducing a string before applying some transformation on it. The shorter string will be processed faster.
<?php
// fast version
$result = strtolower(substr($string, $offset, $length));
// slower version
$result = substr(strtolower($string), $offset, $length);
?>
The gain produced here is greater with longer strings, or greater reductions. They may also be used in loops. This is a micro-optimisation when used on short strings and single string reductions.
This works with any reduction function instead of substr(), like trim(), iconv(), etc.
Drupal Usage
[Since 1.0.3] - [ -P Vendors/Drupal ] - [ Online docs ]
This analysis reports usage of the Drupal CMS. The report is based on the usage of Drupal namespace.
<?php
namespace Drupal\example\Controller;
use Drupal\Core\Controller\ControllerBase;
/**
* An example controller.
*/
class ExampleController extends ControllerBase {
/**
* {@inheritdoc}
*/
public function content() {
$build = array(
'#type' => 'markup',
'#markup' => t('Hello World!'),
);
return $build;
}
}
?>
See also Drupal.
Ambiguous Static
[Since 1.0.3] - [ -P Classes/AmbiguousStatic ] - [ Online docs ]
Methods or properties with the same name, are defined static in one class, and not static in another. This is error prone, as it requires a good knowledge of the code to make it static or not.
Try to keep the methods simple and unique. Consider renaming the methods and properties to distinguish them easily. A method and a static method have probably different responsibilities.
<?php
class a {
function mixedStaticMethod() {}
}
class b {
static function mixedStaticMethod() {}
}
/... a lot more code later .../
$c->mixedStaticMethod();
// or
$c::mixedStaticMethod();
?>
Phalcon Usage
[Since 1.0.3] - [ -P Vendors/Phalcon ] - [ Online docs ]
This analysis reports usage of the Phalcon Framework. The report is based on the usage of Phalcon namespace, which may be provided by PHP code inclusion or the PHP extension.
<?php
use Phalcon\Mvc\Application;
// Register autoloaders
// Register services
// Handle the request
$application = new Application($di);
try {
$response = $application->handle();
$response->s`end() <https://www.php.net/end>`_;
} catch (\Exception $e) {
echo 'Exception: ', $e->getMessage();
}
?>
See also Phalcon.
FuelPHP Usage
[Since 1.0.3] - [ -P Vendors/Fuel ] - [ Online docs ]
This analysis reports usage of the Fuel PHP Framework. The report is based on the usage of Fuel namespace.
<?php
// file located in APPPATH/classes/presenter.php
class Presenter extends \Fuel\Core\Presenter
{
// namespace prefix
protected static $ns_prefix = 'Presenter\';
}?>
See also FuelPHP.
Use List With Foreach
[Since 1.0.4] - [ -P Structures/UseListWithForeach ] - [ Online docs ]
Foreach() structures accepts list() as blind key. If the loop-value is an array with a fixed structure, it is possible to extract the values directly into variables with explicit names.
<?php
// Short way to assign variables
// Works on PHP 7.1, where list() accepts keys.
foreach($names as list('first' => $first, 'last' => $last)) {
doSomething($first, $last);
}
// Short way to assign variables
// Works on all PHP versions with numerically indexed arrays.
foreach($names as list($first, $last)) {
doSomething($first, $last);
}
// Long way to assign variables
foreach($names as $name) {
$first = $name['first'];
$last = $name['last'];
doSomething($first, $last);
}
?>
See also list and foreach.
Don't Send $this In Constructor
[Since 1.0.4] - [ -P Classes/DontSendThisInConstructor ] - [ Online docs ]
Don't use $this as an argument while in the __construct(). Until the constructor is finished, the object is not finished, and may be in an unstable state. Providing it to another code may lead to error.
This is true when the receiving structure puts the incoming object immediately to work, and don't store it for later use.
<?php
// $this is only provided when Foo is constructed
class Foo {
private $bar = null;
private $data = array();
static public function build($data) {
$foo = new Foo($data);
// Can't build in one call. Must make it separate.
$foo->finalize();
}
private function __construct($data) {
// $this is provided too early
$this->data = $data;
}
function finalize() {
$this->bar = new Bar($this);
}
}
// $this is provided too early, leading to error in Bar
class Foo2 extends Foo {
private $bar = null;
private $data = array();
function __construct($data) {
// $this is provided too early
$this->bar = new Bar($this);
$this->data = $data;
}
}
class Bar {
function __construct(Foo $foo) {
// the cache is now initialized with a wrong
$this->cache = $foo->getIt();
}
}
?>
See also Don't pass this out of a constructor.
Argon2 Usage
[Since 1.0.4] - [ -P Php/Argon2Usage ] - [ Online docs ]
Argon2 is an optionally compiled password hashing API.
Argon2 has been added to the password hashing API in PHP 7.2.
It is not available in older version. It also requires PHP to be compiled with the --with-password-argon2 option.
<?php
// Hashing a password with argon2
$hash = password_hash('password', PASSWORD_ARGON2I, ['memory_cost' => 1<<17,
'time_cost' => PASSWORD_ARGON2_DEFAULT_TIME_COST,
'threads' => PASSWORD_ARGON2_DEFAULT_THREADS]);
?>
See also Argon2 Password Hash.
Crypto Usage
[Since 1.0.4] - [ -P Php/CryptoUsage ] - [ Online docs ]
Usage of cryptography and hashes functions.
The functions listed are the native PHP functions, and do not belong to a specific extension, like OpenSSL , mcrypt or mhash .
Cryptography and hashes are mainly used for storing sensitive data, such as passwords, or to verify authenticity of data. They may also be used for name-randomization with cache.
<?php
if (md5($_POST['password']) === $row['password_hash']) {
user_login($user);
} else {
error('Wrong password');
}
?>
See also Cryptography Extensions.
Integer As Property
[Since 1.0.4] - [ -P Classes/IntegerAsProperty ] - [ Online docs ] - [ PHP 7.2 and more recent ]
It is backward incompatible to use integers are property names. This feature was introduced in PHP 7.2.
If the code must be compatible with previous versions, avoid casting arrays to object.
<?php
// array to object
$arr = [0 => 1];
$obj = (object) $arr;
var_dump(
$obj,
$obj->{'0'}, // PHP 7.2+ accessible
$obj->{0} // PHP 7.2+ accessible
$obj->{'b'}, // always been accessible
);
?>
See also PHP RFC: Convert numeric keys in object/array casts.
No get_class() With Null
[Since 1.0.4] - [ -P Structures/NoGetClassNull ] - [ Online docs ]
It is not possible to pass explicitly null to get_class() to get the current's class name. Since PHP 7.2, one must call get_class() without arguments to achieve that result.
<?php
class A {
public function f() {
// Gets the classname
$classname = get_class();
// Gets the classname and a warning
$classname = get_class(null);
}
}
$a = new A();
$a->f('get_class');
?>
Php 7.2 New Class
[Since 1.0.4] - [ -P Php/Php72NewClasses ] - [ Online docs ] - [ PHP older than 7.2]
New classes, introduced in PHP 7.2. If classes where created with the same name, in current code, they have to be moved in a namespace, or removed from code to migrate safely to PHP 7.2.
The new class is : HashContext.
<?php
namespace {
// Global namespace
class HashContext {
// Move to a namespace
// or, remove this class
}
}
namespace B {
class HashContext {
// This is OK : in a namespace
}
}
?>
Avoid set_error_handler $context Argument
[Since 1.0.4] - [ -P Php/AvoidSetErrorHandlerContextArg ] - [ Online docs ]
Avoid configuring set_error_handler() with a method that accepts 5 arguments. The last argument, $errcontext , is deprecated since PHP 7.2, and will be removed later.
<?php
// setting error_handler with an incorrect closure
set_error_handler(function($errno, $errstr, $errfile, $errline) {});
// setting error_handler with an incorrect closure
set_error_handler(function($errno, $errstr, $errfile, $errline, $errcontext) {});
?>
See also set_error_handler();
Hash Will Use Objects
[Since 1.0.4] - [ -P Php/HashUsesObjects ] - [ Online docs ]
The ext/hash extension used resources, and is being upgraded to use resources.
<?php
// Post 7.2 code
$hash = hash_init('sha256');
if (!is_object($hash)) {
trigger_error('error');
}
hash_update($hash, $message);
// Pre-7.2 code
$hash = hash_init('md5');
if (!is_resource($hash)) {
trigger_error('error');
}
hash_update($hash, $message);
?>
See also Move ext/hash from resources to objects.
Can't Count Non-Countable
[Since 1.0.4] - [ -P Structures/CanCountNonCountable ] - [ Online docs ]
Count() emits an error when it tries to count scalars or objects what don't implement Countable interface.
<?php
// Normal usage
$a = array(1,2,3,4);
echo count($a).items\n;
// Error emiting usage
$a = '1234';
echo count($a).chars\n;
// Error emiting usage
echo count($unsetVar).elements\n;
?>
See also Warn when counting non-countable types.
Missing New ?
[Since 1.0.4] - [ -P Structures/MissingNew ] - [ Online docs ]
This functioncall looks like a class instantiation that is missing the new keyword.
Any function definition was found for that function, but a class with that name was. New is probably missing.
<?php
// Functioncall
$a = foo();
// Class definition
class foo {}
// Function definition
function foo {}
// Functioncall
$a = BAR;
// Function definition
class bar {}
// Constant definition
const BAR = 1;
?>
Unknown Pcre2 Option
[Since 1.0.4] - [ -P Php/UnknownPcre2Option ] - [ Online docs ]
PCRE2 supports different options, compared to PCRE1 . PCRE2 was adopted with PHP 7.3.
The S modifier : it used to tell PCRE to spend more time studying the regex, so as to be faster at execution. This is now the default behavior, and may be dropped from the regex.
The X modifier : X is still existing with PCRE2 , though it is now the default for PCRE2 , and not for PHP as time of writing. In particular, Any backslash in a pattern that is followed by a letter that has no special meaning causes an error, thus reserving these combinations for future expansion. . It is recommended to avoid using useless sequence \s in regex to get ready for that change. All the following letters gijkmoqyFIJMOTY . Note that clLpPuU are valid PRCE sequences, and are probably failing for other reasons.
<?php
// \y has no meaning. With X option, this leads to a regex compilation error, and a failed test.
preg_match('/ye\y/', $string);
preg_match('/ye\y/X', $string);
?>
See also Pattern Modifiers and
PHP RFC: PCRE2 migration.
Use PHP7 Encapsed Strings
[Since 1.0.4] - [ -P Performances/PHP7EncapsedStrings ] - [ Online docs ]
PHP 7 has optimized the handling of double-quoted strings. In particular, double-quoted strings are much less memory hungry than classic concatenations.
PHP allocates memory at the end of the double-quoted string, making only one call to the allocator. On the other hand, concatenations are allocated each time they include dynamic content, leading to higher memory consumption.
<?php
$bar = 'bar';
/* PHP 7 optimized this */
$a = "foo and $bar";
/* This is PHP 5 code (aka, don't use it) */
$a = 'foo and ' . $bar;
// Constants can't be used with double quotes
$a = 'foo and ' . __DIR__;
$a = foo and __DIR__; // __DIR__ is not interpolated
?>
Concatenations are still needed with constants, static constants, magic constants, functions, static properties or static methods.
See also PHP 7 performance improvements (3/5): Encapsed strings optimization.
Array Index
[Since 1.0.4] - [ -P Type/ArrayIndex ] - [ Online docs ]
All literal index used in the code.
<?php
// index is an index. it is read
$array['index'] = 1;
// another_index and second_level are read
$array[] = $array['another_index']['second_level'];
// variables index are not reported
$array[$variable] = 1;
?>
Incoming Variable Index Inventory
[Since 1.0.4] - [ -P Type/GPCIndex ] - [ Online docs ]
This collects all the index used in incoming variables : $_GET, $_POST, $_REQUEST, $_COOKIE.
<?php
// x is collected
echo $_GET['x'];
// y is collected, but no z.
echo $_POST['y']['z'];
// a is not collected
echo $_ENV['s'];
?>
Slice Arrays First
[Since 1.0.4] - [ -P Arrays/SliceFirst ] - [ Online docs ]
Always start by reducing an array before applying some transformation on it. The shorter array will be processed faster.
<?php
// fast version
$a = array_map('foo', array_slice($array, 2, 5));
// slower version
$a = array_slice(array_map('foo', $array), 2, 5);
?>
The gain produced here is greater with longer arrays, or greater reductions. They may also be used in loops. This is a micro-optimisation when used on short arrays.
ext/vips
[Since 1.0.4] - [ -P Extensions/Extvips ] - [ Online docs ]
Extension VIPS.
The VIPS image processing system is a very fast, multi-threaded image processing library with low memory needs.
<?php
dl('vips.' . PHP_SHLIB_SUFFIX);
$x = vips_image_new_from_file($argv[1])[out];
vips_image_write_to_file($x, $argv[2]);
?>
See also php-vips-ext,
libvips and
libvips adapter for PHP Imagine.
Dl() Usage
[Since 1.0.4] - [ -P Php/DlUsage ] - [ Online docs ]
Dynamically load PHP extensions with dl().
<?php
// dynamically loading ext/vips
dl('vips.' . PHP_SHLIB_SUFFIX);
?>
See also dl.
Parent First
[Since 1.0.5] - [ -P Classes/ParentFirst ] - [ Online docs ]
When calling parent constructor, always put it first in the __construct method. It ensures the parent is correctly build before the child start using values.
<?php
class father {
protected $name = null;
function __construct() {
$this->name = init();
}
}
class goodSon {
function __construct() {
// parent is build immediately,
parent::__construct();
echo my name is.$this->name;
}
}
class badSon {
function __construct() {
// This will fail.
echo my name is.$this->name;
// parent is build later,
parent::__construct();
}
}
?>
This analysis doesn't apply to Exceptions.
Environment Variables
[Since 1.0.5] - [ -P Variables/UncommonEnvVar ] - [ Online docs ]
Environment variables are used to interact with the hosting system.
They often provides configuration parameter that are set by the host of the application to be used.
That way, information is not hardcoded in the application, and may be changed at production.
<?php
//ENVIRONMENT set the production context
if (getenv('ENVIRONMENT') === 'Production') {
$sshKey = getenv('HOST_KEY');
} elseif (getenv('ENVIRONMENT') === 'Developper') {
$sshKey = 'NO KEY';
} else {
header('No website here.');
die();
}
?>
See also $_ENV.
Invalid Regex
[Since 1.0.5] - [ -P Structures/InvalidRegex ] - [ Online docs ]
The PCRE regex doesn't compile. It isn't a valid regex.
Several reasons may lead to this situation : syntax error, Unknown modifier, missing parenthesis or reference.
<?php
// valid regex
preg_match('/[abc]/', $string);
// invalid regex (missing terminating ] for character class
preg_match('/[abc/', $string);
?>
Regex are check with the Exakat version of PHP.
Dynamic regex are only checked for simple values. Dynamic values may eventually generate a compilation error.
Use Named Boolean In Argument Definition
[Since 1.0.6] - [ -P Functions/AvoidBooleanArgument ] - [ Online docs ]
Boolean in argument definitions is confusing.
It is recommended to use explicit constant names, instead. They are more readable. They also allow for easy replacement when the code evolve and has to replace those booleans by strings. This works even also with classes, and class constants.
<?php
function flipImage($im, $horizontal = NO_HORIZONTAL_FLIP, $vertical = NO_VERTICAL_FLIP) { }
// with constants
const HORIZONTAL_FLIP = true;
const NO_HORIZONTAL_FLIP = true;
const VERTICAL_FLIP = true;
const NO_VERTICAL_FLIP = true;
rotateImage($im, HORIZONTAL_FLIP, NO_VERTICAL_FLIP);
// without constants
function flipImage($im, $horizontal = false, $vertical = false) { }
rotateImage($im, true, false);
?>
See also Flag Argument, to avoid boolean altogether.
Same Variables Foreach
[Since 1.0.5] - [ -P Structures/AutoUnsetForeach ] - [ Online docs ]
A foreach which uses its own source as a blind variable is actually broken.
Actually, PHP makes a copy of the source before it starts the loop. As such, the same variable may be used for both source and blind value.
Of course, this is very confusing, to see the same variables used in very different ways.
The source will also be destroyed immediately after the blind variable has been turned into a reference.
<?php
$array = range(0, 10);
foreach($array as $array) {
print $array.PHP_EOL;
}
print_r($array); // display number from 0 to 10.
$array = range(0, 10);
foreach($array as &$array) {
print $array.PHP_EOL;
}
print_r($array); // display 10
?>
Never Used Parameter
[Since 1.0.6] - [ -P Functions/NeverUsedParameter ] - [ Online docs ]
When a parameter is never used at calltime, it may be turned into a local variable.
It seems that the parameter was set up initially, but never found its practical usage. It is never mentioned, and always fall back on its default value.
Parameter without a default value are reported by PHP, and are usually always filled.
<?php
// $b may be turned into a local var, it is unused
function foo($a, $b = 1) {
return $a + $b;
}
// whenever foo is called, the 2nd arg is not mentionned
foo($a);
foo(3);
foo('a');
foo($c);
?>
ext/igbinary
[Since 1.0.6] - [ -P Extensions/Extigbinary ] - [ Online docs ]
Extension igbinary.
igbinary is a drop in replacement for the standard php serializer. Instead of time and space consuming textual representation, igbinary stores php data structures in compact binary form.
<?php
$serialized = igbinary_serialize($variable);
$unserialized = igbinary_unserialize($serialized);
?>
See also igbinary.
Should Use array_filter()
[Since 1.0.7] - [ -P Php/ShouldUseArrayFilter ] - [ Online docs ]
Should use array_filter().
array_filter() is a native PHP function, that extract elements from an array, based on a closure or a function. Using array_filter() shortens your code, and allows for reusing the filtering logic across the application, instead of hard coding it every time.
<?php
$a = range(0, 10); // integers from 0 to 10
// Extracts odd numbers
$odds = array_filter($a, function($x) { return $x % 2; });
$odds = array_filter($a, 'odd');
// Slow and cumbersome code for extracting odd numbers
$odds = array();
foreach($a as $v) {
if ($a % 2) { // same filter than the closure above, or the odd function below
$bColumn[] = $v;
}
}
function foo($x) {
return $x % 2;
}
?>
array_filter() is faster than foreach() (with or without the isset() test) with 3 elements or more, and it is significantly faster beyond 5 elements. Memory consumption is the same.
See also array_filter.
Identical On Both Sides
[Since 1.0.8] - [ -P Structures/IdenticalOnBothSides ] - [ Online docs ]
Operands should be different when comparing or making a logical combination. Of course, the value each operand holds may be identical. When the same operand appears on both sides of the expression, the result is know before execution.
<?php
// Trying to confirm consistency
if ($login == $login) {
doSomething();
}
// Works with every operators
if ($object->login( ) !== $object->login()) {
doSomething();
}
if ($sum >= $sum) {
doSomething();
}
//
if ($mask && $mask) {
doSomething();
}
if ($mask || $mask) {
doSomething();
}
?>
Identical Consecutive Expression
[Since 1.0.8] - [ -P Structures/IdenticalConsecutive ] - [ Online docs ]
Identical consecutive expressions are worth being checked.
They may be a copy/paste with unmodified content. When the content has to be duplicated, it is recommended to avoid executing the expression again, and just access the cached result.
<?php
$current = $array[$i];
$next = $array[$i + 1];
$nextnext = $array[$i + 1]; // OOps, nextnext is wrong.
// Initialization
$previous = foo($array[1]); // previous is initialized with the first value on purpose
$next = foo($array[1]); // the second call to foo() with the same arguments should be avoided
// the above can be rewritten as :
$next = $previous; // save the processing.
for($i = 1; $i < 200; ++$i) {
$next = doSomething();
}
?>
No Reference For Ternary
[Since 1.0.8] - [ -P Php/NoReferenceForTernary ] - [ Online docs ]
The ternary operator and the null coalescing operator are both expressions that only return values, and not a variable.
This means that any provided reference will be turned into its value. While this is usually invisible, it will raise a warning when a reference is expected. This is the case with methods returning a reference.
A PHP notice is generated when using a ternary operator or the null coalesce operator : Only variable references should be returned by reference . The notice is also emitted when returning objects.
This applies to methods, functions and closures.
<?php
// This works
function &foo($a, $b) {
if ($a === 1) {
return $b;
} else {
return $a;
}
}
// This raises a warning, as the operator returns a value
function &foo($a, $b) { return $a === 1 ? $b : $a; }
?>
See also Null Coalescing Operator,
Ternary Operator.
Sqlite3 Requires Single Quotes
[Since 1.0.10] - [ -P Security/Sqlite3RequiresSingleQuotes ] - [ Online docs ]
The escapeString() method from SQLite3 doesn't escape " , but only ' .
<?php
// OK. escapeString is OK with '
$query = "SELECT * FROM table WHERE col = '".$sqlite->escapeString($x)."'";
// This is vulnerable to " in $x
$query = 'SELECT * FROM table WHERE col = "'.$sqlite->escapeString($x).'"';
?>
To properly handle quotes and NUL characters, use bindParam() instead.
Quote from the PHP manual comments : The reason this function doesn't escape double quotes is because double quotes are used with names (the equivalent of backticks in MySQL), as in table or column names, while single quotes are used for values.
See also SQLite3::escapeString.
No Net For Xml Load
[Since 1.0.11] - [ -P Security/NoNetForXmlLoad ] - [ Online docs ]
Simplexml and ext/DOM load all external entities from the web, by default. This is dangerous, in particular when loading unknown XML code.
Look at this XML code below : it is valid. It defines an entity xxe , that is filled with a file, read on the system and base64 encoded.
<?php <!DOCTYPE replace [<!ENTITY xxe SYSTEM "php://filter/convert.base64-encode/resource=index.php"> ]>&xxe; ?>
This file could be processed with the following code : note, you can replace 'index.php' in the above entity by any valid filepath.
<?php
$dom = new DOMDocument();
$dom->loadXML($xml, LIBXML_NOENT | LIBXML_DTDLOAD);
$info = simplexml_import_dom($dom);
print base64_decode($info[0]);
?>
Here, PHP tries to load the XML file, finds the entity, then solves the entity by encoding a file called index.php . The source code of the file is not used as data in the XML file.
At that point, the example illustrates how a XXE works : by using the XML engine to load external resources, and preprocessing the XML code. in fact, there is only one change to make this XML code arbitrarily injected :
<?php <!DOCTYPE replace [<!ENTITY writer SYSTEM https://www.example.com/entities.dtd> ]>&xxe; ?>
With the above example, the XML code is static (as, it never changes), but the 'xxe' definitions are loaded from a remove website, and are completely under the attacker control.
See also XML External Entity,
XML External Entity (XXE) Processing and
Detecting and exploiting XXE in SAML Interfaces.
Unused Inherited Variable In Closure
[Since 1.0.11] - [ -P Functions/UnusedInheritedVariable ] - [ Online docs ]
Some closures forgot to make usage of inherited variables.
Closure have two separate set of incoming variables : the arguments (between parenthesis) and the inherited variables, in the 'use' clause. Inherited variables are extracted from the local environment at creation time, and keep their value until execution.
The reported closures are requesting some local variables, but do not make any usage of them. They may be considered as dead code.
<?php
// In this closure, $y is forgotten, but $u is used.
$a = function ($y) use ($u) { return $u; };
// In this closure, $u is forgotten
$a = function ($y, $z) use ($u) { return $u; };
?>
See also Anonymous functions.
Inclusion Wrong Case
[Since 1.1.1] - [ -P Files/InclusionWrongCase ] - [ Online docs ]
Inclusion should follow exactly the case of included files and path. This prevents the infamous case-sensitive filesystem bug, where files are correctly included in a case-insensitive system, and failed to be when moved to production.
<?php
// There must exist a path called path/to and a file library.php with this case
include path/to/library.php;
// Error on the case, while the file does exist
include path/to/LIBRARY.php;
// Error on the case, on the PATH
include path/TO/library.php;
?>
See also include_once, about case sensitivity and inclusions.
Missing Include
[Since 1.1.2] - [ -P Files/MissingInclude ] - [ Online docs ]
The included files doesn't exists in the repository. The inclusions target a files that doesn't exist.
The analysis works with every type of inclusion : include(), require(), include_once() and require_once(). It also works with parenthesis when used as parameter delimiter.
The analysis doesn't take into account include_path . This may yield false positives.
<?php
include 'non_existent.php';
// variables are not resolved. This won't be reported.
require ($path.'non_existent.php');
?>
Missing included files may lead to a fatal error, a warning or other error later in the execution.
Useless Referenced Argument
[Since 1.1.3] - [ -P Functions/UselessReferenceArgument ] - [ Online docs ]
The argument has a reference, but is only used for reading.
This is probably a development artefact that was forgotten. It is better to remove it.
This analysis also applies to foreach() loops, that declare the blind variable as reference, then use the variable as an object, accessing properties and methods. When a variable contains an object, there is no need to declare a reference : it is a reference automatically.
<?php
function foo($a, &$b, &$c) {
// $c is passed by reference, but only read. The reference is useless.
$b = $c + $a;
// The reference is useful for $b
}
foreach ($array as &$element) {
$element->method();
}
?>
See also Objects and references.
Fallback Function
[Since 1.1.4] - [ -P Functions/FallbackFunction ] - [ Online docs ]
A function that is called with its name alone, and whose definition is in the global scope.
<?php
namespace {
// global definition
function foo() {}
}
namespace Bar {
// local definition
function foo2() {}
foo(); // definition is in the global namespace
foo2(); // definition is in the Bar namespace
}
?>
See also Using namespaces: fallback to global function/constant.
Reuse Variable
[Since 1.1.4] - [ -P Structures/ReuseVariable ] - [ Online docs ]
A variable is already holding the content that is calculated multiple times over.
It is recommended to use the cached value. This saves some computation, in particular when used in a loop, and speeds up the process.
<?php
function foo($a) {
$b = strtolower($a);
// strtolower($a) is already calculated in $b. Just reuse the value.
if (strtolower($a) === 'c') {
doSomething();
}
}
?>
Double array_flip()
[Since 1.1.4] - [ -P Performances/DoubleArrayFlip ] - [ Online docs ]
Avoid double array_flip() to gain speed. While array_flip() alone is usually useful, a double call to array_flip() is made to make values and keys unique.
<?php
// without array_flip
function foo($array, $value) {
$key = array_search($array, $value);
if ($key !== false) {
unset($array[$key]);
}
return $array;
}
// double array_flip
// `array_flip() <https://www.php.net/array_flip>`_ usage means that $array's values are all unique
function foo($array, $value) {
$flipped = array_flip($value);
unset($flipped[$value]);
return array_flip($flipped);
}
?>
Useless Catch
[Since 1.1.4] - [ -P Exceptions/UselessCatch ] - [ Online docs ]
Catch clause should handle the exception with some work.
Among the task of a catch clause : log the exception, clean any mess that was introduced, fail graciously.
<?php
function foo($a) {
try {
$b = doSomething($a);
} catch (Throwable $e) {
// No log of the exception : no one knows it happened.
// return immediately ?
return false;
}
$b->complete();
return $b;
}
?>
See also Exceptions and
Best practices for PHP exception handling.
Possible Infinite Loop
[Since 1.1.5] - [ -P Structures/PossibleInfiniteLoop ] - [ Online docs ]
Loops on files that can't be open results in infinite loop.
fgets(), and functions like fgetss(), fgetcsv(), fread(), return false when they finish reading, or can't access the file.
In case the file is not accessible, comparing the result of the reading to something that is falsy, leads to a permanent valid condition. The execution will only finish when the max_execution_time is reached.
<?php
$file = fopen('/path/to/file.txt', 'r');
// when `fopen() <https://www.php.net/fopen>`_ fails, the next loops is infinite
// `fgets() <https://www.php.net/fgets>`_ will always return false, and while will always be true.
while($line = fgets($file) != 'a') {
doSomething();
}
?>
It is recommended to check the file resources when they are opened, and always use === or !== to compare readings. feof() is also a reliable function here.
