Dave Bath wrote:
Hi list,
I’m sorry to ask this to the list, as I’m sure I’ve seen the information before but after some googling I can’t really find it. Can anyone shed some light on the status of the presence module at the moment? How far developed is it? Which methods does it now support? Can people subscribe with their regular ser username? I know there’s been some work on it recently, and any info would be gratefully received.
The PA module is still a work in progress, partly because the specs I've been implementing against are internet-drafts that are updated at least every 6 months, though "A Presence Event Package for the Session Initiation Protocol (SIP)" has been published as RFC3865.
PA handles subscribes on behalf of users registered against ser and generates notifies when their presence information changes. One source of presence information is usrloc/registrar but PA also handles PUBLISH messages from UAs. PA is able to composite event state from multiple user agents. For presence information, PA generates NOTIFY messages with lpidf, xpidf, or the preferred pidf format. For authentication of subscribers, PA generates watcherinfo notifications so that the UA can use XCAP to fetch and update watcher authentication documents. I have written a rudimentary XCAP server in python that I believe is available from pals.internet2.edu.
In addition to PIDF, it supports extended status, prescaps, and geographic or civil location.
PA does not subscribe to presence information -- it only uses the local registrar and incoming PUBLISH messages as a source of presence state.
We've been using it in the Internet2 Presence Integrated Communication working group since last January. It mostly works but is not as stable as it should be. Jan Janak found and fixed a race condition but that code has not been tested extensively and is not yet in CVS.
Jamey