Re: [PATCH] Cache-Control overwriting hack

My reading of header_replace only allows replacing header text with a
fixed string, not any sort of dynamic text. The use case is where one
wants this particular Squid instance to use a set of Cache-Control
headers that are explicitly hidden from downstream caches as well as
downstream clients.

-C

On May 4, 2009, at 7:28 PM, Amos Jeffries wrote:

>> Hi,
>>
>> This is a patch of probably limited utility, but I'll send it out
>> anyway and leave it for you folks to decide :) It was written against
>> 2.7STABLE6 but patches cleanly into HEAD.
>>
>> The purpose of this patch is to support the use of an "alternate"
>> Cache-Control header in reverse-proxy environments. The patch
>> consists
>> of a new config directive, replace_client_cc, and code in
>> client_side.c that is called if that config option is enabled.
>>
>> The new code then looks for the existence of a header titled "Client-
>> Cache-Control" which should contain syntax similar to that of a
>> normal
>> Cache-Control header. When present, Squid will delete the existing
>> Cache-Control header if it exists, replace it with the contents of
>> Client-Cache-Control, then delete the Client-Cache-Control header.
>>
>> So, the end result is that you have one Cache-Control header that
>> squid pays attention to, and then a completely different one that
>> client browsers will see.
>>
>> A couple TODOs on this if folks agree it's worthwhile:
>>
>> 1. Change the config option to a named header, eliminating the need
>> to
>> hard-code Client-Cache-Control (at the cost of using
>> httpHeaderFindByName() instead of httpHeaderGetList() which seems
>> much
>> more costly CPU-wise).
>>
>> 2. Allow for some method by which the original Cache-Control header
>> can be preserved for diag purposes (maybe add in as X-Original-Cache-
>> Control?)
>>
>> Feedback appreciated, etc...
>>
>> -C
>
> Oh dear. Why are you thinking this is necessary?
>
> AFAIK, header_access and header_replace even in Squid-2 are supposed
> to do
> exactly that. If not that is a bug which needs to be fixed.
>
> Amos
>
>
Received on Tue May 05 2009 - 00:32:28 MDT