[Ietf-caldav] Re: Notifications [was Re: Client work]
helge.hess at opengroupware.org
Sat Aug 14 07:31:04 PDT 2004
On Aug 13, 2004, at 18:06, Lisa Dusseault wrote:
> It's my opinion that we can do much better than HTTP for notifications
> if we're willing to work a little harder!
Yes, I absolutely agree. Using Jabber for that is certainly a good and
reliable approach. The only issue I have with that is that it adds
another relatively complex component to the server infrastructure
(while httpu is pretty easy to implement).
But can we agree that this is out of scope for the "basic" CalDAV
specification or an "optional" part, eg using protocol levels like in
Personally my goal is too bring as many _available_ servers and clients
together - I'm not sure about your intention (produce a spec which
covers all features of Chandler?).
Currently the only "protocol" which is more or less interoperable
between servers is iCal-File-over-HTTP. And this one is really
inappropriate for almost anything ;-)
For OGo we "solve" the situation only by implementing all the various
protocols starting with iCal/HTTP, Exchange WebDAV, WCAP,
XML-RPC(variants), RSS etc used by the clients. It is a mess that this
is required even for basic things.
To summarize: my _strong_ fear is that if CalDAV ends up being too
complex, few will implement it. The mentioned notification is certainly
one thing which would require a major amount of work in existing
servers (including OGo and PHPgroupware).
Maybe the "level" idea is good?:
CalDAV Level 0: basic DAV/iCal storage of iCal objects + DASL queries
CalDAV Level 1: Level 0 + more complex cal support (fanout, reports?)
CalDAV Level 2: Level 1 + Jabber notifications
What do you think? A calendaring system can work without level 1 and 2
features. Instead of levels we could also use separate documents (like
WebDAV ACL and DASL is separate from WebDAV and certainly not required
for a lot of clients).
(BTW: I think it is already hard enough to make other server vendors
implement DAV/DASL/ACLs properly ..., I already did a lot of talks with
PHPgroupware and exchange4linux people on this ;-)
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