PHP

References

• Language reference on php.net
• php tutorial on w3schools.com (check the menu on the left)

• string functions

Cheat sheets:

• php DZone cheat sheet
• php Quick Reference

Install

On Windows

Download the zip archive on http://windows.php.net/download/:

• PHP 5.6.30 32-bit - Non Thread Safe (faster).

To install

• Create a directory C:\php and unzip archive inside.
• Add C:\php to system environment path PATH.
• Copy C:\php\php.ini-production to C:\php.ini.

Alternatively use the development version for more debug. But production ini is handy to mute deprecated API warnings

Enable a few extensions

• To use HTTPS or SSL, uncomment the line:

extension=php_openssl.dll

• To use SOAP, uncomment the line:

extension=php_soap.dll

• To use Curl, uncomment the line:

extension=php_curl.dll

• To use XML RPC, uncomment the line:

extension=php_xmlrpc.dll

Add/change certificate CA

• Edit php.ini:

openssl.cafile=C:/path/to/sslCertificates/cacert.pem

Invocation

php -a                  # Start PHP in interactive mode

Syntax

Data types

/* boolean */
$x = true;
$y = false;

/* integers */
$i = 42;

/* arrays */
$attr = array();          // an empty array
$cars = array("Volvo","BMW","Toyota");
$cars[0] = "Volvo";
$attr = array("border"=>"myborder", "mode"=>"mymode");   // associative array
$attr['border'] = "myborder";

/* strings */
'abc' . 'def'                                     // concatenation
"abc $var def"                                    // variable reference in strings
$s=str_replace("\n","",$s);                       // Replace a substring in a string
$s=str_replace(array("\r","\n","\t"," "),"",$s;   // ... idem, with several substrings (also support several "replace" strings)

Operators

/* arithmetic */
$x + $y;
$x - $y;
$x * $y;
$x / $y;
$x % $y;
$x ** $y;    // exponentiation

/* assigment */
$x = $y;
$x += $y;A   // ... and all others: -= *= /= %=

/* comparison */
$x == $y;    // ... and all others: != > < >= <=
$x <> $y;    // same as !=
$x === $y;   // identical operator (are equal and of the same type)
$x !== $y;   // not identical operator (are not equal or are not of the same type)

/* increment / decrement */
$x++;        // and $x--
++$x;        // and --$x

/* logical */
$x and $y;   // or '&&'
$x or $y;    // or '||'
$x xor $y;
!$x;

/* string */
$x . $y;     // concatenation
$x .= $y;    // concatenation assignment

/* array */
$x + $y;     // union
$x == $y;    // equality
$x === $y;   // identity
$x != $y;    // inequality, or '<>'
$x !== $y;   // non-identity

/* ternary */
$x = $y < 2 ? 3 : 5;

Miscellaneous

/* OO */
self::$static_property;
$this->property;
self::CONSTANT;

/* special keywords */
self;              // The current class
$this;             // The current object
NULL;              // The null reference

/* magic constants -- http://php.net/manual/en/language.constants.predefined.php */
__FILE__	   // The full path and filename of the file with symlinks resolved
__DIR__            // Equivalent to dirname(__FILE__). Since PHP 5.3.0

/* Scope */
global $wgScriptPath; // Declare $wgScriptPath as global when in a local scope

Control flow

• http://php.net/manual/en/control-structures.foreach.php

$arr = array(1, 2, 3, 4);
foreach ($arr as $value) { echo "$key => $value"; }               // By value
foreach ($arr as $key => $value) { echo "$value"; }               // By key and value
foreach ($arr as &$value) { $value = $value * 2; }                // By reference
unset($value);                                                    // RECOMMENDED! Break the reference with the last element
foreach (array(1, 2, 3, 4) as &$value) { $value = $value * 2; }   // By reference on an array value - only PHP >5.5.0

Include and Require

include 'mylibrary.php';

How-to

Convert string to Boolean

$test_mode = $string === 'true' ? true : false;

Print human-readable information about a variable

Use print_r:

<?php
$a = array ('a' => 'apple', 'b' => 'banana', 'c' => 'orange');
print_r ($a);
?>

This produces:

Array
(
    [a] => apple
    [b] => banana
    [c] => orange
)

Split a string by string

Use explode:

print_r(explode(' ', 'one two three four'));

This produces

Array
(
    [0] => one
    [1] => two
    [2] => three
    [3] => four
)

Detect if an array key is defined

Use either array_key_exists (slow but works even if value is null</code), or isset (faster, but fails if assigned value is null) [1]:

$foo = array();
$foo['bar'] = NULL;

var_dump(isset($foo['bar']));
var_dump(array_key_exists('bar', $foo));

Unicode support

• First, if PHP file contains special character, make sure the PHP file is encoded in UTF-8:

file -bi FenTT.php           # To get current encoding
iconv -f $encoding -t UTF-8 -o FenTT.out.php FenTT.php        # Specify correct source $encoding as given above (note that converting us-ascii is useless)

• Specify the default multi-byte encoding:

mb_internal_encoding("UTF-8");

• Next store unicode char as follows [2]:

$S = '\u2654\u2655\u2656\u2657';
$S = json_decode('"'.$S.'"');

• Then access the string using the multi-byte API [3], like [4]:

$D = mb_substr($S,2,1);    // instead of $D=$S[2]

See php reference - string details for more information on how strings are handled internally in php.

PHP to Javascript

Encode PHP variable in Javascript

Use the json_encode($myarray):

$my_array = array(person => "personA", id => 12);
return "<script>" . json_encode($my_array) . "</script>";
return

To pretty-print JSON, use JSON_PRETTY_PRINT:

echo json_encode($my_array, JSON_PRETTY_PRINT);