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Re: W3C TAG Finding "The Self-Describing Web" has been published

From: Dan Brickley <danbri@danbri.org>
Date: Thu, 12 Feb 2009 16:01:17 +0100
Message-ID: <499439BD.6070109@danbri.org>
To: noah_mendelsohn@us.ibm.com
Cc: RDFa <public-rdf-in-xhtml-tf@w3.org>, www-tag@w3.org

+cc: rdfa tf

On 8/2/09 18:27, noah_mendelsohn@us.ibm.com wrote:
> I am pleased to announce that the W3C TAG has published a new Finding
> titled "The Self-Describing Web" [1].

Apologies for the poor timing, I have only just now noticed the issue.

I think there is a problem with the description of RDFa, as you are 
appending # onto the end of property URI namespaces, e.g. giving 
http://xmlns.com/foaf/0.1/#name instead of http://xmlns.com/foaf/0.1/name

In the Finding, you have FOAF examples, based on the RDFa tutorial. Eg:

     <div typeof="foaf:Person" xmlns:foaf="http://xmlns.com/foaf/0.1/"
     <p property="foaf:name">
     Alice Birpemswick

http://xmlns.com/foaf/0.1/ is indeed the correct FOAF namespace URI.

I have tried to configure it so that property and class URIs redirect 
with 303, per the http-range-13 resolution. I suspect the classes might 
be buggy at the moment, but properties work OK:

eg. http://xmlns.com/foaf/0.1/name

It currently redirects everything to the full FOAF spec (which should 
itself be content negotiable for RDF/XML describing the whole schema, 
and eventually use some RDFa too):

danbri$ telnet xmlns.com 80
Connected to xmlns.com.
Escape character is '^]'.
GET /foaf/0.1/name HTTP/1.1
Host: xmlns.com

HTTP/1.1 303 See Other
Date: Thu, 12 Feb 2009 14:53:15 GMT
Server: Apache/2.0.63 (Unix) PHP/5.2.6 mod_ssl/2.0.63 OpenSSL/0.9.7e 
mod_fastcgi/2.4.2 Phusion_Passenger/2.0.6 DAV/2 SVN/1.4.2
Location: http://xmlns.com/foaf/spec/
Vary: Accept-Encoding
Content-Length: 234
Content-Type: text/html; charset=iso-8859-1

My understanding of RDFa syntax, and what I see with parsers etc., is 
that the above markup corresponds to triples where the property URI is 
something like http://xmlns.com/foaf/0.1/name ... however in the Finding 
you have:

"""The predicates are all named with the same base URI 
http://xmlns.com/foaf/0.1/, for which the shorthand prefix foaf is 
established in the HTML. Using this syntax, the RDFa carries triples for 
relationships such as the full name of the contact 
(http://xmlns.com/foaf/0.1/#name), which is Alice Birpemswick, the 
e-mail address (http://xmlns.com/foaf/0.1/#mbox) which is 
mailto:alice@example.com, and so on. """

As far as FOAF is concerned, this RDFa issue will affect the whole 
narrative in the Finding, since our use of a / namespace means that 
property URIs are all rather different, and redirect as 303s. A # 
namespace would I guess work in the way described.

Hope this makes sense, and apologies again for not catching it early.



> [1] http://www.w3.org/2001/tag/doc/selfDescribingDocuments
> [2] http://www.w3.org/2001/tag/findings
> [3] http://www.w3.org/TR/webarch/
> --------------------------------------
> Noah Mendelsohn
> IBM Corporation
> One Rogers Street
> Cambridge, MA 02142
> 1-617-693-4036
> --------------------------------------
Received on Thursday, 12 February 2009 15:02:00 UTC

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