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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

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].



Simon Schenk | ISWeb | Uni Koblenz
Five sentences policy: http://five.sentenc.es/

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

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