[TYPO3-dev] Core Behaviour: Using Cache-Control Headers to prevent _Clients_ from Caching

[Martin Kutschker]

Ekkehard Gümbel schrieb:
> Hi,
> I am struggling to prevent my friend the IE from caching locally...
> 
> Normally, that is done using HTTP headers. TYPO3 supports these with the 
> "sendCacheHeaders" config option.
> And it behaves just like TSRef says: "In case caching is not allowed, 
> these headers are sent to avoid client caching: Cache-Control: private"
> 
> Now "Cache-Control: private" is fine for regular proxy caches but not 
> for client side caching (see 
> http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html).
> 
> Funny thing is, that in class.t3lib_userauth.php an undocumented (?) 
> additional option called "sendNoCacheHeaders" seems to take care of this 
> issue.

In userauth?!?

> Extending this concept to class.tslib_fe.php is solving my problem - see 
> code below.
> (Another option would of course be to skip the "sendNoCacheHeaders" 
> switch and make this behaviour always-on - but are of course cases where 
> you want to prevent shared-caching but allow client-side caching. In 
> fact this was Ole Tange's sole intention as he just told me.)
> 
> Does this make any sense to someone?

Yes. I agree that both options are valid. I suggest to go the usual 
TYPO3 way. Make config.sendNoCacheHeaders a pseudo boolean. So 1 means 
what it means today: prevent shared caching (proxy) and 2 means what you 
want: prevent private caching (client).

Masi