RDF support for anonymous users in Drupal

[Stephane Corlosquet]

Hi,

I've left out the support for anonymous users support in the initial patch which was committed to Drupal core as I wanted to think about it a little bit more. Time helps to come up with better ideas (I hope!), but we should not wait too much longer. I'm just about to propose a patch to add support for exporting RDFa for anonymous users but I'd like to make sure we get this right as this will be set in stone after Drupal 7 is released.

See some example:
- Registered user comment: http://drupalrdf.openspring.net/comment/1#comment-1
- Anonymous user comment: http://drupalrdf.openspring.net/comment/7#comment-7

In the case of a non registered user leaving a comment, Drupal offers to leave her name, homepage and email address (though the email address is not displayed for privacy reasons). The default markup is:

<a href="http://openspring.net/" rel="nofollow" class="username">Stephane Corlosquet (not verified)</a>

We don't have a user profile URI here, but a homepage URL only. From the initial feedback I got earlier, it seems we could create a blank node of type foaf:Agent or sioc:User and use foaf:page to link it to the homepage. I suggest the following markup:

<span rel="sioc:has_creator">
  <a typeof="sioc:User" rel="foaf:page nofollow" href="http://openspring.net/">Stephane Corlosquet (not verified)</a>
</span>


To keep things simple, I'm very tempted to reuse the sioc:User mapping we already have for the regular registered user. Is it ok not to use a foaf:Agent or foaf:Person in this case, and link a sioc:User to a homepage with foaf:page?

Steph.

[Alexandre Passant]

On 23 Oct 2009, at 17:35, Toby Inkster wrote:

> On Fri, 2009-10-23 at 11:48 -0400, Stephane Corlosquet wrote:
>> To keep things simple, I'm very tempted to reuse the sioc:User
>> mapping
>> we already have for the regular registered user. Is it ok not to
>> use a
>> foaf:Agent or foaf:Person in this case, and link a sioc:User to a
>> homepage with foaf:page?
>

> sioc:has_creator links to a sioc:User by definition, not to a
> foaf:Agent
> or foaf:Person.

Indeed, if you want to use a sioc:User then it should go with
sioc:has_creator but if you require a foaf:Agent, then use foaf:maker.
However, both foaf:page / foaf:homepage have owl:Thing as a range so
you can use it in combination with sioc:User.
I'd yet avoid foaf:homepage as this is an IFP, and may lead to weird
things (esp. for untrusted users)

Alex.

>
> By the way, on http://drupalrdf.openspring.net/node/3 the
> sioc:reply_of
> links aren't getting picked up. They're "masked" by the
> property="content:encoded" of the parent <div> element. A slightly
> annoying feature of RDFa is that any property which results in an
> rdf:XMLLiteral causes any RDF on descendant elements to be ignored.
>
> Possible solution...
>
> Drop this:
>
> <span rel="sioc:reply_of" resource="/node/3" />
>
> Change this (lines wrapped for readability):
>
> <h3 property="dc:title" datatype="">
> <a href="/comment/1#comment-1">a first comment to the blog post</a>
> </h3>
>
> To this:
>
> <h3 property="dc:title" datatype="">
> <a about="/node/3" rel="sioc:has_reply" rev="sioc:reply_of"
> href="/comment/1#comment-1">
> a first comment to the blog post
> </a>
> </h3>
>
> --
> Toby A Inkster
> <mailto:ma...@tobyinkster.co.uk>
> <http://tobyinkster.co.uk>
>
> _______________________________________________
> foaf-dev mailing list
> foaf...@lists.foaf-project.org
> http://lists.foaf-project.org/mailman/listinfo/foaf-dev

--
Dr. Alexandre Passant
Digital Enterprise Research Institute
National University of Ireland, Galway
:me owl:sameAs <http://apassant.net/alex> .

[Stephane Corlosquet]

Thanks Toby and Alex for your feedback,

sioc:has_creator links to a sioc:User by definition, not to a foaf:Agent

or foaf:Person.

right, so sioc:User it is.

By the way, on http://drupalrdf.openspring.net/node/3 the sioc:reply_of
links aren't getting picked up. They're "masked" by the
property="content:encoded" of the parent <div> element. A slightly
annoying feature of RDFa is that any property which results in an
rdf:XMLLiteral causes any RDF on descendant elements to be ignored.

agreed. that's what I explained at [1] and that's due to Drupal internals. We're working on a solution which will in fact move the property attribute one level down on a new tag which will wrap the content. That way the property attribute will be on a tag at the same level (sibling) as

       <span rel="sioc:reply_of" resource="/node/3" />

that should in theory work and produce the intended RDFa...

Steph.

[1] http://drupal.org/node/538164#comment-2182794

[Stephane Corlosquet]

(cc'ing the public mailing list)

On Sun, Oct 25, 2009 at 9:22 PM, Uldis Bojars <capt...@gmail.com> wrote:

Hi Stephane,

What you propose looks fine, especially considering there were no
strong objections on the mailing list.

Having a FOAF Person / Agent (which would add complexity for you) for
anonymous persons can be somewhat more precise, but it boils down to
if you believe you can say that homepage is an IFP or not. If you
think homepage is an IFP for a person, then using FOAF has some more
knowledge than just a sioc:User.

On the other hand using sioc:User can be just as good. After all, the
main thing is to put the data out there. Then people can make use of
it, elaborate the data, etc.

yes, here using sioc:User for any type of user keeps the implementation simple.
 

BTW: How, based on this RDF data, can you know which user is anonymous
and which is a registered user?

Both are sioc:User, but registered users have a URI, while anonymous are blank nodes (and just have a foaf:page to their homepage). So SPARQL should be able to distinguish the two, I think. I just happened to talk to Andreas Langegger this morning over breakfast, he suggested to use the isBlank operator.

Steph.
 

CC: Alex

Cheers,
Uldis