Re: MUST a collection be returned as an Atom feed?

["Roy T. Fielding" <fielding@xxxxxxxx>]

On Jan 3, 2010, at 6:12 AM, Jan Algermissen wrote:
> I think I see where we disagree or misunderstand each other: In my understanding, it is part of the semantics of application/atomsrv+xml that a service that sends that media type to describe itself constrains itself ('promises') to conform to RFC 5023. In our example, it promises to return an Atom feed upon a GET request to a collection.

Atom is a protocol written by a committee to lay out a set of choices
that they deem will be interoperable in practice.  It contains many
such over-specifications. Just ignore them.  The media type cannot bind
a service to do anything -- it only serves as a guide for interpretation
of the current state.

One of the ways to interpret that state is to follow the links within
it with some degree of expectation.  If that expectation fails to be true,
then what are you going to do about it?  Are you going to halt and wait for
the service to be compliant with some external spec?  Or are you going to
interpret that next state independent of the former state?  Those are
application-specific choices, and it doesn't matter to Atom which one
you take.  Unfortunately, it did matter to the committee, so there is an
unnecessary requirement in the spec in order to pretend that such a case
will not occur in practice.  And maybe it won't.

....Roy