Page 1 of 1

HTTP Header Cache-Control:pre-check, post-check

Posted: Tue Sep 30, 2003 9:11 am
by delorian
Hi,

I was reading about anti-caching latetly, and of course the first thing I've found was the following:

Code: Select all

// Date in the past
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");

// always modified
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
 
// HTTP/1.1
header("Cache-Control: no-store, no-cache, must-revalidate");
header("Cache-Control: post-check=0, pre-check=0", false);

// HTTP/1.0
header("Pragma: no-cache");
Ok, I've read about the above HTTP headers in RFC2616 on http://www.w3.org/Protocols/HTTP/1.1/rfc2616.pdf but I can't find the:

Code: Select all

"Cache-Control: post-check=0, pre-check=0"
header. So now I'm confused, because I do the GS and found a lot of things about cache-control, but none of them was about post-check and pre-check. Of course, I can't say that I've read everything. The main idea is the fact I don't know what is that header doing. If someone could provide my with some info or link, I would be very appreciated.

Posted: Fri Oct 03, 2003 1:43 pm
by delorian
TopMaking. :) Someone...

Posted: Fri Oct 03, 2003 8:39 pm
by JAM
http://msdn.microsoft.com/workshop/auth ... Extensions
* post-check
o Defines an interval in seconds after which an entity must be checked for freshness. The check may happen after the user is shown the resource but ensures that on the next roundtrip the cached copy will be up-to-date.
* pre-check
o Defines an interval in seconds after which an entity must be checked for freshness prior to showing the user the resource.

Posted: Sat Oct 04, 2003 11:14 am
by delorian
Thanks, JAM. I didn't even think of looking it on M$ pages, hmmm, I should reconsider my "I didn't find anything usefull on M$" opinion. Thanks again.