- From: Andrea Perego <andrea.perego@uninsubria.it>
- Date: Fri, 2 Jul 2010 18:06:44 +0200
- To: public-xg-socialweb@w3.org
- Cc: Public POWDER <public-powderwg@w3.org>
Dear all, You might be interested in recent work concerning POWDER [1] which has relationship with OGP. Let me first give a sketch of what POWDER is for those who are not acquainted with it. POWDER (Protocol for Web Description Resources) is a W3C Recommendation defining a mechanism thanks to which you can associate a description with a set of resources whose URIs/IRIs match a given pattern. Such descriptions, referred to as Description Resources (DRs), are stored into XML files, called POWDER documents, along with information about the DRs' author, issue date, validity period, etc. POWDER defines also the protocol to be used to discover and process such descriptions, which can be associated with the resources they apply to by using either the HTTP "Link" header [2] or (X)HTML "link" elements. Basically, a POWDER processor takes as input the URI/IRI of a resource and the one of a POWDER document, and returns an RDF/XML description of the resource based on the information contained in the POWDER document. It is however possible to go further: I can convert the RDF/XML document returned by the processor into an RDFa snippet which can then be included into the "head" of the relevant (X)HTML documents - i.e., an RDFa snippet which makes use of "meta" and "link" tags only. In other words, I can use POWDER as a tool to consistently manage and control, with a minimum effort, the RDFa snippets which will be embedded in the pages of a website. One of the existing POWDER processors, namely, 3P [3], has been recently extended in order to support such feature through its RESTful API. The details are available in the section of the 3P's website titled "POWDER and RDFa" [4], where you can find also working examples. Note that this is just a starting point. The plan is to revise and further extend RDFa support based on the feedback we receive. For the moment, we are considering to implement the support to the generation of RDFa snippets to be embedded in the "body" of XHTML documents (as CC's ones) and to improve performance through the enforcement of caching mechanisms. A note on metadata provenance. As mentioned above, any POWDER document comes with information thanks to which you can identify who is the author of the claims made in the POWDER document itself. Now, if an RDFa snippet is generated from a POWDER document, and such POWDER document is referred from the page including the snippet, you are able to verify who is the author of the embedded RDF statements. Note that the author of a POWDER document can be anyone, and not just the owner/administrator of the described resources. Actually, you might also have third-party agencies which release POWDER documents certifying that a given set of Web pages or a whole website satisfies given quality/content constraints - e.g., child-safe content and services, mobileOk-conformant pages. By using POWDER you can then embed such "certificates" into the XHTML code, and then (if you like) you can also check who released such certificates. Another example concerns CC licenses. An author/owner can use a single POWDER document to specify which license applies to which of his/her resources, and to automatically generate the corresponding RDFa snippets, which can then be included into the relevant XHTML documents (even though they are hosted by third-parties). Moreover, such POWDER document will allow anyone to verify who has associated a given license with a given resource and whether the resource has been attributed to its actual author/owner. Comments are more than welcome! Cheers Andrea ---- [1]http://www.w3.org/2007/powder/ [2]http://tools.ietf.org/html/draft-nottingham-http-link-header-10 [3]http://dawsec.dicom.uninsubria.it/andrea/ppp/ [4]http://dawsec.dicom.uninsubria.it/andrea/ppp/#sec-powder_and_rdfa
Received on Friday, 2 July 2010 16:07:18 UTC