Track / expose mixer status

[benlangfeld]

WIP. See adhearsion/adhearsion#411

Todo:

• Watch for mixer CAPS in presence, record as a known mixer (see https://github.com/adhearsion/punchblock/blob/develop/lib/punchblock/connection/xmpp.rb#L131)
• Fire FS event when we first encounter a mixer
• Fire FS event and clear registration when we see a mixer go away

[coveralls]

Coverage decreased (-11.49%) to 87.58% when pulling 195518e on feature/mixer_status into 85f7b2c on develop.

[benlangfeld]

Support for this was recently added to mod_rayo.

[pungoyal]

The rayo spec Section 6.4 Mixers Example 41 suggests that the mixer presence is notified as:

<presence from='[email protected]'
          to='[email protected]/balcony'>
  <c xmlns='http://jabber.org/protocol/caps'
     hash='sha-1'
     node='urn:xmpp:rayo:mixer:1'
     ver='QgayPKawpkPSDYmwT/WM94uAlu0='/>
</presence>

This has a xmlns of http://jabber.org/protocol/caps. How will Punchblock::Event::MixerCreated register itself to be triggered for this presence notification (from: https://github.com/adhearsion/punchblock/blob/develop/lib/punchblock/core_ext/blather/stanza.rb#L10)?

One way out is to put if-else blocks in https://github.com/adhearsion/punchblock/blob/develop/lib/punchblock/connection/xmpp.rb#L132 and manually trigger Punchblock::Event::MixerCreated and Punchblock::Event::MixerDestroyed. That will be ugly.

Is there another way of achieving the same?

[benlangfeld]

So instead of if-else blocks, we'll could use guards with a further set of handlers defined here: https://github.com/adhearsion/punchblock/blob/develop/lib/punchblock/connection/xmpp.rb#L171. If you'd like to make a pass at this, that'd be lovely. I'll happily review any incoming PR.