Special event processing for LastChange events

[lawrenceakka]

Incorporating @robwebset 's ideas into the event processing code - see #189

To see it in operation:

try:
    from queue import Empty
except:  # Py2.7
    from Queue import Empty

import soco
import time
from pprint import pprint
from soco.events import event_listener
# import logging
# logging.basicConfig(level=logging.DEBUG)
# pick a device
device = soco.discover().pop()
sub = device.renderingControl.subscribe()
sub2 = device.avTransport.subscribe()

while True:
    try:
        event = sub.events.get(timeout=0.5)
        pprint (event.variables)
    except Empty:
        pass
    try:
        event = sub2.events.get(timeout=0.5)
        pprint (event.variables)
    except Empty:
        pass

    except KeyboardInterrupt:
        sub.unsubscribe()
        sub2.unsubscribe()
        event_listener.stop()
        break

Then fiddle with your volume/add tracks/play etc

The next step would be to integrate this with #192 so that track metadata is returned as an ML_Library_Item instance, once #192 is committed.

[coveralls]

Coverage decreased (-0.48%) when pulling 336d63f on lawrenceakka:last-change-events into 35ab843 on SoCo:master.

[stefankoegl]

+1

[coveralls]

Coverage decreased (-0.47%) when pulling 2b83cdc on lawrenceakka:last-change-events into d0c7f57 on SoCo:master.

[KennethNielsen]

Hi @lawrenceakka

Looks like a good idea. A few points.

1. Regarding using a data structure for the track metadata I think that is a good idea, but you should probably use the QueueItem class. What characterises the metadata that we get from the active queue (at least when asking the get_queue method), is that it is not enough information to distinguish between ML and MS items and in the case of MS items, not enough information to re-add them to the queue. That is the reason why the QueueItem class exists and it is probably what should be used here.
2. As mentioned in Add a stucture to hold the Last Change Event message #189 I sometimes prefer specialized class for data structures e.g because the allow data type conversion and possibly dublication as described there, but there could of course also be other ways to do that. If it is possible, one could create a global list of variables which can and should be converted or duplicated. If that is not possible due to type clashes, we could do one for each service or something like that. It would be a bit of extra work, but I think worth it.

I will make a few inline comments as well.

[KennethNielsen]

As mentioned in conversation, probably QueueItem

[KennethNielsen]

In general +1 for the code as is, but with a few inline comments to consider.

[coveralls]

Coverage decreased (-0.45%) when pulling c98b64e on lawrenceakka:last-change-events into 4501f70 on SoCo:master.

[coveralls]

Coverage decreased (-0.5%) when pulling 16a6b2e on lawrenceakka:last-change-events into 4501f70 on SoCo:master.

[coveralls]

Coverage decreased (-0.5%) when pulling 21f160b on lawrenceakka:last-change-events into 4501f70 on SoCo:master.

[coveralls]

Coverage decreased (-0.25%) when pulling 67ab9eb on lawrenceakka:last-change-events into 4501f70 on SoCo:master.

[coveralls]

Coverage decreased (-0.28%) when pulling 3bc172f on lawrenceakka:last-change-events into 4501f70 on SoCo:master.

[coveralls]

Coverage decreased (-0.28%) when pulling 5237667 on lawrenceakka:last-change-events into 4501f70 on SoCo:master.