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Re: link metadata cannot override server media type

From: Brad Porter <brad@tellme.com>
Date: Fri, 07 Feb 2003 13:21:34 -0800
Message-ID: <3E44235E.214285EC@tellme.com>
To: Chris Lilley <chris@w3.org>
Cc: www-voice@w3.org, skw@hplb.hpl.hp.com, timbl@w3.org, connolly@w3.org, Scott McGlashan <scott.mcglashan@pipebeach.com>

By the way, just to be clear, I personally completely agree with the
architectural impurity of having local type information take precedence.
Though I also completely agree with fact that unregistered mime types exist and
web server configurations are not always correct.  Which is why I'm very keen
to have a definitive statement and a practical plan to make the choice stick,
as when it comes to a choice of being conformant or working with a wider range
of content providers, business motivations can prevail.

(comments and links embedded below)

--Brad


Chris Lilley wrote:

> On Friday, February 7, 2003, 8:59:40 PM, Brad wrote:
>
> BP> Dan,
>
> BP> Hopefully you didn't intend your comments to sound as inflamatory
> BP> as they might be interpreted.
>
> I am sure Dn did not intend to be inflamatory, any more than the
> initial response intended to be dismissive.
>
> BP> HTML and SMIL are in clear conflict on their use of the type attribute.
>
> Further, SMIL is in conflict with itself on the type attribute,
> depending on what element it is used and what the transport protocol
> is.
>
> SVG also uses a type attribute, as an informative hint and as a way to
> allow client-side selection from available media.
>
> BP>  Other specifications do not make a clear statement either way.
>
> They do, in fact.

In SMIL, local value takes precedence.  In HTML 4.01, type is a hint.  In XHTML
2.0 type is a definition of the allowable mime types for that resource
(http://www.w3.org/TR/xhtml2/mod-attribute-collections.html#adef_attribute-collections_type).

I find the statement of precedence ambiguous here as even though the type is
"advisory" it doesn't specify the precedence.
http://www.w3.org/TR/xmldsig-core/#sec-o-SignatureProperty

> BP> I have not seen a clear statement from the TAG yet.
>
> No, but you will and I hope you will take part in the preceeding
> discussion.
>
> Dans statement was a first heads up, as a matter of courtesy, that the
> TAG has an open issue on this subject.
>
> BP> I have seen
> BP> substantial email threads debating this issue in different working
> BP> groups without clear consensus.
>
> I would appreciate pointers to such, particularly those that
> considered retyping was desirable.

Here are some threads with relevant discussion that I found quickly.  There may
be more:

http://lists.w3.org/Archives/Public/www-html/1999Aug/0035.html
http://lists.w3.org/Archives/Public/www-html/1998Jan/0076.html
http://lists.w3.org/Archives/Public/www-html/1999May/0011.html
http://lists.w3.org/Archives/Public/www-html/2002Aug/0346.html
http://lists.w3.org/Archives/Public/w3c-wai-er-ig/2000Jan/0123.html


> BP> As is documented in the comments, we did work to address this
> BP> question with Martin. The working group did choose to follow the
> BP> language and use from SMIL for the reason that practically
> BP> speaking not all web servers return the right MIME type for the
> BP> content.
>
> Aha. We suspected that might be the reason. The problem is that this
> transparent fixup (and sniffing in general) has a number of
> undesirable knockon effects.
>
> BP> If you are not satisfied with the details provided in the
> BP> response, we would certainly be happy to discuss it further.
>
> I would encourage you to do this.
>
> BP> I personally would welcome the TAG addressing this issue and I
> BP> would be very willing to participate in such a discussion.
>
> Thanks, this is appreciated.
>
> --
>  Chris                            mailto:chris@w3.org
Received on Friday, 7 February 2003 16:22:27 GMT

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