[Standards] Presence extensions
jabber.org at ralphm.ik.nu
Fri Feb 2 15:02:29 UTC 2007
I was testing out Palaver, a MUC implementation, and found out the
following. MUC role changes are pushed to room occupants using presence
stanzas. However, Palaver sends them out without any other presence
information. When a user that previously sent away presence, for
example, the role change stanza doesn't include that and the client
things that the availability for this user changed to plain available.
After a small discussion with Ian, it appears this situation is
underspecified, either in XEP-0045 or in XMPP IM. The question being:
what to do on broadcasting presence stanzas, and in particular a proxy
like situation like MUC, with presence extensions.
I can think of different types of extensions:
* Extensions that really augment availability information. You have to
them every time.
* Extensions that add non-availability information like role changes
or other information orthogonal to availability. These don't have to
every time. It can be argued that these should not be in presence
However, several protocols do this.
* Extensions that contain meta information about the actual presence
sent. An example is a signature to be able to verify the authenticity
(proxied) presence. Note that if entities add data to presence before
broadcasting, such a signature will cease to be valid. So in case of
you probably cannot pass these on.
Ian suggests we need to figure out what to do here and edit RFC3920bis
accordingly. Probably XEP-0045 needs some updated examples, too.
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