What's the status of validation for RDFa in HTML5?

Drupal 8 is moving towards HTML 5. A big question we get asked a lot is "Will my page validate if I use RDFa".

Does anyone know what the current status and plans are for validating RDFa in HTML 5?


the situation is as follows, at least for the W3C HTML5 validator: at this moment, that validator does not have yet an RDFa 1.1 module built in. That validator is, as you can imagine, very much in progress, and cannot be expected to be fully stable as long as the HTML5 suite itself is not stabilized (and that is still further away).

The real issue is, actually, manpower. It would perfectly possible to add an RDFa module to the validator, but we would need somebody who has some experience with Relax NG and corresponding Java programming, and who could contribute a module. I would be more than happy to put that person in contact with our guys at W3C to have the work done, because I would really really like to see that happening myself. So if you, or anybody else reading this, have somebody they know, speak up, contact me!

I also have a beta version of an RDFa 1.1 distiller at: http://www.w3.org/2007/08/pyRdfa/Shadow.html that can be used to extract RDF from an HTML5+RDFa file. It could/should be possible to put a layer on top of this service to provide some form of validation; indeed, the distiller itself returns error and warning messages as RDF triples in the returned graph. It is again an issue of manpower, I am not sure I can do that in the coming weeks:-(. But it would be a great possible start, too...



It seems to me (a casual observer of HTML5 progress) RDFa 1.1 should be expected to pass HTML5 validators. Nothing in the latest update seems to suggest otherwise, but like I said, I'm not closely following developments.