Should Use Math
[Since 1.1.5] - [ -P Structures/ShouldUseMath ] - [ Online docs ]
Use math operators to make the operation readable.
<?php
// Adding one to self
$a *= 2;
// same as above
$a += $a;
// Squaring oneself
$a **= 2;
// same as above
$a *= $a;
// Removing oneself
$a = 0;
// same as above
$a -= $a;
// Dividing oneself
$a = 1;
// same as above
$a /= $a;
// Divisition remainer
$a = 0;
// same as above
$a %= $a;
?>
See also Mathematical Functions.
ext/hrtime
[Since 1.1.5] - [ -P Extensions/Exthrtime ] - [ Online docs ]
High resolution timing Extension.
The HRTime extension implements a high resolution StopWatch class. It uses the best possible APIs on different platforms which brings resolution up to nanoseconds. It also makes possible to implement a custom stopwatch using low level ticks delivered by the underlaying APIs.
<?php
$c = new HRTime\StopWatch;
$c->start();
/* measure this code block execution */
for ($i = 0; $i < 1024*1024; $i++);
$c->stop();
$elapsed0 = $c->getLastElapsedTime(HRTime\Unit::NANOSECOND);
/* measurement is not running here*/
for ($i = 0; $i < 1024*1024; $i++);
$c->start();
/* measure this code block execution */
for ($i = 0; $i < 1024*1024; $i++);
$c->stop();
$elapsed1 = $c->getLastElapsedTime(HRTime\Unit::NANOSECOND);
$elapsed_total = $c->getElapsedTime(HRTime\Unit::NANOSECOND);
?>
See also ext/hrtime manual.
List With Reference
[Since 1.1.6] - [ -P Php/ListWithReference ] - [ Online docs ] - [ PHP 7.3 and more recent ]
Support for references in list calls is not backward compatible with older versions of PHP. The support was introduced in PHP 7.3.
<?php
$array = [1,2,3];
[$c, &$d, $e] = $a;
$d++;
$c++;
print_r($array);
/*
displays
Array
(
[0] => 1 // Not a reference to $c, unchanged
[1] => 3 // Reference from $d
[2] => 3
)
*/
?>
See also list() Reference Assignment.
Test Then Cast
[Since 1.1.6] - [ -P Structures/TestThenCast ] - [ Online docs ]
A test is run on the value, but the cast value is later used.
The cast may introduce a distortion to the value, and still lead to the unwanted situation. For example, comparing to 0, then later casting to an int. The comparison to 0 is done without casting, and as such, 0.1 is different from 0. Yet, (int) 0.1 is actually 0, leading to a Division by 0 error.
<?php
// Here. $x may be different from 0, but (int) $x may be 0
$x = 0.1;
if ($x != 0) {
$y = 4 / (int) $x;
}
// Safe solution : check the cast value.
if ( (int) $x != 0) {
$y = 4 / (int) $x;
}
?>
Could Use Compact
[Since 1.1.6] - [ -P Structures/CouldUseCompact ] - [ Online docs ]
Compact() turns a group of variables into an array. It may be used to simplify expressions.
<?php
$a = 1;
$b = 2;
// Compact call
$array = compact('a', 'b');
$array === [1, 2];
// Detailing all the keys and their value
$array = ['a' => $a, 'b' => $b];
?>
Note that compact accepts any string, and any undefined variable is not set, without a warning.
See also compact.
Foreach On Object
[Since 1.1.6] - [ -P Php/ForeachObject ] - [ Online docs ]
Foreach on object looks like a typo. This is particularly true when both object and member are variables.
Foreach on an object member is a legit PHP syntax, though it is very rare : blind variables rarely have to be securing in an object to be processed.
<?php
// Looks suspicious
foreach($array as $o -> $b) {
doSomething();
}
// This is the real thing
foreach($array as $o => $b) {
doSomething();
}
?>
ext/xxtea
[Since 1.1.7] - [ -P Extensions/Extxxtea ] - [ Online docs ]
Extension xxtea : XXTEA encryption algorithm extension for PHP.
XXTEA is a fast and secure encryption algorithm. This is a XXTEA extension for PHP.
It is different from the original XXTEA encryption algorithm. It encrypts and decrypts string instead of uint32 array, and the key is also string.
<?php
// Example is extracted from the xxtea repository on github : tests/xxtea.phpt
$str = 'Hello World! 你好，中国🇨🇳！';
$key = '1234567890';
$base64 = 'D4t0rVXUDl3bnWdERhqJmFIanfn/6zAxAY9jD6n9MSMQNoD8TOS4rHHcGuE=';
$encrypt_data = xxtea_encrypt($str, $key);
$decrypt_data = xxtea_decrypt($encrypt_data, $key);
if ($str == $decrypt_data && base64_encode($encrypt_data) == $base64) {
echo 'success!';
} else {
echo base64_encode($encrypt_data);
echo 'fail!';
}
?>
See also PECL ext/xxtea and
ext/xxtea on Github.
ext/uopz
[Since 1.1.7] - [ -P Extensions/Extuopz ] - [ Online docs ]
Extension UOPZ : User Operations for Zend.
The uopz extension is focused on providing utilities to aid with unit testing PHP code.
It supports the following activities: Intercepting function execution, Intercepting object creation, Hooking into function execution, Manipulation of function statics, Manipulation of function flags, Redefinition of constants, Deletion of constants, Runtime creation of functions and methods,
<?php
// The example is extracted from the UOPZ extension test suite : tests/001.phpt
class Foo {
public function bar(int $arg) : int {
return $arg;
}
}
var_dump(uopz_set_return(Foo::class, 'bar', true));
$foo = new Foo();
var_dump($foo->bar(1));
uopz_set_return(Foo::class, 'bar', function(int $arg) : int {
return $arg * 2;
}, true);
var_dump($foo->bar(2));
try {
uopz_set_return(Foo::class, 'nope', 1);
} catch(Throwable $t) {
var_dump($t->getMessage());
}
class Bar extends Foo {}
try {
uopz_set_return(Bar::class, 'bar', null);
} catch (Throwable $t) {
var_dump($t->getMessage());
}
uopz_set_something(Bar::class, 'bar', null);
?>
See also ext/uopz and User Operations for Zend.
ext/varnish
[Since 1.1.7] - [ -P Extensions/Extvarnish ] - [ Online docs ]
Extension PHP for varnish.
Varnish Cache is an open source, state of the art web application accelerator. The extension makes it possible to interact with a running varnish instance through TCP socket or shared memory.
<?php
$args = array(
VARNISH_CONFIG_HOST => '::1',
VARNISH_CONFIG_PORT => 6082,
VARNISH_CONFIG_SECRET => '5174826b-8595-4958-aa7a-0609632ad7ca',
VARNISH_CONFIG_TIMEOUT => 300,
);
$va = new VarnishAdmin($args);
?>
See also ext/varnish and pecl/Varnish.
ext/opencensus
[Since 1.1.7] - [ -P Extensions/Extopencensus ] - [ Online docs ]
Extension PHP for OpenCensus :
A stats collection and distributed tracing framework.
<?php
opencensus_trace_begin('root', ['spanId' => '1234']);
opencensus_trace_add_annotation('foo');
opencensus_trace_begin('inner', []);
opencensus_trace_add_annotation('asdf', ['spanId' => '1234']);
opencensus_trace_add_annotation('abc');
opencensus_trace_finish();
opencensus_trace_finish();
$traces = opencensus_trace_list();
echo Number of traces: . count($traces) . \n;
$span = $traces[0];
print_r($span->timeEvents());
$span2 = $traces[1];
print_r($span2->timeEvents());
?>
See also opencensus.
Dynamic Library Loading
[Since 1.1.7] - [ -P Security/DynamicDl ] - [ Online docs ]
Loading a variable dynamically requires a lot of care in the preparation of the library name.
In case of injection in the variable, the dynamic loading of a library gives a lot of power to an intruder.
<?php
// dynamically loading a library
dl($library. PHP_SHLIB_SUFFIX);
// dynamically loading ext/vips
dl('vips.' . PHP_SHLIB_SUFFIX);
// static loading ext/vips (unix only)
dl('vips.so');
?>
See also dl.
PHP 7.3 Last Empty Argument
[Since 1.1.7] - [ -P Php/PHP73LastEmptyArgument ] - [ Online docs ] - [ PHP 7.3 and more recent ]
PHP allows the last element of any functioncall to be empty. The argument is then not send.
This was introduced in PHP 7.3, and is not backward compatible.
The last empty line is easier on the VCS, allowing clearer text diffs.
<?php
function foo($a, $b) {
print_r(`func_get_args() <https://www.php.net/func_get_args>`_);
}
foo(1,
2,
);
foo(1);
?>
See also Allow a trailing comma in function calls and
Trailing commas.
Could Use array_fill_keys
[Since 1.1.7] - [ -P Structures/CouldUseArrayFillKeys ] - [ Online docs ]
array_fill_keys() is a native PHP function that creates an array from keys. It gets the list of keys, and a constant value to assign to each keys.
This is twice faster than doing the same with a loop.
Note that is possible to use an object as initializing value : every element of the final array will be pointing to the same value. And, also, using an object as initializing value means that the same object will be used for each key : the object will not be cloned for each value.
<?php
$array = range('a', 'z');
// Fast way to build the array
$b = array_fill_keys($a, 0);
// Fast way to build the array, but every element will be the same object
$b = array_fill_keys($a, new Stdclass());
// Slow way to build the array
foreach($array as $a) {
$b[$a] = 0;
}
// Setting everything to null, slowly
$array = array_map(function() {}, $array);
?>
See also array_fill_keys.
ext/leveldb
[Since 1.1.7] - [ -P Extensions/Extleveldb ] - [ Online docs ]
PHP Binding for LevelDB.
LevelDB is a fast key-value storage library written at Google that provides an ordered mapping from string keys to string values.
<?php
$db = new LevelDB($leveldb_path);
$batch = new LevelDBWriteBatch();
$batch->set('batch_foo', 'batch_bar');
$batch->put('batch_foo2', 'batch_bar2');
$batch->delete('batch_foo');
$db->write($batch);
$batch->clear();
$batch->delete('batch_foo2');
$batch->set('batch_foo', 'batch again');
?>
See also ext/leveldb on Github and
Leveldb.
Use Count Recursive
[Since 1.1.7] - [ -P Structures/UseCountRecursive ] - [ Online docs ]
The code could use the recursive version of count.
The second argument of count, when set to COUNT_RECURSIVE , count recursively the elements. It also counts the elements themselves.
<?php
$array = array( array(1,2,3), array(4,5,6));
print (count($array, COUNT_RECURSIVE) - count($array, COUNT_NORMAL));
$count = 0;
foreach($array as $a) {
$count += count($a);
}
print $count;
?>
See also count.
Property Could Be Local
[Since 1.1.7] - [ -P Classes/PropertyCouldBeLocal ] - [ Online docs ]
A property only used in one method may be turned into a local variable.
Public an protected properties are omitted here : they may be modified somewhere else, in the code. This analysis may be upgraded to support those properties, when tracking of such properties becomes available.
Classes where only one non-magic method is available are omitted.
Traits with private properties are processed the same way.
<?php
class x {
private $foo = 1;
// Magic method, and constructor in particular, are omitted.
function __construct($foo) {
$this->foo = $foo;
}
function bar() {
$this->foo++;
return $this->foo;
}
function barbar() {}
}
?>
ext/db2
[Since 1.1.8] - [ -P Extensions/Extdb2 ] - [ Online docs ]
Extension for IBM DB2, Cloudscape and Apache Derby.
This extension gives access to IBM DB2 Universal Database, IBM Cloudscape, and Apache Derby databases using the DB2 Call Level Interface (DB2 CLI).
<?php
$conn = db2_connect($database, $user, $password);
if ($conn) {
$stmt = db2_exec($conn, 'SELECT count(*) FROM animals');
$res = db2_fetch_array( $stmt );
echo $res[0] . PHP_EOL;
// Turn AUTOCOMMIT off
db2_autocommit($conn, DB2_AUTOCOMMIT_OFF);
// Delete all rows from ANIMALS
db2_exec($conn, 'DELETE FROM animals');
$stmt = db2_exec($conn, 'SELECT count(*) FROM animals');
$res = db2_fetch_array( $stmt );
echo $res[0] . PHP_EOL;
// Roll back the DELETE statement
db2_rollback( $conn );
$stmt = db2_exec( $conn, 'SELECT count(*) FROM animals' );
$res = db2_fetch_array( $stmt );
echo $res[0] . PHP_EOL;
db2_close($conn);
}
?>
See also IBM Db2.
Too Many Native Calls
[Since 1.1.10] - [ -P Php/TooManyNativeCalls ] - [ Online docs ]
Avoid stuffing too many PHP native call inside another functioncall.
For readability reasons, or, more often, for edge case handling, it is recommended to avoid nesting too many PHP native calls.
This analysis reports any situation where more than 3 PHP native calls are nested.
<?php
// Too many nested functions
$cleanArray = array_unique(array_keys(array_count_values(array_column($source, 'x'))));
// Avoid warning when source is empty
$extract = array_column($source, 'x');
if (empty($extract)) {
$cleanArray = array();
} else {
$cleanArray = array_unique(array_keys(array_count_values($extract)));
}
// This is not readable, although it is short.
// It may easily get out of hand.
echo chr(80), chr(72), chr(80), chr(32), ' is great!';
?>
Too Many Parameters
[Since 1.1.9] - [ -P Functions/TooManyParameters ] - [ Online docs ]
Method has too many parameters. Exakat has a default parameter count which may be configured.
A method that needs more than 8 parameters is trying to do too much : it should be reviewed and split into smaller methods.
<?php
// This methods has too many parameters.
function alertSomeone($name, $email, $title, $message, $attachements, $signature, $bcc, $cc, $extra_headers) {
/* too much code here */
}
?>
See also How many parameters is too many ? and
Too Many Parameters.
Should Preprocess Chr()
[Since 1.1.9] - [ -P Php/ShouldPreprocess ] - [ Online docs ]
Replace literal chr() calls with their escape sequence.
chr() is a functioncall, that cannot be cached. It is only resolved at execution time.
On the other hand, literal values are preprocessed by PHP and may be cached.
<?php
// This is easier on PHP
$a = "\120\110\120\040 is great!";
// This is slow
$a = chr(80), chr(72), chr(80), chr(32), ' is great!';
// This would be the best with this example, but it is not always possible
$a = 'PHP is great!';
?>
This is a micro-optimisation.
See also Escape sequences.
Properties Declaration Consistence
[Since 1.2.1] - [ -P Classes/PPPDeclarationStyle ] - [ Online docs ]
Properties may be declared all at once, or one by one.
The analyzed code has less than 10% of one of them : for consistency reasons, it is recommended to make them all the same.
It happens that choosing unique declarations or multiple depends on coding style and files.
<?php
class x {
// Some declarations are made by batch
private $a1 = 1,
$a2 = 2;
public $c = 1, $c2 = 2, $c4 = 3;
// Most declarations are made one by one
protected $b = 1;
protected $b1 = 1;
protected $b2 = 1;
protected $b3 = 1;
protected $b4 = 1;
protected $b5 = 1;
protected $b6 = 1;
protected $b7 = 1;
protected $b8 = 1;
protected $b9 = 1;
protected $b10 = 1;
protected $b11 = 1;
protected $b12 = 1;
protected $b13 = 1;
protected $b14 = 1;
protected $b15 = 1;
protected $b16 = 1;
protected $b17 = 1;
protected $b18 = 1;
protected $b19 = 1;
}
?>
See also Properties.
Possible Increment
[Since 1.2.1] - [ -P Structures/PossibleIncrement ] - [ Online docs ]
This expression looks like a typo : a missing + would change the behavior.
The same pattern is not reported with -, as it is legit expression. + sign is usually understated, rather than explicit.
<?php
// could it be a ++$b ?
$a = +$b;
?>
See also Incrementing/Decrementing Operators and
Arithmetic Operators.
Drop Substr Last Arg
[Since 1.2.2] - [ -P Structures/SubstrLastArg ] - [ Online docs ]
Substr() works till the end of the string when the last argument is omitted. There is no need to calculate string size to make this work.
<?php
$string = 'abcdef';
// Extract the end of the string
$cde = substr($string, 2);
// Too much work
$cde = substr($string, 2, strlen($string));
?>
See also substr.
Redefined Private Property
[Since 1.2.3] - [ -P Classes/RedefinedPrivateProperty ] - [ Online docs ]
Private properties are local to their defined class. PHP doesn't forbid the re-declaration of a private property in a child class.
However, having two or more properties with the same name, in the class hierarchy tends to be error prone.
<?php
class A {
private $isReady = true;
}
class B {
private $isReady = false;
}
?>
Don't Unset Properties
[Since 1.2.3] - [ -P Classes/DontUnsetProperties ] - [ Online docs ]
Avoid unsetting properties. They would go undefined, and raise more warnings.
When getting rid of a property, assign it to null. This keeps the property in the object, yet allows existence check without errors.
<?php
class Foo {
public $a = 1;
}
$a = new Foo();
var_dump((array) $a) ;
// la propriété est reportée, et null
// ['a' => null]
unset($a->a);
var_dump((array) $a) ;
//Empty []
// Check if a property exists
var_dump($a->b === null);
// Same result as above, but with a warning
var_dump($a->c === null);
?>
This analysis works on properties and static properties. It also reports magic properties being unset.
Thanks for Benoit Burnichon for the original idea.
Strtr Arguments
[Since 1.2.3] - [ -P Php/StrtrArguments ] - [ Online docs ]
Strtr() replaces characters by others in a string. When using strings, strtr() replaces characters as long as they have a replacement. All others are ignored.
In particular, strtr() works on strings of the same size, and cannot be used to remove chars.
<?php
$string = 'abcde';
echo strtr($string, 'abc', 'AB');
echo strtr($string, 'ab', 'ABC');
// displays ABcde
// c is ignored each time
// strtr can't remove a char
echo strtr($string, 'a', '');
// displays a
?>
See also strtr.
Processing Collector
[Since 1.2.4] - [ -P Performances/RegexOnCollector ] - [ Online docs ]
When accumulating data in a variable, within a loop, it is slow to apply repeatedly a function to the variable.
The example below illustrate the problem : $collector is build with element from $array . $collector actually gets larger and larger, slowing the in_array() call each time.
It is better to apply the preg_replace() to $a , a short variable, and then, add $a to the collector.
<?php
// Fast way
$collector = '';
foreach($array as $a){
$a = preg_replace('/__(.*?)__/', '<b>$1</b>', $a);
$collector .= $a;
}
// Slow way
$collector = '';
foreach($array as $a){
$collector .= $a;
$collector = preg_replace('/__(.*?)__/', '<b>$1</b>', $collector);
}
?>
Missing Parenthesis
[Since 1.2.6] - [ -P Structures/MissingParenthesis ] - [ Online docs ]
Add parenthesis to those expression to prevent bugs.
<?php
// Missing some parenthesis!!
if (!$a instanceof Stdclass) {
print Not\n;
} else {
print Is\n;
}
// Could this addition be actually
$c = -$a + $b;
// This one ?
$c = -($a + $b);
?>
See also Operators Precedence.
One If Is Sufficient
[Since 1.2.6] - [ -P Structures/OneIfIsSufficient ] - [ Online docs ]
Nested conditions may be written another way, and reduce the amount of code.
Nested conditions are equivalent to a && condition. As such, they may be switched. When one of the condition has no explicit else, then it is lighter to write it as the first condition. This way, it is written once, and not repeated.
<?php
// Less conditions are written here.
if($b == 2) {
if($a == 1) {
++$c;
}
else {
++$d;
}
}
// ($b == 2) is double here
if($a == 1) {
if($b == 2) {
++$c;
}
}
else {
if($b == 2) {
++$d;
}
}
?>
Could Use array_unique
[Since 1.2.6] - [ -P Structures/CouldUseArrayUnique ] - [ Online docs ]
Use array_unique() to collect unique elements from an array.
Always try to use native PHP functions, instead of rebuilding them with custom PHP code.
<?php
$unique = array();
foreach ($array as $b) {
if (!in_array($b, $unique)) {
/* May be more code */
$unique[] = $b;
}
}
?>
See also array_unique.
Callback Needs Return
[Since 1.2.6] - [ -P Functions/CallbackNeedsReturn ] - [ Online docs ]
When used with array_map() functions, the callback must return something. This return may be in the form of a return statement, a global variable or a parameter with a reference. All those solutions extract information from the callback.
<?php
// This filters each element
$filtered = array_filter($array, function ($x) {return $x == 2; });
// This return void for every element
$filtered = array_filter($array, function ($x) {return ; });
// costly `array_sum() <https://www.php.net/array_sum>`_
$sum = 0;
$filtered = array_filter($array, function ($x) use (&$sum) {$sum += $x; });
// costly `array_sum() <https://www.php.net/array_sum>`_
global $sum = 0;
$filtered = array_filter($array, function () {global $sum; $sum += $x; });
// register_shutown_function() doesn't require any return
register_shutown_function(my_shutdown);
?>
The following functions are omitted, as they don't require the return :
+ forward_static_call_array()
+ forward_static_call()
+ register_shutdown_function()
+ register_tick_function()
See also array_map.
Wrong Range Check
[Since 1.2.5] - [ -P Structures/WrongRange ] - [ Online docs ]
The interval check should use && and not ||.
<?php
//interval correctly checked a is between 2 and 999
if ($a > 1 && $a < 1000) {}
//interval incorrectly checked : a is 2 or more ($a < 1000 is never checked)
if ($a > 1 || $a < 1000) {}
?>
ext/zookeeper
[Since 1.2.5] - [ -P Extensions/Extzookeeper ] - [ Online docs ]
Extension for Apache Zookeeper.
ZooKeeper is an Apache project that enables centralized service for maintaining configuration information, naming, providing distributed synchronization, and providing group services.
<?php
$zookeeper = new Zookeeper('locahost:2181');
$path = '/path/to/node';
$value = 'nodevalue';
$zookeeper->set($path, $value);
$r = $zookeeper->get($path);
if ($r)
echo $r;
else
echo 'ERR';
?>
See also ext/zookeeper,
Install Zookeeper PHP Extension
Zookeeper and .
ext/cmark
[Since 1.2.7] - [ -P Extensions/Extcmark ] - [ Online docs ]
Extension Cmark, for Common Mark.
cmark provides access to the reference implementation of CommonMark, a rationalized version of Markdown syntax with a specification.
<?php
$text = new CommonMark\Node\Text;
$text->literal = 'Hello World';
$document = new CommonMark\Node\Document;
$document->appendChild(
(new CommonMark\Node\Paragraph)
->appendChild($text));
echo CommonMark\Render\HTML($document);
?>
See also Cmark and
ext/cmark.
Cant Instantiate Class
[Since 1.2.8] - [ -P Classes/CantInstantiateClass ] - [ Online docs ]
When constructor is not public, it is not possible to instantiate such a class. Either this is a conception choice, or there are factories to handle that. Either way, it is not possible to call new on such class.
PHP reports an error similar to this one : 'Call to private Y::__construct() from invalid context'.
<?php
//This is the way to go
$x = X::factory();
//This is not possible
$x = new X();
class X {
//This is also the case with proctected __construct
private function __construct() {}
static public function factory() {
return new X();
}
}
?>
See also In a PHP5 class, when does a private constructor get called?,
Named Constructors in PHP and
PHP Constructor Best Practices And The Prototype Pattern.
strpos() Too Much
[Since 1.2.8] - [ -P Performances/StrposTooMuch ] - [ Online docs ]
strpos() covers the whole string before reporting 0. If the expected string is expected be at the beginning, or a fixed place, it is more stable to use substr() for comparison.
The longer the haystack (the searched string), the more efficient is that trick. The string has to be 10k or more to have impact, unless it is in a loop.
<?php
// This always reads the same amount of string
if (substr($html, 0, 6) === '<html>') {
}
// When searching for a single character, checking with a known position ($string[$position]) is even faster
if ($html[0] === '<') {
}
// With `strpos() <https://www.php.net/strpos>`_, the best way is to search for something that exist, and use absence as worst case scenario
if (strpos($html, '<html>') > 0) {
} else {
//
}
// When the search fails, the whole string has been read
if (strpos($html, '<html>') === 0) {
}
?>
This applies to stripos() too.
Typehinted References
[Since 1.2.8] - [ -P Functions/TypehintedReferences ] - [ Online docs ]
Typehinted arguments have no need for references. Since they are only an object, they are already a reference.
In fact, adding the & on the argument definition may lead to error like Only variables should be passed by reference .
This applies to the object type hint, but not the the others, such as int or bool .
<?php
// a class
class X {
public $a = 3;
}
// typehinted reference
//function foo(object &$x) works too
function foo(X &$x) {
$x->a = 1;
return $x;
}
// Send an object
$y = foo(new X);
// This prints 1;
print $y->a;
?>
See also Passing by reference and
Objects and references.
Do In Base
[Since 1.2.8] - [ -P Performances/DoInBase ] - [ Online docs ]
Use SQL expression to compute aggregates.
<?php
// Efficient way
$res = $db->query('SELECT sum(e) AS sumE FROM table WHERE condition');
// The sum is already done
$row = $res->fetchArray();
$c += $row['sumE'];
// Slow way
$res = $db->query('SELECT e FROM table WHERE condition');
// This aggregates the column e in a slow way
while($row = $res->fetchArray()) {
$c += $row['e'];
}
?>
Weak Typing
[Since 1.2.8] - [ -P Classes/WeakType ] - [ Online docs ]
The test on a variable is not enough. The variable is checked for null, then used as an object or an array.
<?php
if ($a !== null) {
echo $a->b;
}
?>
See also From assumptions to assertions.
Cache Variable Outside Loop
[Since 1.2.8] - [ -P Performances/CacheVariableOutsideLoop ] - [ Online docs ]
Avoid recalculating constant values inside the loop.
Do the calculation once, outside the loops, and then reuse the value each time.
One of the classic example if doing count($array) in a for loop : since the source is constant during the loop, the result of count() is always the same.
<?php
$path = '/some/path';
$fullpath = realpath("$path/more/dirs/");
foreach($files as $file) {
// Only moving parts are used in the loop
copy($file, $fullpath.$file);
}
$path = '/some/path';
foreach($files as $file) {
// $fullpath is calculated each loop
$fullpath = realpath("$path/more/dirs/");
copy($file, $fullpath.$file);
}
?>
Depending on the load of the called method, this may increase the speed of the loop from little to enormously.
Use The Blind Var
[Since 1.2.9] - [ -P Performances/UseBlindVar ] - [ Online docs ]
When in a loop, it is faster to rely on the blind var, rather than the original source.
When the key is referenced in the foreach loop, it is faster to use the available container to access a value for reading.
Note that it is also faster to use the value with a reference to handle the writings.
<?php
// Reaching $source[$key] via $value is faster
foreach($source as $key => $value) {
$coordinates = array('x' => $value[0],
'y' => $value[1]);
}
// Reaching $source[$key] via $source is slow
foreach($source as $key => $value) {
$coordinates = array('x' => $source[$key][0],
'y' => $source[$key][1]);
}
?>
Configure Extract
[Since 1.2.9] - [ -P Security/ConfigureExtract ] - [ Online docs ]
The extract() function overwrites local variables when left unconfigured.
Extract imports variables from an array into the local scope. In case of a conflict, that is when a local variable already exists, it overwrites the previous variable.
In fact, extract() may be configured to handle the situation differently : it may skip the conflicting variable, prefix it, prefix it only if it exists, only import overwriting variables... It may also import them as references to the original values.
This analysis reports extract() when it is not configured explicitly. If overwriting is the intended objective, it is not reported.
<?php
// ignore overwriting variables
extract($array, EXTR_SKIP);
// prefix all variables explicitly variables with 'php_'
extract($array, EXTR_PREFIX_ALL, 'php_');
// overwrites explicitly variables
extract($array, EXTR_OVERWRITE);
// overwrites implicitely variables : do we really want that?
extract($array, EXTR_OVERWRITE);
?>
Always avoid using extract() on untrusted sources, such as $_GET , $_POST , $_FILES , or even databases records.
