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Re: GRDDLing Metalink XML

From: Dan Connolly <connolly@w3.org>
Date: Fri, 10 Aug 2007 10:38:26 -0500
To: Danny Ayers <danny.ayers@gmail.com>
Cc: public-grddl-wg <public-grddl-wg@w3.org>
Message-Id: <1186760306.15648.568.camel@pav>

On Fri, 2007-08-10 at 12:03 +0100, Danny Ayers wrote:
> There may be a nice deployment in the pipeline, I'd appreciate another
> eyeball or two on things (- should also make a little extra tutorial
> material somewhere).
> 
> Metalink is an XML format for describing sets of downloadable files,
> primarily for use by download managers. It's got a significant amount
> of adoption, see:
> http://www.metalinker.org/

Hmm... I peeked at this a while back; the amount of adoption
wasn't as clear back then...

> (If this gets GRDDL-enabled ok, it could make a good inclusion for the
> press release).
> 
> Pre-GRDDL, danbri started discussion with them (specifically Anthony
> Bryan) about expressing the data in RDF, and provided code to do a
> translation/mapping. Which is great, but would only work where
> deployed, and the metalink XML can be produced/hosted by anyone.
> Anthony recently contacted me re. GRDDL, and I've just done some XSLT
> for it, links below.
> 
> The namespace URI is that of their homepage, which currently just has
> an HTML representation. Seems like there are two nice ways of
> GRDDL-enabling the format: RDF through conneg, tweaking the homepage
> HTML. I'd appreciate an eyeball check on these:
> 
> In .htaccess, same dir as the homepage:
> 
> AddType application/rdf+xml .rdf
> RewriteEngine On
> RewriteRule ^index.html$ index.rdf
> 
> in index.rdf :
> 
> <rdf:RDF
>   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
>   xmlns:dataview="http://www.w3.org/2003/g/data-view#">
>  <rdf:Description rdf:about="http://www.metalinker.org/">
>    <dataview:namespaceTransformation
>        rdf:resource="http://www.metalinker.org/metalink2rdfxml.xsl"/>
>  </rdf:Description>
> </rdf:RDF>
> 
> Or in the HTML:
> 
> <head profile="http://www.w3.org/2003/g/data-view#">
> <link rel="namespaceTransformation"
> href="http://www.metalinker.org/metalink2rdfxml.xsl" />
> ...

That's not quite enough. You need something to turn
that rel="namespaceTransformation" link to RDF; i.e.:

<link rel="transformation"
       href="http://www.w3.org/2003/g/glean-profile" />


> Here's the latest XSLT, some mapping notes in the top of it:
> 
> http://n2.talis.com/svn/playground/danja/metalink/metalink2rdfxml.xsl
> 
> There's a simple sample input/output (generated using metalink creator,
> describing the XSLT):
> 
> http://n2.talis.com/svn/playground/danja/metalink/samples/generated.metalink
> 
> http://n2.talis.com/svn/playground/danja/metalink/samples/self.metalink.rdf
> 
> A more complete sample output is at:
> 
> http://n2.talis.com/svn/playground/danja/metalink/output.rdf

Hmm... xmlns="http://www.metalinker.org/"
that means that <Metalink ... turns
into http://www.metalinker.org/Metalink , which is 404.

It looks like there's an XML schema at
  http://www.metalinker.org/schema/3.0/metalink.xsd

I'd suggest an RDF schema somewhere near there, and
using
 xmlns="http://www.metalinker.org/schema/3.0/metalink#"
or
 xmlns="http://www.metalinker.org/schema/3.0/metalink_terms#"


> Cheers,
> Danny.
> 
-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Friday, 10 August 2007 15:38:43 GMT

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