Re: strip query terms OnOff

Quoting Henrik Nordstrom <henrik@henriknordstrom.net>:

> tor 2006-03-16 klockan 15:14 +0200 skrev srnoam@t2.technion.ac.il:
>
> > Do you mean no_cache in the request/reply http headers?
>
> No, in squid.conf...

mmm... I worked with squid almost a year & didn't see this option (!@#) I will
check how everything works when it's disabled.
I hope this is the solution I was looking for.

>
> > "last modified" and sometimes "expire" also in cache_control I set new
> type
> > "Dynamic" that I got squid to recognize (as CC_DYNAMIC) & treat as
> cachable
>
> Why adding a new CC flag? Can't you use the max-age or s-max-age already
> defined for this purpose? Or perhaps public?
>
> From the protocol point of view, just adding a Expires or CC
> max-age/s-max-age is sufficient to indicate the object may be cached.
> The only thing special about query URLS in the standard is that they
> SHOULD NOT be cached unless there is explicit freshness information
> available.
>
> RFC 2616 13.9 Side Effects of GET and HEAD
>
> Unless the origin server explicitly prohibits the caching of their
> responses, the application of GET and HEAD methods to any resources
> SHOULD NOT have side effects that would lead to erroneous behavior if
> these responses are taken from a cache. They MAY still have side
> effects, but a cache is not required to consider such side effects in
> its caching decisions. Caches are always expected to observe an
> origin server's explicit restrictions on caching.
>
> We note one exception to this rule: since some applications have
> traditionally used GETs and HEADs with query URLs (those containing a
> "?" in the rel_path part) to perform operations with significant side
> effects, caches MUST NOT treat responses to such URIs as fresh unless
> the server provides an explicit expiration time. This specifically
> means that responses from HTTP/1.0 servers for such URIs SHOULD NOT
> be taken from a cache. See section 9.1.1 for related information.
>
>
> This (the last paragraph) is the reason why the no_cache lines exists in
> the recommended configuration by default as we do not have anything in
> the code implementing this exception, but in reality the lines is not
> needed to comply with the standard as long as min age is kept at 0 in
> refresh_pattern.
>
> What this means is that if you remove the no_cache rules from your
> squid.conf then Squid will not have any exceptions for query URLs than
> they will be processed just like any other URL, just looking at the
> headers returned.

I used this header type in order to track it in squid & use a statistical cost
function only for dynamic type (no need to change the way regular files are
being cached).

>
> Regards
> Henrik
>
Received on Thu Mar 16 2006 - 07:55:49 MST