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Re: Question about "paths as URIs" in the BBC RDF

From: Yves Raimond <yves.raimond@gmail.com>
Date: Thu, 28 Jan 2010 20:58:36 +0000
Message-ID: <82593ac01001281258r22c4d1c4vb9e5fffb4132ee1a@mail.gmail.com>
To: Dan Brickley <danbri@danbri.org>
Cc: Ross Singer <rossfsinger@gmail.com>, Linked Data community <public-lod@w3.org>
On Thu, Jan 28, 2010 at 8:54 PM, Yves Raimond <yves.raimond@gmail.com> wrote:
> Hello!
>
> On Thu, Jan 28, 2010 at 8:36 PM, Dan Brickley <danbri@danbri.org> wrote:
>> On Thu, Jan 28, 2010 at 7:56 PM, Ross Singer <rossfsinger@gmail.com> wrote:
>>> Hi, I have a question about something I've run across when trying to
>>> parse the RDF coming from the BBC.  If you take a document like:
>>>
>>> http://www.bbc.co.uk/music/artists/72c536dc-7137-4477-a521-567eeb840fa8.rdf
>>>
>>> notice how all of the URIs are paths, but there's no xml:base to
>>> declare where these actual paths may reside.
>>>
>>> If I point rapper at that URI, it brings me back fully qualified URIs:
>>> <http://www.bbc.co.uk/music/artists/72c536dc-7137-4477-a521-567eeb840fa8#artist>
>>>
>>> but the only way I can figure it's able to do that is for the parser
>>> and the HTTP agent to be in cahoots somehow, which seems like a
>>> breakdown in the separation of concerns -- this document is useless,
>>> except in the context of living on www.bbc.co.uk.  The moment I cache
>>> it to my local system, if I'm understanding it correctly, it's now
>>> asserting these things about my filesystem (effectively).  Rapper now
>>> says:
>>> <file:///music/artists/72c536dc-7137-4477-a521-567eeb840fa8#artist>
>>>
>>> So my questions would be:
>>> 1) Is this "valid"?
>>> 2) If so, is there an expectation of the parser being aware of the URI
>>> of retrieval? (I have written my own set of parsers, so I'd need to
>>> rethink this assumption, if so)
>>> 3) How do other client libraries handle this?
>>
>> Hi Ross,
>>
>> The relevant specs are
>>
>> http://www.w3.org/TR/2004/REC-rdf-syntax-grammar-20040210/#section-Syntax-ID-xml-base
>>
>> "The XML Infoset provides a base URI attribute xml:base that sets the
>> base URI for resolving relative RDF URI references, otherwise the base
>> URI is that of the document. The base URI applies to all RDF/XML
>> attributes that deal with RDF URI references which are rdf:about,
>> rdf:resource, rdf:ID and rdf:datatype."
>
> This is only relevant for things like rdf:resource="some/path", not
> rdf:resource="/some/path". In the latter case, the URI will be
> resolved from the root path, in our case http://www.bbc.co.uk/ (this
> is the same in the corresponding XHTML pages, btw). I never took a
> look at the relevant spec (yes, I know, it's bad :-)), but all parsers
> seem to understand it correctly...
>

Actually, http://www.w3.org/TR/2001/REC-xmlbase-20010627/#syntax gives
an indication that this is the case. In the example, the xml:base
/hotpicks is resolved to "http://example.org/hotpicks"

Cheers,
y
Received on Thursday, 28 January 2010 20:59:09 UTC

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