Re: ISSUE-84 (Cool URIs and HTTPRange-14): The W3C TAG has asked us to mention that the use of fragment identifiers can be problematic [LC Comment - RDFa Core 1.1]

On Feb 8, 2011, at 10:55 , Nathan wrote:

> Ivan Herman wrote:
>> Would it be possible to ask one of the TAG members a text that would satisfy them? I would hate to spend our time on wording when we have our hands full with other things...
> 
> Sounds like a good idea, because the text/html media type registration specifically says:
> 
>   For documents labeled as text/html, the fragment identifier
>   designates the correspondingly named element; any element may be
>   named with the "id" attribute, and A, APPLET, FRAME, IFRAME, IMG and
>   MAP elements may be named with a "name" attribute.
> 
> and we don't use @id or @name.
> 
> We do however allow authors to use URI-references in @href @src @about and @resource, and any of those URI-references may include a "fragment".
> 
> Thus, RDFa allows authors to make RDF statements about URIs which may contain a fragment, but does not provide a way for authors to use fragment identifiers within the media type text/html.
> 
> Due to this, I know I'd personally struggle to write text on this subject since RDFa doesn't use fragids, and prior to a dereferencing attempt URIs are opaque.

Indeed.

There may be one more additional feature we may want to add to the text, beyond what the TAG might give us: avoid using fragid-s in profile URI-s. That is the only URI that an RDFa processor will dereference, and two different URI-s differing by a fragid only will return the same graph. On the other hand, using two different URI-s for the same graph my make the local caching process inefficient (unless clients would strip the fragid part before caching but I would not expect them to do that...)

Ivan


> 
>> I guess Jonathan would be the best candidate. If we agree, I am also happy to contact him.
> 
> Agree (from me), I believe Jonathan has this as action-502 on the tag.
> 
> Best,
> 
> Nathan
> 
>> Ivan
>> On Feb 8, 2011, at 02:23 , RDFa Working Group Issue Tracker wrote:
>>> ISSUE-84 (Cool URIs and HTTPRange-14): The W3C TAG has asked us to mention that the use of fragment identifiers can be problematic [LC Comment - RDFa Core 1.1]
>>> 
>>> http://www.w3.org/2010/02/rdfa/track/issues/84
>>> 
>>> Raised by: Manu Sporny
>>> On product: LC Comment - RDFa Core 1.1
>>> 
>>> This is very informal, a formal request will come in a few weeks, but we need to start discussing this before the 2nd Last Call for RDFa Core goes out.
>>> 
>>> Basically the TAG wants to ask the RDFa WG not to fix the RDFa fragid problem, but to document it.
>>> 
>>> That is, somewhere in one of your rec-track (not necessarily 'normative') documents, there should be an explanation of the issue (fragid use implicitly encouraged by RDFa specs, but not described in any media type registration), as a sort of warning and disclaimer. Not to tell people don't do it, but to alert everyone that there's an issue with the specs.
>>> 
>>> Then maybe someone later can come along later and clean things up by fixing 3986, AWWW, the registrations, or something else.
>>> 
>>> The goal is for it to be possible to start with RFC 3986 and find through a sequence of normative documents some statement of what the fragid means. In the case of an important RDFa practice this isn't possible - you look at the text/html or application/xhtml+xml media type registration, and they have stories about fragids that don't include the RDFa use.
>>> 
>>> 
>>> 
>>> 
>> ----
>> Ivan Herman, W3C Semantic Web Activity Lead
>> Home: http://www.w3.org/People/Ivan/
>> mobile: +31-641044153
>> PGP Key: http://www.ivan-herman.net/pgpkey.html
>> FOAF: http://www.ivan-herman.net/foaf.rdf
> 


----
Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
PGP Key: http://www.ivan-herman.net/pgpkey.html
FOAF: http://www.ivan-herman.net/foaf.rdf