See also extract.
Compact Inexistant Variable
[Since 1.2.9] - [ -P Php/CompactInexistant ] - [ Online docs ]
Compact() doesn't warn when it tries to work on an inexistant variable. It just ignores the variable.
This behavior changed in PHP 7.3, and compact() now emits a warning when the compacted variable doesn't exist.
<?php
function foo($b = 2) {
$a = 1;
// $c doesn't exists, and is not compacted.
return compact('a', 'b', 'c');
}
?>
For performances reasons, this analysis only works inside methods and functions.
See also compact and
PHP RFC: Make compact function reports undefined passed variables.
Method Signature Must Be Compatible
[Since 1.2.9] - [ -P Classes/MethodSignatureMustBeCompatible ] - [ Online docs ]
Make sure methods signature are compatible.
PHP generates the infamous Fatal error at execution : Declaration of FooParent::Bar() must be compatible with FooChildren::Bar()
<?php
class x {
function xa() {}
}
class xxx extends xx {
function xa($a) {}
}
?>
Currently, the analysis doesn't check for ellipsis nor references.
Mismatch Type And Default
[Since 1.2.9] - [ -P Functions/MismatchTypeAndDefault ] - [ Online docs ]
The argument typehint and its default value don't match.
The code may lint and load, and even work when the arguments are provided. Though, PHP won't eventually execute it.
Most of the mismatch problems are caught by PHP at linting time. It displays the following error message : 'Argument 1 passed to foo() must be of the type integer, string given'.
The default value may be a constant (normal or class constant) : as such, PHP might find its value only at execution time, from another include. As such, PHP doesn't report anything about the situation at compile time.
The default value may also be a constant scalar expression : since PHP 7, some of the simple operators such as +, -, *, %, **, etc. are available to build default values. Among them, the ternary operator and Coalesce. Again, those expression may be only evaluated at execution time, when the value of the constants are known.
<?php
// bad definition : the string is actually an integer
const STRING = 3;
function foo(string $s = STRING) {
echo $s;
}
// works without problem
foo('string');
// Fatal error at compile time
foo();
// Fail only at execution time (missing D), and when default is needed
function foo2(string $s = D ? null : array()) {
echo $s;
}
?>
PHP reports typehint and default mismatch at compilation time, unless there is a static expression that can't be resolved within the compiled file : then it is checked only at runtime, leading to a Fatal error.
See also Type declarations.
Flexible Heredoc
[Since 1.2.9] - [ -P Php/FlexibleHeredoc ] - [ Online docs ] - [ PHP 7.3 and more recent ]
Flexible syntax for Heredoc.
The new flexible syntax for heredoc and nowdoc enable the closing marker to be indented, and remove the new line requirement after the closing marker.
It was introduced in PHP 7.3.
<?php
// PHP 7.3 and newer
foo($a = <<<END
flexible syntax
with extra indentation
END);
// All PHP versions
$a = <<<END
Normal syntax
END;
?>
This syntax is backward incompatible : once adopted in the code, previous versions won't compile it.
See also Heredoc and
Flexible Heredoc and Nowdoc Syntaxes.
Check JSON
[Since 1.3.0] - [ -P Structures/CheckJson ] - [ Online docs ]
Check errors whenever JSON is encoded or decoded.
In particular, NULL is a valid decoded JSON response. If you want to avoid mistaking NULL for an error, it is recommended to call json_last_error .
<?php
$encoded = json_encode($incoming);
// Unless JSON must contains some non-null data, this mistakes NULL and error
if(json_last_error() != JSON_ERROR_NONE) {
die('Error when encoding JSON');
}
$decoded = json_decode($incoming);
// Unless JSON must contains some non-null data, this mistakes NULL and error
if($decoded === null) {
die('ERROR');
}
?>
See also Option to make json_encode and json_decode throw exceptions on errors,
json_last_error.
Const Visibility Usage
[Since 1.3.0] - [ -P Classes/ConstVisibilityUsage ] - [ Online docs ] - [ PHP 7.1 and more recent ]
Visibility for class constant controls the accessibility to class constant.
A public constant may be used anywhere in the code; a protected constant usage is restricted to the class and its relatives; a private constant is restricted to itself.
This feature was introduced in PHP 7.1. It is recommended to use explicit visibility, and, whenever possible, make the visibility private.
<?php
class x {
public const a = 1;
protected const b = 2;
private const c = 3;
const d = 4;
}
interface i {
public const a = 1;
const d = 4;
}
?>
See also Class Constants and
PHP RFC: Support Class Constant Visibility.
Should Use Operator
[Since 1.3.0] - [ -P Structures/ShouldUseOperator ] - [ Online docs ]
Some functions duplicate the feature of an operator. When in doubt, it is better to use the operator.
Beware, some edge cases may apply. In particular, backward compatibility may prevent usage of newer features.
- array_push() is equivalent to []
- is_object() is equivalent to instanceof
- function_get_arg() and function_get_args() is equivalent to ellipsis : ...
- chr() is equivalent to string escape sequences, such as \n , \x69 , u{04699}
- call_user_func() is equivalent to $functionName(arguments) , $object->$method(...$arguments)
- is_null() is equivalent to === null
- php_version() is equivalent to PHP_VERSION (the constant)
- is_array(), is_int(), is_object(), etc. is equivalent to a scalar typehint
Strict Or Relaxed Comparison
[Since 1.3.2] - [ -P Structures/ComparisonFavorite ] - [ Online docs ]
PHP has two comparison styles : strict and relaxed.
The analyzed code has less than 10% of one of them : for consistency reasons, it is recommended to make them all the same.
It is recommended to always use the strict comparison by default, and use the relaxed in case of specific situations.
<?php
// This compares $strict both in terms of value and type
if ($strict === 3) {
} elseif ($strict == 3) {
// This compares $strict after an possible type casting.
// '3', 3.0 or 3 would all be possible solutions.
}
?>
See also Comparison Operators.
> Or < Comparisons
[Since 1.3.2] - [ -P Structures/GtOrLtFavorite ] - [ Online docs ]
Maths has two comparisons styles : > or < . Both may include equality : <= and >= .
The analyzed code has less than 10% of one of them : for consistency reasons, it is recommended to make them all the same.
It is recommended to always use the same comparison style.
<?php
// Always compare in the same direction
if ($a > $c) {
} elseif ($c > $b) {
} else {
// equality case
}
// Alterning comparison style lead to harder to read code
if ($b > 3) {
} elseif ($b < 3) {
}
?>
See also Comparison Operators.
Could Be Static Closure
[Since 1.3.2] - [ -P Functions/CouldBeStaticClosure ] - [ Online docs ]
Closure may be static, and prevent the import of $this .
By preventing the useless import of $this , you avoid useless work.
This also has the added value to prevent the usage of $this from the closure. This is a good security practice.
<?php
class Foo
{
function __construct()
{
// Not possible to use $this
$func = static function() {
var_dump($this);
};
$func();
// Normal import of $this
$closure = function() {
var_dump($this);
};
}
};
new Foo();
?>
This is a micro-optimisation. Apply it in case of intensive usage.
See also Anonymous functions,
GeneratedHydrator and
Static anonymous functions.
move_uploaded_file Instead Of copy
[Since 1.3.2] - [ -P Security/MoveUploadedFile ] - [ Online docs ]
Always use move_uploaded_file() with uploaded files. Avoid using copy or rename with uploaded file.
move_uploaded_file() checks to ensure that the file designated by filename is a valid upload file (meaning that it was uploaded via PHP's HTTP POST upload mechanism).
<?php
// $a->file was filled with $_FILES at some point
move_uploaded_file($a->file['tmp_name'], $target);
// $a->file was filled with $_FILES at some point
rename($a->file['tmp_name'], $target);
?>
See also move_uploaded_file and
Uploading Files with PHP.
Dont Mix ++
[Since 1.3.2] - [ -P Structures/DontMixPlusPlus ] - [ Online docs ]
++ operators have two distinct behaviors, and should be used in isolation.
When mixed with a larger expression, it is difficult to read, and may lead to unwanted behaviors.
<?php
// Clear and defined behavior
$i++;
$a[$i] = $i;
// $i is modified twice
$i = --$i + 1;
?>
See also EXP30-C. Do not depend on the order of evaluation for side effects.
Can't Throw Throwable
[Since 1.3.3] - [ -P Exceptions/CantThrow ] - [ Online docs ]
Classes extending Throwable can't be thrown. The same applies to interfaces.
Although this code lints, PHP throws a Fatal error when executing or including it : Class fooThrowable cannot implement interface Throwable, extend Exception or Error instead .
<?php
// This is the way to go
class fooException extends \Exception { }
// This is not possible and a lot of work
class fooThrowable implements \throwable { }
?>
See also Throwable,
Exception and
Error.
Abstract Or Implements
[Since 1.3.3] - [ -P Classes/AbstractOrImplements ] - [ Online docs ]
A class must implements all abstract methods of it parent, or be abstract too.
While PHP lints this code, it won't execute it and stop with a Fatal Error : Class BA contains 1 abstract method and must therefore be declared abstract or implement the remaining methods (A::aFoo) .
<?php
abstract class Foo {
abstract function FooBar();
}
// This is in another file : php -l would detect it right away
class FooFoo extends Foo {
// The method is not defined.
// The class must be abstract, just like Foo
}
?>
See also Class Abstraction.
ext/eio
[Since 1.3.3] - [ -P Extensions/Exteio ] - [ Online docs ]
Extension EIO.
This is a PHP extension wrapping functions of the libeio library written by Marc Lehmann.
Libeio is a an asynchronous I/O library. Features basically include asynchronous versions of POSIX API(read, write, open, close, stat, unlink, fdatasync, mknod, readdir etc.); sendfile (native on Solaris, Linux, HP-UX, FreeBSD); readahead. libeio itself emulates the system calls, if they are not available on specific(UNIX-like) platform.
<?php
$str = str_repeat('1', 20);
$filename = '/tmp/tmp_file' .`uniqid() <https://www.php.net/uniqid>`_;
@unlink($filename);
touch($filename);
eio_open($filename, EIO_O_RDWR, NULL, EIO_PRI_DEFAULT, function($filename, $fd) use ($str) {
eio_write($fd, $str, strlen($str), 0, null, function($fd, $written) use ($str, $filename) {
var_dump([
'written' => $written,
'strlen' => strlen($str),
'filesize' => filesize($filename),
'count' => substr_count(file_get_contents($filename), '1')
]);
}, $fd);
}, $filename);
eio_event_loop();
?>
See also libeio,
PHP extension for libeio .
Incompatible Signature Methods
[Since 1.3.3] - [ -P Classes/IncompatibleSignature ] - [ Online docs ]
Methods should have the same signature when being overwritten.
The same signatures means the children class must have :
+ the same name
+ the same visibility or less restrictive
+ the same typehint or removed
+ the same default value or removed
+ a reference like its parent
This problem emits a fatal error, for abstract methods, or a warning error, for normal methods. Yet, it is difficult to lint, because classes are often stored in different files. As such, PHP do lint each file independently, as unknown parent classes are not checked if not present. Yet, when executing the code, PHP lint the actual code and may encounter a fatal error.
<?php
class a {
public function foo($a = 1) {}
}
class ab extends a {
// foo is overloaded and now includes a default value for $a
public function foo($a) {}
}
?>
See also Object Inheritance.
Ambiguous Visibilities
[Since 1.3.4] - [ -P Classes/AmbiguousVisibilities ] - [ Online docs ]
The properties have the same name, but have different visibilities, across different classes.
While it is legit to have a property with the same name in different classes, it may easily lead to confusion. As soon as the context is need to understand if the property is accessible or not, the readability suffers.
It is recommended to handle the same properties in the same way across classes, even when the classes are not related.
<?php
class person {
public $name;
private $address;
}
class gangster {
private $name;
public $nickname;
private $address;
}
$someone = Human::load(123);
echo 'Hello, '.$someone->name;
?>
ext/csprng
[Since 1.3.4] - [ -P Extensions/Extcsprng ] - [ Online docs ]
CSPRNG Functions : cryptographically secure pseudo-random number generator.
The CSPRNG API provides an easy and reliable way to generate crypto-strong random integers and bytes for use within cryptographic contexts.
<?php
$bytes = random_bytes(5);
var_dump(bin2hex($bytes));
//string(10) 385e33f741
?>
See also CSPRNG and
Cryptographically secure pseudorandom number generator.
Hash Algorithms Incompatible With PHP 7.1-
[Since 1.3.4] - [ -P Php/HashAlgos71 ] - [ Online docs ] - [ PHP older than 7.1]
List of hash algorithms incompatible with PHP 7.1 and more recent. At the moment of writing, this is compatible up to 7.3.
The hash algorithms were introduced in PHP 7.1.
<?php
// Compatible only with 7.1 and more recent
echo hash('sha512/224', 'The quick brown fox jumped over the lazy dog.');
// Always compatible
echo hash('ripemd320', 'The quick brown fox jumped over the lazy dog.');
?>
See also hash_algos.
Undefined ::class
[Since 1.3.5] - [ -P Classes/UndefinedStaticclass ] - [ Online docs ]
::class doesn't check if a corresponding class exists.
::class must be checked with a call to class_exists(). Otherwise, it may lead to a Class 'foo' not found or even silent dead code : this happens also with Catch and instanceof commands with undefined classes. PHP doesn't raise an error in that case.
<?php
class foo() {}
// prints foo
echo foo::class;
// prints bar though bar doesn't exist.
echo bar::class;
?>
See also Class Constants.
PHP 7.0 Scalar Typehints
[Since 1.3.5] - [ -P Php/PHP70scalartypehints ] - [ Online docs ] - [ PHP 7.0 and more recent ]
New scalar typehints were introduced : bool , int , float , string .
They cannot be used before PHP 7.0, and will be confused with classes or interfaces.
<?php
function foo(string $name) {
print Hello $name;
}
foo(Damien);
// display 'Hello Damien'
foo(33);
// displays an error
?>
See also Scalar type declarations, and
PHP 7 SCALAR TYPE DECLARATIONS.
PHP 7.1 Scalar Typehints
[Since 1.3.5] - [ -P Php/PHP71scalartypehints ] - [ Online docs ] - [ PHP 7.1 and more recent ]
A new scalar typehint was introduced : iterable.
It can't be used before PHP 7.1, and will be confused with classes or interfaces.
<?php
function foo(iterable $iterable) {
foreach ($iterable as $value) {
echo $value.PHP_EOL;
}
}
foo(range(1,20));
// works with array
foo(new ArrayIterator([1, 2, 3]));
// works with an iterator
foo((function () { yield 1; })() );
// works with a generator
?>
See also iterable pseudo-type, and
The iterable Pseudo-Type.
PHP 7.2 Scalar Typehints
[Since 1.3.5] - [ -P Php/PHP72scalartypehints ] - [ Online docs ] - [ PHP 7.2 and more recent ]
A new scalar typehint was introduced : object.
It can't be used before PHP 7.2, and will be confused with classes or interfaces.
<?php
function test(object $obj) : object
{
return new SplQueue();
}
test(new StdClass());
?>
See also New object type, and
PHP 7.2 and Object Typehint.
ext/lzf
[Since 1.3.5] - [ -P Extensions/Extlzf ] - [ Online docs ]
Extension LZF.
LZF is a very fast compression algorithm, ideal for saving space with only slight speed cost. It can be optimized for speed or space at the time of compilation.
<?php
$compressed = lzf_compress(This is test of LZF extension);
echo base64_encode($compressed);
?>
See also lzf and
liblzf.
ext/msgpack
[Since 1.3.5] - [ -P Extensions/Extmsgpack ] - [ Online docs ]
Extension msgPack.
This extension provide API for communicating with MessagePack serialization.
<?php
$serialized = msgpack_serialize(array('a' => true, 'b' => 4));
$unserialized = msgpack_unserialize($serialized);
?>
See also msgpack for PHP and
MessagePack.
Case Insensitive Constants
[Since 1.3.9] - [ -P Constants/CaseInsensitiveConstants ] - [ Online docs ]
PHP constants may be case insensitive, when defined with define() and the third argument.
This feature is deprecated since PHP 7.3 and will be removed in PHP 8.0.
<?php
// case sensitive
define('A', 1);
// case insensitive
define('B', 1, true);
echo A;
// This is not possible
//echo a;
// both possible
echo B;
echo b;
?>
See also define.
Handle Arrays With Callback
[Since 1.3.7] - [ -P Arrays/WithCallback ] - [ Online docs ]
Use functions like array_map().
<?php
// Handles arrays with callback
$uppercase = array_map('strtoupper', $source);
// Handles arrays with foreach
foreach($source as &$s) {
$s = uppercase($s);
}
?>
See also array_map.
Use is_countable
[Since 1.3.8] - [ -P Php/CouldUseIsCountable ] - [ Online docs ] - [ PHP 7.3 and more recent ]
is_countable() checks if a variables holds a value that can be counted. It is recommended to use it before calling count().
is_countable() accepts arrays and object whose class implements \countable.
<?php
function foo($arg) {
if (!is_countable($arg)) {
// $arg cannot be passed to `count() <https://www.php.net/count>`_
return 0
}
return count($arg);
}
function bar($arg) {
if (!is_array($arg) and !$x instanceof \Countable) {
// $arg cannot be passed to `count() <https://www.php.net/count>`_
return 0
}
return count($arg);
}
?>
See also PHP RFC: is_countable.
Detect Current Class
[Since 1.3.8] - [ -P Php/DetectCurrentClass ] - [ Online docs ] - [ PHP older than 8.0]
Detecting the current class should be done with ::class operator.
__CLASS__ may be replaced by self::class .
get_called_class() may be replaced by static::class .
__CLASS__ and get_called_class() are set to be deprecated in PHP 7.4.
<?php
class X {
function foo() {
echo __CLASS__.\n; // X
echo self::class.\n; // X
echo get_called_class().\n; // Y
echo static::class.\n; // Y
}
}
class Y extends X {}
$y = new Y();
$y->foo();
?>
See also PHP RFC: Deprecations for PHP 7.4.
Avoid Real
[Since 1.3.9] - [ -P Php/AvoidReal ] - [ Online docs ]
PHP has two float data type : real and double. real is rarely used, and might be deprecated in PHP 7.4.
To prepare code, avoid using is_real() and the (real) typecast.
<?php
// safe way to check for float
if (!is_float($a)) {
$a = (float) $a;
}
// Avoid doing that
if (!is_real($a)) {
$a = (real) $a;
}
?>
See also PHP RFC: Deprecations for PHP 7.4.
Const Or Define Preference
[Since 1.3.9] - [ -P Constants/ConstDefinePreference ] - [ Online docs ]
Const and define() have almost the same functional use : they create constants.
The analyzed code has less than 10% of one of them : for consistency reasons, it is recommended to make constant definition consistent.
It is recommended to use const for global constants, as this keyword is processed at compile time, while define() is executed.
Note that define() used to allow the creation of case-insensitive constants, but this is deprecated since PHP 7.3 and will be removed in PHP 8.0.
<?php
define('A1', 1);
define('A2', 1);
define('A3', 1);
define('A4', 1);
define('A5', 1);
define('A6', 1);
define('A7', 1);
define('A8', 1);
define('A9', 1);
define('A10',1);
const B = 3;
?>
See also Constant definition and
Define.
Constant Case Preference
[Since 1.3.8] - [ -P Constants/DefineInsensitivePreference ] - [ Online docs ]
Define() creates constants which are case sensitive or not.
The analyzed code has less than 10% of one of them : for consistency reasons, it is recommended to make constant sentivity definition consistent.
Note that define() used to allow the creation of case-sensitive constants, but this is deprecated since PHP 7.3 and will be removed in PHP 8.0.
<?php
define('A1', 1);
define('A2', 1);
define('A3', 1);
define('A4', 1);
define('A5', 1);
define('A6', 1);
define('A7', 1);
define('A8', 1);
define('A9', 1);
define('A10',1);
define('A10',1, true);
?>
See also Constant definition.
Assert Function Is Reserved
[Since 1.3.9] - [ -P Php/AssertFunctionIsReserved ] - [ Online docs ]
Avoid defining an assert function in namespaces.
While they work fine when the assertions are active ( zend.assertions=1 ), calls to unqualified assert are optimized away when assertions are not active.
Since PHP 7.3, a fatal error is emitted : Defining a custom assert() function is deprecated, as the function has special semantics .
<?php
// Run this with zend.assertions=1 and
// Then run this with zend.assertions=0
namespace Test {
function `assert() <https://www.php.net/assert>`_ {
global $foo;
$foo = true;
}
}
namespace Test {
`assert() <https://www.php.net/assert>`_;
var_dump(isset($foo));
}
?>
See also assert and
User-defined assert function is optimized away with zend.assertions=-1.
Could Be Abstract Class
[Since 1.3.9] - [ -P Classes/CouldBeAbstractClass ] - [ Online docs ]
An abstract class is never instantiated, and has children class that are. As such, a 'parent' class that is never instantiated by itself, but has its own children instantiated could be marked as abstract.
That will prevent new code to try to instantiate it.
<?php
// Example code would actually be split over multiple files.
// That class could be abstract
class motherClass {}
// Those classes shouldn't be abstract
class firstChildren extends motherClass {}
class secondChildren extends motherClass {}
class thirdChildren extends motherClass {}
new firstChildren();
new secondChildren();
new thirdChildren();
//Not a single : new motherClass()
?>
See also Class Abstraction
Abstract classes and methods.
Continue Is For Loop
[Since 1.3.9] - [ -P Structures/ContinueIsForLoop ] - [ Online docs ]
break and continue are very similar in PHP : they both break out of loop or switch. Yet, continue should be reserved for loops.
Since PHP 7.3, the execution will emit a warning when finding a continue inside a switch inside a loop : '"continue" targeting switch is equivalent to "break". Did you mean to use "continue 2"?'
<?php
while ($foo) {
switch ($bar) {
case 'baz':
continue; // In PHP: Behaves like 'break;'
// In C: Behaves like 'continue 2;'
}
}
?>
See also Deprecate and remove continue targeting switch.
PHP 7.3 Removed Functions
[Since 1.4.0] - [ -P Php/Php73RemovedFunctions ] - [ Online docs ] - [ PHP older than 7.3]
The following PHP native functions were removed in PHP 7.3.
- image2wbmp()
This analysis skips redefined PHP functions : when a replacement for a removed PHP function was created, with condition on the PHP version, then its usage is considered valid.
See also PHP 7.3 Removed Functions.
Trailing Comma In Calls
[Since 1.4.0] - [ -P Php/TrailingComma ] - [ Online docs ]
The last argument may be left empty.
This feature was introduced in PHP 7.3.
<?php
// VCS friendly call
// PHP 7.3 and more recent
foo(1,
2,
3,
);
// backward compatible call
// All PHP versions
foo(1,
2,
3
);
?>
See also PHP RFC: Allow a trailing comma in function calls.
Must Call Parent Constructor
[Since 1.4.1] - [ -P Php/MustCallParentConstructor ] - [ Online docs ]
Some PHP native classes require a call to parent::__construct() to be stable.
As of PHP 7.3, two classes currently need that call : SplTempFileObject and SplFileObject.
The error is only emitted if the class is instantiated, and a parent class is called.
<?php
class mySplFileObject extends \SplFileObject {
public function __construct() {
// Forgottent call to parent::__construct()
}
}
(new mySplFileObject())->`passthru() <https://www.php.net/passthru>`_;
?>
See also Why, php? WHY???.
Undefined Variable
[Since 1.4.2] - [ -P Variables/UndefinedVariable ] - [ Online docs ]
Variable that is used before any creation.
It is recommended to use a default value for every variable used. When not specified, the default value is set to NULL by PHP.
<?php
// Adapted from the PHP manual
$var = 'Bob';
$Var = 'Joe';
// The following line may emit a warning : Undefined variable: $undefined
echo $var, $Var, $undefined; // outputs Bob, Joe,
?>
Variable may be created in various ways : assignation, arguments, foreach blind variables, static and global variables.
This analysis doesn't handle dynamic variables, such as $$x . It also doesn't handle variables outside a method or function.
See also Variable basics.
Undefined Insteadof
[Since 1.4.2] - [ -P Traits/UndefinedInsteadof ] - [ Online docs ]
Insteadof tries to replace a method with another, but it doesn't exists. This happens when the replacing class is refactored, and some of its definition are dropped.
Insteadof may replace a non-existing method with an existing one, but not the contrary.
<?php
trait A {
function C (){}
}
trait B {
function C (){}
}
class Talker {
use A, B {
B::C insteadof A;
B::D insteadof A;
}
}
new Talker();
?>
This error is not linted : it only appears at execution time.
See also Traits.
Method Collision Traits
[Since 1.4.2] - [ -P Traits/MethodCollisionTraits ] - [ Online docs ]
Two or more traits are included in the same class, and they have methods collisions.
Those collisions should be solved with a use expression. When they are not, PHP stops execution with a fatal error : Trait method M has not been applied, because there are collisions with other trait methods on C .
<?php
trait A {
public function A() {}
public function M() {}
}
trait B {
public function B() {}
public function M() {}
}
class C {
use A, B;
}
class D {
use A, B{
B::M insteadof A;
};
}
?>
The code above lints, but doesn't execute.
See also Traits.
Use json_decode() Options
[Since 1.4.3] - [ -P Structures/JsonWithOption ] - [ Online docs ]
json_decode() returns objects by default, unless the second argument is set to TRUE or JSON_OBJECT_AS_ARRAY . Then, it returns arrays.
Avoid casting the returned value from json_decode(), and use the second argument to directly set the correct type.
<?php
$json = '{a:b}';
// Good syntax
$array = json_decode($json, JSON_OBJECT_AS_ARRAY);
// GoToo much work
$array = (array) json_decode($json);
?>
Note that all objects will be turned into arrays, recursively. If you're expecting an array of objects, don't use the JSON_OBJECT_AS_ARRAY constant, and change your JSON code.
Note that JSON_OBJECT_AS_ARRAY is the only constant : there is no defined constant to explicitly ask for an object as returned value.
See also json_decode.
Class Could Be Final
[Since 1.4.3] - [ -P Classes/CouldBeFinal ] - [ Online docs ]
Any class that has no extension should be final by default.
As stated by Matthias Noback : If a class is not marked final, it has at least one subclass .
Prevent your classes from being subclassed by making them final . Sometimes, classes are not meant or thought to be derivable.
<?php
class x {} // This class is extended
class y extends x {} // This class is extended
class z extends y {} // This class is not extended
final class z2 extends y {} // This class is not extended
?>
See also Negative architecture, and assumptions about code.
Closure Could Be A Callback
[Since 1.4.3] - [ -P Functions/Closure2String ] - [ Online docs ]
Closure or arrowfunction could be simplified to a callback. Callbacks are strings or arrays.
A simple closure that only returns arguments relayed to another function or method, could be reduced to a simpler expression. They
Closure may be simplified with a string, for functioncall, with an array for methodcalls and static methodcalls.
Performances : simplifying a closure tends to reduce the call time by 50%.
<?php
// Simple and faster call to strtoupper
$filtered = array_map('strtoupper', $array);
// Here the closure doesn't add any feature over strtoupper
$filtered = array_map(function ($x) { return strtoupper($x);}, $array);
// Methodcall example : no fix
$filtered = array_map(function ($x) { return $x->`strtoupper() <https://www.php.net/strtoupper>`_ ;}, $array);
// Methodcall example : replace with array($y, 'strtoupper')
$filtered = array_map(function ($x) use ($y) { return $y->strtoupper($x) ;}, $array);
// Static methodcall example
$filtered = array_map(function ($x) { return $x::`strtoupper() <https://www.php.net/strtoupper>`_ ;}, $array);
// Static methodcall example : replace with array('A', 'strtoupper')
$filtered = array_map(function ($x) { return A::strtoupper($x) ;}, $array);
?>
See also Closure class and
Callbacks / Callables.
Inconsistent Elseif
[Since 1.4.3] - [ -P Structures/InconsistentElseif ] - [ Online docs ]
Chaining if/elseif requires a consistent string of conditions. The conditions are executed one after the other, and the conditions shouldn't overlap.
