Re: Re[2]: [squid-users] Issue with header_access and validation

> But wouldnt that only override max-age which is received in headers sent
> by servers?
> The ones we want to override are from client requests only.
> Plus refresh_pattern can not take an acl since it's global and only based
> on path.(ie no acls)
>
> Or am I not seeing things clearly?
>

refresh_pattern gets involved when updating something already in cache.
AFTER the IMS has been actioned.

header_access gets involved when sending the request to the server or the
response to the client. Thus it was working too late for your earlier
config.

The closest thing I know of squid offering is the 'reload_into_ims' or
'refresh_stale_hit' options. The first to reduce possibly large full
object requests down to the smaller 304's. The latter to reduce the amount
of 304's to one at a time.

Amos

>
> Thanks for any help again.
>
>
>>?Use refresh_pattern entries to override the max-age.
>
>
>>?On Fri, May 02, 2008, Paul-Kenji Cahier wrote:
>>>?Hello,
>
>>>?In our current situation, we are trying to have "Cache-control:
>>> max-age=0" headers from clients to be ignored
>>>?in the cache decision process, while keeping all of the 'Cache-control:
>>> no-cache' and 'Pragma: no-cache'
>>>?still valid as making revalidation mandatory.
>
>>>?Without trying to do anything, when squid receives the max-age=0
>>> directive, it decides to TCP_REFRESH_HIT since
>>>?the client asks it.
>
>>>?Our current approach was the following:
>>>?acl static_content req_header Cache-control max.age=0
>>>?header_access Cache-Control deny static_content
>
>>>?While the acl is properly matched, it seems the header_access does not
>>> ever get applied when deciding of what to do,
>>>?with the result that it's effectively being ignored.
>
>>>?Is there any way to make it be applied earlier/another way to ignore
>>> only 'Cache-control: max.age=0' headers?
>>>?(we would also preferably rather be able to define that with an acl so
>>> we can only apply that directive to
>>>?really probably static content)
>
>>>?The whole goal is to avoid firefox's F5/refresh button from forcing
>>> thousands of TCP_REFRESH_HIT/304 all the time,
>>>?which not only strains the servers but takes longer. Of course we also
>>> want users that want to force a refresh
>>>?(through ctrl+shift+R, which actually adds the no-cache directives) to
>>> be able to do so.(Caching is good,
>>>?but forcing delays before things are checked again is not)
>
>>>?Any suggestions will be really appreciated... We have tried to rewrite
>>> urls through privoxy, but it came messy
>>>?and fairly heavy on load, so a squid only solution would really be
>>> best.
>
>>>?--
>>>?Best regards,
>>>? Paul-Kenji Cahier
>>>?mailto:pkc_at_F1-Photo.com
>
>
Received on Thu May 22 2008 - 03:49:58 MDT