Apache - Force caching dynamic PHP content with mod_headers

Normally you want dynamic content to be fresh and not cacheable. But sometimes it may be useful to cache it, like when you have website behind reverse proxy¹. To do this try something like this:

<filesmatch "\.(php|cgi|pl)$">
Header unset Pragma
Header unset Expires
Header set Cache-Control "max-age=3600, public"
</filesmatch>