Page not changed

[Anon]

Hi all,

Does anybody know how to send back a 'Page Not Changed' code to the browser rather than the page itself if the server knows it hasn't been updated since last requested?

I know the web server does it automatically, but I would like to send the same message in place of some dynamically created pages.

Thanks for your help!

-- John G.

[Anon]

The header to send back is :

Header("HTTP/1.1 304 Not Modified");

To determine when to do so, you'll have to examine the If-Modified-Since header the client sent you. To get the Unix time from it, just do this :

$t=strtotime($HTTP_IF_MODIFIED_SINCE);

Finally, when returning a real page, don't forget to send the appropriate Last-Modified header with the time that reflects the page's timestamp :

$GMT=gmstrftime("%a, %d %b %Y %H:%M:%S",$t)." GMT";
Header("Last-Modified: $GMT");

Et voilà, it should work.