note 57707 added to function.header

If you want to enable caching of your page, you have two solutions: use Etag or use Last-Modified. Someone has already posted here the code to use Etag. However, sometimes, it is easier (better) to use Last-Modified. The full code is here: <?php function get_http_mdate() { return gmdate("D, d M Y H:i:s",filemtime($SCRIPT_FILENAME))." GMT"; } function check_modified_header() { // This function is based on code from http://ontosys.com/php/cache.html $headers=apache_request_headers(); $if_modified_since=preg_replace('/;.*$/', '', $headers['If-Modified-Since']); if(!$if_modified_since) return; $gmtime=get_http_mdate(); if ($if_modified_since == $gmtime) { header("HTTP/1.1 304 Not Modified"); exit; } } check_modified_header(); header("Last-Modified: ".get_http_mdate()); ?> The script checks if time from "If-Modified-Since" header is equal to current modified-time. If it is, a 304 code is returned, and PHP exits. If it is not, PHP continues normally. You may want to change how "get_http_mdate()" function gets the time. You may want to get time from another file, or from somewhere else (like a date field on database). ---- Manual Page -- http://www.php.net/manual/en/function.header.php Edit -- http://master.php.net/manage/user-notes.php?action=edit+57707 Delete: added to the manual -- http://master.php.net/manage/user-notes.php?action=delete+57707&report=yes&reason=added+to+the+manual Delete: bad code -- http://master.php.net/manage/user-notes.php?action=delete+57707&report=yes&reason=bad+code Delete: spam -- http://master.php.net/manage/user-notes.php?action=delete+57707&report=yes&reason=spam Delete: useless -- http://master.php.net/manage/user-notes.php?action=delete+57707&report=yes&reason=useless Delete: non-english -- http://master.php.net/manage/user-notes.php?action=delete+57707&report=yes&reason=non-english Delete: already in docs -- http://master.php.net/manage/user-notes.php?action=delete+57707&report=yes&reason=already+in+docs Delete: other reasons -- http://master.php.net/manage/user-notes.php?action=delete+57707&report=yes Reject -- http://master.php.net/manage/user-notes.php?action=reject+57707&report=yes Search -- http://master.php.net/manage/user-notes.php