Re: [squid-users] unexplainable MISSes - found the problem

From: Adrian Dascalu <>
Date: Wed, 10 Nov 2010 13:57:27 +0200

I see ... My eyes stopped at \r\n :)

It's worth mentioning that other tools and even another proxy that I've
tested (varnish) are parsing the Vary header and eliminate spaces, tabs,
line-brakes and even multiple occurrences of the same header name in
Vary; for my case the two texts are considered equivalent by varnish and
it is NOT invalidating the other variants.

Perhaps something worth doing for squid too? I mean, it's obviously not
a squid bug but it will be consistent to the way developer tools
(firebug, chrome dev tools etc) are treating this header.


On 11/10/2010 04:41 AM, Amos Jeffries wrote:
> On Tue, 09 Nov 2010 17:37:55 +0200, Adrian Dascalu
> <> wrote:
>> Ok, it's a bit late for me but for other people browsing this list I'm
>> sharing my findings:
>> It looks like squid is really picky about the way Vary header text is
>> formed: the vary headers in my case where not "identical" due to a bug
>> in the backed server. A header name was repeated for the anonymous users
>> (", Accept-encoding" added at the end of the list). Developer tools in
>> firefox and chrome were silently correcting this and even squid
>> access.log with headers (see below) was only showing an extra coma that
>> was difficult to spot.
> Aha! great.
> Hmm, squid should be logging exactly what it received (URL-encoded to
> protect against binary blobs). And sure enough now that you point out what
> to look for it is there...
>>> GMT\r\nVary: Accept-Encoding, Accept,
>>> X-Username,\r\n%09Accept-Encoding\r\nLast-Modified: Fri, 28 Nov 2008
> NOTE: the "%09" or tab character folded-line .
> Amos
Received on Wed Nov 10 2010 - 11:57:32 MST

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