[squid-users] vary headers

[Amos Jeffries]

On 5/05/2015 4:38 a.m., Hussam Al-Tayeb wrote:
> 
> 
>> Sent: Monday, May 04, 2015 at 6:32 PM
>> From: "Amos Jeffries" <squid3 at treenet.co.nz>
>> To: "Hussam Al-Tayeb" <hussam.tayeb at gmx.com>
>> Cc: squid-users at lists.squid-cache.org
>> Subject: Re: [squid-users] vary headers
>>
>> On 5/05/2015 3:15 a.m., Hussam Al-Tayeb wrote:
>>>
>>>
>>>> Sent: Monday, May 04, 2015 at 12:49 PM
>>>> From: "Amos Jeffries" <squid3 at treenet.co.nz>
>>>> To: squid-users at lists.squid-cache.org
>>>> Subject: Re: [squid-users] vary headers
>>>>
>>>> On 4/05/2015 6:54 a.m., Hussam Al-Tayeb wrote:
>>>>>> Sent: Sunday, May 03, 2015 at 9:45 PM
>>>>>> From: "Yuri Voinov"
>>>>>
>>>>>>
>>>>>> I understand what do your want. But for what?
>>>>>>>
>>>>>
>>>>> because a "wget --server-response http://someurl" operation that
>>>>> replies with a "Vary: user-agent" header always results in a MISS
>>>>> even if the same wget version (same user-agent) and computer.
>>>>> Instead, multiple copies of the file are stored.
>>>>
>>>> That is not right, the wget being used twice should be MISS then HIT,
>>>> just like any oter cacheable traffic.
>>>>
>>>> The nasty thing with Vary:User-Agent is that browsers UA string embeds
>>>> so much plugin info they are changing between each different client
>>>> request. Which defeats the purpose of caching one clients reply for use
>>>> by other clients.
>>>>
>>>> NP: what you had with the store_miss should be working.
>>>>  Are you using Squid-3.5 ?
>>>>  How are you identifying a fail ?
>>>>
>>
>>> Hello. I am using 3.5.4
>>> There are new objects on disk that have the Vary: User-Agent Http header.
>>> I can tell for example if type head -n13 /home/squid/04/D1/0004D122
>>>
>>
>> That is not a good way to identify. All it means is that the object used
>> a disk file for its transfer. Cache files are also sometimes used as
>> on-disk buffers.
>>
>> If you check with store.log for ID (0004D122) you should expect to see
>> that file pushed to disk, then a cache index RELEASED action performed.
>> The file part may stay on disk until something else needs to use the
>> same filename.
>>
>> The ways to identify caching activity is:
>>  * access.log - checking that no HIT or REFRESH occur on the relevant
>> URLs, or
>>  * store.log - checking that objects with the URLs are all getting that
>> RELEASED action.
>>  * cache.log - setting "debug_options 20,3" and watching for "store_miss
>> prohibits caching"
>>
>> There is unfortunatly currently no easy debugs linking what URL
>> store_miss prohibited to correlate the logs :-(
>>
>> Amos
>>
>>
>>
>>
> ok, I tried setting debug_options.
> this is part of what I found:
> http://pastebin.com/raw.php?i=4HTw9es3
> 
> So it looks like it only blocks caching of Vary header if followed by "Accept-Encoding: gzip,deflate"?
> 

Ah, your regex pattern was "." so if Vary header exists at all it will
block that response caching.

Since its working now use:

 acl hasVary rep_header Vary User-Agent


Amos