1  $r = date_parse("8:16:12 01.02.2008");
   2  $d = mktime($r['hour'], $r['minute'], $r['second'], $r['month'], $r['day'], $r['year']);
   3  echo date("H:i:s d.m.Y", $d); 

Prints out the following:

   1  8:16:12 01.02.2008

PHP cookie management is a good example of how incredibly badly designed PHP is:

Set a cookie that expires when browser is closed

Note that you most probably want to set the path, which we do here:

   1  $value = 0;
   2  $expires = 0;
   3  setcookie('cookie_name', $value, $expires, '/');

Remove cookie

   1  setcookie ('cookie_name', FALSE, time()-10000);

Get cookie value

   1  $_COOKIE['cookie_name']

Xdebug is a good tool for finding the root cause of memory allocation problems such as the one shown here:

   1  Fatal error: Allowed memory size of X bytes exhausted (tried to allocate X bytes)

First install Xdebug by following the Xdebug installation instructions.

Next surround the code you suspect is causing the problem with the following function calls:

   1  xdebug_start_trace('/tmp/mytrace');
   2  ...
   3  Bad bad PHP code
   4  ...
   5  xdebug_stop_trace();

Read this blog entry by splitbrain.org for more details

   1  function link_back($blacklist = array())
   2  	{
   3  		$parameters = split("&", $_SERVER['QUERY_STRING']);
   4  		
   5  		$uri = array_shift(split("\?", $_SERVER['REQUEST_URI']));
   6  
   7  		$index = 0;
   8  		
   9  		foreach($parameters as $parameter)
  10  		{
  11  			$parameter = split("=", $parameter);
  12  			
  13  			$name = $parameter[0];
  14  			$value = $parameter[1];
  15  			
  16  			if(in_array($name, $blacklist))
  17  			{
  18  				unset($parameters[$index]);
  19  			}
  20  			
  21  			$index++;
  22  		}
  23  		
  24  		if(count($parameters) > 0)
  25  		{
  26  			$parameters = "?".join("&", $parameters);	
  27  		}
  28  		else
  29  		{
  30  			$parameters = '';
  31  		}
  32  		
  33  		return $uri.$parameters;
  34  	}

Usage:

   1  # URI is /wow_amazing_code?not_wanted=23&wanted=1
   2  
   3  echo link_back(array('not_wanted')); # prints out /wow_amazing_code?wanted=1

This is a very simple utility class that I created which combines multiple files into one—in contrast to all other PHP scripts I’ve found elsewhere, which all work badly and are a million lines long, this one is simple to understand and maintain:

   1  <?php
   2  class Files
   3  {
   4  	private static function process($files, $output, $base_dir = '')
   5  	{
   6  		$contents 	= '';
   7  		
   8  		# If this is a string then it's a search pattern
   9  		if(is_string($files))
  10  		{
  11  			$files = glob($files);
  12  		}
  13  		
  14  		foreach ($files as $file) 
  15  		{
  16  			$contents .= file_get_contents($base_dir.$file) . "\n\n";
  17  		}
  18  	
  19  		# TODO locking 
  20  		if ($fp = fopen($output, 'wb')) 
  21  		{
  22  			fwrite($fp, $contents);
  23  			fclose($fp);
  24  		}
  25  	
  26  		return $contents;
  27  	}
  28  	
  29  	#
  30  	# Combine all CSS files in the css directory:
  31  	#
  32  	#	echo Files::combine("css/*.css", "css/all.css");
  33  	#
  34  	# Combine only specified files in the given order:
  35  	#
  36  	#	echo Files::combine(array("css/core.css", "css/default.css"), "css/all.css");
  37  	#
  38  	#
  39  	static function combine($files, $output_filename, $base_dir = '')
  40  	{
  41  		# Combine the files
  42  		if(!file_exists($output_filename))
  43  		{
  44  			self::process($files, $output_filename, $base_dir);
  45  		}
  46  	}
  47  }
  48  ?>

The call to Files::combine should go in a file that is called on each request. On the first request to this file, the files are combined into one, on subsequent requests nothing is done, the only overhead is a call to file_exists.

Ideally the name of the output filename should contain a version number, so that an updated CSS file is not taken from the browser cache. This can easily be supported by reading the build number from somewhere and appending it to the output filename:

   1  Files::combine("css/*.css", "css/all-v$version.css");

Now all you have to do is add this to your HTML :

   1  <link rel="stylesheet" type="text/css" href="/css/all-v<?php echo $version ?>.css" media="screen" />

This also works for JavaScript files. Note that I don’t make an effort to minify anything as GZIP usually does a great job at minimizing bandwidth costs.