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Re: Possible issue: Accept-language priority based on language order

From: Amos Jeffries <squid3@treenet.co.nz>
Date: Thu, 24 Nov 2011 11:29:28 +1300
To: <ietf-http-wg@w3.org>
Message-ID: <27ace3781b4871cc017480ab8795085a@treenet.co.nz>
 On Wed, 23 Nov 2011 17:22:29 +0100, Harald Alvestrand wrote:
> On 11/23/2011 04:55 PM, Julian Reschke wrote:
>> On 2011-11-23 16:41, Harald Alvestrand wrote:
>>> I ran across this in a discussion, and went to check it up; it 
>>> might
>>> need fixing.
>>> ...
>>
>> I'm not sure that "fixing" is the right term; HTTP doesn't assign 
>> semantics to the ordering, and AFAIU never has.
>>
>> How is this a problem in practice?
>
> Well... either the semantics of the header
>
> Accept-language: en, no
>
> is that the languages are ordered by preference, or it does not imply
> an ordering.
>
> As of the time I wrote the RFC (2002), I observed multiple browsers
> offering an UI that let people rank their preferences for language,
> and observed the relevant Accept-Language: headers being sent without
> q= values.
>
> When I inquired, the response was that "leftmost language wins".
> If this is still "what people do", it should be documented.
>
> Note: Firefox and Chrome seem to send q= values in my current
> versions. The world might have changed.
> But digging around in server-side code, I find that some code (which
> I hope is not used) actually ignores q values totally and just picks
> languages starting at left. Perhaps it hasn't.
>
>
>                         Harald


 I've been keeping an eye on this since implementing language 
 negotiation in Squid.

 It appears that nearly all agents are sending the language codes sorted 
 by q value anyway. Whether they send the q value or not it is still 
 possible to optimize by using the left-most wins assumption.

 If anyone is interested in doing a deeper analysis I have a dataset 
 available covering the last year on several networks linking the 
 Accept-Language and User-Agent header pair.

 Amos
Received on Wednesday, 23 November 2011 22:30:17 GMT

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