Question

If a user has a file cached in their browser and they send a http request with an If-Modified-Since header, is there a way to automatically serve them a 304 Not Modified response using .htaccess?

Answer 1

An indirect solution:

.htaccess:

RewriteCond %{HTTP:if-modified-since} .
RewriteRule . /not_modified.php [L]

not_modified.php:

header($_SERVER['SERVER_PROTOCOL'].' 304 Not Modified');