Please.... Please.... Don't anyone restart the "What is an update?" discussion... Too many lives have been wasted on that one already.
bob wyman On Wed, Oct 21, 2009 at 6:11 PM, Tim Bray <[email protected]> wrote: > > >> 3. High-level Protocol Flow, last bullet point. "The hub caches > >> minimal metadata..." I read this a few times and it seems to be > >> describing one particular implementation strategy. If so, why not say > >> so? The current language makes it look like this is maybe a normative > >> part of what you have to do to implement PuSH, which I'm pretty sure > >> it isn't. > > > > I think this is intended to be normative. A stateless hub can't > > function properly (doing feed diffs). The language here was chosen > > specifically to imply stateful handling of content without dictating > > the specific implementation. > > In fact, what you're specifying is that the hub MUST be able to detect > a delta so it can inform subscribers. Normative text should specify > policy not mechanism. > > This touches on a nasty subject that you probably don't want to go > near. If I were implementing, I think it might be perfectly OK to > stash just atom:feed/atom:updated and //atom:entry/atom:updated. > > I am quite sure there are others who would disagree & insist on > stashing enough to detect differences in the white space between > attribute values. Don't laugh, I speak from bitter experience. If > there's one thing we learned in the process of building 4287, it is > hopeless to expect consensus on what constitutes an "update". I have > a thousand emails to show you if you disagree. > > So I think it's probably inappropriate to specify "minimal" metadata. > Just say "The hub stores sufficient state information about each topic > to detect changes so that it can notify subscribers." -T >
