POWDER Working Group Blog

The meeting began with a quick tour of the latest version of the Grouping of Resources Document followed by a resolution for this to be published as our next working draft (TBA on this blog). There was then a discussion of the new use accessibility-centric cases that have been developed since receiving input from Liddy Nevile. Two revised use cases will replace the current use case 2.1.5. While looking at the Use Cases document, two further issues were discussed. Firstly requirement 3.3.4 Compact says: It must be possible to express DRs in a compact form. As pointed out by Dan Connolly, this is un-testable and therefore is to be dropped. A further requirement, 3.1.9 Standard Vocabularies says 'There must be standard vocabularies for assertions about DRs.' This has not been addressed yet and therefore it was resolved to create a new RDF property of wdr:certifies to provide such a standardised way of creating the certificate shown in section 6.2 of the current Description Resources draft. It was noted that the use of wdr:certifies and wdr:certifiedBy are independent of each other - i.e. using one does not entail using the other - although it's probably a good idea to do so. [Looking at the example now, it seems that wdr:certifies shouldn't be a property, rather it should be a sub Class of Descriptors]. This raised the issue of whether the grouping document should support definition of resources by reference to a hash of them so that a DR could indicate that it only applied to resources if they have remained unchanged. A proposal will be made to the group on this issue shortly (should we specify a limited number of hash types, such as with wdr:sha-1 or a more generic wdr:hash with a separate wdr:hashAlgorithm predicate?) The chair reported on the recent establishment of the HTTPBIS Working Group at the IETF and the statement in the charter: "The WG is not tasked with producing new methods, headers, or extension mechanisms, but may introduce new protocol elements if necessary as part of revising existing functionality which has proven to be problematic." On present evidence it seems unlikely therefore that the HTTP Link Header will be standardised although this working group would support such a move. The normative POWDER documents will not refer to usage of the HTTP Link header, however, informative documents will (because it's very useful and works!). The meeting closed with a realistic expectation of announcing Last Call on its Rec Track documents following the face to face meeting in Boston 8 - 9 November.