RE: Caching responses with "Vary" responses

Hi Alexander,

I assume that you have gzip encoding activated in your apache server.

In that case, when I normally request for an object, I do find 2 entries in the cache - one which says it is internal request, and the other with a Accept-encoding set to gzip + actual gzipped content.

In short, I do feel squid caches the replies but with an additional entry..

Regards,
Anita

-----Original Message-----
From: Alexander Komyagin [mailto:komyagin_at_altell.ru]
Sent: 09 July 2012 19:44
To: squid-dev_at_squid-cache.org
Subject: Caching responses with "Vary" responses

Hi! I've just noticed that when remote server replies with Vary header
parameter set, squid won't cache that reply. For example:

aaa@bbb:~$ wget -O /dev/null -S http://www.ietf.org/rfc/rfc3280.txt
--2012-07-09 18:03:20-- http://www.ietf.org/rfc/rfc3280.txt
Connecting to 10.0.0.89:3128... connected.
Proxy request sent, awaiting response...
  HTTP/1.1 200 OK
  Date: Mon, 09 Jul 2012 14:03:55 GMT
  Server: Apache/2.2.10 (Linux/SUSE) mod_ssl/2.2.10 OpenSSL/0.9.8h
PHP/5.2.13 with Suhosin-Patch mod_python/3.3.1 Python/2.6 mod_wsgi/3.3
mod_perl/2.0.4 Perl/v5.10.0
  Last-Modified: Fri, 10 May 2002 00:17:43 GMT
  ETag: "9fe907-48284-3a095ba1a77c0"
  Accept-Ranges: bytes
  Content-Length: 295556
  Vary: Accept-Encoding
  Content-Type: text/plain
  X-Cache: MISS from my_proxy
  Via: 1.1 my_proxy (squid/3.2.0.16)
  Connection: close
Length: 295556 (289K) [text/plain]


Reason:
StoreEntry::setPublicKey() is called for the reply, since originally it
seems cacheable, but when "vary" header is detected

/* if (mem_obj->vary_headers && !storeGetPublic(mem_obj->url,
mem_obj->method)) */

squid creates new StoreEntry (which is created with KEY_PRIVATE flag
set, since neighbors_do_private_keys is 1) and
writes to it -- this way the result won't be stored because KEY_PRIVATE
is set (I failed to find any place where this flag shall be
cleared).

Is this behavior normal? Or is it a bug or something?

--
Best wishes,
Alexander Komyagin


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Received on Thu May 02 2013 - 10:02:37 MDT