W3C home > Mailing lists > Public > public-ldp-wg@w3.org > October 2012

Re: Review and Comments for Linked Data Platform FPWD

From: <steve.battle@sysemia.co.uk>
Date: Mon, 29 Oct 2012 19:42:07 +0000
Cc: "public-ldp-wg@w3.org" <public-ldp-wg@w3.org>
Message-Id: <101E0ADA-B811-468A-A968-0DA84ED32557@sysemia.co.uk>
To: David Wood <david@3roundstones.com>

On 28 Oct 2012, at 20:09, David Wood <david@3roundstones.com> wrote:

> Hi all,
> On Oct 28, 2012, at 11:23, David Wood <david@3roundstones.com> wrote:
>> - Section 5.4.8 says that "LDPC servers MUST interpret the null relative URI for the subject of triples... as referring to the entity in the request body". I understand why you would want to do that, but this is another case where implementors should be expected to scream.  You are asking them to introspect each triple during ingest just in case it might contain a null relative URI in the. subject position.  Then you are asking them to assign a URI for the resource before the parsing is known to be valid...
> The more I think about this, the more I think that this is a real problem for implementors.  Load speeds are always an issue and this would make things much worse.

David, no introspection is required, implementors would parse the POSTed RDF serialization with the document base set to the created resource URI. Expansion of the null relative URI proceeds according to the usual semantics of the language (at least for Turtle and RDF/XML). 

Admittedly generating the pesky null relative URIs on the client side presents a problem for many of today's tools - not entirely sure why.

> Would the WG accept a compromise?  I propose that clients MUST inform servers if they expect null relative URIs to be placed with the newly created URI for the resource.  That way, servers only need to incur the cost of the extra parsing and computation when they are told they need to do it.  Does that work?

In that case, how otherwise would we refer to the subject of the resource creation? The URI is unknown at the time of the POST.

> The flag can be passed to the server on the PUT URL by appending ?updateNull or some such.
> Regards,
> Dave

Steve Battle

Steve Battle
Semantic Engineer

E-mail: steve.battle@sysemia.co.uk
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Received on Monday, 29 October 2012 19:42:39 UTC

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