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What should my Pragma HTTP response header be set to?

Answer 1

+1 A:

You don't have to set pragma, pragma is set only if you want a no-cache directive. Have a look here for more information: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.32

hellvinz 2010-09-29 14:10:09

My server automatically sets Pragma to no-cache (which I do not have access to change). So I want to change the pragma value to something more consistent with the cache settings I outlines above, or somehow null out the entire pragma field, all via my php script. Any ideas?

Drew2345 2010-09-29 14:19:46

if it's apache, it is taking .htaccess into account and have the headers module you can use this directive "Header unset Pragma"

hellvinz 2010-09-29 14:30:38

I don't think the mod_headers.c is activated.

Drew2345 2010-09-29 14:44:12

then it will be difficult to disable the pragma: no-cache. It seems that there is a precedence between Cache-Control and Pragma directive, and that in HTTP 1.1 Pragma is ignored if Cache-Control is set. Have a look at the directive precedence part in this documentation http://www.mnot.net/javascript/xmlhttprequest/cache.html

hellvinz 2010-09-29 15:12:51

What about this: header('Cache-Control: private, max-age=28800, must-revalidate'); header('Expires:' . gmdate('D, d M Y H:i:s T', strtotime('+8 hours'))); header('Pragma: private');

Drew2345 2010-09-29 15:13:37

You can try, maybe you webserver is not overriding pragma if it is set by the application.

hellvinz 2010-09-29 15:29:25

Answer 2

A:

See the PHP doc for session_cache_limiter. You will see the correct cache headers to send:

public:

Expires: (sometime in the future, according session.cache_expire)
Cache-Control: public, max-age=(sometime in the future, according to session.cache_expire)
Last-Modified: (the timestamp of when the session was last saved)

private_no_expire:

Cache-Control: private, max-age=(session.cache_expire in the future), pre-check=(session.cache_expire in the future)
Last-Modified: (the timestamp of when the session was last saved)

private:

Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: private, max-age=(session.cache_expire in the future), pre-check=(session.cache_expire in the future)
Last-Modified: (the timestamp of when the session was last saved)

nocache:

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

AlexV 2010-09-29 14:45:25

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What should my Pragma HTTP response header be set to?

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