This analysis reports chains of elseif that don't share a common variable (or array, or property, etc.. ). As such, testing different conditions are consistent.
<?php
// $a is always common, so situations are mutually exclusive
if ($a === 1) {
doSomething();
} else if ($a > 1) {
doSomethingElse();
} else {
doSomethingDefault();
}
// $a is always common, so situations are mutually exclusive
// although, it may be worth checking the consistency here
if ($a->b === 1) {
doSomething();
} else if ($a->c > 1) {
doSomethingElse();
} else {
doSomethingDefault();
}
// if $a === 1, then $c doesn't matter?
// This happens, but then logic doesn't appear in the code.
if ($a === 1) {
doSomething();
} else if ($c > 1) {
doSomethingElse();
} else {
doSomethingDefault();
}
?>
Can't Disable Class
[Since 0.8.4] - [ -P Security/CantDisableClass ] - [ Online docs ]
This is the list of potentially dangerous PHP class being used in the code, such as \Phar.
<?php
// This script uses ftp_connect(), therefore, this function shouldn't be disabled.
$phar = new Phar();
?>
This analysis is the base for suggesting values for the disable_classes directive.
ext/seaslog
[Since 1.4.4] - [ -P Extensions/Extseaslog ] - [ Online docs ]
Extension Seaslog.
An effective,fast,stable log extension for PHP.
<?php
$basePath_1 = SeasLog::getBasePath();
SeasLog::setBasePath('/log/base_test');
$basePath_2 = SeasLog::getBasePath();
var_dump($basePath_1,$basePath_2);
/*
string(19) /log/seaslog-ciogao
string(14) /log/base_test
*/
$lastLogger_1 = SeasLog::getLastLogger();
SeasLog::setLogger('testModule/app1');
$lastLogger_2 = SeasLog::getLastLogger();
var_dump($lastLogger_1,$lastLogger_2);
/*
string(7) default
string(15) testModule/app1
*/
?>
See also ext/SeasLog on Github, and
SeasLog.
Add Default Value
[Since 1.4.5] - [ -P Functions/AddDefaultValue ] - [ Online docs ]
Parameter in methods definition may receive a default value. This allows the called method to set a value when the parameter is omitted.
<?php
function foo($i) {
if (!is_integer($i)) {
$i = 0;
}
}
?>
See also Function arguments.
Only Variable For Reference
[Since 1.4.6] - [ -P Functions/OnlyVariableForReference ] - [ Online docs ]
When a method is requesting an argument to be a reference, it cannot be called with a literal value.
The call must be made with a variable, or any assimilated data container : array, property or static property.
<?php
// This is not possible
foo(1,2);
// This is working
foo($a, $b);
function foo($a, &$b) {}
?>
Note that PHP may detect this error at linting time, if the method is defined after being called : at that point, PHP will only check the problem during execution. This is definitely the case for methods, compared to functions or static methods.
See also Passing arguments by reference.
Direct Call To __clone()
[Since 1.4.8] - [ -P Php/DirectCallToClone ] - [ Online docs ] - [ PHP 7.0 and more recent ]
Direct call to magic method __clone() was forbidden. It is allowed since PHP 7.0.
From the RFC : Doing calls like $obj->__clone( ) is now allowed. This was the only magic method that had a compile-time check preventing some calls to it, which doesn't make sense. If we allow all other magic methods to be called, there's no reason to forbid this one .
<?php
class Foo {
function __clone() {}
}
$a = new Foo;
$a->__clone();
?>
See also Directly calling __clone is allowed.
filter_input() As A Source
[Since 1.4.8] - [ -P Security/FilterInputSource ] - [ Online docs ]
The filter_input() and filter_input_array() functions access directly to $_GET . They represent a source for external data just like $_GET , $_POST , etc.
The main feature of filter_input() is that it is already filtered. The main drawback is that FILTER_FLAG_NONE is the none filter, and that default configuration is `FILTER_UNSAFE_RAW`.
The filter extension keeps access to the incoming data, even after the super globals, such as $_GET , are unset.
<?php
// Removing $_GET
$_GET = [];
// with the default : FILTER_UNSAFE_RAW, this means XSS
echo filter_input(INPUT_GET, 'i');
// Same as above :
echo filter_var(_GET, 'i');
?>
Thanks to Frederic Bouchery for reporting this special case.
See also Data filtering.
Wrong Access Style to Property
[Since 1.4.9] - [ -P Classes/UndeclaredStaticProperty ] - [ Online docs ]
Use the right syntax when reaching for a property. Static properties use the :: operator, and non-static properties use -> .
Mistaking one of the other raise two different reactions from PHP : Access to undeclared static property is a fatal error, while PHP Notice: Accessing static property aa::$a as non static is a notice.
<?php
class a {
static public $a = 1;
function foo() {
echo self::$a; // right
echo $this->a; // WRONG
}
}
class b {
public $b = 1;
function foo() {
echo $this->$b; // right
echo b::$b; // WRONG
}
}
?>
This analysis reports both static properties with a `->` access, and non-static properties with a `::` access.
See also Static Keyword.
Named Regex
[Since 1.4.9] - [ -P Structures/NamedRegex ] - [ Online docs ]
Captured subpatterns may be named, for easier reference.
From the manual : It is possible to name a subpattern using the syntax (?P
Naming subpatterns makes it easier to know what is read from the results of the subpattern : for example, $r['name'] has more meaning than $r[1] .
Named subpatterns may also be shifted in the regex without impact on the resulting array.
<?php
$x = 'abc';
preg_match_all('/(?<name>a)/', $x, $r);
print_r($r[1]);
print_r($r['name']);
preg_match("/(?<name>a)(?'sub'b)/", $x, $s);
print $s[2];
print $s['sub'];
?>
See also Subpatterns.
Invalid Pack Format
[Since 1.4.9] - [ -P Structures/InvalidPackFormat ] - [ Online docs ]
Some characters are invalid in a pack() format string.
pack() and unpack() accept the following format specifiers : aAhHcCsSnviIlLNVqQJPfgGdeExXZ .
unpack() also accepts a name after the format specifier and an optional quantifier.
All other situations is not a valid, and produces a warning : pack()
<?php
$binarydata = pack(nvc*, 0x1234, 0x5678, 65, 66);
// the first unsigned short is stored as 'first'. The next matches are names with numbers.
$res = unpack('nfirst/vc*', $binarydata);
?>
Check pack() documentation for format specifiers that were introduced in various PHP version, namely 7.0, 7.1 and 7.2.
See also pack and
unpack.
No Return For Generator
[Since 1.4.9] - [ -P Php/NoReturnForGenerator ] - [ Online docs ] - [ PHP 7.0 and more recent ]
Return is not allowed in generator. In PHP versions older than 5.6 and older, they yield a fatal Error.
<?php
function generatorWithReturn() {
yield 1;
return 2;
}
?>
See also Generators overview.
Repeated Interface
[Since 1.4.9] - [ -P Interfaces/RepeatedInterface ] - [ Online docs ]
A class should implements only once an interface. An interface can only extends once another interface. In both cases, parent classes or interfaces must be checked.
PHP accepts multiple times the same interface in the implements clause. In fact, it doesn't do anything beyond the first implement.
<?php
use i as j;
interface i {}
// Multiple ways to reference an interface
class foo implements i, \i, j {}
// This applies to interfaces too
interface bar extends i, \i, j {}
?>
This code may compile, but won't execute.
See also Object Interfaces and
The Basics.
No Reference For Static Property
[Since 1.4.9] - [ -P Php/NoReferenceForStaticProperty ] - [ Online docs ] - [ PHP older than 7.3]
Static properties used to behave independently when set to a reference value. This was fixed in PHP 7.3.
According to the PHP 7.3 changelog : In PHP, static properties are shared between inheriting classes, unless the static property is explicitly overridden in a child class. However, due to an implementation artifact it was possible to separate the static properties by assigning a reference. This loophole has been fixed. .
<?php
class Test {
public static $x = 0;
}
class Test2 extends Test { }
Test2::$x = &$x;
$x = 1;
var_dump(Test::$x, Test2::$x);
// Previously: int(0), int(1)
// Now: int(1), int(1)
?>
See also PHP 7.3 UPGRADE NOTES.
Don't Read And Write In One Expression
[Since 1.4.9] - [ -P Structures/DontReadAndWriteInOneExpression ] - [ Online docs ]
Avoid giving value and using it at the same time, in one expression. This is an undefined behavior of PHP, and may change without warning.
One of those changes happens between PHP 7.2 and 7.3 :
<?php
$arr = [1];
$ref =& $arr[0];
var_dump($arr[0] + ($arr[0] = 2));
// PHP 7.2: int(4)
// PHP 7.3: int(3)
?>
See also UPGRADING 7.3.
Pack Format Inventory
[Since 1.5.0] - [ -P Type/Pack ] - [ Online docs ]
All format used in the code with pack() and unpack().
<?php
$binarydata = "\x04\x00\xa0\x00";
$array = unpack("cn", $binarydata);
$initial = pack("cn", ...$array);
?>
Printf Format Inventory
[Since 1.5.0] - [ -P Type/Printf ] - [ Online docs ]
All format used in the code with printf(), vprintf(), sprintf(), scanf() and fscanf().
<?php
// Display a number with 2 digits
echo printf("%'.2d\n", 123);
?>
idn_to_ascii() New Default
[Since 1.5.0] - [ -P Php/IdnUts46 ] - [ Online docs ]
The default parameter value of idn_to_ascii() and idn_to_utf8() is now INTL_IDNA_VARIANT_UTS46 instead of the deprecated INTL_IDNA_VARIANT_2003.
<?php
echo idn_to_ascii('täst.de');
?>
See also idn_to_ascii,
idn_to_utf8 and
Unicode IDNA Compatibility Processing.
Could Use Try
[Since 1.5.0] - [ -P Exceptions/CouldUseTry ] - [ Online docs ]
Some commands may raise exceptions. It is recommended to use the try/catch block to intercept those exceptions, and process them.
- / : DivisionByZeroError
- % : DivisionByZeroError
- intdiv() : DivisionByZeroError
- << : ArithmeticError
- >> : ArithmeticError
- Phar::mungserver : PharException
- Phar::webphar : PharException
See also Predefined Exceptions,
PharException.
Use Basename Suffix
[Since 1.5.1] - [ -P Structures/BasenameSuffix ] - [ Online docs ]
basename() will remove extension when it is provided as argument. The second argument will be removed from the name of the file.
<?php
$path = 'phar:///path/to/file.php';
// Don't forget the .
$filename = basename($path, '.php');
// Too much work for this
$filename = substr(basename($path), 0, -4);
?>
Using basename() instead of substr() or else, makes the intention clear.
See also basename.
ext/decimal
[Since 1.5.2] - [ -P Extensions/Extdecimal ] - [ Online docs ]
Extension php-decimal, by Rudi Theunissen .
This library provides a PHP extension that adds support for correctly-rounded, arbitrary-precision decimal floating point arithmetic. Applications that rely on accurate numbers (ie. money, measurements, or mathematics) can use Decimal instead of float or string to represent numerical values.
<?php
use Decimal\Decimal;
$op1 = new Decimal(0.1, 4);
$op2 = 0.123456789;
print_r($op1 + $op2);
use Decimal\Decimal;
/**
* @param int $n The factorial to calculate, ie. $n!
* @param int $p The precision to calculate the factorial to.
*
* @return Decimal
*/
function factorial(int $n, int $p = Decimal::DEFAULT_PRECISION): Decimal
{
return $n < 2 ? new Decimal($n, $p) : $n * factorial($n - 1, $p);
}
echo factorial(10000, 32);
?>
See also PHP Decimal and
libmpdec.
ext/psr
[Since 1.5.2] - [ -P Extensions/Extpsr ] - [ Online docs ]
Extension PSR : PHP Standards Recommendations.
This PHP extension provides the interfaces from the PSR standards as established by the PHP-FIG group. You can use interfaces provided by this extension in another extension easily - see this example.
Currently supported PSR :
- PSR-3 - `psr/http-message`
- PSR-11 - `psr/container`
- PSR-13 - `psr/link`
- PSR-15 - `psr/http-server`
- PSR-16 - `psr/simple-cache`
- PSR-17 - `psr/http-factory`
<?php
// Example from the tests, for Cache (PSR-6)
use Psr\Cache\CacheException;
class MyCacheException extends Exception implements CacheException {}
$ex = new MyCacheException('test');
var_dump($ex instanceof CacheException);
var_dump($ex instanceof Exception);
try {
throw $ex;
} catch( CacheException $e ) {
var_dump($e->getMessage());
}
?>
See also php-psr and
PHP-FIG.
Should Yield With Key
[Since 1.5.2] - [ -P Functions/ShouldYieldWithKey ] - [ Online docs ]
iterator_to_array() will overwrite generated values with the same key.
PHP generators are based on the yield keyword. They also delegate some generating to other methods, with yield from .
When delegating, yield from uses the keys that are generated with yield , and otherwise, it uses auto-generated index, starting with 0.
The trap is that each yield from reset the index generation and start again with 0. Coupled with iterator_to_array(), this means that the final generated array may lack some values, while a foreach() loop would yield all of them.
<?php
function g1() : Generator {
for ( $i = 0; $i < 4; $i++ ) { yield $i; }
}
function g2() : Generator {
for ( $i = 5; $i < 10; $i++ ) { yield $i; }
}
function aggregator() : Generator {
yield from g1();
yield from g2();
}
print_r(`iterator_to_array() <https://www.php.net/iterator_to_array>`_);
/*
Array
(
[0] => 6
[1] => 7
[2] => 8
[3] => 9
[4] => 4 // Note that 4 and 5 still appears
[5] => 5 // They are not overwritten by the second yield
)
*/
foreach ( aggregator() as $i ) {
print $i.PHP_EOL;
}
/*
0 // Foreach has no overlap and yield it all.
1
2
3
4
5
6
7
8
9
*/
?>
Thanks to Holger Woltersdorf for pointing this.
See also Generator syntax and
Yielding values with keys.
Don't Loop On Yield
[Since 1.5.3] - [ -P Structures/DontLoopOnYield ] - [ Online docs ]
Use yield from , instead of looping on a generator with yield .
yield from delegate the yielding to another generator, and keep calling that generator until it is finished. It also works with implicit generator datastructure, like arrays.
<?php
function generator() {
for($i = 0; $i < 10; ++$i) {
yield $i;
}
}
function delegatingGenerator() {
yield from generator();
}
// Too much code here
function generator2() {
foreach(generator() as $g) {
yield $g;
}
}
?>
There is a performance gain when delegating, over looping manually on the generator. You may even consider writing the loop to store all values in an array, then yield from the array.
See also Generator delegation via yield from.
Unreachable Class Constant
[Since 1.5.4] - [ -P Classes/UnreachableConstant ] - [ Online docs ]
Class constants may be unreachable due to visibility configuration.
Since PHP 7.1, class constants support visibility. Their usage may be restricted to the current class, or private , to classes that extends or are extended by the current class, or protected . They may also be public , just like it was before.
<?php
class Foo{
private const PRIVATE = 1;
const PUBLIC = 3;
}
// PHP 7.1- and older
echo Foo::PUBLIC;
// This is not accessible
echo Foo::PRIVATE;
?>
See also Class Constant and
PHP RFC: Support Class Constant Visibility.
Avoid Self In Interface
[Since 1.5.4] - [ -P Interfaces/AvoidSelfInInterface ] - [ Online docs ]
Self and Parent are tricky when used in an interface.
self refers to the current interface or its extended parents : as long as the constant is defined in the interface family, this is valid. On the other hand, when self refers to the current class, the resolution of names will happen at execution time, leading to confusing results.
parent has the same behavior than self , except that it doesn't accept to be used inside an interface, as it will yield an error. This is one of those error that lint but won't execute in certain conditions.
Static can't be used in an interface, as it needs to be resolved at call time anyway.
<?php
interface i extends ii {
// This 'self' is valid : it refers to the interface i
public const I = self::I2 + 2;
// This 'self' is also valid, as it refers to interface ii, which is a part of interface i
public const I2 = self::IP + 4;
// This makes interface i dependant on the host class
public const I3 = parent::A;
}
?>
See also Scope Resolution Operator (::).
Should Have Destructor
[Since 1.5.4] - [ -P Classes/ShouldHaveDestructor ] - [ Online docs ]
PHP destructors are called when the object has to be destroyed. By default, PHP calls recursively the destructor on internal objects, until everything is unset.
Unsetting objects and resources explicitly in the destructor is a good practice to reduce the amount of memory in use. It helps PHP resource counter to keep the numbers low, and easier to clean. This is a major advantage for long running scripts.
<?php
class x {
function __construct() {
$this->p = new y();
}
function __destruct() {
print __METHOD__.PHP_EOL;
unset($this->p);
}
}
class y {
function __construct() {
print __METHOD__.PHP_EOL;
$this->p = new y();
}
function __destruct() {
print __METHOD__.PHP_EOL;
unset($this->p);
}
}
$a = (new x);
sleep(1);
// This increment the resource counter by one for the property.
$p = $a->p;
unset($a);
sleep(3);
print 'end'.PHP_EOL;
// Y destructor is only called here, as the object still exists in $p.
?>
See also Destructor, and
Php Destructors.
Safe HTTP Headers
[Since 1.5.5] - [ -P Security/SafeHttpHeaders ] - [ Online docs ]
Avoid configuring HTTP headers with lax restriction from within PHP.
There are a lot of HTTP headers those days, targeting various vulnerabilities. To ensure backward compatibility, those headers have a default mode that is lax and permissive. It is recommended to avoid using those from within the code.
<?php
//Good configuration, limiting access to origin
header('Access-Control-Allow-Origin: https://www.exakat.io');
//Configuration is present, but doesn't restrict anything : any external site is a potential source
header('Access-Control-Allow-Origin: *');
?>
See also Hardening Your HTTP Security Headers,
How To Secure Your Web App With HTTP Headers and
SecurityHeaders.
fputcsv() In Loops
[Since 1.5.5] - [ -P Performances/CsvInLoops ] - [ Online docs ]
fputcsv() is slow when called on each row. It actually flushes the data to the disk each time, and that results in a inefficient dump to the disk, each call.
To speed up this process, it is recommended to dump the csv to memory first, then dump the memory to the disk, in larger chunks. Since fputcsv() works only on stream, it is necessary to use a memory stream.
<?php
// Speedy yet memory intensive version
$f = fopen('php://memory', 'w+');
foreach($data_source as $row) {
// You may configure fputcsv as usual
fputcsv($f, $row);
}
rewind($f); // Important
$fp = fopen('final.csv', 'w+');
fputs($fp, stream_get_contents($f));
fclose($fp);
fclose($f);
// Slower version
$fp = fopen('final.csv', 'w+');
foreach($data_source as $row) {
// You may configure fputcsv as usual
fputcsv($fp, $row);
}
fclose($fp);
?>
The speed improvement is significant on small rows, while it may be less significant on larger rows : with more data in the rows, the file buffer may fill up more efficiently. On small rows, the speed gain is up to 7 times.
Directly Use File
[Since 1.5.5] - [ -P Structures/DirectlyUseFile ] - [ Online docs ]
Some PHP functions have a close cousin that work directly on files : use them. This is faster and less code to write.
- md5() => md5_file()
- highlight_string() => highlight_file(), show_source()
- parsekit_compile_string() => parsekit_compile_file()
- parse_ini_string() => parse_ini_file()
- sha1() => sha1_file()
- simplexml_load_string() => simplexml_load_file()
- yaml_parse() => yaml_parse_file()
- hash() => hash_file()
- hash_hmac() => hash_mac_file()
- hash_update() => hash_update_file()
- recode() => recode_file()
- recode_string() => recode_file()
<?php
// Good way
$file_hash = hash_file('sha512', 'example.txt');
// Slow way
$file_hash = hash('sha512', file_get_contents('example.txt'));
?>
See also hash_file.
Useless Alias
[Since 1.5.6] - [ -P Traits/UselessAlias ] - [ Online docs ]
It is not possible to declare an alias of a method with the same name.
PHP reports that Trait method f has not been applied, because there are collisions with other trait methods on x , which is a way to say that the alias will be in conflict with the method name.
When the method is the only one bearing a name, and being imported, there is no need to alias it. When the method is imported in several traits, the keyword insteadof is available to solve the conflict.
<?php
trait t {
function h() {}
}
class x {
use t {
// This is possible
t::f as g;
// This is not possible, as the alias is in conflict with itself
// alias are case insensitive
t::f as f;
}
}
?>
This code lints but doesn't execute.
See also Conflict resolution.
ext/sdl
[Since 1.5.6] - [ -P Extensions/Extsdl ] - [ Online docs ]
Extensions ext/sdl.
Simple DirectMedia Layer (SDL) is a cross-platform software development library designed to provide a hardware abstraction layer for computer multimedia hardware components.
<?php
/**
* Example of how to change screen properties such as title, icon or state using the PHP-SDL extension.
*
* @author Santiago Lizardo <santiagolizardo@php.net>
*/
require 'common.php';
SDL_Init( SDL_INIT_VIDEO );
$screen = SDL_SetVideoMode( 640, 480, 16, SDL_HWSURFACE );
if( null == $screen )
{
fprintf( STDERR, 'Error: %s' . PHP_EOL, SDL_GetError() );
}
for( $i = 3; $i > 0; $i-- )
{
SDL_WM_SetCaption( Switching to fullscreen mode in $i seconds..., null );
SDL_Delay( 1000 );
}
SDL_WM_ToggleFullscreen( $screen );
SDL_Delay( 3000 );
SDL_WM_ToggleFullscreen( $screen );
SDL_WM_SetCaption( Back from fullscreen mode. Quitting in 2 seconds..., null );
SDL_Delay( 2000 );
SDL_FreeSurface( $screen );
SDL_Quit();
?>
See also phpsdl,
Simple DirectMedia Layer and
About SDL.
Isset() On The Whole Array
[Since 1.5.6] - [ -P Performances/IssetWholeArray ] - [ Online docs ]
Isset() works quietly on a whole array. There is no need to test all previous index before testing for the target index.
<?php
// Straight to the point
if (isset($a[1]['source'])) {
// Do something with $a[1]['source']
}
// Doing too much work
if (isset($a) && isset($a[1]) && isset($a[1]['source'])) {
// Do something with $a[1]['source']
}
?>
There is a gain in readability, by avoiding long and hard to read logical expression, and reducing them in one simple isset call.
There is a gain in performances by using one call to isset, instead of several, but it is a micro-optimization.
See also Isset.
ext/async
[Since 1.5.6] - [ -P Extensions/Extasync ] - [ Online docs ]
Concurrent Task Extension for PHP.
This extension provides concurrent Zend VM executions using native C fibers in PHP.
<?php
namespace Concurrent;
register_shutdown_function(function () {
echo "===> Shutdown function(s) execute here.\n";
});
$work = function (string $title): void {
var_dump($title);
};
Task::await(Task::async(function () use ($work) {
$defer = new Deferred();
Task::await(Task::async($work, 'A'));
Task::await(Task::async($work, 'B'));
Task::async(function () {
$defer = new Deferred();
Task::async(function () use ($defer) {
(new Timer(1000))->awaitTimeout();
$defer->resolve('H :)');
});
var_dump(Task::await($defer->awaitable()));
});
Task::async(function () use ($defer) {
var_dump(Task::await($defer->awaitable()));
});
$timer = new Timer(500);
Task::async(function () use ($timer, $defer, $work) {
$timer->awaitTimeout();
$defer->resolve('F');
Task::async($work, 'G');
});
var_dump('ROOT TASK DONE');
}));
Task::async($work, 'C');
Task::async(function () use ($work) {
(new Timer(0))->awaitTimeout();
Task::async($work, 'E');
});
Task::async(function ($v) {
var_dump(Task::await($v));
}, Deferred::value('D'));
var_dump('?>
See also ext-async.
ext/wasm
[Since 1.5.7] - [ -P Extensions/Extwasm ] - [ Online docs ]
Extension WASM.
The goal of the project is to be able to run WebAssembly binaries from PHP directly. So much fun coming!
From the php-ext-wasm documentation :
<?php
//There is a toy program in examples/simple.rs, written in Rust (or any other language that compiles to WASM):
// Stored in file __DIR__ . '/simple.wasm'
/*
#[no_mangle]
pub extern C fn sum(x: i32, y: i32) -> i32 {
x + y
}
*/
$instance = new WASM\Instance(__DIR__ . '/simple.wasm');
var_dump(
$instance->sum(5, 37) // 42!
);
?>
See also php-ext-wasm.
Self Using Trait
[Since 1.5.7] - [ -P Traits/SelfUsingTrait ] - [ Online docs ]
Trait uses itself : this is unnecessary. Traits may use themselves, or be used by other traits, that are using the initial trait itself.
PHP handles the situation quietly, by ignoring all extra use of the same trait, keeping only one valid version.
<?php
// empty, but valid
trait a {}
// obvious self usage
trait b { use b; }
// less obvious self usage
trait c { use d, e, f, g, h, c; }
// level 2 self usage
trait i { use j; }
trait j { use i; }
?>
See also Traits.
Multiple Usage Of Same Trait
[Since 1.5.7] - [ -P Traits/MultipleUsage ] - [ Online docs ]
The same trait is used several times. One trait usage is sufficient.
<?php
// C is used twice, and could be dropped from B
trait A { use B, C;}
trait B { use C;}
?>
PHP doesn't raise any error when traits are included multiple times.
See also Traits.
Method Could Be Static
[Since 1.5.7] - [ -P Classes/CouldBeStatic ] - [ Online docs ]
A method that doesn't make any usage of $this could be turned into a static method.
While static methods are usually harder to handle, recognizing the static status is a first step before turning the method into a standalone function.
<?php
class foo {
static $property = 1;
// legit static method
static function staticMethod() {
return self::$property;
}
// This is not using $this, and could be static
function nonStaticMethod() {
return self::$property;
}
// This is not using $this nor self, could be a standalone function
function nonStaticMethod() {
return self::$property;
}
}
?>
Path lists
[Since 1.5.8] - [ -P Type/Path ] - [ Online docs ]
List of all paths that were found in the code.
Path are identified with this regex : ^(.*/)([^/]*)\.\w+$ . In particular, the directory delimiter is / : Windows delimiter \ are not detected.
<?php
// the first argument is recognized as an URL
fopen('/tmp/my/file.txt', 'r+');
// the string argument is recognized as an URL
$source = 'https://www.other-example.com/';
?>
URL are ignored when the protocol is present in the literal : http://www.example.com is not mistaken with a file.
See also Dir predefined constants and
Supported Protocols and Wrappers.
Possible Missing Subpattern
[Since 1.6.1] - [ -P Php/MissingSubpattern ] - [ Online docs ]
When capturing subpatterns are the last ones in a regex, PHP doesn't fill their spot in the resulting array. This leads to a possible missing index in the result array.
<?php
// displays a partial array, from 0 to 1
preg_match('/(a)(b)?/', 'adc', $r);
print_r($r);
/*
Array
(
[0] => a
[1] => a
)
*/
// displays a full array, from 0 to 2
preg_match('/(a)(b)?/', 'abc', $r);
print_r($r);
/*
Array
(
[0] => ab
[1] => a
[2] => b
)
*/
// double 'b' when it is found
print preg_replace(',^a(b)?,', './$1$1', 'abc'); // prints ./abbc
print preg_replace(',^a(b)?,', './$1$1', 'adc'); // prints ./dc
?>
?>
The same applies to preg_replace() : the pattern may match the string, but no value is available is the corresponding sub-pattern.
In PHP 7.4, a new option was added : PREG_UNMATCHED_AS_NULL, which always provides a value for the subpatterns.
See also Bug #50887 preg_match , last optional sub-patterns ignored when empty and
Bug #73948 Preg_match_all should return NULLs on trailing optional capture groups..
array_key_exists() Speedup
[Since 1.6.1] - [ -P Performances/ArrayKeyExistsSpeedup ] - [ Online docs ]
isset() used to be the fastest, but array_key_exists() is. Since PHP 7.4, array_key_exists() has its own opcode, leading to better features and speed.
isset() is faster for all non-empty values, but is limited when the value is NULL or empty : then, array_key_exists() has the good features.
