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Re: My point about the negotiation algorithm

From: Shane McCarron <shane@aptest.com>
Date: Wed, 31 Mar 2010 08:23:10 -0500
Message-ID: <4BB34CBE.4060604@aptest.com>
To: Steven Pemberton <Steven.Pemberton@cwi.nl>
CC: XHTML WG <public-xhtml2@w3.org>
So, your position is that the document should instruct people to ignore 
'the relative importance ("weight")' that is specified via the q value 
because even if the user agent thinks text/html would be better, the 
document should STILL be sent as application/xhtml+xml?  That surprises 
me.  Granted this document is not a tutorial on all the intricacies of 
content negotiation, but I feel it is a mistake to tell a document 
author to ignore the mandate of another standard.  Am I missing 
something here?

Steven Pemberton wrote:
> On Wed, 31 Mar 2010 15:04:27 +0200, Shane McCarron <shane@aptest.com> 
> wrote:
>
>> What if the q value for application/xhtml+xml is 0?
>
> Is is the same as saying it doesn't accept it:
>
> 3.9 Quality Values
>
>    HTTP content negotiation (section 12) uses short "floating point"
>    numbers to indicate the relative importance ("weight") of various
>    negotiable parameters.  A weight is normalized to a real number in
>    the range 0 through 1, where 0 is the minimum and 1 the maximum
>    value. If a parameter has a quality value of 0, then content with
>    this parameter is `not acceptable' for the client.
>
> http://tools.ietf.org/html/rfc2616#section-3.9
>
> Steven
>
>> Steven Pemberton wrote:
>>> The point of the XHTML Media Types note 
>>> (http://www.w3.org/MarkUp/2010/ED-xhtml-media-types-20100218/) is to 
>>> explain how to deliver XHTML to a browser.
>>>
>>> If the browser says it accepts application/xhtml+xml, our job is 
>>> done: use that media type; you don't have to follow any extra 
>>> guidelines.
>>>
>>> However, if it is a legacy browser, and doesn't accept 
>>> application/xhtml+xml, then there is a fallback: deliver it as 
>>> text/html (but make sure it won't hiccup on your content by 
>>> following a number of guidelines).
>>>
>>> So even if a browser says it accepts both media types, even if it 
>>> says it 'prefers' text/html (via a q value), our aim is to deliver 
>>> XHTML, and so should use the application/xhtml+xml media type.
>>>
>>> Steven
>>
>

-- 
Shane P. McCarron                          Phone: +1 763 786-8160 x120
Managing Director                            Fax: +1 763 786-8180
ApTest Minnesota                            Inet: shane@aptest.com
Received on Wednesday, 31 March 2010 13:23:47 GMT

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