Sinfest Feed

<?php$cache = "sinfest_feed.txt";$expires = 30*60;  // in 30 minutesif (!(@filemtime($cache) > time() - $expires)) {  // Cache expired, or does not exist  $feed = file_get_contents("http://www.sinfest.net/rss.php");  $feed = preg_replace('!(\s*)<link>(.+?\.(?:gif|png|jpe?g))</link>!', '$0$1<description>&lt;img src="$2" alt="Comic"&gt;</description>', $feed);  $feed = preg_replace('/^\s*/', '', $feed);  // Source feed has illegal initial whitespace   $c = fopen($cache, "w");  fwrite($c, $feed);  fclose($c);} else {  // Was cached, so retrieve  $feed = file_get_contents($cache);}header('Content-type: application/rss+xml');echo $feed;?>