This change makes array_key_exists() actually faster than isset() by ~25% (tested with GCC 8, -O3, march=native, mtune=native). .
<?php
$foo = [123 => 456];
// This is sufficient and efficient since PHP 7.4
if (array_search_key($foo[123])) {
// do something
}
// taking advantages of performances for PHP 7.4 and older
if (isset($foo[123]) || array_search_key($foo[123])) {
// do something
}
?>
See also Implement ZEND_ARRAY_KEY_EXISTS opcode to speed up `array_key_exists()
Assign And Compare
[Since 1.6.3] - [ -P Structures/AssigneAndCompare ] - [ Online docs ]
Assignation has a lower precedence than comparison. As such, the assignation always happens after the comparison. This leads to the comparison being stored in the variable, and not the value being compared.
<?php
if ($id = strpos($string, $needle) !== false) {
// $id now contains a boolean (true or false), but not the position of the $needle.
}
// probably valid comparison, as $found will end up being a boolean
if ($found = strpos($string, $needle) === false) {
doSomething();
}
// always valid comparison, with parenthesis
if (($id = strpos($string, $needle)) !== false) {
// $id now contains a boolean (true or false), but not the position of the $needle.
}
// Being a lone instruction, this is always valid : there is no double usage with if condition
$isFound = strpos($string, $needle) !== false;
?>
See also Operator Precedence.
Typed Property Usage
[Since 1.6.2] - [ -P Php/TypedPropertyUsage ] - [ Online docs ]
Traditionally, PHP properties aren't typed. Since PHP 7.4, it is possible to type properties, just like arguments.
<?php
class User {
public int $id;
public string $name;
public function __construct(int $id, string $name) {
$this->id = $id;
$this->name = $name;
}
}
?>
See also Typed Properties 2.0.
Variable Is Not A Condition
[Since 1.6.5] - [ -P Structures/NoVariableIsACondition ] - [ Online docs ]
Avoid using a lone variable as a condition. It is recommended to use a comparative value, or one of the filtering function, such as isset(), empty().
Using the raw variable as a condition blurs the difference between an undefined variable and an empty value. By using an explicit comparison or validation function, it is easier to understand what the variable stands for.
<?php
if (isset($error)) {
echo 'Found one error : '.$error!;
}
//
if ($errors) {
print count($errors).' errors found : '.join('', $errors).PHP_EOL;
echo 'Not found';
}
?>
Thanks to the PMB team for the inspiration.
String Initialization
[Since 1.6.5] - [ -P Arrays/StringInitialization ] - [ Online docs ]
It used to be possible to initialize a variable with an string, and use it as an array. It is not the case anymore in PHP 7.1.
<?php
// Initialize arrays with array()
$a = array();
$a[3] = 4;
// Don't start with a string
$a = '';
$a[3] = 4;
print $a;
// Don't start with a string
if (is_numeric($a)) {
$a[] = $a;
}
?>
See also PHP 7.1 no longer converts string to arrays the first time a value is assigned with square bracket notation.
ext/weakref
[Since 1.6.5] - [ -P Extensions/Extweakref ] - [ Online docs ]
Weak References for PHP.
Weak references provide a non-intrusive gateway to ephemeral objects. Unlike normal (strong) references, weak references do not prevent the garbage collector from freeing that object. For this reason, an object may be destroyed even though a weak reference to that object still exists. In such conditions, the weak reference seamlessly becomes invalid.
<?php
class MyClass {
public function __destruct() {
echo Destroying object!\n;
}
}
$o1 = new MyClass;
$r1 = new WeakRef($o1);
if ($r1->valid()) {
echo Object still exists!\n;
var_dump($r1->get());
} else {
echo Object is dead!\n;
}
unset($o1);
if ($r1->valid()) {
echo Object still exists!\n;
var_dump($r1->get());
} else {
echo Object is dead!\n;
}
?>
See also Weak references and
PECL extension that implements weak references and weak maps in PHP.
ext/pcov
[Since 1.6.5] - [ -P Extensions/Extpcov ] - [ Online docs ]
CodeCoverage compatible driver for PHP
A self contained CodeCoverage compatible driver for PHP7
<?php
\pcov\start();
$d = [];
for ($i = 0; $i < 10; $i++) {
$d[] = $i * 42;
}
\pcov\stop();
var_dump(\pcov\collect());
?>
See also PCOV.
Insufficient Typehint
[Since 1.6.6] - [ -P Functions/InsufficientTypehint ] - [ Online docs ]
An argument is typehinted, but it actually calls methods that are not listed in the interface.
Classes may be implementing more methods than the one that are listed in the interface they also implements. This means that filtering objects with a typehint, but calling other methods will be solved at execution time : if the method is available, it will be used; if it is not, a fatal error is reported.
<?php
class x implements i {
function methodI() {}
function notInI() {}
}
interface i {
function methodI();
}
function foo(i $x) {
$x->methodI(); // this call is valid
$x->notInI(); // this call is not garanteed
}
?>
Inspired by discussion with Brandon Savage.
Constant Dynamic Creation
[Since 1.6.7] - [ -P Constants/DynamicCreation ] - [ Online docs ]
Registering constant with dynamic values. Dynamic values include values read in external sources (files, databases, remote API, ... ), random sources (time, rand(), ...)
Dynamic constants are not possible with the const keyword, though static constant expression allows for a good range of combinations, including conditions.
<?php
$a = range(0, 4);
foreach($array as $i) {
define(A$i, $i);
define(N$i, true);
}
define(C, 5);
?>
An OOP Factory
[Since 1.6.7] - [ -P Patterns/Factory ] - [ Online docs ]
A method or function that implements a factory. A factory is a class that handles the creation of an object, based on parameters. The factory hides the logic that leads to the creation of the object.
<?php
class AutomobileFactory {
public static function create($make, $model) {
$className = \\Automaker\\Brand\\$make;
return new $className($model);
}
}
// The factory is able to build any car, based on their
$fuego = AutomobileFactory::create('Renault', 'Fuego');
print_r($fuego->getMakeAndModel()); // outputs Renault Fuego
?>
See also Factory (object-oriented programming) and
Factory.
Typehint Must Be Returned
[Since 1.6.9] - [ -P Functions/TypehintMustBeReturned ] - [ Online docs ]
When using a typehint for a method, it is compulsory to use a at least one return in the method's body.
<?php
// Empty function :
function foo() : Bar { return new Bar(); }
// Empty function :
function foo() : Bar { }
?>
PHP lint this, but won't execute it.
See also Return Type Declaration and
Type hint in PHP function parameters and return values.
Should Deep Clone
[Since 1.7.0] - [ -P Classes/ShouldDeepClone ] - [ Online docs ]
By default, PHP makes a shallow clone. It only clone the scalars, and keep the reference to any object already referenced. This means that the cloned object and its original share any object they hold as property.
This is where the magic method __clone() comes into play. It is called, when defined, at clone time, so that the cloned object may clone all the needed sub-objects.
It is recommended to use the __clone() method whenever the objects hold objects.
<?php
class a {
public $b = null;
function __construct() {
$this->b = new Stdclass();
$this->b->c = 1;
}
}
class ab extends a {
function __clone() {
$this->b = clone $this->b;
}
}
// class A is shallow clone, so $a->b is not cloned
$a = new a();
$b = clone $a;
$a->b->c = 3;
echo $b->b->c;
// displays 3
// class Ab is deep clone, so $a->b is cloned
$a = new ab();
$b = clone $a;
$a->b->c = 3;
echo $b->b->c;
// displays 1
?>
See also PHP Clone and Shallow vs Deep Copying and
Cloning objects.
Clone With Non-Object
[Since 1.7.0] - [ -P Classes/CloneWithNonObject ] - [ Online docs ]
The clone keyword must be used on variables, properties or results from a function or method call.
clone cannot be used with constants or literals.
<?php
class x { }
$x = new x();
// Valid clone
$y = clone $x;
// Invalid clone
$y = clone x;
?>
Cloning a non-object lint but won't execute.
See also Object cloning.
Check On __Call Usage
[Since 1.7.2] - [ -P Classes/CheckOnCallUsage ] - [ Online docs ]
When using the magic methods __call() and __staticcall(), make sure the method exists before calling it.
If the method doesn't exists, then the same method will be called again, leading to the same failure. Finally, it will crash PHP.
<?php
class safeCall {
function __class($name, $args) {
// unsafe call, no checks
if (method_exists($this, $name)) {
$this->$name(...$args);
}
}
}
class unsafeCall {
function __class($name, $args) {
// unsafe call, no checks
$this->$name(...$args);
}
}
?>
See also Method overloading and
`Magical PHP: __call.
PHP Overridden Function
[Since 1.7.6] - [ -P Php/OveriddenFunction ] - [ Online docs ]
It is possible to declare and use PHP native function in a namespace.
Within the declaration namespace, it is easy to confuse the local version and the global version, unless the function has been prefixed with \ .
<?php
namespace A {
use function A\dirname as split;
function dirname($a, $b) { return __FUNCTION__; }
echo dirname('/a/b/c');
echo split('a', 'b');
echo \dirname('/a/b/c');
}
?>
When a piece of code use overridden function, any newcomer may be confused by the usage of classic PHP native function in surprising situations.
It is recommended to avoid redeclare PHP native function in namespaces.
Caught Variable
[Since 1.7.6] - [ -P Exceptions/CatchE ] - [ Online docs ]
Multiple Unset()
[Since 1.7.6] - [ -P Structures/MultipleUnset ] - [ Online docs ]
Unset() accepts multiple arguments, unsetting them one after each other. It is more efficient to call unset() once, than multiple times.
<?php
// One call to unset only
unset($a, $b, $c, $d);
// Too many calls to unset
unset($a);
unset($b);
unset($c);
unset($d);
?>
See also unset.
Implode One Arg
[Since 1.7.7] - [ -P Php/ImplodeOneArg ] - [ Online docs ]
implode() may be called with one arg. It is recommended to avoid it.
Using two arguments makes it less surprising to new comers, and consistent with explode() syntax.
<?php
$array = range('a', 'c');
// empty string is the glue
print implode('', $array);
// only the array : PHP uses the empty string as glue.
// Avoid this
print implode($array);
?>
See also implode.
Integer Conversion
[Since 1.7.7] - [ -P Security/IntegerConversion ] - [ Online docs ]
Comparing incoming variables to integer may lead to injection.
When comparing a variable to an integer, PHP applies type juggling, and transform the variable in an integer too. When the value converts smoothly to an integer, this means the validation may pass and yet, the value may carry an injection.
<?php
// This is safer
if ($_GET['x'] === 2) {
echo $_GET['x'];
}
// Using (int) for validation and display
if ((int) $_GET['x'] === 2) {
echo (int) $_GET['x'];
}
// This is an injection
if ($_GET['x'] == 2) {
echo $_GET['x'];
}
// This is unsafe, as $_GET['x'] is tester as an integer, but echo'ed raw
if ((int) $_GET['x'] === 2) {
echo $_GET['x'];
}
?>
This analysis spots situations where an incoming value is compared to an integer. The usage of the validated value is not considered.
See also Type Juggling Authentication Bypass Vulnerability in CMS Made Simple,
PHP STRING COMPARISON VULNERABILITIES and
PHP Magic Tricks: Type Juggling.
ext/svm
[Since 1.7.8] - [ -P Extensions/Extsvm ] - [ Online docs ]
Extension SVM .
SVM is in interface with the libsvm , from . libsvm is a library for Support Vector Machines, a classification tool for machine learning.
<?php
$data = array(
array(-1, 1 => 0.43, 3 => 0.12, 9284 => 0.2),
array(1, 1 => 0.22, 5 => 0.01, 94 => 0.11),
);
$svm = new SVM();
$model = $svm->train($data);
$data = array(1 => 0.43, 3 => 0.12, 9284 => 0.2);
$result = $model->predict($data);
var_dump($result);
$model->save('model.svm');
?>
See also SVM,
LIBSVM -- A Library for Support Vector Machines,
ext/apcu and
ianbarber/php-svm.
Useless Default Argument
[Since 1.7.9] - [ -P Functions/UselessDefault ] - [ Online docs ]
One of the argument has a default value, and this default value is never used. Every time the method is called, the argument is provided explicitly, rendering the default value actually useless.
<?php
function goo($a, $b = 3) {
// do something here
}
// foo is called 3 times, and sometimes, $b is not provided.
goo(1,2);
goo(1,2);
goo(1);
function foo($a, $b = 3) {
// do something here
}
// foo is called 3 times, and $b is always provided.
foo(1,2);
foo(1,2);
foo(1,2);
?>
Avoid option arrays in constructors
[Since 1.7.9] - [ -P Classes/AvoidOptionArrays ] - [ Online docs ]
Avoid option arrays in constructors. Use one parameter per injected element.
<?php
class Foo {
// Distinct arguments, all typehinted if possible
function __constructor(A $a, B $b, C $c, D $d) {
$this->a = $a;
$this->b = $b;
$this->c = $c;
$this->d = $d;
}
}
class Bar {
// One argument, spread over several properties
function __constructor(array $options) {
$this->a = $options['a'];
$this->b = $options['b'];
$this->c = $options['c'];
$this->d = $options['d'];
}
}
?>
See also Avoid option arrays in constructors.
ext/ffi
[Since 1.7.9] - [ -P Extensions/Extffi ] - [ Online docs ]
Extension FFI : Foreign Function Interface .
This extension allows the loading of shared libraries (.DLL or .so), calling of C functions and accessing of C data structures in pure PHP, without having to have deep knowledge of the Zend extension API, and without having to learn a third “intermediate” language. The public API is implemented as a single class FFI with several static methods (some of them may be called dynamically), and overloaded object methods, which perform the actual interaction with C data.
<?php
//Example : Calling a function from shared library
// create FFI object, loading libc and exporting function `printf() <https://www.php.net/printf>`_
$ffi = FFI::cdef(
"int printf(const char *format, ...);", // this is a regular C declaration
"libc.so.6");
// call C's `printf() <https://www.php.net/printf>`_
$ffi->printf("Hello %s!\n", "world");
?>
See also Foreign Function Interface, and
ext/ffi and
A PHP Compiler, aka The FFI Rabbit Hole.
ext/password
[Since 0.8.4] - [ -P Extensions/Extpassword ] - [ Online docs ]
Extension password.
The password hashing API provides an easy to use wrapper around crypt() and some other password hashing algorithms, to make it easy to create and manage passwords in a secure manner.
<?php
// See the `password_hash() <https://www.php.net/password_hash>`_ example to see where this came from.
$hash = '$2y$07$BCryptRequires22Chrcte/VlQH0piJtjXl.0t1XkA8pw9dMXTpOq';
if (password_verify('rasmuslerdorf', $hash)) {
echo 'Password is valid!';
} else {
echo 'Invalid password.';
}
?>
See also Password Hashing and
crypt.
ext/zend_monitor
[Since 1.7.9] - [ -P Extensions/Extzendmonitor ] - [ Online docs ]
Extension zend_monitor .
See also Zend Monitor - PHP API.
ext/uuid
[Since 1.7.9] - [ -P Extensions/Extuuid ] - [ Online docs ]
Extension UUID . A universally unique identifier (UUID) is a 128-bit number used to identify information in computer systems.
An interface to the libuuid system library. The libuuid library is used to generate unique identifiers for objects that may be accessible beyond the local system. The Linux implementation was created to uniquely identify ext2 filesystems created by a machine. This library generates UUIDs compatible with those created by the Open Software Foundation (OSF) Distributed Computing Environment (DCE) utility uuidgen.
<?php
// example from the test suitee of the extension.
// check basic format of generated UUIDs
$uuid = uuid_create();
if (preg_match("/[[:xdigit:]]{8}-[[:xdigit:]]{4}-[[:xdigit:]]{4}-[[:xdigit:]]{4}-[[:xdigit:]]{12}/", $uuid)) {
echo "basic format ok\n";
} else {
echo "basic UUID format check failed, generated UUID was $uuid\n";
}
?>
See also libuuid and
ext/uuid.
Already Parents Trait
[Since 1.8.0] - [ -P Traits/AlreadyParentsTrait ] - [ Online docs ]
Trait is already used a parent's class or trait. There is no use to include it a second time.
<?php
trait ta {
use tb;
}
trait t1 {
use ta;
use tb; // also used by ta
}
class b {
use t1; // also required by class c
use ta; // also required by trait t1
}
class c extends b {
use t1;
}
?>
See also Traits.
Trait Not Found
[Since 1.7.9] - [ -P Traits/TraitNotFound ] - [ Online docs ]
A unknown trait is mentioned in the use expression.
The used traits all exist, but in the configuration block, some unmentioned trait is called.
Be aware that the traits used in any configuration block may originate in any use expression. PHP will check the configuration block at instantiation only, and after compiling : at that moment, it will know all the used traits across the class.
<?php
class x {
// c is not a used trait
use a, b { c::d insteadof e;}
// e is a used trait, even if is not in the use above.
use e;
}
?>
See also Traits.
Casting Ternary
[Since 1.8.0] - [ -P Structures/CastingTernary ] - [ Online docs ]
Type casting has a precedence over ternary operator, and is applied first. When this happens, the condition is cast, although it is often useless as PHP will do it if needed.
This applies to the ternary operator, the coalesce operator ?: and the null-coalesce operator ??.
<?php
$a = (string) $b ? 3 : 4;
$a = (string) $b ?: 4;
$a = (string) $b ?? 4;
?>
The last example generates first an error `Undefined variable: b`, since $b is first cast to a string. The result is then an empty string, which leads to an empty string to be stored into $a. Multiple errors cascade.
See also Operators Precedence.
Concat Empty String
[Since 1.8.0] - [ -P Structures/ConcatEmpty ] - [ Online docs ]
Using a concatenation to make a value a string should be replaced with a type cast.
Type cast to a string is done with (string) operator. There is also the function strval(), although it is less recommended.
<?php
$a = 3;
// explicite way to cast a value
$b = (string) $a; // $b is a string with the content 3
// Wrong way to cast a value
$c = $a . ''; // $c is a string with the content 3
$c = '' . $a; // $c is a string with the content 3
$a .= ''; // $a is a string with the content 3
// Wrong way to cast a value
$c = $a . '' . $b; // This is not reported. The empty string is useless, but not meant to type cast
?>
See also Type Casting and
PHP Type Casting.
Concat And Addition
[Since 1.8.0] - [ -P Php/ConcatAndAddition ] - [ Online docs ]
Precedence between addition and concatenation has changed. In PHP 7.4, addition has precedence, and before, addition and concatenation had the same precedence.
From the RFC : Currently the precedence of '.', '+' and '-' operators are equal. Any combination of these operators are simply evaluated left-to-right .
This is counter-intuitive though: you rarely want to add or subtract concatenated strings which in general are not numbers. However, given PHP's capability of seamlessly converting an integer to a string, concatenation of these values is desired.
<?php
// Extracted from the RFC
echo sum: . $a + $b;
// current behavior: evaluated left-to-right
echo (sum: . $a) + $b;
// desired behavior: addition and subtraction have a higher precendence
echo sum : . ($a + $b);
?>
This analysis reports any addition and concatenation that are mixed, without parenthesis. Addition also means substraction here, aka using `+` or `-`.
The same applies to bitshift operations, << and >>``. There is no RFC for this change.
See also Change the precedence of the concatenation operator.
Useless Argument
[Since 1.8.0] - [ -P Functions/UselessArgument ] - [ Online docs ]
The argument is always used with the same value. This value could be hard coded in the method, and save one argument slot.
There is no indication that this argument will be used with other values. It may be a development artifact, that survived without cleaning.
<?php
// All foo2 arguments are used with different values
function foo2($a, $b) {}
foo2(1, 2);
foo2(2, 2);
foo2(3, 3);
// The second argument of foo is always used with 2
function foo($a, $b) {}
foo(1, 2);
foo(2, 2);
foo(3, 2);
?>
Methods with less than 3 calls are not considered here, to avoid reporting methods used once.
New Functions In PHP 7.4
[Since 1.8.0] - [ -P Php/Php74NewFunctions ] - [ Online docs ] - [ PHP older than 7.3]
New functions are added to new PHP version.
The following functions are now native functions in PHP 7.3. It is compulsory to rename any custom function that was created in older versions. One alternative is to move the function to a custom namespace, and update the use list at the beginning of the script.
Note : At the moment of writing, all links to the manual are not working.
Unpacking Inside Arrays
[Since 1.8.0] - [ -P Php/UnpackingInsideArrays ] - [ Online docs ]
The variadic operator is now available inside arrays. Until PHP 7.4, it is not possible to use the variadic operator, or ... inside arrays.
The workaround is to use array_merge(), after checking that arrays are not empty.
<?php
$a = ['a', 'b', 'c'];
$b = ['d', 'e', 'f'];
// PHP 7.4
$c = [...$a, ...$b];
// PHP 7.3 and older
$c = array_merge($a, $b);
?>
See also Spread Operator in Array Expression and
PHP 5.6 and the Splat Operator .
Minus One On Error
[Since 1.8.0] - [ -P Security/MinusOneOnError ] - [ Online docs ]
Some PHP native functions return -1 on error. They also return 1 in case of success, and 0 in case of failure. This leads to confusions.
In case the native function is used as a condition without explicit comparison, PHP type cast the return value to a boolean. In this case, -1 and 1 are both converted to true, and the condition applies. This means that an error situation is mistaken for a successful event.
<?php
// Proper check of the return value
if (openssl_verify($data, $signature, $public) === 1) {
$this->loginAsUser($user);
}
// if this call fails, it returns -1, and is confused with true
if (openssl_verify($data, $signature, $public)) {
$this->loginAsUser($user);
}
?>
This analysis searches for if/then structures, ternary operators inside while() / do...while() loops.
See also Can you spot the vulnerability? (openssl_verify) and
Incorrect Signature Verification.
No Need For get_class()
[Since 1.8.1] - [ -P Structures/NoNeedGetClass ] - [ Online docs ]
There is no need to call get_class() to build a static call. The argument of get_class() may be used directly.
<?php
//
$a->b::$c
// This is too much code
get_class($a->b)::$c?>
See also Scope Resolution Operator (::).
No Append On Source
[Since 1.8.2] - [ -P Structures/NoAppendOnSource ] - [ Online docs ]
Do not append new elements to an array in a foreach loop. Since PHP 7.0, the array is still used as a source, and will be augmented, and used again.
<?php
// Relying on the initial copy
$a = [1];
$initial = $a;
foreach($initial as $v) {
$a[] = $v + 1;
}
// Keep new results aside
$a = [1];
$tmp = [];
foreach($a as $v) {
$tmp[] = $v + 1;
}
$a = array_merge($a, $tmp);
unset($tmp);
// Example, courtesy of Frederic Bouchery
// This is an infinite loop
$a = [1];
foreach($a as $v) {
$a[] = $v + 1;
}
?>
Thanks to Frederic Bouchery for the reminder.
See also foreach and
What will this code return? #PHP.
Autoappend
[Since 1.8.3] - [ -P Performances/Autoappend ] - [ Online docs ]
Appending a variable to itself leads to enormous usage of memory.
<?php
// Always append a value to a distinct variable
foreach($a as $b) {
$c[] = $b;
}
// This copies the array to itself, and double the size each loop
foreach($a as $b) {
$c[] = $c;
}
?>
Memoize MagicCall
[Since 1.8.3] - [ -P Performances/MemoizeMagicCall ] - [ Online docs ]
Cache calls to magic methods in local variable. Local cache is faster than calling again the magic method as soon as the second call, provided that the value hasn't changed.
__get is slower, as it turns a simple member access into a full method call.
<?php
class x {
private $values = array();
function __get($name) {
return $this->values[$name];
}
// more code to set values to this class
}
function foo(x $b) {
$a = $b->a;
$c = $b->c;
$d = $c; // using local cache, no new access to $b->__get($name)
$e = $b->a; // Second access to $b->a, through __get
}
function bar(x $b) {
$a = $b->a;
$c = $b->c;
$b->bar2(); // this changes $b->a and $b->c, but we don't see it
$d = $b->c;
$e = $b->a; // Second access to $b->a, through __get
}
?>
The caching is not possible if the processing of the object changes the value of the property.
See also __get performance questions with PHP,
Classes/MakeMagicConcrete and
Benchmarking magic.
Make Magic Concrete
[Since 1.8.3] - [ -P Classes/MakeMagicConcrete ] - [ Online docs ]
Speed up execution by replacing magic calls by concrete properties.
Magic properties are managed dynamically, with __get and __set . They replace property access by a methodcall, and they are much slower than the first.
When a property name is getting used more often, it is worth creating a concrete property, and skip the method call. The threshold for 'magicMemberUsage' is 1, by default.
<?php
class x {
private $values = array('a' => 1,
'b' => 2);
function __get($name) {
return $this->values[$name] ?? '';
}
}
$x = new x();
// Access to 'a' is repeated in the code, at least 'magicMemberUsage' time (cf configuration below)
echo $x->a;
?>
See also Performances/MemoizeMagicCall.
Substr To Trim
[Since 1.8.3] - [ -P Structures/SubstrToTrim ] - [ Online docs ]
When removing the first or the last character of a string, trim() does a more readable job.
trim(), ltrim() and rtrim() accept a string as second argument. Those will all be removed from the endings of the string.
<?php
$a = '$drop the dollar';
$b = substr($a, 1); // drop the first char
$b = ltrim($a, '$'); // remove the initial '$'s
$b = substr($a, 1); // replace with `ltrim() <https://www.php.net/ltrim>`_
$b = substr($a, 0, -1); // replace with `rtrim() <https://www.php.net/rtrim>`_
$b = substr($a, 1, -1); // replace with `trim() <https://www.php.net/trim>`_
?>
trim() will remove all occurrences of the requested char(). This may remove a loop with substr(), or remove more than is needed.
trim() doesn't work with multi-bytes strings, but so does substr(). For that, use mb_substr(), as there isn't any mb_trim function (yet).
See also trim, ltrim, rtrim.
Regex On Arrays
[Since 1.8.4] - [ -P Performances/RegexOnArrays ] - [ Online docs ]
Avoid using a loop with arrays of regex or values. There are several PHP function which work directly on arrays, and much faster.
preg_grep() is able to extract all matching strings from an array, or non-matching strings. This usually saves a loop over the strings.
preg_filter() is able to extract all strings from an array, matching at least one regex in an array. This usually saves a double loop over the strings and the regex. The trick here is to provide '$0' as replacement, leading preg_filter() to replace the found string by itself.
Finally, preg_replace_callback() an preg_replace_callback_array() are also able to apply an array of regex to an array of strings, and then, apply callbacks to the found values.
<?php
$regexs = ['/ab+c/', '/abd+/', '/abe+/'];
$strings = ['/abbbbc/', '/abd/', '/abeee/'];
// Directly extract all strings that match one regex
foreach($regexs as $regex) {
$results[] = preg_grep($regex, $strings);
}
// extract all matching regex, by string
foreach($strings as $string) {
$results[] = preg_filter($regexs, array_fill(0, count($regexs), '$0'), $string);
}
// very slow way to get all the strings that match a regex
foreach($regexs as $regex) {
foreach($strings as $string) {
if (preg_match($regex, $string)) {
$results[] = $string;
}
}
}
?>
See also preg_filter.
Always Use Function With array_key_exists()
[Since 1.8.4] - [ -P Performances/Php74ArrayKeyExists ] - [ Online docs ]
array_key_exists() has been granted a special VM opcode, and is much faster. This applies to PHP 7.4 and more recent.
It requires that array_key_exists() is statically resolved, either with an initial \ , or a use function expression. This doesn't affect the global namespace.
<?php
namespace my/name/space;
// do not forget the 'function' keyword, or it will apply to classes.
use function array_key_exists as foo; // the alias is not necessary, and may be omitted.
