Re: Facebook Linked Data

On 9/26/11 11:05 AM, Alvaro Graves wrote:
> Hi Sebastian,
>
> AFAIK it's not a bug, but a feature :). This is done to comply with 
> the httpRange-14 issue (i.e., you can't retrieve a person through HTTP 
> but you can retrieve a document _about_ a person through HTTP). Since 
> a person and a document about a person are different entities, they 
> should have different URIs.
>
> http://www.w3.org/2001/tag/issues.html#httpRange-14

In alternative lingo, its a feature that results in a fine grained data 
object that's endowed with:

1. a Distinct and Unambiguous Identifier (de-referencable HTTP URI based 
Name)
2. structured Data Representation via an EAV/SPO based directed graph
3. a Distinct Data Access Address (URL).

We don't have to bring httpRange-14 and its timeless imbroglio into 
every conversation re. Linked Data :-)

This is just about the basic principle of Object Identity [1] exploited 
via ingenious useof de-referencable URIs.

Links:

1. 
http://www.cs.cmu.edu/afs/cs.cmu.edu/user/clamen/OODBMS/Manifesto/htManifesto/node4.html 
-- Object Identity

Kingsley
>
> ----
> Alvaro Graves
>
> On Mon, Sep 26, 2011 at 7:46 AM, Sebastian Schaffert 
> <sebastian.schaffert@salzburgresearch.at 
> <mailto:sebastian.schaffert@salzburgresearch.at>> wrote:
>
>     Dear Jesse,
>
>     Thanks for the effort! I am just experimenting with this. If I
>     request my own Vanity URL
>
>     http://graph.facebook.com/sebastian.schaffert
>
>     The data I get back is:
>
>     @prefix rdf: <http://www.w3.org/1999/02/22-df-syntax-ns#> .
>     @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
>     @prefix owl: <http://www.w3.org/2002/07/owl#> .
>     @prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
>     @prefix api: <tag:graph.facebook.com
>     <http://graph.facebook.com>,2011:/> .
>     @prefix og: <http://ogp.me/ns#> .
>     @prefix fb: <http://ogp.me/ns/fb#> .
>     @prefix : <http://graph.facebook.com/schema/~/
>     <http://graph.facebook.com/schema/%7E/>> .
>     @prefix user: <http://graph.facebook.com/schema/user#> .
>     </561666514#>
>            user:id "561666514" ;
>            user:name "Sebastian Schaffert" ;
>            user:first_name "Sebastian" ;
>            user:last_name "Schaffert" ;
>            user:link <http://www.facebook.com/sebastian.schaffert>
>
>
>
>     Now the problem I see here is that the URI I requested is not the
>     same URI as used in the subject of the RDF triples. Same holds btw
>     if I request the data using the ID including "#". Which is bad in
>     our case because we filter out triples that do not fulfill this
>     condition to avoid importing "invalid" data.
>
>     Also, the data should IMHO contain a @base statement defining the
>     base for the </561666514#>, because when importing the data the
>     original URI is sometimes no longer available.
>
>     Lastly, the returned data does not contain the trailing "."
>     required by turtle (see
>     http://www.w3.org/TeamSubmission/turtle/#sec-grammar-grammar).
>
>     Are there plans to fix this? For me, the more readable data would
>     look like this:
>
>     @prefix rdf: <http://www.w3.org/1999/02/22-df-syntax-ns#> .
>     @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
>     @prefix owl: <http://www.w3.org/2002/07/owl#> .
>     @prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
>     @prefix api: <tag:graph.facebook.com
>     <http://graph.facebook.com>,2011:/> .
>     @prefix og: <http://ogp.me/ns#> .
>     @prefix fb: <http://ogp.me/ns/fb#> .
>     @prefix user: <http://graph.facebook.com/schema/user#> .
>     <http://graph.facebook.com/sebastian.schaffert>
>            user:id "561666514" ;
>            user:name "Sebastian Schaffert" ;
>            user:first_name "Sebastian" ;
>            user:last_name "Schaffert" ;
>            user:link <http://www.facebook.com/sebastian.schaffert>
>
>
>
>     Am 23.09.2011 um 14:09 schrieb Jesse Weaver:
>
>     > APOLOGIES FOR CROSS-POSTING
>     >
>     > I would like to bring to subscribers' attention that Facebook now
>     > supports RDF with Linked Data URIs from its Graph API.  The RDF
>     is in
>     > Turtle syntax, and all of the HTTP(S) URIs in the RDF are
>     dereferenceable
>     > in accordance with httpRange-14.  Please take some time to check
>     it out.
>     >
>     > If you have a vanity URL (mine is jesserweaver), you can get RDF
>     about you:
>     >
>     > curl -H 'Accept: text/turtle' http://graph.facebook.com/<vanity-url>
>     > curl -H 'Accept: text/turtle' http://graph.facebook.com/jesserweaver
>     > If you don't have a vanity URL but know your Facebook ID, you
>     can use
>     > that instead (which is actually the fundamental method).
>     >
>     > curl -H 'Accept: text/turtle'
>     http://graph.facebook.com/<facebook-id>
>     > curl -H 'Accept: text/turtle' http://graph.facebook.com/1340421292
>     >> From there, try dereferencing URIs in the Turtle.  Have fun!
>     >
>     > Jesse Weaver
>     > Ph.D. Student, Patroon Fellow
>     > Tetherless World Constellation
>     > Rensselaer Polytechnic Institute
>     > http://www.cs.rpi.edu/~weavej3/ <http://www.cs.rpi.edu/%7Eweavej3/>
>     >
>     >
>     >
>     >
>     >
>
>     Sebastian
>     --
>     | Dr. Sebastian Schaffert sebastian.schaffert@salzburgresearch.at
>     <mailto:sebastian.schaffert@salzburgresearch.at>
>     | Salzburg Research Forschungsgesellschaft
>     http://www.salzburgresearch.at
>     | Head of Knowledge and Media Technologies Group +43 662 2288 423
>     <tel:%2B43%20662%202288%20423>
>     | Jakob-Haringer Strasse 5/II
>     | A-5020 Salzburg
>
>
>


-- 

Regards,

Kingsley Idehen	
President&  CEO
OpenLink Software
Web: http://www.openlinksw.com
Weblog: http://www.openlinksw.com/blog/~kidehen
Twitter/Identi.ca: kidehen