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Re: IBM Graph Update Protocol document

From: Kjetil Kjernsmo <Kjetil.Kjernsmo@computas.com>
Date: Tue, 14 Jul 2009 14:08:05 +0200
Message-ID: <3AB73B68D1E8054D83E06CE02A1DEF2E406EEF@ATLAS.computas.int>
To: "Simon K Johnston" <skjohn@us.ibm.com>, <public-rdf-dawg@w3.org>
Hi Simon, All,

I think this is a very interesting proposal. I have a few comments.

First, in both replace graph and delete graph, the text says that the request should be made against the {graph-store} URI. Is this correct? Shouldn't it be the {graph-uri}? It seems to be the latter in the list earlier in the document and the following examples, and it seems to be the right thing. 

I see two main issues with respect to the proposals that have been circulating around here. 

The largest issue is whether it should be possible to manipulate graphs that has a graph-URI which is not dereferenceable on the host of the SPARQL endpoint, i.e. if the endpoint is http://example.org/sparql should it be possible to manipulate a graph with the URI http://graphs.example.com/graph/dahut ?
As far as I can see from your proposal, it would be possible to insert such a graph by using the Graph header, but no further manipulation would be possible. Is that correct?

This issue seems to be where Simon Schenk and I went in diametrically different directions; I feel that manipulating those graphs should be time-permitting only, whereas Simon felt we should do only that and that the case where the graph-uri can be manipulated directly is not very interesting. I suppose he is on vacation and cannot correct me if I misrepresent his opinions, if I do it is unintentional. 

The other issue you bring to the table, which is new I believe, is the PATCH HTTP verb. This never made it into HTTP, did it? I think the ideas that have circulated around here is that PUT will insert a graph if it doesn't exist and replace if it does. POST will insert if the graph doesn't exist, and update if it does. 

I think the ideas expressed in your document is well aligned with what the group has been discussing previously, except for this, so I'd like to bring that to the surface: Do people want to standardise a Graph header and a PATCH verb as extensions to HTTP?

I hope that we can reach a consensus very soon on whether we should only manipulate graph URIs that can be dereferenced. The other details can be dealt with later, but I think it is an interesting topic.

Best,

Kjetil
Received on Tuesday, 14 July 2009 12:08:54 GMT

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