W3C home > Mailing lists > Public > public-rdf-dawg@w3.org > July to September 2009

Re: Drawing the line on HTTP "Case 2b"

From: Simon Schenk <sschenk@uni-koblenz.de>
Date: Tue, 28 Jul 2009 11:40:06 +0000
To: Kjetil Kjernsmo <Kjetil.Kjernsmo@computas.com>
Cc: public-rdf-dawg@w3.org
Message-Id: <1248781207.11715.82.camel@tweety>
Sorry for the late reply due to vacation.

Am Dienstag, den 14.07.2009, 16:00 +0200 schrieb Kjetil Kjernsmo:
> Some time ago we discussed a HTTP based update scenario which Steve
> dubbed case 2b:
> http://lists.w3.org/Archives/Public/public-rdf-dawg/2009AprJun/0306.html
> 
> I'm trying to figure out where to draw the line on where this is
> actually needed.
> Consider the case where your SPARQL endpoint is at
> http://example.org/sparql and you want to insert a few triples into a
> graph named http://graphs.example.org/graph/dahut.
> 
> With the language, you can do this by POSTing
> 
> INSERT DATA INTO <http://graphs.example.org/graph/dahut> {
>   <some> ex:triples <here> .
> }
> 
> to endpoint. Now, the question is whether this should be possible to
> do with the protocol as well.
> 
> I believe that it isn't quite as Steve says in the message above, the
> line can't be drawn at "where the graph URI does not 
> start with the URI of the endpoint", since it is trivial to implement
> a server so that a
> PUT http://graphs.example.org/graph/dahut
> with the triples inserts those triples to the
> http://example.org/sparql endpoint if it has privileges to do so.
> 
> What remains is thus the cases where it doesn't have the privileges,
> an obvious example is if you want to insert triples into e.g. a local
> copy of DBpedia and you want to retain its graph name
> http://dbpedia.org
> It could also be that the server cannot know the credentials to
> interact with the endpoint or they cannot be forwarded from the
> original client. I suppose the latter is hard to achieve with digest
> authentication?
> 
> In conclusion, I think we can say that the the feature is about
> manipulating the content of graphs when the client is not privileged
> to PUT, POST or DELETE the graph URI.

I disagree. The question is not just credentials. An obvious use case
would be a working copy of my foaf file, which I use for editing. I
certainly have the privileges to update the actual graph, but maybe I
would like to have a copy in a GRAPH store, which can be used for
fiddling around without damaging the actual graph. Another example would
be the dozens of personal copies of DBPedia, which might still be named
<http://dbpedia.org>.

One does not always want automatic updates at the graph URI, even if
this would be technically feasible. That is the reason, why I referred
to "the copy of the graph held by the graph store" in [1].

Cheers,
Simon

[1]
http://lists.w3.org/Archives/Public/public-rdf-dawg/2009AprJun/0335.html

-- 
Simon Schenk | ISWeb | Uni Koblenz
http://isweb.uni-koblenz.de
http://www.uni-koblenz.de/~sschenk
Five sentences policy: http://five.sentenc.es/

Received on Tuesday, 28 July 2009 11:40:44 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 16:15:39 GMT