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RE: Are attributes (in particular, xml:lang) part of WebDAV property model?

From: Jim Whitehead <ejw@ics.uci.edu>
Date: Wed, 5 Aug 1998 15:23:10 -0700
To: Jim Davis <jdavis@parc.xerox.com>, w3c-dist-auth@w3.org
Message-ID: <004701bdc0bf$a0d76880$d115c380@galileo.ics.uci.edu>

> Does the WebDAV data model for properties say anything at all about the
> significance of attributes?  In particular, if a client does a PROPPATCH
> and specifies an attribute, will that attribute be returned by
> the PROPFIND?
>
> The reason I am concerned is that to compare two strings that hold natural
> language values (as opposed to, say, a date expressed in ISO
> 8601) one must
> know the language in which the strings were stored.  The xml:lang
> attribute
> (section 2.12 of the XML draft) seems ideal for this, but only if WebDAV
> requires servers to preserve this attribute in property values.
>
> If WebDAV does not requires this of *all* servers, would there be
> objection
> to stating that WebDAV servers that also support the DASL extensions MUST
> preserve this attribute?

The following is my interpretation (for properties) of the requirement in
Section 15 that "WebDAV applications MUST support the character set tagging,
character set encoding, and the language tagging functionality fo the XML
specification."

For dead properties, a WebDAV server MUST persistently store the xml:lang
attribute if specified in property values.

Since live properties can arbitrarily modify the value of a property, it is
possible that a server could change the language of a live property value,
and hence it is impossible to make across-the-board assertions about
xml:lang and live properties.  On the other hand, if xml:lang is submitted
as part of the value of a live property, and there is no compelling reason
to remove or modify it, then I would expect a server to maintain and
persistently store the xml:lang attribute. Since this sounds like a SHOULD
to me (i.e., you should do this unless you have a good reason not to), for
live properties a WebDAV server SHOULD persistently store the xml:lang
attribute if specified in property values.

That said, I do agree with Yaron that attributes are not as scalable as full
elements, and that they have nearly equivalent expressive power.  But, I
didn't design XML, and so this is how WebDAV should make use of the
existing, specified mechanism in XML for labeling the language of an XML
element.

- Jim
Received on Wednesday, 5 August 1998 18:39:04 GMT

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