php压缩多个CSS为一个css的代码并缓存

<?php 
/* 
Compress multiple CSS files into one and cache for an hour. Use the same code for Javascript, but replace below "text/css" with "text/javascript" and of course make sure you include .js files instead of .css ones. 
*/ 
ob_start("ob_gzhandler"); 
header("Content-type: text/css; charset: UTF-8");     
header("Expires: ".gmdate("D, d M Y H:i:s", time() + 60*60)." GMT"); 
include('somefile.css'); 
echo "\n\n"; 
include('anotherfile.css'); 
echo "\n\n"; 
ob_flush();