PHP

Basics

PHP Variables

$DOCUMENT_ROOT
$PHP_SELF
$_GET['url_param']
$_POST['form_param']
$my_param = htmlentities($_POST['form_param']);

Check variables

is_numeric()
is_file()
is_dir()

Strings

Usefull stuff

strtolower
strtoupper
trim  // trims spaces at the ends of string 
nl2br // \n -> 


// Search in string
ereg[i](was,wo);          // i: case insensitive
// Replace chars
ereg[i]_replace (was,womit,wo);  // i: case insensitive
str_replace(was,womit,wo);       // case sensitive, works on arrays as well
// Pos of substring
strpos ($file_name,"."[,startint]); // start from left
strrpos($file_name,"."[,startint]); // start from right

// Part of string
$ext = strrchr($file_name,".");  // start from right and take all up to the end
$filename = str[i]str($file_name,"."); // start from left, i: case insensitive
// Return a substring
substr($string, pos [, number]); // pos can be negative

Work on special chars

stripslashes // removes \
addslashes   // adds \ to " \ NULL
quotemeta    // adds \ to . \\ + * ? [ ] ^ ( ) $ 
htmlentities // converts into HTML chars
// Umlaute: utf8 -> htmlcode
$text = htmlentities(utf8_decode($text));

Arrays

Split string to array

explode(" und ",$str);
split[i](" UnD ",$Str);  // i: case insensitive

Array to string

implode(", ",$moin);

Sort

sort($array);
natsort($array); // 2 before 10

Remove items

unset($array[$x]);
// nicer:
$raus = array();
$raus[] = $array[$x];
$array = array_diff($array,$raus);

while (($id = array_search($what,$where))>-1)
  unset ($files[$id]);

Remove duplicates

$a = array_values(array_unique($a));

Compare arrays

$c = array_diff ($a, $b);
$c = array_intersect ($a, $b);
$c = array_merge ($a, $b);

Print a hash

foreach ($array as $key=>$val)
  echo "key = $key, val = $val";

Regular Expressions

Special chars

.  = 1 char
.? = 0,1 chars
.* = 0-oo chars
.+ = 1-oo chars

\s = whitespace
\S = no whitespace
\w = word char (=a-z,0-9,_)
\W = no word char
\d = decimal number
\D = no decimal number
\b = word boundary
\B = no word boundary
\n = new line (Linux)
\r = CR (Windows: \n\r)

Options

i = case insensitive
e = execute php code inside expression
s = single string, (search passes lineends)
U = ungreegy

Search

eregi('EXPRESSION', $string)
preg_match("'EXPRESSION'is", $where, $results);
preg_match_all("'EXPRESSION'is", $where, $results);
$result1 = $results[1];
//Check eMail-Syntax

Replace

preg_replace($patterns, $replacements, $where);
preg_replace("'<title>[^<]*</title>'is","",$htmlinhalt);

$was = array();
$womit = array();
 ..
$text = preg_replace($was,$womit,$text);

Other Stuff

$date = date("Y-m-d"); // Date to mysql format

Run External Command

exec("command"); //waits until command is finnished
exec("command >/dev/null 2>&1"); // ignores output, so php continues right away

Images

Read Image Size

$array = getimagesize($file);

Char Encoding

[1] The simplest way to handle this problem is to send the encoding yourself, via your programming language. The appropriate code is:

header('Content-Type:text/html; charset=UTF-8');

This code must come before any output, so be careful about stray whitespace in your application (i.e., any whitespace before output excluding whitespace within <?php ?> tags).

Encode spaces etc from a string for usage as url-paramter:

$file = rawurlencode ($file);
$file = rawurldecode ($file);

Functions

function delTree($dir) {
     $files = glob( $dir . '*', GLOB_MARK );
     foreach( $files as $file ){
         if( is_dir( $file ) )
             delTree( $file );
         else
             unlink( $file );
     }
     if (is_dir($dir)) rmdir( $dir );
 }

function recurse_chown_chgrp($mypath, $uid, $gid) {
  $d = opendir ($mypath) ;
  while(($file = readdir($d)) !== false) {
    if ($file != "." && $file != "..") {
      $typepath = $mypath . "/" . $file ;
      if (filetype ($typepath) == 'dir') {
        recurse_chown_chgrp ($typepath, $uid, $gid); }
      chown($typepath, $uid);
      chgrp($typepath, $gid);
} } }

function recurse_chmod($mypath, $mod) {
  $d = opendir ($mypath) ;
  while(($file = readdir($d)) !== false) {
    if ($file != "." && $file != "..") {
      $typepath = $mypath . "/" . $file ;
      if (filetype ($typepath) == 'dir') {
        recurse_chmod ($typepath, $mod); }
      chmod($typepath, $mod);
} } }

Login

function auth()
{
header('WWW-authenticate: basic realm="Name of realm"');
header('HTTP/1.0 401 Unauthorized');
exit("text...");  
}

// username / passwd in $PHP_AUTH_USER / $PHP_AUTH_PW
if(!isset($PHP_AUTH_USER))
  auth();
else {
 // check if $PHP_AUTH_USER / $PHP_AUTH_PW are fine. If not run auth()
}