http://phecoopkj4ytf3fokcfvykymg7zuhkwsoqbh5dgnwwee423delgexyqd.onion/page-1804050751-Supporting-conditional-HTTP-requests-in-PHP-PHP.html
If the metadata validates, then a HTTP 304 (Not Modified) will be returned, otherwise the requested content will be returned using whatever status code is appropriate for the request (usually a 200, but it could equally be a 206 if the request specifies a range) Because PHP is used in dynamic pages, conditional requests won't simply work out of the box.