Web Hosting Talk : Web Hosting Main Forums : Hosting Security and Technology : Apache sending Pragma: no-cache directive

[bloom]

Hi,

I've just set up a LAMP box (Linux, Apache, mySQL, PHP, etc.) and I'm having a problem with Apache sending no-cache headers.

I checked my PHP code and I'm not sending out *any* headers or meta-tags to control caching. On my old server with a similar setup I didn't have the problem.

I used Mozilla's "Live Headers" extension to capture the headers:

HTTP/1.x 200 OK
Date: Wed, 20 Aug 2003 04:40:08 GMT
Server: Apache/1.3.28 (Unix) PHP/4.3.2 mod_gzip/1.3.26.1a mod_auth_passthrough/1.6 mod_log_bytes/1.2 mod_bwlimited/1.0 FrontPage/5.0.2.2634 mod_ssl/2.8.15 OpenSSL/0.9.7a PHP-CGI/0.1b
Vary: Accept-Encoding
X-Powered-By: PHP/4.3.2
Set-Cookie: PHPSESSID=[some id]; path=/
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache
Keep-Alive: timeout=15, max=100
Connection: Keep-Alive
Content-Type: text/html
Content-Encoding: gzip

What's up with the Cache-Control headers telling the browser not to store or cache the pages? And that 1981 expiration date will pretty much mean that *everything* refreshes from the server every time, which defeats the purpose of using mod_gzip to begin with.

I've tried looking through my httpd.conf file for anything having to do with Caching and there's nothing there. Is this something that's controlled by PHP, or is there some conflict with one of the Apache modules, like mod_gzip or something else?

It's driving me crazy.

[qm8309]

did u do a test to see if it actually caches or not by clearing ur IE cache and open up a page from the server?

as of the nocache header its sent by a setting in the php.ini session section
session.cache_limiter = nocache

this is the default php setting and it only tells the browser not to cache the php dynamic pages. it should not affect any static pages on the server.

just make sure ur mod_gzip parameters are set correctly in httpd.conf and there shouldnt be any problem.

[qm8309]

i think this thread is broken.

[bloom]

I think the problem *was* in teh session cache limiter, but it seems to have the adverse effect of the browser not caching *any* part of the page, not just the php page itself.

So images, css files, other includes (javascript, etc.) were not being cached.

I *think* it's fixed now, although I still get an impage "blip" where the images will disappear for a second and then reappear just before the page finishes loading, which didn't happen on my previous server.

Here's a page where it's pretty noticeable (work safe, ad free):

http://poetryx.com