[sugar] Couple of questions

[Dan Williams]

On Fri, 2006-07-21 at 22:48 +0100, Mike Hearn wrote:
> Hiya!
> 
> First question - the Sugar mockups have little avatar photos in the
> buddy list. How are people with no digital cameras supposed to get
> such a thing?
> 
>     http://wiki.laptop.org/go/Image:Sugar.png
> 
> Second question - the Presence DBUS service bears a strong resemblence
> to the Galago presence service. Is there some reason you're creating a
> new one?

First off, the problem with the current implementations of presence in
most everything, including Telepathy & Galago, is that they are geared
towards traditional notions of presence.  By which I mean "Is Tommy
online?  What capabilities does Tommy have?"  That's about it, as far as
I can tell from the Telepathy D-Bus API and what I've read about Galago.

In our case, we have an expanded notion of presence beyond whether or
not a buddy is simply present and whether or not they can do video chat.
In our model, each buddy provides certain services (in the mDNS/ZeroConf
sense of the word), for example a chat service or a voip service, or an
activity service.  Advertisement of an activity service determines a
person's participation on the activity.  This matches up much more
closely to Jabber/XMPP's Service Discovery specification, except that
instead of jabber servers advertising services like directories and
conference rooms, the _buddys_ are advertising their own services.  Or,
if you prefer, it's much more of a ZeroConf view, if you include
publishing.

We're not trying to combine and reconcile presence attributes from users
of different accounts and services and match that up to stored
information, which is what I understand is one of Galago's purposes.
I'd view the Sugar PresenceService as more parallel to Galago, rather
than built on top of Galago, though we likely could do that.  But I
don't see the advantage to building this on top of Galago, which is in
turn just built on top of Telepathy.

The point is that we're not just doing presence in the traditional term
of the word, like AIM, Jabber, MSN, Yahoo, etc. all think of presence.
That's a pretty simple idea of presence.  We also need to do this sort
of stuff without a central server, on the local mesh, where mDNS works
great and provides exactly the model we want.  Perhaps that could be
done with a plugin for Telepathy, but I'm not sure what the benefit of
adding Galago on top of all this is, if we're just going to have to do a
bunch of processing aside from Galago too.

Dan