W3C home > Mailing lists > Public > www-tag@w3.org > January 2002

Re: Media types

From: Roy T. Fielding <fielding@ebuilt.com>
Date: Thu, 17 Jan 2002 16:08:03 -0800
To: "Simon St.Laurent" <simonstl@simonstl.com>
Cc: www-tag@w3.org, ietf-xml-mime@imc.org
Message-ID: <20020117160803.B20375@waka.ebuilt.net>
On Thu, Jan 17, 2002 at 07:31:10PM -0500, Simon St.Laurent wrote:
> On Thu, 2002-01-17 at 18:18, Roy T. Fielding wrote:
> > I think the mistake is in assigning such messages a type that implies
> > it should be handled by a generic XML processor.  There is no such thing,
> No such thing?  There are all kinds of processing gidgets and storage
> systems that work on XML generically.  You might want to choose more
> precise language.

There are all types of procesing gadgets and storage systems that work on
bytes generically.  If that was a useful distinction at the message level
then there wouldn't have been any need for media types.  

> > even though it is possible to view all XML types via generic XML tools.
> Viewing is just one possibility.

Of course.  The point is that the media type indicates the purpose of the
message body by way of its most semantically meaningful data format.
Therefore, it is not useful to send something as application/xml unless
the sender specifically wishes it to be processed as generic XML. In all
other cases, there exists some semantically significant data format type
(which just happens to use XML as a structuring syntax) for which there
should be a corresponding Internet media type, and that media type is
what should be listed in Content-Type.  The number of potential xmlns
declarations within the XML structure of the data is not relevant to
how it should be processed by the MIME (or HTTP) user agent, even though
it may be relevant to whatever does the processing of the XML.

Received on Thursday, 17 January 2002 19:11:27 UTC

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