cache.php

<?php
// Number of seconds a page should remain cached for
$cache_expires = 33600;
// Path to the cache folder
$cache_folder = "cache/";
// Checks whether the page has been cached or not
function is_cached($file) {
 global $cache_folder, $cache_expires;
 $cachefile = $cache_folder . $file;
 $cachefile_created = (file_exists($cachefile)) ? @filemtime($cachefile) : 0;
 return ((time() - $cache_expires) < $cachefile_created);
}
// Reads from a cached file
function read_cache($file) {
 global $cache_folder;
 $cachefile = $cache_folder . $file;
 return file_get_contents($cachefile);
}
// Writes to a cached file
function write_cache($file, $out) {
 global $cache_folder;
 $cachefile = $cache_folder . $file;
 $fp = fopen($cachefile, 'w');
 fwrite($fp, $out);
 fclose($fp);
}
// Let's begin, first work out the cached filename
$cache_file = md5($_SERVER['REQUEST_URI']) . ".html";
// Check if it has already been cached and not expired
// If true then we output the cached file contents and finish
if (is_cached($cache_file)) {
 echo read_cache($cache_file);
 exit();
}
// Ok so the page needs to be cached
// Turn on output buffering
ob_start();