Monthly Archives: February 2009

Just a quick snippet to help you tell useragents accessing your site that the content hasn’t changed. ?View Code PHPfunction caching_headers ($file, $timestamp) { $gmt_mtime = gmdate('r', $timestamp); header('ETag: "'.md5($timestamp.$file).'"');   if(isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) || isset($_SERVER['HTTP_IF_NONE_MATCH'])) { if ($_SERVER['HTTP_IF_MODIFIED_SINCE'] == $gmt_mtime || str_replace('"', '', stripslashes($_SERVER['HTTP_IF_NONE_MATCH'])) == md5($timestamp.$file)) { header('HTTP/1.1 304 Not Modified'); exit(); } }   header('Last-Modified: '.$gmt_mtime); header('Cache-Control: public'); return 1; } Then call this in the top of your code like [...]