Re: [squid-users] Re: Create acl based on Accept-Language?

On 26/08/2013 10:42 a.m., Manuel wrote:
> I just found out that Squid caches the content properly from the right
> cache_peer but once another user request the same URL the content is fetched
> always from the first cached copy which is always based on the first
> request.

caching != fetching.

Caching will always be done the same with your config regardless of
which peer the response is fetched from.
Your ACL exepriments only affact the fetching decision.

The very definition of caching is that second request gets sent the
*cached* copy of the first request (this is known as a cache HIT). It is
the origin servers responsibility to decide which language the response
is written in and setup the HTTP response headers indicating Language as
a variant differentiator for the relevant URLs.

> This problems does not seem to happen with another config that I
> have where the acl is based on an IP (not based on Accept-Language). In this
> other case even when the user request an URL that has already been cached,
> because the user matches an specific IP the content is fetched from the
> right cache_peer.

No. When an object is cached and served from cache the cache_peer are
not even consulted.
What exactly are you observing happen?

>
> Examples 1 (not working properly):
>
> acl itlanguage req_header Accept-Language ^it

NP: This will only match if Italian language is the first listed option
by the client. It will not match if Italian was for example the second
most preferred language.

> cache_peer 127.0.0.1 parent 81 0 no-query no-digest originserver
> name=maincontent
> cache_peer_access maincontent allow !itlanguage
> cache_peer_access maincontent deny all
>
> cache_peer 127.0.0.1 parent 81 0 no-query no-digest originserver
> name=itcontent
> cache_peer_access itcontent allow itlanguage
> cache_peer_access itcontent deny all
>
> Example 2 (working properly):
>
> cache_peer 127.0.0.1 parent 81 0 no-query no-digest originserver
> name=webserver weight=1000 connect-timeout=2
> cache_peer 127.0.0.2 parent 81 0 no-query no-digest originserver
> name=webserver2 weight=5 connect-timeout=2
> acl maindomain dstdomain www.mydomain.com
> acl specialuser src 80.80.80.80/32
> cache_peer_access webserver allow maindomain !specialuser
> cache_peer_access webserver deny all
> cache_peer_access webserver2 allow maindomain !specialuser
> cache_peer_access webserver2 deny all
>
> cache_peer 127.0.0.3 parent 81 0 no-query no-digest originserver
> name=specialserver
> cache_peer_access specialserver allow specialuser maindomain
> cache_peer_access specialserver deny all
>
>
> The only differences I can see are:
> - ACL is based on an IP rather than in req_header Accept-Language
> - In the second case the cache_peer are not only named different but also
> have a different IP (127.0.0.1, 127.0.0.2...) while in the first case both
> cache_peer have the same address but it are named different (because the
> webserver delivers different content based on the Accept-Language).

Also,
  - your HTTP responses are lacking all the HTTP feature syntax that
specific Language as a factor in response variation.

Amos
Received on Mon Aug 26 2013 - 02:29:30 MDT