[Building Sakai] Displaying Users Present (or not)

[Matthew Buckett]

Ok, currently in our production installation we have all sites
displaying the list of users present. We are looking at switching this
off and relying on the portal to generate events so that we can still
track accesses to sites.

I had a quick look at this and it seems that the PresenceService
stashes a Presence object into a presence tool session. This is
normally done as part of the setPresence() call. setPresence() also
looks through all the presence locations for expired presence status.

If setPresence() isn't called for a short while for a particular user
then none of the existing presences get expired.

If it was only the portal that called setPresence() and we weren't
displaying users present then being and end events for a site would
tie up, but other tools (eg chat) also make calls to setPresence()
which can result in your presence in the site getting timed out but
in-fact you are still in the site. Then when you do reload the portal
it will show you as having entered the site again, when infact you
never left.

Is this an issue?

Does site stats cope with this?

Is it worth changing the presence so it's active but can be set to not
display the users present in a site? This way the status of someone's
presence in a site remains accurate without the privacy concerns.

-- 
  Matthew Buckett
  VLE Developer, LTG, Oxford University Computing Services