CSS Compressing and Caching with PHP

Web developers always worried about there website's loading time. Because loading time is very important for a website's popularity. CSS compression and cache can speed up your website. I have created a PHP script for making CSS compression easy.
This script will allow you these functionalists:

1. Reduce CSS file size by removing comments and white space characters
2. Keep server side cache for rapid delivery.
3. Enable GZip for compressed encode
4. Enable user side cache smartly.

Download Source

css.php:

include('function.php');

$css = $_GET['css'];
$expires = 60*60*24*14; // Cache lifetime 14 days
$baseName = basename($css); 
$cssCache = 'cache/'.$baseName;
$etag = md5_file($css); // Generate Etag
$fileModified = @filemtime($css);
$cacheModefied = @filemtime($cssCache);

/*
Set 304 Not Modified if old visitor
*/
if( @strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) == $fileModified && @trim($_SERVER['HTTP_IF_NONE_MATCH']) == $etag) {
 header($_SERVER['SERVER_PROTOCOL'].' 304 Not Modified');
 exit;
}
/*
 Read CSS file from server side cache
*/
 else if($cacheModefied > $fileModified){
 set_header($fileModified, $expires, $etag);
 readfile($cssCache);
 exit;
}
/*
 New CSS file new browser set everythis
*/
 else{
 set_header($fileModified, $expires, $etag);
 $cssData = file_get_contents($css);
 $compressed = compress($cssData);
 echo $compressed;
 cache($compressed, $cssCache); // Server side caching
}

Function.php:

function set_header($modefied, $expires, $etag){
 ob_start("ob_gzhandler"); //Gzip compress
 header("Etag: {$etag}");
 header("Content-type: text/css; charset: UTF-8");
 header("Pragma: public; maxage={$expires}");
 header('Expires: ' . gmdate('D, d M Y H:i:s', time()+$expires). ' GMT');
 header("Last-Modified: ".gmdate("D, d M Y H:i:s",$modefied).' GMT');
}


function compress($css){
 // Compress css
 $css = preg_replace('!/\*[^*]*\*+([^/][^*]*\*+)*/!', '', $css);
 $css = preg_replace('/(\s(?=\W))|((?<=\W)\s)/', '', $css);
 $css = str_replace(array("\r\n","\r","\n","\t",'  ','    ','    '), '', $css);
 return $css;
}

function cache($data, $path){
 // Write server side cache
 $handle = fopen( $path ,'w+');  
    fwrite($handle, $data);
    fclose($handle);
}

General Usage:

 Store save this script at the root directory as css.php and create a directory named cache. Now you can use this script like this on your project:

<link rel="stylesheet" type="text/css" href="css.php?css=css/style.css">