Re: WebDAV PUSH based on RFC 6202

[Cyrus Daboo <[e-mail]>]

Hi Peter,

--On April 9, 2014 at 10:57:31 AM -0700 Peter Saint-Andre 
<[e-mail]> wrote:

> Well, I mention this Internet-Draft mostly to show that people have been
> thinking about this problem for at least 10 years. You could use XMPP for
> such notifications, although it might depend on what kinds of endpoints
> you're trying to support (e.g., do they or can they do XMPP). Other
> options are technologies like pubsubhubbub. There are also lots of
> proprietary technologies for such notifications, although of course we
> don't want anything proprietary. However IMHO long polling is not the
> best approach these days - we wrote RFC 6202 mostly to say that long
> polling is a bad idea and that it's better to use WebSockets instead (RFC
> 6455). But WebSockets only gives you "TCP for the Web" and you'd need to
> define some kind of application over WebSocket in order to get anything
> done (examples are SIP over WebSocket, XMPP over WebSocket, etc.).

So the big issue here of course is that nothing has happend to standardize 
a general solution to push, so we do have proprietary solutions. There are 
really two parts to what we would like to do here:

1) Recognizing that multiple proprietary solutions exist today, clients 
currently have to "probe" a server (or use hard-coded defaults based on 
hostnames) to determine which one is actually supported. What would be 
better is if there was a standard way for servers to advertise support for 
any type of push protocol. That could simply be specific DAV header items, 
or a WebDAV property that enumerates what is supported (be it proprietary 
or any new standard approach).

2) Some client folks have expressed interest in having a base "minimum to 
implement" standard push protocol that would suffice for at least 
desktop-based clients (recognizing that the mobile environment is a lot 
trickier to deal with - though of course no less important these days). The 
initial thought we had was to go the route of IMAP's IDLE command - i.e., 
make use of the existing protocol to provide an in-band solution. 
Long-polling with the WebDAV sync REPORT would seem like the best fit for 
that approach - but operational concerns with that obviously come into play.

Now, if the time is ripe for the IETF to tackle the push problem in a more 
generic way, then lets do that - but I'm not optimistic given the past 
history and the current diversity of proprietary solutions.

-- 
Cyrus Daboo