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Accept-xmlns

From: Etan Wexler <ewexler@stickdog.com>
Date: Thu, 17 Apr 2003 01:47:44 -0700
To: Mikko Rantalainen <mira@cc.jyu.fi>, www-html@w3.org
Message-id: <BAC3B109.EDF%ewexler@stickdog.com>

Mikko Rantalainen wrote to <mailto:www-html@w3.org> on 11 April 2003 in "Re:
XHTML2 MIME type" (<mid:3E9711C6.9090002@cc.jyu.fi>):

I [immediately] thought something along [these] lines:

> Accept-xmlns: http://www.w3.org/1999/xhtml;q=1.0,
> http://www.w3.org/2000/svg;q=0.9,
> http://www.w3.org/1998/Math/MathML;q=0.7

From a syntactic perspective, that just doesn't work. The would-be
parameters are parts of the various URIs. One solution is to use delimiter
characters:

Accept-xmlns: <http://www.w3.org/1999/xhtml>;q=1.0,
  <http://www.w3.org/2000/svg>;q=0.9,
  <http://www.w3.org/1998/Math/MathML>;q=0.7

> I can still [envision] quite long Accept-xmlns headers: perhaps some
> kind of abbreviated form should be allowed. For example:
> 
> Accept-xmlns: */xhtml;q=1.0, */svg;q=0.9, */MathML;q=0.7
> or
> Accept-xmlns: W3/xhtml;q=1.0, W3/svg;q=0.9, W3/MathML;q=0.7

I prefer the second form, but I believe that we can be still briefer while
losing no functionality:

Accept-xmlns: xhtml;q=1.0, svg;q=0.9, MathML;q=0.7

As I imagine things, the IANA will maintain a registry of namespace tokens
for easy use in content negotiation and delivery. Namespaces with no
registered token will have to use the full URI delimited by less-than signs
and greater-than signs.

> How [should the user agent] express that it can render generic XML+CSS
> - or some other stylesheet language?? Yet another header?

Rather than extending HTTP until it tears at the seams, I think that we
should rely more on Composite Capabilties/Preferences Profile (CC/PP). I
admit that I've barely studied CC/PP, but it seems like a more comprehensive
solution.

How, for instance, can a user agent ask for particular mixtures of namespace
while avoiding other mixtures? A user agent might handle XHTML containing
MathML and SVG containing SMIL, but not handle XHTML containing SVG.

(And where would be appropriate to discuss these issues? www-tag?)

-- 
Etan Wexler <mailto:ewexler@stickdog.com>
Ceci nčest pas un « Fugazi shirt. »
Received on Thursday, 17 April 2003 04:48:00 GMT

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