[asterisk-dev] MeetMe, setting MEETMEUNIQUEID

[Tony Mountifield]

In article <49F08058.9050407 at digium.com>,
Mark Michelson <mmichelson at digium.com> wrote:
> Tony Mountifield wrote:
> > In article <49EDFFFE.6020501 at gmail.com>,
> > Grigoriy Puzankin <gpuzankin at gmail.com> wrote:
> >> Hi,
> >>
> >> In Asterisk 1.6.0.6 I noticed that after the first member has entered
> >> into meetme conference MEETMEUNIQUEID variable is set to the uniqueid of
> >> the first member. Even when the first member left the conference
> >> MEETMEUNIQUEID still points to his uniqueid for the new members joining
> >> the conference.
> >>
> >> Is it supposed to be so? I would expect to see the uniqueid of the
> >> pseudo channel, which is the "base" of meetme conference.
> >>
> >> So the change would be in app_meetme.c:
> >>
> >>         pbx_builtin_setvar_helper(chan, "MEETMEUNIQUEID", conf->uniqueid);
> >> to
> >>         pbx_builtin_setvar_helper(chan, "MEETMEUNIQUEID",
> >> conf->chan->uniqueid);
> > 
> > The value of MEETMEUNIQUEID is not intended to be used to find the original
> > channel whose Unique ID it contains. It is just an opaque value that will
> > be common to all calls that participate in that conference, so that they
> > can easily be related to each other. The unique ID of the creating channel
> > was just a convenient value to use. The unique ID of the pseudo channel
> > would be just as good, but no better, IMHO.
> 
> Actually, I could see some value for using the pseudo channel's unique ID 
> instead. The reason is that there could be some oddball dialplan that allows for 
> the same channel to create multiple conferences. In such a case, would the 
> MEETMEUNIQUEID be the same for all conferences created by the same channel?

Yes, it would, and that is a good point. I guess something like Vicidial,
which uses conferences as a convenient way to bridge channels, could create
several conferences in succession on the same channel as calls get redirected.

> However, using the pseudo channel's unique ID doesn't seem like a good universal 
> solution either. The problem with using the pseudo channel's unique ID is that, 
> iirc, a conference can actually run even if the pseudo channel is not created 
> properly. For example, app_meetme can run even if chan_dahdi is not loaded.

Yes, I think Meetme can run without chan_zap/chan_dahdi provided you don't
want to do recording, or possibly play username intros. If it can't request
a Zap channel it falls back to opening /dev/zaptel/pseudo directly, to get
an fd for playing the enter and leave sounds on.

> A simple way of uniquely identifying all conferences would be to use a 
> monotonically-increasing static int.

Except that this wouldn't make them unique across reboots. You probably
need to use the same scheme as for channel unique IDs - construct it from
the current time_t and a sequence number.

Cheers
Tony
-- 
Tony Mountifield
Work: tony at softins.co.uk - http://www.softins.co.uk
Play: tony at mountifield.org - http://tony.mountifield.org