How do you implemented etags inside a PHP file? What do I upload to the server and what do I insert into my PHP file?
Create / edit your .htaccess file and add the following:
FileETag MTime Size
Either place the following inside a function or put it at the top of the PHP file that you need etags to work on:
<?php
$file = 'myfile.php';
$last_modified_time = filemtime($file);
$etag = md5_file($file);
header("Last-Modified: ".gmdate("D, d M Y H:i:s", $last_modified_time)." GMT");
header("Etag: $etag");
if (@strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) == $last_modified_time ||
trim($_SERVER['HTTP_IF_NONE_MATCH']) == $etag) {
header("HTTP/1.1 304 Not Modified");
exit;
}
?>