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RE: rfc2518bis DAV DTD (was Re: How to use DTDs, or not ...)

From: Julian Reschke <julian.reschke@gmx.de>
Date: Wed, 15 Oct 2003 12:06:28 +0200
To: <dennis.hamilton@acm.org>, <w3c-dist-auth@w3.org>
Message-ID: <JIEGINCHMLABHJBIGKBCMEAFINAA.julian.reschke@gmx.de>


I appreciate the time you're spending thinking about this subject. The
question that started this thread was what to do with the DTD notation that
is used in current WebDAV specs and that disappeared in RFC2518bis. My
position is that we should keep it and make sure that the spec clearly says
what it means for developers.

Other comments inline...

> 4.	Concerning the question of whether or not Document Type
> Declarations (<!DOCTYPE ...>) should be allowed in the XML
> document prolog of DAV request and response bodies, I see my
> recommendation for 24.2 as orthogonal to that.
> Also, I don't believe there is agreement to disallow Document
> Type Declarations at this time.  (I will keep repeating that
> presence of a Document Type Declaration and using a
> non-validating processor are separate but interacting matters.)

Yes. They haven't been forbidden before, and they don't seem to cause harm.

> Dealing with a server that provides Document Type Declarations in
> responses is something I don't want to think about.  In practice,
> that borders on a hostile act, since it imposes processing on the
> client and has the interpretation of the response be
> unpredictable in some cases.  It raises the bar for universal
> client processors.

Nope. The spec should clearly state that messages must be processed in
non-validating mode. In this case, it's really irrelevant whether a DOCTYPE
is present (except for the well-known recursive entity substition problem).

> 6.	Is it worth it?  I don't know.  I demonstrated the degree
> to which it could be done.  Developers of other XML-family
> specifications have found it worthwhile.  Does it hurt?  How can it?
> Would I do it?  Yes.
> This can clearly be done.  Whether it is included in the
> specification or not seems to be the question.  We need some
> other countries to be heard from.

I don't argue with automatic "checking" (avoiding "validation" because it
implies DTD to many readers) of messages based on a formal description being
useful. However, we were discussing the role of DTD fragments in the spec
*as they are*. My take is that it's best to

- first get a consensus about what they are supposed to mean - I've been
repeating my proposal many times now (before *this* discussion started), and
I'd really like to see whether we finally agree on that

- then find out whether we can keep that syntax - I think it's worthwhole
keeping it for the simple reason that it's present on published specs

If we keep the syntax *and* agree about what it means, it will be simple to
specify a process by which an arbitrary WebDAV message can be transformed
into a format that *can* be validated.


<green/>bytes GmbH -- http://www.greenbytes.de -- tel:+492512807760
Received on Wednesday, 15 October 2003 06:07:46 UTC

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