Sunday, December 17, 2006, 1:55:39 AM, Bob Wyman wrote:
> 2.3. Inherited Licenses > The license on a feed MAY be inherited by entries. James, I'm not sure exactly what you are trying to achieve with the inheritance rule for licenses, but I think that it could do with the term "feed" being more accurately specified. Whilst it would be very useful for extensions to be able to support inheritance rules like the ones that Atom specifies for atom:author and atom:rights, which cause properties applied to a "feed document" to inherit to the entries declared within the "feed document"; there is nothing in Atom's specification of extensions elements that supports this short-hand notation, and attempting to emulate this behaviour in an extension will cause real-world implementations of feed stores to incorrectly assign, or not assign, licenses to the wrong entries. Simply because Atom implementations tend to give entries and feeds seperate life-cycles, and implementations that maintain a feed-state over multiple pollings of a feed are unlikely to associate each entry with the set of feed document metadata from each of the documents that it occurred in. Eg, if you store a feed in an implementation such as Microsoft's Feed Engine, only a single set of feed extensions will be associated with the feed. This will mean that if you change the license in the feed document when a feed is subsequently polled, intending it only to apply to the entries within that new feed document, you will effectively retroactively apply the license to the old entries too. Atom, unfortunately, doesn't have a way of indicating that an extension applies at "feed document"-level and MUST be processed at the feed document parsing stage. What you can do however, is to specify that feed licenses apply to the "feed", and inherit to the entries in the feed. This behaviour doesn't require implementations to be psychic and guess that an unknown extension needs to be processed at the document parsing stage. It means that the license applies to all entries in that feed, not just ones in that specific feed document. This is probably reasonable behaviour for licenses anyway. This might be your intention, but I'm not clear from the draft. -- Dave
