My challenge with the idea of mustUnderstand in Atom is in trying to figure out how the heck it would realistically be used for anything worthwhile. Take blog content for instance, if my blog reader accesses a feed that contains an entry with a mustUnderstand metadata element that my reader does not understand, does that mean my reader is not allowed to show me that content? If so, that's kinda stupid when I can open the same feed in a browser and view the angle bracket version without any problem. In SOAP, mustUnderstand makes sense given that the messages passed around are generally intended for automated consumption designed to kick of or affect processes in some way. Atom feeds are not typically going to be used that way. There may be some of that going on, but nothing that would warrant any intense need to have mustUnderstand built into the Atom core. If anything, it could be moved off into an extension and implemented only by those few who may actually need it.
- James M Snell
Roy T. Fielding wrote:
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On Feb 5, 2005, at 9:48 AM, Mark Nottingham wrote:
What does that mean? SOAP is a "Must Ignore format," but it also has a way of saying that you have to understand a particular extension; as I said before, this is one of the big problems with HTTP. mustUnderstand should be used sparingly, but sometimes it's necessary.
In fact, "must understand" has no value in a network-based application except as positive guidance for intermediaries, which is something that can still be accomplished under mustIgnore with a bit of old-fashioned advocacy.
....Roy
