Re: Proposal to register rel="about"

[Aristotle Pagaltzis <pagaltzis@xxxxxx>]

* Herbert van de Sompel <hvdsomp@xxxxxxxxx> [2008-09-12 01:00]:
> The ORE effort [1] that proposes a profile of Atom to meet its
> requirements [2], has a need to express that an Atom Entry
> provides information/metadata about some other resource.

That’s `rel="alternate"` – it states that the metadata in the
Entry applies to the linked resource.

> The Atom use cases we refer to use Entries as containers to
> provide "metadata" about some web resource other than the Entry
> itself. For example, the GData Entry
> <http://gdata.youtube.com/feeds/api/videos/S_bcAOlK0io > is
> about the YouTube video by the Cribs <
> http://www.youtube.com/watch?v=S_bcAOlK0io>: the atom:author,
> atom:title, and atom:content elements are metadata about the
> video. The same approach is used in Entries published by
> academic publishers: the atom:author, atom:title, etc. elements
> are metadata about a journal article that is described by the
> Entry.

An Entry can have more than one alternate representation.

> This class of Atom use cases contrasts with cases in which Atom
> Entries do not describe other resources, but are just ... err
> ... themselves. This is the case with most blog entries, in
> which e.g. atom:author is the creator of the Entry, atom:title
> is a title for the Entry assigned by the creator, etc. This
> metadata does pertain to the Entry itself, not to some external
> resource.

If you really need to provide metadata about the metadata, rather
than metadata about the actual resource, wrap an Entry in an
Entry. (Yes, `<content type="application/atom+xml;type=entry">`.)

That isn’t the case you have outlined in the rest of your entry
however.

> This class of Atom use cases contrasts with cases in which Atom
> Entries do not describe other resources, but are just ... err
> ... themselves. This is the case with most blog entries, in
> which e.g. atom:author is the creator of the Entry, atom:title
> is a title for the Entry assigned by the creator, etc. This
> metadata does pertain to the Entry itself, not to some external
> resource.

External or not is a red herring. Either the metadata describes
that other resource, in which case the Entry is an alternate
representation, or it doesn’t, and it’s not, so the other
resource is merely related.

You can’t use Atom elements in a single Entry to provide metadata
about different resources anyway. To achieve that you would need
extension elements, not a new link relation, otherwise documents
you claim are Atom will actually be something very similar to
Atom but not Atom, since 100% RFC 4287-compliant implementations
will process such documents in an unintended manner.

> We would very much appreciate your feedback, both regarding the
> general idea of registering an "about" relationship, and
> regarding the specifics of the interpretation of child elements
> of atom:entry.

I think it’s unnecessary. Atom as specified can already express
the relationships you want.

Regards,
-- 
Aristotle Pagaltzis // <http://plasmasturm.org/>