// array_key_exists is aliased to foo :
$c = foo($a, $b);
// This call requires a fallback to global, and will be slow.
$c = array_key_exists($a, $b);
?>
This analysis is related to Php/ShouldUseFunction, and is a special case, that only concerns array_key_exists().
See also Add array_key_exists to the list of specialy compiled functions.
Complex Dynamic Names
[Since 1.8.4] - [ -P Variables/ComplexDynamicNames ] - [ Online docs ]
Avoid using expressions as names for variables or methods.
There are no place for checks or flow control, leading to any rogue value to be used as is. Besides, the expression is often overlooked, and not expected there : this makes the code less readable.
It is recommended to build the name in a separate variable, apply the usual checks for existence and validity, and then use the name.
<?php
$a = new foo();
// Code is more readable
$name = strolower($string);
if (!property_exists($a, $name)) {
throw new missingPropertyexception($name);
}
echo $a->$name;
// This is not check
echo $a->{strtolower($string)};
?>
This analysis only accept simple containers, such as variables, properties.
See also Dynamically Access PHP Object Properties with $this.
curl_version() Has No Argument
[Since 1.8.4] - [ -P Structures/CurlVersionNow ] - [ Online docs ]
curl_version() used to accept CURLVERSION_NOW as argument. Since PHP 7.4, it is a function without arguments.
<?php
// Compatible syntax
$details = curl_version(CURLVERSION_NOW);
// New PHP 7.4 syntax
$details = curl_version();
?>
See also curl_version.
Php 7.4 New Class
[Since 1.0.4] - [ -P Php/Php74NewClasses ] - [ Online docs ] - [ PHP older than 7.2]
New classes, introduced in PHP 7.4. If classes where created with the same name, in current code, they have to be moved in a namespace, or removed from code to migrate safely to PHP 7.4.
The new classes are :
+ ReflectionReference
+ WeakReference
<?php
namespace {
// Global namespace
class WeakReference {
// Move to a namespace
// or, remove this class
}
}
namespace B {
class WeakReference {
// This is OK : in a namespace
}
}
?>
New Constants In PHP 7.4
[Since 1.8.4] - [ -P Php/Php74NewConstants ] - [ Online docs ] - [ PHP older than 7.4]
The following constants are now native in PHP 7.4. It is advised to avoid using such names for constant before moving to this new version.
- MB_ONIGURUMA_VERSION
- SO_LABEL
- SO_PEERLABEL
- SO_LISTENQLIMIT
- SO_LISTENQLEN
- SO_USER_COOKIE
- PHP_WINDOWS_EVENT_CTRL_C
- PHP_WINDOWS_EVENT_CTRL_BREAK
- TIDY_TAG_ARTICLE
- TIDY_TAG_ASIDE
- TIDY_TAG_AUDIO
- TIDY_TAG_BDI
- TIDY_TAG_CANVAS
- TIDY_TAG_COMMAND
- TIDY_TAG_DATALIST
- TIDY_TAG_DETAILS
- TIDY_TAG_DIALOG
- TIDY_TAG_FIGCAPTION
- TIDY_TAG_FIGURE
- TIDY_TAG_FOOTER
- TIDY_TAG_HEADER
- TIDY_TAG_HGROUP
- TIDY_TAG_MAIN
- TIDY_TAG_MARK
- TIDY_TAG_MENUITEM
- TIDY_TAG_METER
- TIDY_TAG_NAV
- TIDY_TAG_OUTPUT
- TIDY_TAG_PROGRESS
- TIDY_TAG_SECTION
- TIDY_TAG_SOURCE
- TIDY_TAG_SUMMARY
- TIDY_TAG_TEMPLATE
- TIDY_TAG_TIME
- TIDY_TAG_TRACK
- TIDY_TAG_VIDEO
- STREAM_CRYPTO_METHOD_TLSv1_3_CLIENT
- STREAM_CRYPTO_METHOD_TLSv1_3_SERVER
- STREAM_CRYPTO_PROTO_TLSv1_3
- T_COALESCE_EQUAL
- T_FN
See also New global constants in 7.4.
Unused Class Constant
[Since 1.8.4] - [ -P Classes/UnusedConstant ] - [ Online docs ]
The class constant is unused. Consider removing it.
<?php
class foo {
public const UNUSED = 1; // No mention in the code
private const USED = 2; // used constant
function bar() {
echo self::USED;
}
}
?>
Could Be Constant
[Since 1.8.4] - [ -P Constants/CouldBeConstant ] - [ Online docs ]
Literals may be replaced by an existing constant.
Constants makes the code easier to read, as they may bear a meaningful name. They also hide implementation values, with a readable name, such as const READABLE= true; . Later, upgrading constant values is easier than scouring the code with a new literal.
Not all literal can be replaced by a constant values : sometimes, literal may have the same literal value, but different meanings. Check with your application semantics before changing any literal with a constant.
<?php
const A = 'abc';
define('B', 'ab');
class foo {
const X = 'abcd';
}
// Could be replaced by B;
$a = 'ab';
// Could be replaced by A;
$a = 'abc';
// Could be replaced by foo::X;
$a = 'abcd';
?>
This analysis currently doesn't support arrays.
This analysis also skips very common values, such as boolean, 0 and 1 . This prevents too many false positive.
Infinite Recursion
[Since 1.8.6] - [ -P Structures/InfiniteRecursion ] - [ Online docs ]
A method is calling itself, with unchanged arguments. This will probably repeat indefinitely.
This applies to recursive functions without any condition. This also applies to function which inject the incoming arguments, without modifications.
<?php
function foo($a, $b) {
if ($a > 10) {
return;
}
foo($a, $b);
}
function foo2($a, $b) {
++$a; // $a is modified
if ($a > 10) {
return;
}
foo2($a, $b);
}
?>
Null Or Boolean Arrays
[Since 1.8.6] - [ -P Arrays/NullBoolean ] - [ Online docs ]
Null and booleans are valid PHP array base. Yet, they only produces null values. They also did not emits any warning until PHP 7.4.
This analysis has been upgraded to cover int and float types too.
<?php
// outputs NULL
var_dump(null[0]);
const MY_CONSTANT = true;
// outputs NULL
var_dump(MY_CONSTANT[10]);
?>
See also Null and True.
Dependant Abstract Classes
[Since 1.8.6] - [ -P Classes/DependantAbstractClass ] - [ Online docs ]
Abstract classes should be autonomous. It is recommended to avoid depending on methods, constant or properties that should be made available in inheriting classes, without explicitly abstracting them.
The following abstract classes make usage of constant, methods and properties, static or not, that are not defined in the class. This means the inheriting classes must provide those constants, methods and properties, but there is no way to enforce this.
This may also lead to dead code : when the abstract class is removed, the host class have unused properties and methods.
<?php
// autonomous abstract class : all it needs is within the class
abstract class c {
private $p = 0;
function foo() {
return ++$this->p;
}
}
// dependant abstract class : the inheriting classes needs to provide some properties or methods
abstract class c2 {
function foo() {
// $p must be provided by the extending class
return ++$this->p;
}
}
class c3 extends c2 {
private $p = 0;
}
?>
See also Traits/DependantTrait.
Wrong Returned Type
[Since 1.8.7] - [ -P Functions/WrongReturnedType ] - [ Online docs ]
The returned value is not compatible with the specified return type.
<?php
// classic error
function bar() : int {
return 'A';
}
// classic static error
const B = 2;
function bar() : string {
return B;
}
// undecideable error
function bar($c) : string {
return $c;
}
// PHP lint this, but won't execute it
function foo() : void {
// No return at all
}
?>
See also Returning values and
Void Return Type.
Generator Cannot Return
[Since 1.8.7] - [ -P Functions/GeneratorCannotReturn ] - [ Online docs ]
Generators could not use return and yield at the same time. In PHP 7.0, generator can now use both of them.
<?php
// This is not allowed until PHP 7.0
function foo() {
yield 1;
return 'b';
}
?>
Use DateTimeImmutable Class
[Since 1.8.7] - [ -P Php/UseDateTimeImmutable ] - [ Online docs ]
The DateTimeImmutable class is the immutable version of the Datetime class.
While DateTime may be modified 'in situ', DateTimeImmutable cannot be modified. Any modification to such an object will return a new and distinct object. This avoid interferences that are hard to track.
<?php
// Example extracted from Derick Rethans' article (link below)
function formatNextMondayFromNow( DateTime $dt )
{
return $dt->modify( 'next monday' )->format( 'Y-m-d' );
}
$d = new DateTime(); //2014-02-17
echo formatNextMondayFromNow( $d ), \n;
echo $d->format( 'Y-m-d' ), \n; //2014-02-17
?>
See also What's all this 'immutable date' stuff, anyway?,
DateTimeImmutable,
The DateTime class and
The DateTimeImmutable class.
Set Aside Code
[Since 1.8.8] - [ -P Structures/SetAside ] - [ Online docs ]
Setting aside code should be made into a method.
Setting aside code happens when one variable or member is stored locally, to be temporarily replaced by another value. Once the new value has been processed, the original value is reverted.
The temporary change of the value makes the code hard to read.
It is a good example of a piece of code that could be moved to a separate method or function. Using the temporary value as a parameter makes the change visible, and avoid local pollution.
<?php
// Setting aside database
class cache extends Storage {
private $database = null;
function __construct($database) {
$this->database = $database;
}
function foo($values) {
// handling storage with sqlite3
$secondary = new cache(new Sqlite3(':memory:'));
$secondary->store($values);
$this->store($values); // handling storage with injection
}
}
// Setting aside database to cache data in two distinct backend
class cache extends Storage {
private $database = null;
function __construct(\Pdo $database) {
$this->database = $database;
}
function foo($values) {
// $this->database is set aside for secondary configuration
$side = $this->database;
$this->database = new Sqlite3(':memory:');
$this->store($values); // handling storage with sqlite3
$this->database = $side;
// $this->database is restored
$this->store($values); // handling storage with injection
}
}
?>
Use Array Functions
[Since 1.8.8] - [ -P Structures/UseArrayFunctions ] - [ Online docs ]
There are a lot of native PHP functions for arrays. It is often faster to take advantage of them than write a loop.
- array_push() : use array_merge()
- array_slice() : use array_chunk()
- index access : use array_column()
- append []`: use `array_merge()
- addition : use array_sum()
- multiplication : use array_product()
- concatenation : use implode()
- ifthen : use array_filter()
<?php
$all = implode('-', $s).'-';
// same as above
$all = '';
foreach($array as $s) {
$all .= $s . '-';
}
?>
See also Array Functions and
Performances/ArrayMergeInLoops.
Useless Type Check
[Since 1.8.9] - [ -P Functions/UselessTypeCheck ] - [ Online docs ]
With typehint, some checks on the arguments are now handled by the type system.
In particular, a type hinted argument can't be null, unless it is explicitly nullable, or has a null value as default.
<?php
// The test on null is useless, it will never happen
function foo(A $a) {
if (is_null($a)) {
// do something
}
}
// Either nullable ? is too much, either the default null is
function barbar(?A $a = null) {
}
// The test on null is useful, the default value null allows it
function bar(A $a = null) {
if ($a === null) {
// do something
}
}
?>
See also Type Declarations.
Disconnected Classes
[Since 1.8.9] - [ -P Classes/DisconnectedClasses ] - [ Online docs ]
One class is extending the other, but they do not use any features from one another. Basically, those two classes are using extends, but they are completely independent and may be separated.
When using the 'extends' keyword, the newly created classes are now acting together and making one. This should be visible in calls from one class to the other, or simply by property usage : they can't live without each other.
On the other hand, two completely independent classes that are merged, although they should be kept separated.
<?php
class A {
private $pa = 1;
function fooA() {
$this->pa = 2;
}
}
// class B and Class A are totally independent
class B extends A {
private $pb = 1;
function fooB() {
$this->pb = 2;
}
}
// class C makes use of class A : it is dependent on the parent class
class C extends A {
private $pc = 1;
function fooB() {
$this->pc = 2 + $this->fooA();
}
}
?>
Not Or Tilde
[Since 1.8.9] - [ -P Structures/NotOrNot ] - [ Online docs ]
There are two NOT operator in PHP : ! and ~ . The first is a logical operator, and returns a boolean. The second is a bit-wise operator, and flips each bit.
Although they are distinct operations, there are situations where they provide the same results. In particular, when processing booleans.
Yet, ! and ~ are not the same. ~ has a higher priority, and will not yield to instanceof , while ! does.
The analyzed code has less than 10% of one of them : for consistency reasons, it is recommended to make them all the same.
<?php
// be consistent
if (!$condition) {
doSomething();
}
if (~$condition) {
doSomething();
}
?>
See also Bitwise Operators,
Logical Operators and
Operators Precedences .
Overwritten Source And Value
[Since 1.8.9] - [ -P Structures/ForeachSourceValue ] - [ Online docs ]
In a foreach(), it is best to keep source and values distinct. Otherwise, they overwrite each other.
Since PHP 7.0, PHP makes a copy of the original source, then works on it. This makes possible to use the same name for the source and the values.
<?php
// displays 0-1-2-3-3
$array = range(0, 3);
foreach($array as $array) {
print $array . '-';
}
print_r($array);
/* displays 0-1-2-3-Array
(
[0] => 0
[1] => 1
[2] => 2
[3] => 3
)
*/
$array = range(0, 3);
foreach($array as $v) {
print $v . '-';
}
print_r($array);
?>
When the source is used as the value, the elements in the array are successively assigned to itself. After the loop, the original array has been replaced by its last element.
The same applies to the index, or to any variable in a list() structure, used in a foreach().
Avoid mb_dectect_encoding()
[Since 1.8.9] - [ -P Php/AvoidMbDectectEncoding ] - [ Online docs ]
mb_dectect_encoding() is bad at guessing encoding.
For example, UTF-8 and ISO-8859-1 share some common characters : when a string is build with them it is impossible to differentiate the actual encoding.
<?php
$encoding = mb_encoding_detect($_GET['name']);
?>
See also mb_encoding_detect,
PHP vs. The Developer: Encoding Character Sets,
DPC2019: Of representation and interpretation: A unified theory - Arnout Boks.
PHP 7.4 Removed Functions
[Since 1.9.0] - [ -P Php/Php74RemovedFunctions ] - [ Online docs ] - [ PHP older than 7.3]
The following PHP native functions were deprecated in PHP 7.4.
- hebrevc()
- convert_cyr_string()
- ezmlm_hash()
- money_format()
- restore_include_path()
- get_magic_quotes_gpc()
- get_magic_quotes_runtime()
This analysis skips redefined PHP functions : when a replacement for a removed PHP function was created, with condition on the PHP version, then its usage is considered valid.
See also PHP 7.4 Removed Functions and
PHP 7.4 Deprecations : Introduction.
mb_strrpos() Third Argument
[Since 1.8.9] - [ -P Php/Php74mbstrrpos3rdArg ] - [ Online docs ]
Passing the encoding as 3rd parameter to mb_strrpos() is deprecated. Instead pass a 0 offset, and encoding as 4th parameter.
<?php
// Finds the position of the last occurrence of of a string in a string, starting at position 10
$extract = mb_strrpos($haystack, $needle, 10, 'utf8');
// This is the old behavior. Here, the offset will be 0, by default
$extract = mb_strrpos($haystack, $needle, 'utf8');
?>
See also mb_strrpos().
array_key_exists() Works On Arrays
[Since 1.9.0] - [ -P Php/ArrayKeyExistsWithObjects ] - [ Online docs ]
array_key_exists() requires arrays as second argument. Until PHP 7.4, objects were also allowed, yet it is now deprecated.
<?php
// Valid way to check for key
$array = ['a' => 1];
var_dump(array_key_exists('a', $array))
// Deprecated since PHP 7.4
$object = new Stdclass();
$object->a = 1;
var_dump(array_key_exists('a', $object))
?>
See also `array_key_exists() with objects
array_key_exists, and.
Reflection Export() Is Deprecated
[Since 1.9.0] - [ -P Php/ReflectionExportIsDeprecated ] - [ Online docs ]
export() method in Reflection classes is now deprecated. It is obsolete since PHP 7.4 and will disappear in PHP 8.0.
The Reflector interface, which is implemented by all reflection classes, specifies two methods: __toString() and export().
<?php
ReflectionFunction::export('foo');
// same as
echo new ReflectionFunction('foo'), \n;
$str = ReflectionFunction::export('foo', true);
// same as
$str = (string) new ReflectionFunction('foo');
?>
See also Reflection export() methods and
Reflection.
Unbinding Closures
[Since 1.9.0] - [ -P Functions/UnbindingClosures ] - [ Online docs ]
Never drop $this , once a closure was created in a non-static method.
From the PHP wiki : Currently it is possible to unbind the $this variable from a closure that originally had one by using $closure->bindTo(null). Due to the removal of static calls to non-static methods in PHP 8, we now have a guarantee that $this always exists inside non-static methods. We would like to have a similar guarantee that $this always exists for non-static closures declared inside non-static methods. Otherwise, we will end up imposing an unnecessary performance penalty either on $this accesses in general, or $this accesses inside such closures.
<?php
class x {
private $a = 3;
function foo() {
return function () { echo $this->a; };
}
}
$closure = (new x)->foo();
// $this was expected, and it is not anymore
$closure->bindTo(null);
$closure->bindTo(new x);
?>
Calling bindTo() with a valid object is still valid.
See also Unbinding $this from non-static closures.
Numeric Literal Separator
[Since 1.9.0] - [ -P Php/IntegerSeparatorUsage ] - [ Online docs ]
Integer and floats may be written with internal underscores. This way, it is possible to separate large number into smaller groups, and make them more readable.
Numeric Literal Separators were introduced in PHP 7.4 and are not backward compatible.
<?php
$a = 1_000_000_000; // A billion
$a = 1000000000; // A billion too...
$b = 107_925_284.88; // 6 light minute to kilometers = 107925284.88 kilometers
$b = 107925284.88; // Same as above
?>
See also PHP RFC: Numeric Literal Separator.
Class Without Parent
[Since 1.9.0] - [ -P Classes/NoParent ] - [ Online docs ]
Classes should not refer to parent when it is not extending another class.
In PHP 7.4, it is a Deprecated warning. In PHP 7.3, it was a Fatal error, when the code was finally executed.
<?php
class x {
function foo() {
parent::foo();
}
}
?>
Scalar Are Not Arrays
[Since 1.9.0] - [ -P Php/ScalarAreNotArrays ] - [ Online docs ]
It is wrong to use a scalar as an array, a Warning is emitted. PHP 7.4 emits a Warning in such situations.
<?php
// Here, $x may be null, and in that case, the echo will fail.
function foo(?A $x) {
echo $x[2];
}
?>
Typehinted argument with a scalar are reported by this analysis. Also, nullable arguments, both with typehint and return type hint.
See also E_WARNING for invalid container read array-access.
PHP 7.4 Reserved Keyword
[Since 1.9.2] - [ -P Php/Php74ReservedKeyword ] - [ Online docs ]
fn is a new PHP keyword. In PHP 7.4, it is used to build the arrow functions. When used at an illegal position, fn generates a Fatal error at compile time.
As a key word, fn is not allowed as constant name, function name, class name or inside namespaces.
<?php
// PHP 7.4 usage of fn
function array_values_from_keys($arr, $keys) {
return array_map(fn($x) => $arr[$x], $keys);
}
// PHP 7.3 usage of fn
const fn = 1;
function fn() {}
class x {
// This is valid in PHP 7.3 and 7.4
function fn() {}
}
?>
fn is fine for method names. It may also be used for constants with define(), and constant() but it is not recommended.
See also PHP RFC: Arrow Functions.
No ENT_IGNORE
[Since 1.9.2] - [ -P Security/NoEntIgnore ] - [ Online docs ]
Certain characters have special significance in HTML, and should be represented by HTML entities if they are to preserve their meanings.
ENT_IGNORE is a configuration option for htmlspecialchars(), that ignore any needed character replacement. This mean the raw input will now be processed by PHP, or a target browser.
It is recommended to use the other configuration options : ENT_COMPAT, ENT_QUOTES, ENT_NOQUOTES, ENT_SUBSTITUTE, ENT_DISALLOWED, ENT_HTML401, ENT_XML1, ENT_XHTML or ENT_HTML5.
<?php
// This produces a valid HTML tag
$new = htmlspecialchars("<a href='test'>Test</a>", ENT_IGNORE);
echo $new; // <a href='test'>Test</a>
// This produces a valid string, without any HTML special value
$new = htmlspecialchars("<a href='test'>Test</a>", ENT_QUOTES);
echo $new; // <a href='test'>Test</a>
?>
See also htmlspecialchars and
Deletion of Code Points.
No More Curly Arrays
[Since 1.9.2] - [ -P Php/NoMoreCurlyArrays ] - [ Online docs ]
Only use square brackets to access array elements. The usage of curly brackets for array access is deprecated since PHP 7.4.
<?php
$array = [1,2,3];
// always valid
echo $array[1];
// deprecated in PHP 7.4
echo $array{1};
?>
See also Deprecate curly brace syntax.
array_merge() And Variadic
[Since 1.9.2] - [ -P Structures/ArrayMergeAndVariadic ] - [ Online docs ]
Always check value in variadic before using it with array_merge() and array_merge_recursive().
Before PHP 7.4, array_merge() and array_merge_recursive() would complain when no argument was provided. As such, using the spread operator `...` on an empty array() would yield no argument, and an error.
<?php
//
$b = array_merge(...$x);
?>
PHP 7.4 Constant Deprecation
[Since 1.9.3] - [ -P Php/Php74Deprecation ] - [ Online docs ] - [ PHP older than 7.4]
One constant is deprecated in PHP 7.4.
- CURLPIPE_HTTP1
See also Deprecations for PHP 7.2.
Implode() Arguments Order
[Since 1.9.2] - [ -P Structures/ImplodeArgsOrder ] - [ Online docs ]
implode() accepted two signatures, but is only recommending one. Both types orders of string then array, and array then string have been possible until PHP 7.4.
In PHP 7.4, the order array then string is deprecated, and emits a warning. It will be removed in PHP 8.0.
<?php
$glue = ',';
$pieces = range(0, 4);
// documented argument order
$s = implode($glue, $pieces);
// Pre 7.4 argument order
$s = implode($pieces, $glue);
// both produces 0,1,2,3,4
?>
See also implode().
PHP 7.4 Removed Directives
[Since 1.9.3] - [ -P Php/Php74RemovedDirective ] - [ Online docs ]
List of directives that are removed in PHP 7.4.
+ allow_url_include
See Deprecation allow_url_include.
Hash Algorithms Incompatible With PHP 7.4-
[Since 1.3.4] - [ -P Php/HashAlgos74 ] - [ Online docs ] - [ PHP older than 7.4]
List of hash algorithms incompatible with PHP 7.3 and older recent. At the moment of writing, this is compatible up to 7.4s.
The hash algorithms were introduced in PHP 7.4s.
<?php
// Compatible only with 7.1 and more recent
echo hash('crc32cs', 'The quick brown fox jumped over the lazy dog.');
// Always compatible
echo hash('ripemd320', 'The quick brown fox jumped over the lazy dog.');
?>
See also hash_algos.
openssl_random_pseudo_byte() Second Argument
[Since 1.9.3] - [ -P Structures/OpensslRandomPseudoByteSecondArg ] - [ Online docs ]
openssl_random_pseudo_byte() uses exceptions to signal an error. Since PHP 7.4, there is no need to use the second argument.
On the other hand, it is important to catch the exception that openssl_random_pseudo_byte() may emit.
<?php
// PHP 7.4 way to check on random number generation
try {
$bytes = openssl_random_pseudo_bytes($i);
} catch(\Exception $e) {
die(Error while loading random number);
}
// Old way to check on random number generation
$bytes = openssl_random_pseudo_bytes($i, $cstrong);
if ($cstrong === false) {
die(Error while loading random number);
}
?>
See also openssl_random_pseudo_byte and
PHP RFC: Improve openssl_random_pseudo_bytes().
strip_tags Skips Closed Tag
[Since 1.9.3] - [ -P Structures/StripTagsSkipsClosedTag ] - [ Online docs ]
strip_tags() skips non-self closing tags. This means that tags such as
will be ignored from the 2nd argument of the function.
<?php
$input = 'a<br />';
// Displays 'a' and clean the tag
echo strip_tags($input, '<br>');
// Displays 'a<br />' and skips the allowed tag
echo strip_tags($input, '<br/>');
?>
See also strip_tags.
No Spread For Hash
[Since 1.9.3] - [ -P Arrays/NoSpreadForHash ] - [ Online docs ]
The spread operator ... only works on integer-indexed arrays.
<?php
// This is valid, as -33 is cast to integer by PHP automagically
var_dump(...[1,-33 => 2, 3]);
// This is not valid
var_dump(...[1,C => 2, 3]);
?>
See also Variable-length argument lists.
Use Covariance
[Since 1.9.3] - [ -P Php/UseCovariance ] - [ Online docs ]
Covariance is compatible return typehint. A child class may return an object of a child class of the return type of its parent's method.
Since a children class may return a children class of the return type, the evolution is in the same order.
Covariance is a PHP 7.4 feature. Covariance is distinct from argument contravariance.
<?php
class X {
function m(Y $z): X {}
}
// m is overwriting the parent's method.
// The return type is different.
// The return type is compatible, as Y is also a sub-class of X.
class Y extends X {
function m(X $z): Y {}
}
?>
See also Covariant Returns and Contravariant Parameters and
`Php/UseContravariance`.
Use Contravariance
[Since 1.9.3] - [ -P Php/UseContravariance ] - [ Online docs ]
Contravariance is compatible argument typehint. A child class may accept an object of a parent class of the argument type of its parent's method.
Since a children class may accept a parent class of the argynebt type, the evolution is in opposite order.
Contravariance is a PHP 7.4 feature. Contravariance is distinct from return type covariance.
<?php
class X {
function m(Y $z): X {}
}
// m is overwriting the parent's method.
// The return type is different.
// The return type is compatible, as Y is also a sub-class of X.
class Y extends X {
function m(X $z): Y {}
}
?>
See also Covariant Returns and Contravariant Parameters and
`Php/UseCovariance`.
Use Arrow Functions
[Since 1.9.4] - [ -P Functions/UseArrowFunctions ] - [ Online docs ]
Arrow functions are closures that require less code to write.
Arrow functions were introduced in PHP 7.4. They added the reserved keyword fn . s
<?php
array_map(fn(A $b): int => $b->c, $array);
function array_values_from_keys($arr, $keys) {
return array_map(fn($x) => $arr[$x], $keys);
}
?>
See also RFC : Arrow functions and
Arrow functions in PHP.
Max Level Of Nesting
[Since 1.9.3] - [ -P Structures/MaxLevelOfIdentation ] - [ Online docs ]
Avoid nesting structures too deep, as it hurts readability.
Nesting structures are : if/then, switch, for, foreach, while, do...while. Ternary operator, try/catch are not considered a nesting structures.
Closures, and more generally, functions definitions are counted separatedly.
This analysis checks for 4 levels of nesting, by default. This may be changed by configuration.
<?php
// 5 levels of indentation
function foo() {
if (1) {
if (2) {
if (3) {
if (4) {
if (5) {
51;
} else {
5;
}
} else {
4;
}
} else {
3;
}
} else {
2;
}
} else {
1;
}
}
// 2 levels of indentation
function foo() {
if (1) {
if (2) {
// 3 levels of indentation
return function () {
if (3) {
if (4) {
if (5) {
51;
} else {
5;
}
} else {
4;
}
} else {
3;
}
}
} else {
2;
}
} else {
1;
}
}
?>
Environnement Variable Usage
[Since 1.9.5] - [ -P Dump/EnvironnementVariables ] - [ Online docs ]
Collects all environnement variable in the application, for inventory purposes.
Indentation Levels
[Since 1.9.3] - [ -P Dump/IndentationLevels ] - [ Online docs ]
Collect all level of nesting for methods and functions.
Spread Operator For Array
[Since 1.9.4] - [ -P Php/SpreadOperatorForArray ] - [ Online docs ]
The variadic operator may be used with arrays. This has been introduced in PHP 7.4.
list() is not allowed to use this operator, as list() expected variables, not values.
