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Re: Media types for XSL stylesheets



John Cowan writes:
> MURATA Makoto scripsit:
> 
> > I think that such an embedded portion INHERITS the media type of the 
> > document.  Even if a stylesheet linking PI specifies a different media type, 
> > it is merely ignored.
> 
> Not necessarily.  A portion of image/gif is by no means an image/gif.
> Media types exist so that uninterpreted bytes get an interpretation,
> but internal resources have already been interpreted.

The GIF format indeed defines a set of chunk codes, so embeddings in
GIF are implicitly typed by the GIF spec and do not need MIME.

On the other hand, if you have a format that allows a wide, maybe even
open-ended range of things to be embedded in it, such as a multipart
MIME message, or the SCRIPT element of HTML, then you need a more
flexible way to label the embedding. MIME types seem to do that very
well, so both these formats have adopted them as the labeling
mechanism.


That leads to another issue: MIME type are not only used to get the
interpretation started, but also to negotiate capabilities between a
client and a server, e.g., in HTTP. In that context, sending a
document with embedded XSL to a client that has indicated not being
able to handle XSL is not very smart.

In other words, that document with its embedded XSL needs not just a
MIME type for its first byte, but also a description (a "profile") of
the other capabilities a client needs. That would be something like a
CC/PP[1] profile, I assume, and inside that there *would* be an entry
that says "application/xsl" (or whatever the MIME type will be).

[1] http://www.w3.org/Mobile/CCPP/


Bert
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  Bert Bos                                ( W 3 C ) http://www.w3.org/
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