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Re: Design rationale behind the current schema for Facebook Open Graph Protocol

From: Ian Jacobi <jacobi@csail.mit.edu>
Date: Sat, 1 May 2010 18:25:05 -0400
Cc: Fabien Gandon <Fabien.Gandon@sophia.inria.fr>, Ivan Herman <ivan@w3.org>, David Recordon <recordond@gmail.com>, Dan Brickley <danbri@danbri.org>, "public-xg-socialweb@w3.org" <public-xg-socialweb@w3.org>, Tim Berners-Lee <timbl@w3.org>, Marie-Claire Forgue <mcf@w3.org>, Murray Maloney <murray@muzmo.com>, Richard Cyganiak <richard@cyganiak.de>, RaphaŽl Troncy <raphael.troncy@eurecom.fr>, Bernard Vatant <bernard.vatant@mondeca.com>, Toby A Inkster <tai@g5n.co.uk>
Message-Id: <EC6CA948-0342-4185-820C-BE4081F00CDE@csail.mit.edu>
To: Peter Mika <pmika@yahoo-inc.com>
On May 1, 2010, at 5:35 PM, Peter Mika wrote:

> Hi Fabien,
>
> Thanks for encoding our agreement from the workshop! I agree with  
> all the points below.
>
> Two additional comments:
>
> #1
>
> To strengthen commitment,  I would still encourage us to create a  
> custom XSLT that maps OGP to the desired representation in RDF/XML.  
> I'm not sure RIF or SPARQL Construct is powerful enough to express  
> this mapping, and almost everyone has an XSLT parser at hand.
>
> Would you take a crack at it? In a similar fashion, an OGP to JSON  
> mapping would be also highly desirable, otherwise implementations  
> will diverge on the JSON serialization.

I would be more than happy to try my hand at a RIF variant of the  
N3Rules file I wrote up and posted on the EtherPad page.  (Sandro in  
particular was insistent that I use RIF instead of N3Rules when  
writing the original file, so I know there's some desire for it.)  I  
don't think RIF would necessarily preclude an implementation (and the  
default set of built-ins might have capitalization, which cwm does not  
currently do with strings (as best I can tell).

> #2
>
> The four generic attributes are required, i.e. something is not an  
> OGP document unless it has all four  (per spec, but maybe David can  
> comment).
>
> It seems tricky to model this without a class (what would you put  
> the constraint on?), so maybe time to introduce an og:Document class  
> as a holder for these properties.

I suspect this is the case.  We would need to bring in OWL to express  
this though.

>
> Peter
>
> p.s. Tools are already diverging? It looks like IMDB has OGP data,  
> but this tool listed on the OGP page doesn't find it:
>
> http://www.opengraph.in/?url=http%3A%2F%2Fwww.imdb.com%2Ftitle%2Ftt1315981%2F&format=html

I actually ran into this while testing my N3Rules file.  David stated  
that IMDB was using an earlier 'pre-release' version of OGP and thus  
does not reflect the current standard (e.g. the old "object_type" meta  
tag vs. "og:type").

Ian
Received on Sunday, 2 May 2010 19:30:33 GMT

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