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Re: [http-range14] how to publish RDF for Information Resources

From: Kjetil Kjernsmo <kjetil@kjernsmo.net>
Date: Sat, 18 Feb 2012 00:14:15 +0100
To: public-lod@w3.org
Message-id: <1564998.VF96HkBTra@owl>
On Friday 17. February 2012 02.19.15 Yang Squared wrote:
> Hi all,
> 
> I have an Web architecture question here.
> 
> Assume I have a information resource URI  http://example.com/homepage.html
> 
> I would like to publish a RDF metadata
> (http://example.com/data/homepagerdf) about
> this information resource (e.g. homepage isCreatedBy steve). What
> publishing mechanism can I use?

As far as I can tell, no special publishing mechanism is required.

> since http://example.com/homepage.html is an Information Resource, when
> dereferencing it, we should get that homepage.html document returned. How
> can we possible redirect to a RDF?

You shouldn't. They are two different resources, so they should be kept 
separate.

> 
> Content negotiation can use to serve two different representation of the
> resource, but both representation is for the same resource. So we cannot
> use it.

Right.

> Can anyone please suggest anything? 

You should just publish two different resources, the HTML document and metadata 
about it. They should have different URLs. 

> Or the conclusion is that the RDFa (or
> by using the link element to RDF) is the only way to publish RDF metadata
> for information resources?

No, you can use RDF, from
http://example.com/homepage.html
you return HTML and on 
http://example.com/data/homepagerdf
you may return something like 
<http://example.com/homepage.html> a foaf:Document ;
   dc:title "Steve's Homepage" ;
   dc:creator </steve#foaf> .

Now, can I suggest that your problem isn't how to publish, but rather how to 
link between them?

I would suggest that you use RDFa just for the linking, in the HTML document, 
you could have something like:

<link xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" rel="rdfs:seeAlso" 
href="http://example.com/data/homepagerdf"/>

> I am writing a paper and I would like to conclude that there will be no
> case that a hashURI publishing mechanism and 303 redirection can be used
> for Information Resource to publish RDF metadata. Do you have any object
> case?

I'm not quite sure of the implications of this. The hash URI can also be used 
as a fragment identifier, so my guess is that it wouldn't hold true in the case 
where a HTML document has a id="foo", in which case I my first hunch would be 
that <#foo> is an information resource, but I haven't actually thought about 
it, but you should consider the case if you make an argument about it.

> 
> ------------------------------
> One may recommend me to use RDFa. However, I consider that the RDFa is not
> ideal solution to publish Linked Data at all.
> First of all, embedding metadata together with data prohibits the
> independent curation of data and metadata.

Prohibits is a strong word. You could easily generate a web page that gets 
data from different sources, so it seems to me that this would be rather 
implementation specific, but I would agree that having two different resources 
is a better solution.

> Secondly, following the
> principles of the Web Architecture, any distinct resource of significance
> should be given a distinct URI, but in this approach a single URI is used
> to identify two information resources.

Indeed.

> In general, the RDFa embedded
> metadata approach can be replaced by using the <link> element href in XHTML
> to pointing to an external RDF document, where the rel=”meta” attribute can
> be used to indicate a relationship between resources.

Yes, but rel="meta" is not standardized as far as I know, see
http://www.w3.org/TR/html4/types.html#type-links
but it is rather common.

Best,

Kjetil
Received on Friday, 17 February 2012 23:14:47 UTC

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