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+4 votes
1.5k views
in Q2A Core by
edited by

I've noticed that Q2A sends several headers to prevent caching on all pages:

	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

However, for old questions the chance of them changing is quite low. So wouldn't it be beneficial to remove those headers if a question is more than a week old, or set them to cache for at least a few hours?

Also, would it be at all feasible to cache pages server-side, or parts of pages? If a user is logged in there will be certain parts that can't be cached, but a good chunk of the HTML should be cacheable, right?

2 Answers

0 votes
by
For now, Q2A doesn't modify the standard HTTP headers that PHP adds. You can certainly change this using PHP's header() function in a custom theme (use print_r($this->content) to see everything passed to the theme layer - you'll find info direct from the database in the 'raw' subarray elements).

As for server-side caching, it's a long-term goal, but there is so much to be done in the meantime! The next version will have a simple integrated caching mechanism (used for caching scaled down avatars) so in the meantime you could plug into that.
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Are you saying those headers are not added by Q2A? Where would they be coming from then? The regular pages on my site don't return them.
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PHP is adding those headers - try making a simple PHP file and they should also appear when the file is requested. It's also possible some of them are a side effect of the Gzip compression that Q2A activates.
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I found the culprit - the sessions. On every Q2A page load, a session is started whether the user is logged in or not. I don't know if that's necessary when the user is not logged in... I guess if they log in then get returned to the previous page you don't want it cached in the browser.
+3 votes
by

Hi!

If you need to cache pages for unregistered users, check out my plugin:  https://github.com/bndr/q2a-caching

It's a work in progress, Caching for registered users is in the todo list.

by
Error! When enabled cache does not work entry through facebook.
by
Hi! I think I fixed the issue.

I removed caching from register/login pages. And stopped caching for users with cookies values that contain fbs_

It should work now. Get the new version from the repository and try it
by
Hi.
So we get an error:
Warning: preg_match() [function.preg-match]: No ending delimiter '#' found in /var/www/szh/data/www/szh.kz/qa-plugin/q2a-caching/qa-caching-main.php on line 122
by
Sorry about that. Fixed.
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