<?php
$array = [1, 2, 3];
$extended_array = [...$array, 4, 5, 6];
// invalid syntax
[...$a] = [1,2,3];
?>
See also Spread Operator in Array Expression.
Nested Ternary Without Parenthesis
[Since 1.9.4] - [ -P Php/NestedTernaryWithoutParenthesis ] - [ Online docs ]
It is not allowed to nest ternary operator within itself, without parenthesis. This has been implemented in PHP 7.4.
The reason behind this feature is to keep the code expressive. See the Warning message for more explanations
<?php
$a ? 1 : ($b ? 2 : 3);
// Still valid, as not ambiguous
$a ? $b ? 1 : 2 : 3;
// Produces a warning
//Unparenthesized `a ? b : c ? d : e` is deprecated. Use either `(a ? b : c) ? d : e` or `a ? b : (c ? d : e)`
$a ? 1 : $b ? 2 : 3;
?>
See also PHP RFC: Deprecate left-associative ternary operator.
Cyclomatic Complexity
[Since 1.9.4] - [ -P Dump/CyclomaticComplexity ] - [ Online docs ]
Calculate cyclomatic complexity for each methods, function, and closures.
Should Use Explode Args
[Since 1.9.4] - [ -P Structures/ShouldUseExplodeArgs ] - [ Online docs ]
explode() has a third argument, which limits the amount of exploded elements. With it, it is possible to collect only the first elements, or drop the last ones.
<?php
$exploded = explode(DELIMITER, $string);
// use explode(DELIMITER, $string, -1);
array_pop($exploded);
// use explode(DELIMITER, $string, -2);
$c = array_slice($exploded, 0, -2);
// with `explode() <https://www.php.net/explode>`_'s third argument :
list($a, $b) = explode(DELIMITER, $string, 2);
// with list() omitted arguments
list($a, $b, ) = explode(DELIMITER, $string);
?>
See also explode.
Use array_slice()
[Since 1.9.5] - [ -P Performances/UseArraySlice ] - [ Online docs ]
Array_slice is de equivalent of substr() for arrays.
array_splice() is also possible, to remove a portion of array inside the array, not at the ends. This has no equivalent for strings.
<?php
$array = range(0, 9);
// Extract the 5 first elements
print_r(array_slice($array, 0, 5));
// Extract the 4 last elements
print_r(array_slice($array, -4));
// Extract the 2 central elements : 4 and 5
print_r(array_splice($array, 4, 2));
// slow way to remove the last elementst of an array
for($i = 0; $i < 4) {
array_pop($array);
}
?>
See also array_slice and
array_splice.
PHP 74 New Directives
[Since 1.9.4] - [ -P Php/Php74NewDirective ] - [ Online docs ]
List of directives that are new in PHP 7.4.
+ zend.exception_ignore_args : From the php.ini : Allows to include or exclude arguments from stack traces generated for exceptions. Default: Off
+ opcache.preload_user
See RFC Preload.
Too Many Array Dimensions
[Since 1.9.4] - [ -P Arrays/TooManyDimensions ] - [ Online docs ]
When arrays a getting to many nesting.
<?php
$a = array(); // level 1;
$a[1] = array(); // level 2
$a[1][2] = array(); // level 3 : still valid by default
$a[1][2][3] = array(); // level 4
?>
PHP has no limit, and accepts any number of nesting levels. Yet, this is usually very memory hungry.
Coalesce And Concat
[Since 1.9.4] - [ -P Structures/CoalesceAndConcat ] - [ Online docs ]
The concatenation operator dot has precedence over the coalesce operator ??.
<?php
// Parenthesis are the right solution when in doubt
echo a . ($b ?? 'd') . $e;
// 'a' . $b is evaluated first, leading ot a useless ?? operator
'a' . $b ?? $c;
// 'd' . 'e' is evaluated first, leading to $b OR 'de'.
echo $b ?? 'd' . 'e';
?>
Constant Comparison
[Since 1.9.4] - [ -P Structures/AlwaysFalse ] - [ Online docs ]
Based on the incoming types of arguments, the comparison never change.
<?php
function foo(array $a) {
// This will always fail
if ($a === 1) {
} elseif (is_int($a)) {
}
// This will always succeed
if ($a !== null) {
} elseif (is_null($a)) {
}
}
?>
Incompatible Signature Methods With Covariance
[Since 1.3.3] - [ -P Classes/IncompatibleSignature74 ] - [ Online docs ]
Methods should have the compatible signature when being overwritten.
The same signatures means the children class must have :
+ the same name
+ the same visibility or less restrictive
+ the same contravariant typehint or removed
+ the same covariant return typehint or removed
+ the same default value or removed
+ a reference like its parent
This problem emits a fatal error, for abstract methods, or a warning error, for normal methods. Yet, it is difficult to lint, because classes are often stored in different files. As such, PHP do lint each file independently, as unknown parent classes are not checked if not present. Yet, when executing the code, PHP lint the actual code and may encounter a fatal error.
<?php
class a {
public function foo($a = 1) {}
}
class ab extends a {
// foo is overloaded and now includes a default value for $a
public function foo($a) {}
}
?>
See also Object Inheritance,
PHP RFC: Covariant Returns and Contravariant Parameters and
Classes/IncompatibleSignature.
Interfaces Is Not Implemented
[Since 1.9.5] - [ -P Interfaces/IsNotImplemented ] - [ Online docs ]
Classes that implements interfaces, must implements each of the interface's methods.
<?php
class x implements i {
// This method implements the foo method from the i interface
function foo() {}
// The method bar is missing, yet is requested by interface i
function foo() {}
}
interface i {
function foo();
function bar();
}
?>
This problem tends to occur in code that splits interfaces and classes by file. This means that PHP's linting will skip the definitions and not find the problem. At execution time, the definitions will be checked, and a Fatal error will occur.
This situation usually detects code that was forgotten during a refactorisation of the interface or the class and its sibblings.
See also Interfaces.
No Literal For Reference
[Since 1.9.5] - [ -P Functions/NoLiteralForReference ] - [ Online docs ]
Method arguments and return values may be by reference. Then, they need to be a valid variable.
Objects are always passed by reference, so there is no need to explicitely declare it.
Expressions, including ternary operator, produce value, and can't be used by reference directly. This is also the case for expression that include one or more reference.
<?php
// variables, properties, static properties, array items are all possible
$a = 1;
foo($a);
//This is not possible, as a literal can't be a reference
foo(1);
function foo(&$int) { return $int; }
// This is not a valid reference
function &bar() { return 2; }
function &bar2() { return 2 + $r; }
?>
Wrongly passing a value as a reference leads to a PHP Notice.
See also References.
Magic Properties
[Since 1.9.5] - [ -P Classes/MagicProperties ] - [ Online docs ]
List of magic properties used in the code
Interfaces Don't Ensure Properties
[Since 1.9.5] - [ -P Interfaces/NoGaranteeForPropertyConstant ] - [ Online docs ]
When using an interface as a typehint, properties are not enforced, nor available.
An interface is a template for a class, which specify the minimum amount of methods and constants. Properties are never defined in an interface, and should not be relied upon.
<?php
interface i {
function m () ;
}
class x implements i {
public $p = 1;
function m() {
return $this->p;
}
}
function foo(i $i, x $x) {
// this is invalid, as $p is not defined in i, so it may be not available
echo $i->p;
// this is valid, as $p is defined in $x
echo $x->p;
}
?>
Collect Literals
[Since 1.9.5] - [ -P Dump/CollectLiterals ] - [ Online docs ]
Collects all literals in the application, for inventory purposes.
No Weak SSL Crypto
[Since 1.9.6] - [ -P Security/NoWeakSSLCrypto ] - [ Online docs ]
When enabling PHP's stream SSL, it is important to use a safe protocol.
All the SSL protocols (1.0, 2.0, 3.0), and TLS (1.0 are unsafe. The best is to use the most recent TLS, version 1.2.
stream_socket_enable_crypto() and curl_setopt() are checked.
<?php
// This socket will use SSL v2, which
$socket = 'sslv2://www.example.com';
$fp = fsockopen($socket, 80, $errno, $errstr, 30);
?>
Using the TLS transport protocol of PHP will choose the version by itself.
See also Insecure Transportation Security Protocol Supported (TLS 1.0),
The 2018 Guide to Building Secure PHP Software and
Internet Domain: TCP, UDP, SSL, and TLS.
Internet Domains
[Since 1.9.6] - [ -P Type/UdpDomains ] - [ Online docs ]
List all internet domain used
No mb_substr In Loop
[Since 1.9.6] - [ -P Performances/MbStringInLoop ] - [ Online docs ]
Do not use loops on mb_substr().
mb_substr() always starts at the beginning of the string ot search for the nth char, and recalculate everything. This means that the first iterations are as fast as substr() (for comparison), while the longer the string, the slower mb_substr().
The recommendation is to use preg_split() with the `u` option, to split the string into an array. This save multiple recalculations.
<?php
// Split the string by characters
$array = preg_split('//u', $string, -1, PREG_SPLIT_NO_EMPTY);
foreach($array as $c) {
doSomething($c);
}
// Slow version
$nb = mb_strlen($mb);
for($i = 0; $i < $nb; ++$i) {
// Fetch a character
$c = mb_substr($string, $i, 1);
doSomething($c);
}
?>
See also Optimization: How I made my PHP code run 100 times faster and
How to iterate UTF-8 string in PHP?.
Collect Parameter Counts
[Since 1.9.6] - [ -P Dump/CollectParameterCounts ] - [ Online docs ]
This analysis collects the number of parameter per method.
The count applies to functions, methods, closures and arrow functions.
<?php
// parameter count on function : 1
function foo($a) { }
// parameter count on closure : 2
function ($b, $c = 2) {}
// parameter count on method : 0 (none)
class x {
function moo() { }
}
?>
Collect Local Variable Counts
[Since 2.1.2] - [ -P Dump/CollectLocalVariableCounts ] - [ Online docs ]
This analysis collects the number of local variables used in a method or a function.
The count applies to functions, methods, closures and arrow functions.
Arguments and global variables are not counted. Static variables are.
<?php
function foo($arg) {
global $w;
// This is a local variable
$x = rand(1, 2);
return $x + $arg + $w;
}
?>
Non Nullable Getters
[Since 1.9.6] - [ -P Classes/NonNullableSetters ] - [ Online docs ]
A getter needs to be nullable when a property is injected.
In particular, if the injection happens with a separate method, there is a time where the object is not consistent, and the property holds a default non-object value.
<?php
class Consistent {
private $db = null;
function __construct(Db $db) {
$this->db = $db;
// Object is immediately consistent
}
// Db might be null
function getDb() {
return $this->db;
}
}
class Inconsistent {
private $db = null;
function __construct() {
// No initialisation
}
// This might be called on time, or not
// This typehint cannot be nullable, nor use null as default
function setDb(DB $db) {
return $this->db;
}
// Db might be null
function getDb() {
return $this->db;
}
}
?>
Use Case Value
[Since 1.9.6] - [ -P Structures/UseCaseValue ] - [ Online docs ]
When switch() has branched to the right case, the value of the switched variable is know : it is the case.
This doesn't work with complex expression cases, nor with default.
<?php
switch($a) {
case 'a' :
// $a == 'a';
echo $a;
break;
case 'b' :
// $a == 'b';
echo 'b';
break;
}
?>
Dump/DereferencingLevels
[Since 1.9.6] - [ -P Dump/DereferencingLevels ] - [ Online docs ]
Too Many Dereferencing
[Since 1.9.7] - [ -P Classes/TooManyDereferencing ] - [ Online docs ]
Linking too many properties and methods, one to the other.
This analysis counts both static calls and normal call; methods, properties and constants. It also takes into account arrays along the way.
The default limit of chaining methods and properties is set to 7 by default.
<?php
// 9 chained calls.
$main->getA()->getB()->getC()->getD()->getE()->getF()->getG()->getH()->getI()->property;
?>
Too many chained methods is harder to read.
Use Url Query Functions
[Since 1.9.7] - [ -P Structures/UseUrlQueryFunctions ] - [ Online docs ]
PHP features several functions dedicated to processing URL's query string.
+ parse_str()
+ parse_url()
+ http_build_query()
Those functions include extra checks : for example, http_build_query() adds urlencode() call on the values, and allow for choosing the separator and the Query string format.
<?php
$data = array(
'foo' => 'bar',
'baz' => 'boom',
'cow' => 'milk',
'php' => 'hypertext processor'
);
// safe and efficient way to build a query string
echo http_build_query($data, '', '&') . PHP_EOL;
// slow way to produce a query string
foreach($data as $name => &$value) {
$value = $name.'='.$value;
}
echo implode('&', $data) . PHP_EOL;
?>
Foreach() Favorite
[Since 1.9.7] - [ -P Dump/CollectForeachFavorite ] - [ Online docs ]
Collect the name used in foreach() loops. Then, sorts them in order of popularity.
Cant Implement Traversable
[Since 1.9.8] - [ -P Interfaces/CantImplementTraversable ] - [ Online docs ]
It is not possible to implement the Traversable interface. The alternative is to implement Iterator or IteratorAggregate .
Traversable may be useful when used with instanceof .
<?php
// This lints, but doesn't run
class x implements Traversable {
}
if( $argument instanceof Traversable ) {
// doSomething
}
?>
See also Traversable,
Iterator and
IteratorAggregate..
Is_A() With String
[Since 1.9.9] - [ -P Php/IsAWithString ] - [ Online docs ]
When using is_a() with a string as first argument, the third argument is compulsory.
<?php
// `is_a() <https://www.php.net/is_a>`_ works with string as first argument, when the third argument is 'true'
if (is_s('A', 'B', true)) {}
// `is_a() <https://www.php.net/is_a>`_ works with object as first argument
if (is_s(new A, 'A')) {}
?>
See also is_a().
Mbstring Unknown Encoding
[Since 1.9.9] - [ -P Structures/MbstringUnknownEncoding ] - [ Online docs ]
The encoding used is not known to the ext/mbstring extension.
This analysis takes in charge all mbstring encoding and aliases. The full list of supported mbstring encoding is available with mb_list_encodings(). Each encoding alias is available with mb_encoding_aliases().
<?php
// Invalid encoding
$str = mb_strtolower($str, 'utf_8');
// Valid encoding
$str = mb_strtolower($str, 'utf8');
$str = mb_strtolower($str, 'UTF8');
$str = mb_strtolower($str, 'UTF-8');
?>
See also ext/mbstring.
Collect Mbstring Encodings
[Since 1.9.9] - [ -P Dump/CollectMbstringEncodings ] - [ Online docs ]
This analysis collects the encoding names, used by ext/mb functions.
<?php
mb_stotolower('PHP', 'iso-8859-1');
mb_stotolower('PHP', 'iso-8859-1');
?>
Filter To add_slashes()
[Since 1.9.9] - [ -P Php/FilterToAddSlashes ] - [ Online docs ]
FILTER_SANITIZE_MAGIC_QUOTES is deprecated. In PHP 7.4, it should be replaced with addslashes()
According to the migration RDFC : 'Magic quotes were deprecated all the way back in PHP 5.3 and later removed in PHP 5.4. The filter extension implements a sanitization filter that mimics this behavior of magic_quotes by calling addslashes() on the input in question.'
<?php
// Deprecated way to filter input
$var = filter_input($input, FILTER_SANITIZE_MAGIC_QUOTES);
// Alternative way to filter input
$var = addslashes($input);
?>
addslashes() used to filter data while building SQL queries, to prevent injections. Nowadays, prepared queries are a better option.
See also Deprecations for PHP 7.4.
Mbstring Third Arg
[Since 1.9.9] - [ -P Structures/MbstringThirdArg ] - [ Online docs ]
Some mbstring functions use the third argument for offset, not for encoding.
Those are the following functions :
- mb_strrichr()
- mb_stripos()
- mb_strrpos()
- mb_strstr()
- mb_stristr()
- mb_strpos()
- mb_strripos()
- mb_strrchr()
- mb_strrichr()
- mb_substr()
<?php
// Display BC
echo mb_substr('ABC', 1 , 2, 'UTF8');
// Yields Warning: `mb_substr() <https://www.php.net/mb_substr>`_ expects parameter 3 to be int, string given
// Display 0 (aka, substring from 0, for length (int) 'UTF8' => 0)
echo mb_substr('ABC', 1 ,'UTF8');
?>
See also mb_substr() manual pages.
Typehinting Stats
[Since 1.9.9] - [ -P Dump/TypehintingStats ] - [ Online docs ]
This module collects statistics about typehinting usage.
Typo 3 usage
[Since 1.9.9] - [ -P Vendors/Typo3 ] - [ Online docs ]
This analysis reports usage of the Typo 3 CMS.
<?php
namespace MyVendor\SjrOffers\Controller;
use TYPO3\CMS\Extbase\Mvc\Controller\ActionController;
class OfferController extends ActionController
{
// Action methods will be following here
}
?>
See also Typo3.
Concrete usage
[Since 1.9.9] - [ -P Vendors/Concrete5 ] - [ Online docs ]
This analysis reports usage of the Concrete 5 framework.
<?php
namespace Application\Controller\PageType;
use Concrete\Core\Page\Controller\PageTypeController;
class BlogEntry extends PageTypeController
{
public function view()
{
}
}
?>
See also Concrete 5.
Immutable Signature
[Since 1.9.9] - [ -P Classes/ImmutableSignature ] - [ Online docs ]
Overwrites makes refactoring a method signature difficult. PHP enforces compatible signature, by checking if arguments have the same type, reference and default values.
In PHP 7.3, typehint had to be the same, or dropped. In PHP 7.4, typehint may be contravariant (arguments), or covariant (returntype).
This analysis may be configured with maxOverwrite . By default, a minimum of 8 overwritten methods is considered difficult to update.
<?php
// Changing any of the four foo() method signature will trigger a PHP warning
class a {
function foo($a) {}
}
class ab1 extends a {
// four foo() methods have to be refactored at the same time!
function foo($ab1) {}
}
class ab2 extends a {
function foo($ab2) {}
}
class ab3 extends ab1 {
function foo($abc1) {}
}
?>
When refactoring a method, all the related methodcall may have to be updated too. Adding a type, a default value, or a new argument with default value won't affect the calls, but only the definitions. Otherwise, calls will also have to be updated.
IDE may help with signature refactoring, such as Refactoring code.
See also Covariance and contravariance (computer science),
extends.
Merge If Then
[Since 1.9.9] - [ -P Structures/MergeIfThen ] - [ Online docs ]
Two successive if/then into one, by merging the two conditions.
<?php
// two merge conditions
if ($a == 1 && $b == 2) {
// doSomething()
}
// two distinct conditions
// two nesting
if ($a == 1) {
if ($b == 2) {
// doSomething()
}
}
?>
Wrong Type With Call
[Since 1.9.9] - [ -P Functions/WrongTypeWithCall ] - [ Online docs ]
This analysis checks that a call to a method uses the right literal values' types.
Currently, this analysis doesn't take into account strict_types = 1 .
<?php
function foo(string $a) {
}
// wrong type used
foo(1);
// wrong type used
foo("1");
?>
Shell commands
[Since 1.9.9] - [ -P Type/Shellcommands ] - [ Online docs ]
Shell commands, called from PHP.
Shell commands are detected with the italic quotes, and using shell_exec(), system(), exec() and proc_open().
<?php
// Shell command in a `shell_exec() <https://www.php.net/shell_exec>`_ call
shell_exec('ls -1');
// Shell command with backtick operator
`ls -1 $path`;
?>
Insufficient Property Typehint
[Since 2.0.2] - [ -P Classes/InsufficientPropertyTypehint ] - [ Online docs ]
The typehint used for a class property doesn't cover all it usage.
The typehint is insufficient when a undefined method is called, or if members are access while the typehint is an interface.
<?php
class A {
function a1() {}
}
// PHP 7.4 and more recent
class B {
private A $a = null;
function b2() {
// this method is available in A
$this->a->a1();
// this method is NOT available in A
$this->a->a2();
}
}
// Supported by all PHP versions
class C {
private $a = null;
function __construct(A $a) {
$this->a = $a;
}
function b2() {
// this method is available in A
$this->a->a1();
// this method is NOT available in A
$this->a->a2();
}
}
?>
This analysis relies on typehinted properties, as introduced in PHP 7.4. It also relies on typehinted assignations at construct time : the typehint of the assigned argument will be used as the property typehint. Getters and setters are not considered here.
Dump/Inclusions
[Since 2.0.2] - [ -P Dump/Inclusions ] - [ Online docs ]
Typehint Order
[Since 2.0.2] - [ -P Dump/Typehintorder ] - [ Online docs ]
Topological order, based on typehints.
Each function, method that use typehint is a link between a type of data and another one. The argument typehint acts as a filter, and the returned type hint is the next step.
<?php
// This library imposes the following order : A -> B -> C
function foo(A $a) : B { }
function bar(B $b) : C { }
?>
Dump/NewOrder
[Since 2.0.2] - [ -P Dump/NewOrder ] - [ Online docs ]
Links Between Parameter And Argument
[Since 2.0.6] - [ -P Dump/ParameterArgumentsLinks ] - [ Online docs ]
Collect various stats about arguments and parameter usage.
A parameter is one slot in the method definition. An argument is a slot in the method call. Both are linked by the method and their respective position in the argument list.
+ Total number of argument usage, linked to a parameter : this excludes arguments from external libraries and native PHP functions. For reference.
+ Number of identical parameter : cases where argument and parameter have the same name.
+ Number of different parameter : cases where argument and parameter have the different name.
+ Number of expression argument : cases where argument is an expression
+ Number of constant argument : cases where the argument is a constant
<?php
function foo($a, $b) {
// some code
}
// $a is the same as the parameter
// $c is different from the paramter $b
foo($a, $c);
const C = 1;
// Foo is called with a constant (1rst argument)
// Foo is called with a expression (2nd argument)
foo(C, 1+3);
?>
Exceeding Typehint
[Since 2.0.3] - [ -P Functions/ExceedingTypehint ] - [ Online docs ]
The typehint is not fully used in the method. Some of the defined methods in the typehint are unused. A tighter typehint could be used, to avoid method pollution.
<?php
interface i {
function i1();
function i2();
}
interface j {
function j1();
function j2();
}
function foo(i $a, j $b) {
// the i typehint is totally used
$a->i1();
$a->i2();
// the i typehint is not totally used : j2() is not used.
$b->j1();
}
?>
Tight typehint prevents the argument from doing too much. They also require more maintenance : creation of dedicated interfaces, method management to keep all typehint tight.
See also Functions/InsufficientTypehint.
Nullable Without Check
[Since 2.0.2] - [ -P Functions/NullableWithoutCheck ] - [ Online docs ]
Nullable typehinted argument should be checked before usage.
<?php
// This will emit a fatal error when $a = null
function foo(?A $a) {
return $a->m();
}
// This is stable
function foo(?A $a) {
if ($a === null) {
return 42;
} else {
return $a->m();
}
}
?>
Collect Class Interface Counts
[Since 2.0.3] - [ -P Dump/CollectClassInterfaceCounts ] - [ Online docs ]
Collect the number of interfaces implemented per class.
<?php
// This class implements 3 interfaces
class x implements i, j, k {
// Some code
}
?>
Collect Class Depth
[Since 2.0.3] - [ -P Dump/CollectClassDepth ] - [ Online docs ]
Count the number of level of extends for classes.
<?php
class a {}
class b extends a {}
class c extends b {}
class d extends a {}
?>
Collect Class Children Count
[Since 2.0.3] - [ -P Dump/CollectClassChildren ] - [ Online docs ]
Count the number of class children for each class.
<?php
// 2 children
class a {}
// 1 children
class b extends a {}
// no children
class c extends b {}
// no children
class d extends a {}
?>
Fossilized Method
[Since 2.0.6] - [ -P Classes/FossilizedMethod ] - [ Online docs ]
A method is fossilized when it is overwritten so often that changing a default value, a return type or an argument type is getting difficult.
This happens when a class is extended. When a method is overwritten once, it may be easy to update the signature in two places. The more methods are overwriting a parent method, the more difficult it is to update it.
This analysis counts the number of times a method is overwriten, and report any method that is ovrewriten more than 6 times. This threshold may be configured.
<?php
class x1 {
// foo1() is never overwritten. It is easy to update.
function foo1() {}
// foo7() is overwritten seven times. It is hard to update.
function foo7() {}
}
// classes x2 to x7, all overwrite foo7();
// Only x2 is presente here.
class x2 extends x1 {
function foo7() {}
}
?>
Not Equal Is Not !==
[Since 2.0.6] - [ -P Structures/NotEqual ] - [ Online docs ]
Not and Equal operators, used separately, don't amount to the different operator !== .
!$a == $b first turns $a into the opposite boolean, then compares this boolean value to $b . On the other hand, $a !== $b compares the two variables for type and value, and returns a boolean.
<?php
if ($string != 'abc') {
// doSomething()
}
// Here, string will be an boolean, leading
if (!$string == 'abc') {
// doSomething()
}
// operator priority may be confusing
if (!$object instanceof OneClass) {
// doSomething()
}
?>
Note that the instanceof operator may be use with this syntax, due to operator precedence.
See also Operator Precedence.
Coalesce Equal
[Since 2.0.4] - [ -P Php/CoalesceEqual ] - [ Online docs ] - [ PHP 7.4 and more recent ]
Usage of coalesce assignement operator. The operator is available in PHP since PHP 7.4.
<?php
// Coalesce operator, since PHP 5.3
$a ??= 'default value';
// Equivalent to $a = $a ?? 'default value';
?>
See also Ternary Operator.
Constant Order
[Since 2.0.7] - [ -P Dump/ConstantOrder ] - [ Online docs ]
Order of dependency of constants.
Constants, either global or class, may be built using static expression. In turn, this means that constants have now a build order. For example :
<?php
// A is an independant global constant
const A = 1;
// B is an dependant global constant : it is built with A
const B = A + 1;
class x {
// x::C is an dependant class constant : it is built with A
const C = A + 3;
}
?>
The code above leads to the following order : A - B , C . A can be built without constraints, while B and C must be build when A is available. Note that B and C are both dependant on A , but are not dependant on each other.
The resulting tree displays the different relationship between the constants.
Note : define constants are not considered here. Only const constants, global or class.
Php 8.0 Variable Syntax Tweaks
[Since 2.0.8] - [ -P Php/Php80VariableSyntax ] - [ Online docs ]
Several variable syntaxes are added in version 8.0. They extends the PHP 7.0 syntax updates, and fix a number of edges cases.
In particular, new and instanceof now support a way to inline the expression, rather than use a temporary variable.
Magic constants are now accessible with array notation, just like another constant. It is also possible to use method calls : although this is Syntacticly correct for PHP, this won't be executed, as the left operand is a string, and not an object.
<?php
// array name is dynamically build
echo foo$bar[0];
// static method
foo$bar::baz();
// static property
foo$bar::$baz;
// Syntactly correct, but not executable
foo$bar->baz();
// expressions with instanceof and new
$object = new (class_.$name);
$x instanceof (class_$name);
// PHP 7.0 style
$className = class_.$name;
$object = new $className;
?>
See also PHP RFC: Variable Syntax Tweaks and
scalar_objects in PHP.
New Functions In PHP 8.0
[Since 2.0.8] - [ -P Php/Php80NewFunctions ] - [ Online docs ] - [ PHP older than 8.0]
New functions are added to new PHP version.
The following functions are now native functions in PHP 7.3. It is compulsory to rename any custom function that was created in older versions. One alternative is to move the function to a custom namespace, and update the use list at the beginning of the script.
Note : At the moment of writing, all links to the manual are not working.
Dont Collect Void
[Since 2.0.9] - [ -P Functions/DontUseVoid ] - [ Online docs ]
When a method returns void, there is no need to collect the result. The collected value will actually be null .
