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RE: contents of src and dst XML elements

From: Yaron Goland <yarong@microsoft.com>
Date: Wed, 10 Feb 1999 11:42:17 -0800
Message-ID: <3FF8121C9B6DD111812100805F31FC0D08792EC9@RED-MSG-59>
To: "'Jim Davis'" <jdavis@parc.xerox.com>, w3c-dist-auth@w3.org
Jim, the source of your confusion is that the spec doesn't do a good job of
defining how we use the value argument in defining XML elements. XML DTDs
fail to provide sufficient granularity for us to define the exact syntax of
the character content of an XML element. Therefore we use the value argument
to provide BNF which should be used to define the contents of the XML
element. Sections 12.4.1 and 12.4.2 both clearly define their values as URI.
Following the same BNF rules used in RFC 2068 once we define a BNF element
we do not redefine it for subsequent use. The BNF token URI was defined in
section 12.3, the definition of HREF. Therefore the value of src and dst
elements should be the same as the value of an HREF, a URI. Thus the example
in 13.10.1 is correct.

To address your particular example your friend should use
<src>http://foo.bar/program<byte-range><start>100</start><length>255</length
></byte-range></src>. According to the WebDAV XML ignore rules defined in
section 14 and discussed further in section 23.3 any existing WebDAV system
handed that src element MUST ignore the byte-range element and its content.
Thus an existing WebDAV system handed the previous MUST treat it as if it
received <src>http://foo.bar/program</src> or it is in gross violation of
the most basic extensibility mechanism in WebDAV.

				Yaron

> -----Original Message-----
> From: Jim Davis [mailto:jdavis@parc.xerox.com]
> Sent: Wednesday, February 10, 1999 10:00 AM
> To: w3c-dist-auth@w3.org
> Subject: contents of src and dst XML elements
> 
> 
> The spec (RFC 2518) is inconsistent about the expected 
> contents of the src
> and dst XML elements.  In particular are they supposed to 
> contain an href
> XML element, or a 'raw' URI.
> 
> 1. The description of the link XML element (12.4) says:
> 
>    The values in the href XML elements inside
>    the src and dst XML elements of the link XML element MUST NOT be
>    rejected if they point to resources which do not exist."
> 
> which implies the former.
> 
> 2.  The definition of dst (12.4.1) and src (12.4.2) say that 
> the value is a
> URI and the contents is PCDATA, which implies the latter.
> 
> 3. The example of the source property (13.10.1) shows src 
> without an href
> 
>     <D:src>http://foo.bar/program</D:src>
> 
> So which is it?
> 
> One reason I ask is that someone asked me how to express anchors with
> smaller granularity than an entire resource, for example byte 
> ranges or
> Xpointers.
> 
> Could I write, e.g.
> 
> <src><href>http://foo.bar/program</href>
>      
> <byte-range><start>100</start><length>255</length></byte-range></src>
> 
> 
Received on Wednesday, 10 February 1999 14:42:23 GMT

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