Cache big PHP files in client browser - status '200 ok' instead of '304 not modified' - Apache

Question

I modified the .htaccess at root like that:

ExpiresActive On
ExpiresDefault "access plus 300 seconds"

ExpiresByType text/css "access plus 1 month"
ExpiresByType text/javascript "access plus 1 month"
ExpiresByType image/gif "access plus 1 month"
ExpiresByType image/jpg "access plus 1 month"
ExpiresByType image/png "access plus 1 month"
ExpiresByType application/x-shockwave-flash "access plus 1 day"
ExpiresByType text/php "access plus 1 day"
ExpiresByType text/html "access plus 1 day"

I also added those lines to the Apache file configuration ( httpd.conf ):

LoadModule expires_module modules/mod_expires.so
LoadModule headers_module modules/mod_headers.so
LoadModule deflate_module modules/mod_deflate.so

But browser doesn't seem to cache the katalog.php .

I tried to change headers via the php but it just crashed the file, I couldn't access it.

I would like to cache it with "no-cache" (to check if it's still the same) because it takes time to download it every time (13.3MB ...), even when user press "backspace" button...

Answer 1

Finally managed to cache this big html content I used this : jonasjohn.de/snippets/php/caching.htm (without using e-tag) and apcu php extension to store an application scoped variable. ( to check if katalog has been updated : I compare the app scoped varaible to a $_session variable , if they're the same I dont load the content)