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RE: Impact of XML 1.1 and namespaces 1.1 on WebDAV

From: Julian Reschke <julian.reschke@gmx.de>
Date: Wed, 13 Nov 2002 23:58:06 +0100
To: "WebDAV" <w3c-dist-auth@w3.org>
Message-ID: <JIEGINCHMLABHJBIGKBCCEJMFMAA.julian.reschke@gmx.de>

(here's a minor update for usage during the IETF meeting)

Hi,

as the W3C is finishing these specs, I'd like to make the WG aware of the
questions we'll have to answer about how these changes impact WebDAV.

Changes that are IMHO relevant to WebDAV are:

1) The set of characters that can appear in an XML name has been extended
(it now includes more Unicode characters). Infosets using these names can
*not* be marshalled as XML 1.0 documents.

2a) The set of characters that can be marshalled as text data has been
extended to include the control characters 1..31 (although only as character
reference; null is still forbidden). Again: infosets containing these
characters can *not* be marshalled as XML 1.0 documents.

2b) The characters 128..159 (Unicode control characters) can not be
marshalled as is (only as character references). Infosets containing these
characters can be marshalled as XML 1.1 documents, but requires
serialization as character references (which will be XML 1.0 compatible as
well).

3) XML 1.1 processors may reject documents if they contain non-normalized
Unicode (yes, this is optional).

4) Namespaces 1.1 allows IRIs rather than only URIs as namespace names.

One possible position would be that we just ignore it. Nothing would change
immediately. However we lose the ability to marshall "any" kind of XML
through WebDAV properties.

Allowing XML 1.1 request bodies for PROPPATCH *will* have a big impact. For
instance, properties are identified by QNames, and with XML 1.1 both the
valid character sets for the namespace name (can now be a IRI and thus
contain non-quoted non-ASCII characters) and the local name (just a bigger
subset of Unicode) will change. It may not be possible to marshall these
"extended" property names back to a client that only understands XML 1.0.

Similar problems appear with control characters in property values -- once
they appear in a property value, the property can only be marshalled back to
clients with XML-1.1 compliant parsers.

At this point, I don't have a recommendation how to treat this, but maybe
some more WG members should take a look at the current drafts. XML
namespaces 1.1 allowing IRIs is currently under debate on the W3C TAG
(Technical Architecture Mailing List) -- people interested in this topic
might want to check the mailing list archives.

Julian

--
<green/>bytes GmbH -- http://www.greenbytes.de -- tel:+492512807760

> -----Original Message-----
> From: Julian Reschke [mailto:julian.reschke@gmx.de]
> Sent: Tuesday, October 22, 2002 10:04 AM
> To: WebDAV
> Subject: Impact of XML 1.1 and namespaces 1.1 on WebDAV
>
>
> Hi,
>
> as the W3C is finishing these specs, I'd like to make the WG
> aware of the questions we'll have to answer about how these
> changes impact WebDAV.
>
> Changes that are IMHO relevant to WebDAV are:
>
> 1) The set of characters that can appear in an XML name has been
> extended (it now includes more Unicode characters).
>
> 2) The set of characters that can be marshalled as text data has
> been extended to include the control characters 1..31 (although
> only as character reference; null is still forbidden)
>
> 3) XML 1.1 processors may reject documents if they contain
> non-normalized Unicode (yers, this is optional).
>
> 4) Namespaces 1.1 allows IRIs rather than only URIs as namespace names.
>
> One possible position would be that we just ignore it. Nothing
> would change immediately. However we lose the ability to marshall
> "any" kind of XML through WebDAV properties.
>
> Allowing XML 1.1 request bodies for PROPPATCH *will* have a big
> impact. For instance, properties are identified by QNames, and
> with XML 1.1 both the valid character sets for the namespace name
> (can now be a IRI and thus contain non.quoted non-ASCII
> characters) and the local name (just a bigger subset of Unicode)
> will change. It may not be possible to marshall these "extended"
> property names back to a client that only understands XML 1.0.
>
> Similar problems appear with control characters in property
> values -- once they appear in a property value, the property can
> only be marshalled back to clients with XML-1.1 compliant parsers.
>
> At this point, I don't have a recommendation how to treat this,
> but maybe some more WG members should take a look at the current drafts.
>
> Julian
> --
> <green/>bytes GmbH -- http://www.greenbytes.de -- tel:+492512807760
>
Received on Wednesday, 13 November 2002 17:58:42 GMT

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