Add media base class (#267)

* Add media base class

* Clean up media base vocabulary keywords

* Rename header for common MediaSkill settings to "MediaSkill"

* Stop procedure cleaned up

* mycroft.media.stop now contains information of the message origin, this is used by the handler to make sure the calling skill doesn't stop itself.
* the play() method was renamed before_play() for clarity

* Rename _set_sink to something understandable.

mycroft/skills/media/__init__.py

@@ -0,0 +1,141 @@
+from os.path import join, dirname
+
+from adapt.intent import IntentBuilder
+from mycroft.skills import time_rules
+from mycroft.skills.core import MycroftSkill
+from mycroft.messagebus.message import Message
+from mycroft.configuration import ConfigurationManager
+
+from mycroft.util.log import getLogger
+import mycroft.skills.media.mopidy
+
+logger = getLogger(__name__)
+
+__author__ = 'forslund'
+
+
+class MediaSkill(MycroftSkill):
+    """
+        The MediaSkill class is a base class for media skills containing
+        vocabulary and intents for the common functions expected by a media
+        skill. In addition event handlers to lower volume when mycroft starts
+        to speak and raise it again when (s)he stops.
+
+        But wait there is one more thing! A small event emitter and matching
+        handler to stop media currently playing when new media is started.
+    """
+    def __init__(self, name):
+        super(MediaSkill, self).__init__(name)
+        self.isPlaying = False
+        config = ConfigurationManager.get()
+        self.base_conf = config.get('MediaSkill')
+
+    def initialize(self):
+        logger.info('Initializing MediaSkill commons')
+        logger.info('loading vocab files from ' + join(dirname(__file__),
+                    'vocab', self.lang))
+        self.load_vocab_files(join(dirname(__file__), 'vocab', self.lang))
+
+        self._register_common_intents()
+        self._register_event_handlers()
+
+    def _register_common_intents(self):
+        """
+           Register common intents, these include basically all intents
+           except the intents to start playback.
+        """
+        intent = IntentBuilder('NextIntent').require('NextKeyword')
+        self.register_intent(intent, self.handle_next)
+
+        intent = IntentBuilder('PrevIntent').require('PrevKeyword')
+        self.register_intent(intent, self.handle_prev)
+
+        intent = IntentBuilder('PauseIntent').require('PauseKeyword')
+        self.register_intent(intent, self.handle_pause)
+
+        intent = IntentBuilder('PlayIntent') \
+            .one_of('PlayKeyword', 'ResumeKeyword')
+        self.register_intent(intent, self.handle_play)
+
+        intent = IntentBuilder('CurrentlyPlayingIntent')\
+            .require('CurrentlyPlayingKeyword')
+        self.register_intent(intent, self.handle_currently_playing)
+
+    def _register_event_handlers(self):
+        """
+           Register event handlers for stopping currently playing media
+           when new media is started and handlers for lowering media volume
+           while mycroft is speaking.
+        """
+        self.emitter.on('mycroft.media.stop', self._media_stop)
+        self.emitter.on('recognizer_loop:audio_output_start',
+                        self.lower_volume)
+        self.emitter.on('recognizer_loop:audio_output_end',
+                        self.restore_volume)
+
+    def handle_next(self, message):
+        """
+           handle_next() should be implemented by the skill to switch to next
+           song/channel/video in queue.
+        """
+        logger.debug('handle_next not implemented in ' + self.name)
+
+    def handle_prev(self, message):
+        """
+           handle_prev() should be implemented by the skill to switch to
+           previous song/channel/video in queue
+        """
+        logger.debug('handle_prev not implemented in ' + self.name)
+
+    def handle_currently_playing(self, message):
+        """
+           handle_currently_playing() should be implemented to tell the user
+           what is currently playing
+        """
+        logger.debug('handle_currently_playing not implemented in ' +
+                     self.name)
+
+    def before_play(self):
+        """
+           Stop currently playing media before starting the new. This method
+           should always be called before the skill starts playback.
+        """
+        logger.info('Stopping currently playing media if any')
+        self.emitter.emit(Message('mycroft.media.stop',
+                          metadata={'origin': self.name}))
+
+    def handle_pause(self, message):
+        """ handle_pause() should pause currently playing media """
+        logger.debug('handle_pause not implemented in ' + self.name)
+
+    def handle_play(self, message):
+        """ handle_play() generic play handler. Should resume paused media
+            and/or implement generic playback functionality.
+
+            The skill creator should make sure to call before_play() here
+            if applicable"""
+        logger.debug('handle_play not implemented in ' + self.name)
+
+    def _media_stop(self, message):
+        """ handler for 'mycroft.media.stop' """
+        origin = message.metadata.get('origin', '')
+        if origin != self.name:
+            self.stop()
+
+    def stop(self):
+        """
+           stop() should be implemented to stop currently playing media. This
+           function will be called by either the general mycroft 'stop'
+           functionallity or internal message bus communication.
+        """
+        logger.debug('Stop not implemented in ' + self.name)
+
+    def lower_volume(self, message):
+        logger.debug('Lower volume not implemented in ' + self.name)
+
+    def restore_volume(self, message):
+        logger.debug('Restore volume not implemented in ' + self.name)
+
+    def _set_output_device(self, message):
+        """ Selects the output device """
+        pass

mycroft/skills/media/vocab/en-us/CurrentlyPlayingKeyword.voc

@@ -0,0 +1,6 @@
+what's currently playing
+what is currently playing
+what are you playing
+What are we listening to
+what's playing
+what is playing

mycroft/skills/media/vocab/en-us/NextKeyword.voc

@@ -0,0 +1,2 @@
+next track
+skip

mycroft/skills/media/vocab/en-us/PauseKeyword.voc

@@ -0,0 +1 @@
+pause

mycroft/skills/media/vocab/en-us/PlayKeyword.voc

@@ -0,0 +1 @@
+play

mycroft/skills/media/vocab/en-us/PrevKeyword.voc

@@ -0,0 +1 @@
+previous track

mycroft/skills/media/vocab/en-us/ResumeKeyword.voc

@@ -0,0 +1,2 @@
+resume
+unpause

mycroft/skills/npr_news/test/intent/sample2.intent.json

@@ -1,7 +1,7 @@
 {
-  "utterance": "play the news",
+  "utterance": "is there any news",
   "intent_type": "NPRNewsIntent",
   "intent": {
     "NPRNewsKeyword": "news"
   }
-}
+}