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Re: Section 5.4.8 null relative URI

From: Henry Story <henry.story@bblfish.net>
Date: Thu, 14 Mar 2013 14:20:50 +0100
Cc: public-ldp@w3.org
Message-Id: <34E3DB06-2E9E-4098-B7E0-7BDA211358BE@bblfish.net>
To: James Leigh <james@3roundstones.com>

On 14 Mar 2013, at 14:16, James Leigh <james@3roundstones.com> wrote:

> Hello ldp wg,
> http://www.w3.org/TR/2013/WD-ldp-20130307/#http-post-1 says:
>        5.4.8 In RDF representations, LDPC servers must interpret the
>        null relative URI for the subject of triples in the LDPR
>        representation in the request entity body as referring to the
>        entity in the request body. Commonly, that entity is the model
>        for the “to be created” LDPR, so triples whose subject is the
>        null relative URI will usually result in triples in the created
>        resource whose subject is the created resource.
> According to the above the term <> in turtle should be replaced with the
> to-be-created URI. However, the term <#adr> would still be resolved
> against the base URI of the document (either in the @base directive,
> Content-Location, or the request-uri). This will be hard to implement as
> most Turtle parsers do not expose the relative lexical term used in the
> document, but often only the absolute URI.

Well spotted. 

Clearly all <> and all <#uri> should be relative to the base.
A better way to specify this ( I have not read the whole spec, as I am 
following the teleconf right now ) would be to say that the whole RDF document
sent should be interpreted relative to the base URI of the created resource.

Then there is no need to specify all the different relative URI scenarios.
They all fall out.

> In Callimachus we experimented with overriding the base URI while
> parsing, but that proved problematic as many turtle writers don't allow
> explicit term representations and it prevented the use of general
> purpose entity handling (on either client or server). In the end we
> realized that by overriding the base URI we were essentially /forking/
> Turtle and only parsers/writers that were aware of this could be trusted
> preserve the null relative URI.
> Callimachus now requires the client to create a URI and use it in the
> RDF document. However, the server may end up substituting the primary
> URI with a canonical variant. I suggest the LDP spec adopt a similar
> approach.
> Regards,
> James

Social Web Architect

Received on Thursday, 14 March 2013 13:21:28 UTC

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