<?php
function foo() : void {
// doSomething()
}
// This is useless
$result = foo();
// This is useless. It looks like this is a left over from code refactoring
echo foo();
?>
Php 8.0 Only TypeHints
[Since 2.0.9] - [ -P Php/Php80OnlyTypeHints ] - [ Online docs ]
Two scalar typehints are introduced in version 8. They are false and null . In PHP 7.0, both those values could not be used as a class or interface name, to avoid confusion with the actual booleans, nor null value.
false represents a false boolean, and nothing else. It is more restrictive than a boolean, which accepts true too.
null is an alternative syntax to ? : it allows the type to be null .
Both the above typehints are to be used in cunjunction with other types : they can't be used alone.
<?php
// function accepts an A object, or null.
function foo(A|null $x) {}
// same as above
function foo2(A|null $x) {}
// returns an object of class B, or false
function bar($x) : false|B {}
?>
See also PHP RFC: Union Types 2.0.
Union Typehint
[Since 2.0.9] - [ -P Php/Php80UnionTypehint ] - [ Online docs ]
Union typehints allows the specification of several typehint for the same argument or return value. This is a PHP 8.0 new feature.
Several typehints are specified at the same place as a single one. The different values are separated by a pipe character | , like for exceptions
<?php
// Example from the RFC https://wiki.php.net/rfc/union_types_v2
class Number {
private int|float $number;
public function setNumber(int|float $number): void {
$this->number = $number;
}
public function getNumber(): int|float {
return $this->number;
}
}
?>
Union types are not compatible with PHP 7 and older.
See also PHP RFC: Union Types 2.0.
Uninited Property
[Since 2.0.9] - [ -P Classes/UninitedProperty ] - [ Online docs ]
Uninited properties are not fully bootstrapped at the end of the constructor.
Properties may be inited at definition time, along with their visibility and type. Some types are not inited at definition time, as any object, so they should be inited during constructor. At the end of the former, all properties shall have a legit value, and be ready for usage.
<?php
class x {
private $foo = null;
private $uninited;
function __construct($arg) {
$this->foo = $args;
// $this->uninited is not inited, nor at definition, nor in constructor
// it will hold null at the beginning of the next method call
}
}
?>
Wrong Typed Property Init
[Since 2.0.9] - [ -P Classes/WrongTypedPropertyInit ] - [ Online docs ]
Property is typed with an incompatible init type.
Init type might be a new instance, the return of a method call or an interface compatible object.
<?php
class x {
private A $property;
private B $incompatible;
function __construct() {
// This is compatible
$this->property = new A();
// This is incompatible : new B() expected
$this->incompatible = new C();
}
}
?>
PHP compiles such code, but won't execute it, as it detects the incompatibility.
Signature Trailing Comma
[Since 2.1.0] - [ -P Php/SignatureTrailingComma ] - [ Online docs ]
Trailing comma in method signature. This feature was added in PHP 8.0.
Allowing the trailing comma makes it possible to reduce the size of VCS's diff, when adding , removing a parameter.
<?php
// Example from the RFC
class Uri {
private function __construct(
?string $scheme,
?string $user,
?string $pass,
?string $host,
?int $port,
string $path,
?string $query,
?string $fragment // <-- ARGH!
) {
...
}
}
?>
See also PHP RFC: Allow trailing comma in parameter list.
[Since 2.1.0] - [ -P Classes/HiddenNullable ] - [ Online docs ]
Argument with default value of null are nullable. Even when the null typehint (PHP 8.0), or the ? operator are not used, setting the default value to null is allowed, and makes the argument nullable.
This doesn't happen with properties : they must be defined with the nullable type to accept a null value as default value.
This doesn't happen with constant, which can't be typehinted.
<?php
// explicit nullable parameter $s
function bar(?string $s = null) {
// implicit nullable parameter $s
function foo(string $s = null) {
echo $s ?? 'NULL-value';
}
// both display NULL-value
foo();
foo(null);
?>
See also Nullable types and
Type declaration.
Fn Argument Variable Confusion
[Since 2.1.0] - [ -P Functions/FnArgumentVariableConfusion ] - [ Online docs ]
Avoid using local variables as arrow function arguments.
When a local variable name is used as an argument's name in an arrow function, the local variable from the original scope is not imported. They are now two distinct variables.
When the local variable is not listed as argument, it is then imported in the arrow function.
<?php
function foo() {
$locale = 1;
// Actually ignores the argument, and returns the local variable $locale .
$fn2 = fn ($argument) => $locale;
// Seems similar to above, but returns the incoming argument
$fn2 = fn ($locale) => $locale;
}
?>
See also Arrow functions.
Missing Abstract Method
[Since 2.1.0] - [ -P Classes/MissingAbstractMethod ] - [ Online docs ]
Abstract methods must have a non-abstract version for the class to be complete. A class that is missing one abstract definition cannot be instantiated.
<?php
// This is a valid definition
class b extends a {
function foo() {}
function bar() {}
}
// This compiles, but will emit a fatal error if instantiated
class c extends a {
function bar() {}
}
// This illustration lint but doesn't run.
// moving this class at the beginning of the code will make lint fail
abstract class a {
abstract function foo() ;
}
?>
See also Classes Abstraction.
Throw Was An Expression
[Since 2.1.1] - [ -P Php/ThrowWasAnExpression ] - [ Online docs ]
Throw used to be an expression. In PHP 7.0, there were some location where one couldn't use a throw : this was the case for arrow functions, which expect one expression as function's body.
Using throw as an instruction makes the code incompatible with PHP 7 version and older.
<?php
// Valid in PHP 8.0 and more recent
$fn = fn($a) => throw new Exception($a);
?>
See also Throw Expression and
Exceptions.
OpenSSL Ciphers Used
[Since 2.1.1] - [ -P Type/OpensslCipher ] - [ Online docs ]
List of all the OpenSSL ciphers used in the code.
It is important to always use valid cipher modes for SSL. In case of non-existent cipher, the crypting or decrypting will not happen. Ciphers are marked as weak after their security is breached, and shall be removed from OpenSSL, and later, from PHP.
By reviewing this inventory, it is possible to detect forgotten ciphers, and fix them.
The full list of available ciphers for the PHP installation is available with the function openssl_get_cipher_methods().
<?php
// PHP documentation example, for PHP 7.1 and more recent
//$key should have been previously generated in a cryptographically safe way, like openssl_random_pseudo_bytes
$plaintext = message to be encrypted;
$cipher = aes-128-gcm;
if (in_array($cipher, openssl_get_cipher_methods()))
{
$ivlen = openssl_cipher_iv_length($cipher);
$iv = openssl_random_pseudo_bytes($ivlen);
$ciphertext = openssl_encrypt($plaintext, $cipher, $key, $options=0, $iv, $tag);
//store $cipher, $iv, and $tag for decryption later
$original_plaintext = openssl_decrypt($ciphertext, $cipher, $key, $options=0, $iv, $tag);
echo $original_plaintext.\n;
}
?>
See also openssl_encrypt() and
OpennSSL [PHP manual].
Unused Trait In Class
[Since 2.1.1] - [ -P Traits/UnusedClassTrait ] - [ Online docs ]
A trait has been summoned in a class, but is not used. Traits may be used as a copy/paste of code, bringing a batch of methods and properties to a class. In the current case, the imported trait is never called. As such, it may be removed.
Currently, the analysis covers only traits that are used in the class where they are imported. Also, the properties are not covered yet.
<?php
trait t {
function foo() { return 1;}
}
// this class imports and uses the trait
class UsingTrait {
use t;
function bar() {
return $this->foo() + 1;
}
}
// this class imports but doesn't uses the trait
class UsingTrait {
use t;
function bar() {
return 1;
}
}
?>
There are some sneaky situations, where a trait falls into decay : for example, creating a method in the importing class, with the name of a trait class, will exclude the trait method, as the class method has priority. Other precedence rules may lead to the same effect.
See also Traits.
Keep Files Access Restricted
[Since 2.1.1] - [ -P Security/KeepFilesRestricted ] - [ Online docs ]
Avoid using 0777 as file or directory mode. In particular, setting a file or a directory to 0777 (or universal read-write-execute) may lead to security vulnerabilities, as anything on the server may read, write and even execute
File mode may be changed using the chmod() function, or at directory creation, with mkdir().
<?php
file_put_contents($file, $content);
// this file is accessible to the current user, and to his group, for reading and writing.
chmod($file, 0550);
// this file is accessible to everyone
chmod($file, 0777);
?>
By default, this analysis report universal access (0777). It is possible to make this analysis more restrictive, by providing more forbidden modes in the filePrivileges parameter. For example : 511,510,489 . Only use a decimal representation.
See also Security/MkdirDefault and
Least Privilege Violation.
Check Crypto Key Length
[Since 2.1.1] - [ -P Security/CryptoKeyLength ] - [ Online docs ]
Each cryptographic algorithm requires a reasonable length. Make sure an up-to-date length is used.
This rule use the following recommendations :
+ \OPENSSL_KEYTYPE_RSA' => 3072
+ \OPENSSL_KEYTYPE_DSA' => 2048
+ \OPENSSL_KEYTYPE_DH' => 2048
+ \OPENSSL_KEYTYPE_EC' => 512
The values above are used with the openssl PHP extension.
<?php
// Extracted from the documentation
// Generates a new and strong key
$private_key = openssl_pkey_new(array(
private_key_type => OPENSSL_KEYTYPE_EC,
private_key_bits => 1024,
));
// Generates a new and weak key
$private_key = openssl_pkey_new(array(
private_key_type => OPENSSL_KEYTYPE_EC,
private_key_bits => 256,
));
?>
See also The Definitive 2019 Guide to Cryptographic Key Sizes and Algorithm Recommendations and
Cryptographic Key Length Recommendation.
Undefined Constant Name
[Since 2.1.1] - [ -P Variables/UndefinedConstantName ] - [ Online docs ]
When using the syntax for variable, the name used must be a defined constant. It is not a simple string, like 'x', it is an actual constant name.
Interestingly, it is possible to use a qualified name within , full or partial. PHP will lint such code, and will collect the value of the constant immediately. Since there is no fallback mechanism for fully qualified names, this ends with a Fatal error.
<?php
const x = a;
$a = Hello;
// Display 'Hello' -> $a -> Hello
echo ;
// Yield a PHP Warning
// Use of undefined constant y - assumed 'y' (this will throw an Error in a future version of PHP)
echo ;
// Yield a PHP Fatal error as PHP first checks that the constant exists
//Undefined constant 'y'
echo ;
?>
Using Deprecated Method
[Since 2.1.2] - [ -P Functions/UsingDeprecated ] - [ Online docs ]
A call to a deprecated method has been spotted. A method is deprecated when it bears a @deprecated parameter in its typehint definition.
Deprecated methods which are not called are not reported.
<?php
// not deprecated method
not_deprecated();
// deprecated method
deprecated();
/**
* @deprecated since version 2.0.0
*/
function deprecated() {}
function not_deprecated() {}
?>
See also @deprecated.
Too Long A Block
[Since 2.1.2] - [ -P Structures/LongBlock ] - [ Online docs ]
The loop is operating on a block that is too long.
This analysis is applied to loops (for, foreach, while, do..while) and if/then/else/elseif structures.
Then length of a block is managed with the longBlock parameter. By default, it is 200 lines, from beginning to the end. Comments are taken into account.
<?php
$i = 0;
do {
// 200 lines of PHP code
++$i;
} while($i < 100);
?>
Static Global Variables Confusion
[Since 2.1.2] - [ -P Structures/SGVariablesConfusion ] - [ Online docs ]
PHP can't have variable that are both static and variable. While the syntax is legit, the variables will be alternatively global or static.
It is recommended to avoid using the same name for a global variable and a static variable.
<?php
function foo() {
$a = 1; // $a is a local variable
global $a; // $a is now a global variable
static $a; // $a is not w static variable
}
?>
Possible Alias Confusion
[Since 2.1.2] - [ -P Namespaces/AliasConfusion ] - [ Online docs ]
An alias is used for a class that doesn't belong to the current namespace, while there is such a class. This also applies to traits and interfaces.
When no alias is used, PHP will search for a class in the local space. Since classes, traits and interfaces are usually stored one per file, it is a valid syntax to create an alias, even if this alias name is the name of a class in the same namespace.
Yet, with an alias refering to a remote class, while a local one is available, it is possible to generate confusion.
<?php
// This should be in a separate file, but has been merged here, for display purposes.
namespace A {
//an alias from a namespace called C
use C\A as C_A;
//an alias from a namespace called C, which will superseed the local A\B class (see below)
use C\D as B;
}
namespace A {
// There is a class B in the A namespace
class B {}
}
?>
Collect Property Counts
[Since 2.1.2] - [ -P Dump/CollectPropertyCounts ] - [ Online docs ]
This analysis collects the number of properties per class or trait.
The count applies to classes, anonymous classes and traits. They are considered distinct one from another.
Properties may be static or not. Visibility, default values and typehints are omitted.
<?php
class foo {
// 3 properties
private $p1, $p2, $p3;
}
trait foo {
// 3 properties
protected $p1;
public $p2 = 1, $p3;
}
?>
Collect Method Counts
[Since 2.1.2] - [ -P Dump/CollectMethodCounts ] - [ Online docs ]
This analysis collects the number of methods per class, trait or interface.
The count applies to classes, anonymous classes, traits and interfaces. They are considered distinct one from another.
<?php
class foo {
// 2 methods
function __construct() {}
function foo() {}
}
interface bar {
// 1 method
function a() ;
}
class barbar {
// 3 methods
function __construct() {}
function foo() {}
function a() {}
}
?>
Collect Class Constant Counts
[Since 2.1.2] - [ -P Dump/CollectClassConstantCounts ] - [ Online docs ]
This analysis collects the number of class constants per class or interface.
The count applies to classes, anonymous classes and interfaces. They are considered distinct one from another.
<?php
class foo {
// 3 constant
const A =1, B =2;
}
interface bar {
// 3 properties
const A=1, B=2, C=3;
}
?>
Too Much Indented
[Since 2.1.2] - [ -P Functions/TooMuchIndented ] - [ Online docs ]
Reports methods that are using more than one level of indentation on average.
Indentations levels are counted for each for, foreach, if...then, while, do..while, try..catch..finally structure met. Compulsory expressions, such as conditions, are not counted in the total. Levels of indentation start at 0 (no indentation needed)
This analysis targets methods which are build around large conditions : the actual useful code is nested inside the branches of the if/then/else (for example).
The default threshold indentationAverage of 1 is a good start for spotting large methods with big conditional code, and will leave smaller methods, even when they only contain one if/then. Larger methods shall be refactored in smaller size.
The parameter minimumSize set aside methods which are too small for refactoring.
<?php
// average 0
function foo0() {
$a = rand(1,2);
$a *= 3;
return $a;
}
// average 0.66 = (0 + 1 + 1) / 3
function foo0_66() {
// if () is at level 0
if ($a == 2) { // condition is not counted
$a = 1; // level 1
} else {
$a = 2; // level 1
}
}
// average 1 = (0 + 2 + 1 + 1) / 4
function foo1() {
// if () is at level 0
if ($a == 2) {
// if () is at level 1
if ($a == 2) {
$a = 1; // level 2
}
$a = 1; // level 1
} else {
$a = 2; // level 1
}
}
?>
This analysis is distinct from Structures/MaxLevelOfIdentation, which only reports the highest level of indentation. This one reports how one method is build around one big
See also Structures/MaxLevelOfIdentation.
Could Be String
[Since 2.1.2] - [ -P Typehints/CouldBeString ] - [ Online docs ]
Mark arguemnts and return types that can be set to string.
<?php
// Accept a string as input
function foo($a) {
// Returns a string
return $a . 'string';
}
?>
Could Be Boolean
[Since 2.1.2] - [ -P Typehints/CouldBeBoolean ] - [ Online docs ]
Mark arguments and return types that can be set to boolean.
<?php
// Accept a boolean as input
function foo($b) {
// Returns a boolean
return $b === true;
}
?>
Could Be Void
[Since 2.1.2] - [ -P Typehints/CouldBeVoid ] - [ Online docs ]
Mark return types that can be set to void.
<?php
// No return, this should be void.
function foo() {
++$a; // Not useful
}
?>
All abstract methods (in classes or in interfaces) are omitted here.
Could Be Array Typehint
[Since 2.1.2] - [ -P Typehints/CouldBeArray ] - [ Online docs ]
This rule spots arguments, properties or return values that may be labeled with the array scalar typehint.
<?php
// $arg is used as an array in this function, so it may be typed : array
functions foo($arg) {
// the returned value is always an array, so this function might be typed as : array
return array($arg[3]);
}
?>
See also Type declarations .
Could Be CIT
[Since 2.1.2] - [ -P Typehints/CouldBeCIT ] - [ Online docs ]
Mark arguments and return types that can be set to a class, interface definition.
<?php
// Accept an object as input
function foo($b) {
// Returns new object
return new ($b->classname);
}
?>
Protocol lists
[Since 2.1.3] - [ -P Type/Protocols ] - [ Online docs ]
List of all protocols that were found in the code.
From the manual : PHP comes with many built-in wrappers for various URL-style protocols for use with the filesystem functions such as fopen(), copy(), file_exists() and filesize().
<?php
// Example from the PHP manual, with the glob:// wrapper
// Loop over all *.php files in ext/spl/examples/ directory
// and print the filename and its size
$it = new DirectoryIterator(glob://ext/spl/examples/*.php);
foreach($it as $f) {
printf(%s: %.1FK\n, $f->getFilename(), $f->getSize()/1024);
}
?>
See also Supported Protocols and Wrappers.
Cyclic References
[Since 2.1.3] - [ -P Classes/CyclicReferences ] - [ Online docs ]
Avoid cyclic references.
Cyclic references happen when an object points to another object, which reciprocate. This is particularly possible with classes, when the child class has to keep a reference to the parent class.
<?php
class a {
private $p = null;
function foo() {
$this->p = new b();
// the current class is stored in the child class
$this->p->m($this);
}
}
class b {
private $pb = null;
function n($a) {
// the current class keeps a link to its parent
$this->pb = $a;
}
}
?>
Cyclic references, or circular references, are memory intensive : only the garbage collector can understand when they may be flushed from memory, which is a costly operation. On the other hand, in an acyclic reference code, the reference counter will know immediately know that an object is free or not.
See also About circular references in PHP and
A Journey to find a memory leak.
Double Object Assignation
[Since 2.1.2] - [ -P Structures/DoubleObjectAssignation ] - [ Online docs ]
Make sure that assigning the same object to two variables is the intended purpose.
<?php
// $x and $y are the same object, as they both hold a reference to the same object.
// This means that changing $x, will also change $y.
$x = $y = new Z();
// $a and $b are distinct values, by default
$a = $b = 1;
?>
Could Not Type
[Since 2.1.2] - [ -P Typehints/CouldNotType ] - [ Online docs ]
Mark arguments, return types and properties that could not be typed.
Arguments, return types and properties that have no explicit typehint, and that could yield no guess from the following analysis, are deemed untypable.
+ `Typehints/CouldBeCIT`_
+ `Typehints/CouldBeString`_
+ `Typehints/CouldBeArray`_
+ `Typehints/CouldBeBoolean`_
+ `Typehints/CouldBeVoid`_
+ `Typehints/CouldBeCallable`_
mixed typehint, which acts as the universal typehint, is not processed here : it would yield little information.
There are situation which are not typeable, and legit : the example below is an illustration. array_fill is a native PHP example, where the second argument may be of any type. __get and __set are also notoriously difficult to type, given the broad usage of arguments.
<?php
// Accepts any input, and returns any input
// This may be used, but not typed.
function foo($b) {
return $b;
}
?>
Could Be Callable
[Since 2.1.2] - [ -P Typehints/CouldBeCallable ] - [ Online docs ]
Mark arguments and return types that can be set to callable .
<?php
// Accept a callable as input
function foo($b) {
// Returns value as return
return $b();
}
?>
Wrong Argument Type
[Since 2.1.3] - [ -P Functions/WrongArgumentType ] - [ Online docs ]
Checks that the type of the argument is consistent with the type of the called method.
<?php
function foo(int $a) { }
//valid call, with an integer
foo(1);
//invalid call, with a string
foo('asd');
?>
This analysis is valid with PHP 8.0.
Could Be Integer
[Since 2.1.4] - [ -P Typehints/CouldBeInt ] - [ Online docs ]
Mark arguments, properties and return types that can be set to int .
<?php
// Accept an int as input
function foo($b) {
// Returns an int
return $b + 8;
}
?>
Call Order
[Since 2.1.4] - [ -P Dump/CallOrder ] - [ Online docs ]
This is a representation of the code. Each node is a function or method, and each link a is call from a method to another.
The only link is the possible call from a method to the other. All control flow is omitted, including conditional calls and loops.
<?php
function foo() {
bar();
foobar();
}
function bar() {
foobar();
}
function foobar() {
}
?>
From the above script, the resulting network will display 'foo() -> bar(), foo() -> foobar(), bar() -> foobar()' calls.
Could Be Null
[Since 2.1.2] - [ -P Typehints/CouldBeNull ] - [ Online docs ]
Mark arguments and return types that can be null.
<?php
// Accept null as input, when used as third argument of file_get_contents
function foo($b) {
$s = file_get_contents(URL, false, $b);
// Returns a string
return shell_exec($s);
}
?>
Could Be Iterable
[Since 2.1.4] - [ -P Typehints/CouldBeIterable ] - [ Online docs ]
Mark arguments, properties and return types that can be set to iterable .
<?php
// Accept an array or a traversable Object as input
function foo($b) {
foreach($b as $c) {
}
// Returns an array
return [$b];
}
?>
Php/UseMatch
[Since 2.1.4] - [ -P Php/UseMatch ] - [ Online docs ]
Could Be Integer
[Since 2.1.4] - [ -P Typehints/CouldBeFloat ] - [ Online docs ]
Mark arguments, properties and return types that can be set to float .
<?php
// Accept an int as input
function foo($b) {
// Returns a float (cubic root of $b);
return pow($b, 1 / 3);
}
?>
Mismatch Properties Typehints
[Since 2.1.4] - [ -P Classes/MismatchProperties ] - [ Online docs ]
Properties must match within the same family.
When a property is declared both in a parent class, and a child class, they must have the same type. The same type includes a possible null value.
This doesn't apply to private properties, which are only visible locally.
// property $p is declared as an object of type a
class x {
protected A $p;
}
// property $p is declared again, this time without a type
class a extends x {
protected $p;
}
This code will lint, but not execute.
Could Be Self
[Since 2.1.2] - [ -P Typehints/CouldBeSelf ] - [ Online docs ]
Mark arguments, return types and properties that can be set to self .
This analysis works when typehints have already been configured.
<?php
class x {
// Accept a x object as input
function foo(x $b) : x {
// Returns a x object
return $b;
}
}
?>
Could Be Parent
[Since 2.1.2] - [ -P Typehints/CouldBeParent ] - [ Online docs ]
Mark arguments, return types and properties that can be set to parent .
This analysis works when typehints have already been configured.
<?php
class x extends w {
// Accept a w object as input
function foo(w $b) : w {
// Returns a w object
return $b;
}
}
?>
Collect Parameter Names
[Since 2.1.5] - [ -P Dump/CollectParameterNames ] - [ Online docs ]
This analysis collects the names of all parameters. It also counts the number of occurrences of each name.
The names are collected from functions, methods, closures and arrow functions. Compulsory and optional parameters are all processed.
<?php
// parameter $a
function foo($a) { }
// parameter $b, $c
function ($b, $c = 2) {}
// parameters in interfaces are counted too.
// Here, $a will be counted with the one above.
interfaces x {
function moo($a);
}
?>
No Need For Triple Equal
[Since 2.1.4] - [ -P Structures/NoNeedForTriple ] - [ Online docs ]
There is no need for the identity comparison when the methods returns the proper type.
<?php
// foo() returns a string.
if ('a' === foo()) {
// doSomething()
}
function foo() : string {
return 'a';
}
?>
Array_merge Needs Array Of Arrays
[Since 2.1.4] - [ -P Structures/ArrayMergeArrayArray ] - [ Online docs ]
When collecting data to feed array_merge(), use an array of array as default value. array(array()) is the neutral value for array_merge();
This analysis also reports when the used types are not an array : array_merge() does not accept scalar values, but only arrays.
<?php
// safe default value
$a = array(array());
// when $list is empty, it is
foreach($list as $l) {
$a[] = $l;
}
$b = array_merge($a);
?>
Since PHP 7.4, it is possible to call array_merge() without an argument : this means the default value may an empty array. This array shall not contain scalar values.
See also array_merge.
Dont Compare Typed Boolean
[Since 2.1.5] - [ -P Structures/DontCompareTypedBoolean ] - [ Online docs ]
There is no need to compare explicitly a functioncal call to a boolean, when the definition has a boolean returntypehint.
The analysis checks for equality and identity comparisons. It doesn't check for the not operator usage.
<?php
// Sufficient check
if (foo()) {
doSomething();
}
// Superfluous check
if (foo() === true) {
doSomething();
}
function foo() : bool {}
?>
Abstract Away
[Since 2.1.5] - [ -P Patterns/AbstractAway ] - [ Online docs ]
Avoid using PHP native functions that produce data direcly in the code. For example, date() or random_int(). They should be abstracted away in a method, that will be replaced later for testing purposes, or even debugging.
To abstract such calls, place them in a method, and add an interface to this method. Then, create and use those objects.
<?php
// abstracted away date
$today = new MyDate();
echo 'Date : '.$today->date('r');
// hard coded date of today : it changes all the time.
echo 'Date : '.date('r');
interface MyCalendar{
function date($format) : string ;
}
class MyDate implements MyCalendar {
function date($format) : string { return date('r'); }
}
// Valid implementation, reserved for testing purpose
// This prevents from waiting 4 years for a test.
class MyDateForTest implements MyCalendar {
function date($format) : string { return date('r', strtotime('2016-02-29 12:00:00')); }
}
?>
See also Being in control of time in PHP and
How to test non-deterministic code.
Wrong Type For Native PHP Function
[Since 2.1.5] - [ -P Php/WrongTypeForNativeFunction ] - [ Online docs ]
This analysis reports calls to a PHP native function with a wrongly typed value.
<?php
// valid calls
echo exp(1);
echo exp(2.5);
// invalid calls
echo exp(1);
echo exp(array(2.5));
// valid call, but invalid math
// -1 is not a valid value for `log() <https://www.php.net/log>`_, but -1 is a valid type (int) : it is not reported by this analysis.
echo log(-1);
?>
Large Try Block
[Since 2.1.5] - [ -P Exceptions/LargeTryBlock ] - [ Online docs ]
Try block should enclosing only the expression that may emit an exception.
When writing large blocks of code in a try, it becomes difficult to understand wherethe expression is coming from. Large blocks may also lead to catch multiples exceptions, with a long list of catch clause.
In particular, the catch clause will resume the execution without knowing where the try was interrupted : there are no indication of achievement, even partial. In fact, catching an exception signals a very dirty situation.
<?php
// try is one expression only
try {
$database->query($query);
} catch (DatabaseException $e) {
// process exception
}
// Too many expressions around the one that may actually emit the exception
try {
$SQL = build_query($arguments);
$database = new Database($dsn);
$database->setOption($options);
$statement = $database->prepareQuery($SQL);
$result = $statement->query($query);
} catch (DatabaseException $e) {
// process exception
}
?>
This analysis reports try-blocks that are 5 lines or more. This threshold may be configured with the directive tryBlockMaxSize. Catch clause, and finally are not considered here.
Catch Undefined Variable
[Since 2.1.5] - [ -P Exceptions/CatchUndefinedVariable ] - [ Online docs ]
Always initialize variable before the try block, when they are used in a catch block. If the exception is raised before the variable is defined, the catch block may have to handle an undefined variable, leading to more chaos.
<?php
$a = 1;
try {
mayThrowAnException();
$b = 2;
} catch (\Exception $e) {
// $a is already defined, as it was done before the try block
// $b may not be defined, as it was initialized after the exception-throwing expression
echo $a + $b;
}
?>
Dump/FossilizedMethods
[Since 2.1.5] - [ -P Dump/FossilizedMethods ] - [ Online docs ]