[Standards-JIG] JEP-126 (Invisibility)

Justin Karneges justin-keyword-jabber.093179 at affinix.com
Mon Apr 10 23:43:33 UTC 2006


On Monday 10 April 2006 15:19, Peter Saint-Andre wrote:
> But not all servers (and even fewer clients) implemented visible. So we
> never really had consensus on how invisibility is supposed to work via
> the presence stanza. That lack of consensus concerned me then, and it
> concerns me now.

One thing that always bothered me about the old way is how it would play with 
directed presence.  Even with privacy lists, I'm still unsure how to handle 
an "away-to" or "invisible-to" scenario.  Perhaps this has less to do with 
invisibility and more to do with how statuses play with directed presence.

I've resisted adding a per-contact directed presence feature into Psi, because 
it could potentially be misleading.  What if I send a directed presence to 
someone indicating that I'm offline:

  <presence type='unavailable' to='otherUser at example.com'/>

Then sometime later, I change my global status:

  <presence>
    <show>away</show>
  </presence>

Does otherUser get my presence?  I guess I ask this question both about RFC 
3921 and also about what servers in the wild actually do.

If the answer is that he does get the presence, and privacy lists must be used 
in order to block out the later presence packets, how would it fit with the 
"away-to" scenario?

  <presence to='otherUser at example.com'>
    <show>away</show>
  </presence>

  <iq ... privacy list stuff here to block otherUser />

  <presence/>

OtherUser gets the away packet, and does not get the future online packet.  
Now, what happens if otherUser signs off and then back on?  I assume he will 
see me as offline, when the correct behavior would be for him to see me as 
away.

If we want these features, then we need an explicit protocol, otherwise the 
user will have flaky experiences.

-Justin



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