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Re: ldp-ISSUE-90 (Named Graph): An LDPC/LDPR is a Named Graph [Linked Data Platform Spec]

From: Alexandre Bertails <bertails@w3.org>
Date: Sun, 24 Nov 2013 09:55:35 -0500
Message-ID: <52921367.2060709@w3.org>
To: Eric Prud'hommeaux <eric@w3.org>, Linked Data Platform Working Group <public-ldp-wg@w3.org>
On 11/24/2013 09:42 AM, Eric Prud'hommeaux wrote:
> * Linked Data Platform (LDP) Working Group Issue Tracker <sysbot+tracker@w3.org> [2013-11-22 21:22+0000]
>> ldp-ISSUE-90 (Named Graph): An LDPC/LDPR is a Named Graph [Linked Data Platform Spec]
>>
>> http://www.w3.org/2012/ldp/track/issues/90
>>
>> Raised by: Alexandre Bertails
>> On product: Linked Data Platform Spec
>>
>> An LDPC/LDPR acts as a Named Graph (now defined in RDF 1.1 [1]). An HTTP GET on an LDPR URL should return its representation, and *nothing* else.
>>
>> The specification currently says:
>> [[
>> 4.3.3 LDP servers MUST provide a text/turtle representation of the requested LDPR [TURTLE].
>> ]]
>
> Is the goal to prohibit content negotiation to other representations?

Indeed, my "nothing else" was only for the representation. What I
meant is that in the case of an RDF Resource, only the triples that
belong to that resource must be returned.

>
>
>> I propose that the specification explicitly refers to RDF Named Graphs and makes the constraint on the GET explicit.
>
> Referring to named graphs implies an RDF dataset in all specs that refer to named graphs (SPARQL, Trig, RDF Concepts). Are there specific dataset features that you would like to enable in LDP?

No sure I understand your comment. I was just saying that with LDP,
the Web itself is an RDF dataset. And I was just referring to the
definition of Named Graph in RDF 1.1.

>
>
>> This does not prevent one to later define a service (eg. SPARQL) which would allow a user to retrieve the representations of an LDPC and its LDPR in one single request.
>>
>> Also, all the examples (eg. 1, 2, 9, etc.) with GETs on LDPCs must not return the content of the "contained" LDPRs. They should be rewritten in terms of several GETs, one for the LDPC and one for each LDPR.
>
> I read this as a proposal to change
> <https://dvcs.w3.org/hg/ldpwg/raw-file/default/ldp.html#ldp-rdfconcepts-extra-triples-members>
> from
> [[
> The representation of an LDPC can include an arbitrary number of
> additional triples whose subjects are the members of the container, or
> that are from the representations of the members (if they have RDF
> representations). This allows a LDP server to provide clients with
> information about the members without the client having to do a GET on
> each member individually.
> ]]
> to
> [[
> The representation of an LDPC MUST NOT include any
> additional triples whose subjects are the members of the container, or
> that are from the representations of the members (if they have RDF
> representations).
> ]]

Almost. A triple whose subject is a member of the container might me
fine if it belongs to the container itself, and not the member
document. For example, an LDPC might return some server-managed
metadata associated with the members.

So a better text would be:

[[
The representation of an LDPC MUST NOT include any additional triples
that are from the representations of the members (if they have RDF
representations).
]]

Alexandre.

>
>> Alexandre.
>>
>> [1] http://www.w3.org/TR/rdf11-concepts/#dfn-named-graph
>>
>>
>>
>
Received on Sunday, 24 November 2013 14:55:20 UTC

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