Add volume control support to BaseBackend through alsaaudio.Mixer

docs/installation.rst

@@ -14,6 +14,7 @@ Dependencies
 ============
 
 * Python >= 2.5
+* pyalsaaudio >= 0.2 (Debian/Ubuntu: python-alsaaudio)
 * Dependencies for at least one Mopidy backend:
 
   * :ref:`despotify`

mopidy/backends/__init__.py

@@ -3,6 +3,8 @@ import logging
 import random
 import time
 
+import alsaaudio
+
 from mopidy.models import Playlist
 
 logger = logging.getLogger('backends.base')
@@ -242,13 +244,10 @@ class BasePlaybackController(object):
     #:     The current track is played once.
     repeat = False
 
-    #: The audio volume as an int in the range [0, 100]. :class:`None` if
-    #: unknown.
-    volume = None
-
-    def __init__(self, backend):
+    def __init__(self, backend, mixer=alsaaudio.Mixer):
         self.backend = backend
         self._state = self.STOPPED
+        self._mixer = mixer()
 
     @property
     def next_track(self):
@@ -325,6 +324,19 @@ class BasePlaybackController(object):
     def _play_time_resume(self):
         self._play_time_started = int(time.time())
 
+    @property
+    def volume(self):
+        """
+        The audio volume as an int in the range [0, 100].
+
+        :class:`None` if unknown.
+        """
+        return self._mixer.getvolume()[0]
+
+    @volume.setter
+    def volume(self, volume):
+        self._mixer.setvolume(volume)
+
     def new_playlist_loaded_callback(self):
         """Tell the playback controller that a new playlist has been loaded."""
         self.current_track = None

mopidy/backends/dummy.py

@@ -7,7 +7,7 @@ class DummyBackend(BaseBackend):
     def __init__(self):
         self.current_playlist = DummyCurrentPlaylistController(backend=self)
         self.library = DummyLibraryController(backend=self)
-        self.playback = DummyPlaybackController(backend=self)
+        self.playback = DummyPlaybackController(backend=self, mixer=DummyMixer)
         self.stored_playlists = DummyStoredPlaylistsController(backend=self)
         self.uri_handlers = [u'dummy:']
 
@@ -37,3 +37,12 @@ class DummyPlaybackController(BasePlaybackController):
 class DummyStoredPlaylistsController(BaseStoredPlaylistsController):
     def search(self, query):
         return [Playlist(name=query)]
+
+class DummyMixer(object):
+    volume = 0
+
+    def getvolume(self):
+        return [self.volume, self.volume]
+
+    def setvolume(self, volume):
+        self.volume = volume

mopidy/mpd/handler.py

@@ -419,14 +419,15 @@ class MpdHandler(object):
     def _seekid(self, songid, seconds):
         raise MpdNotImplemented # TODO
 
-    @register(r'^setvol "(?P<volume>-*\d+)"$')
+    @register(r'^setvol (?P<volume>[-+]*\d+)$')
+    @register(r'^setvol "(?P<volume>[-+]*\d+)"$')
     def _setvol(self, volume):
         volume = int(volume)
         if volume < 0:
             volume = 0
         if volume > 100:
             volume = 100
-        raise MpdNotImplemented # TODO
+        self.backend.playback.volume = volume
 
     @register(r'^shuffle$')
     @register(r'^shuffle "(?P<start>\d+):(?P<end>\d+)*"$')

tests/mpd/handlertest.py

@@ -290,7 +290,8 @@ class StatusHandlerTest(unittest.TestCase):
 
 class PlaybackOptionsHandlerTest(unittest.TestCase):
     def setUp(self):
-        self.h = handler.MpdHandler(backend=DummyBackend())
+        self.b = DummyBackend()
+        self.h = handler.MpdHandler(backend=self.b)
 
     def test_consume_off(self):
         result = self.h.handle_request(u'consume "0"')
@@ -322,23 +323,33 @@ class PlaybackOptionsHandlerTest(unittest.TestCase):
 
     def test_setvol_below_min(self):
         result = self.h.handle_request(u'setvol "-10"')
-        self.assert_(u'ACK Not implemented' in result)
+        self.assert_(u'OK' in result)
+        self.assertEqual(0, self.b.playback.volume)
 
     def test_setvol_min(self):
         result = self.h.handle_request(u'setvol "0"')
-        self.assert_(u'ACK Not implemented' in result)
+        self.assert_(u'OK' in result)
+        self.assertEqual(0, self.b.playback.volume)
 
     def test_setvol_middle(self):
         result = self.h.handle_request(u'setvol "50"')
-        self.assert_(u'ACK Not implemented' in result)
+        self.assert_(u'OK' in result)
+        self.assertEqual(50, self.b.playback.volume)
 
     def test_setvol_max(self):
         result = self.h.handle_request(u'setvol "100"')
-        self.assert_(u'ACK Not implemented' in result)
+        self.assert_(u'OK' in result)
+        self.assertEqual(100, self.b.playback.volume)
 
     def test_setvol_above_max(self):
         result = self.h.handle_request(u'setvol "110"')
-        self.assert_(u'ACK Not implemented' in result)
+        self.assert_(u'OK' in result)
+        self.assertEqual(100, self.b.playback.volume)
+
+    def test_setvol_plus_is_ignored(self):
+        result = self.h.handle_request(u'setvol "+10"')
+        self.assert_(u'OK' in result)
+        self.assertEqual(10, self.b.playback.volume)
 
     def test_single_off(self):
         result = self.h.handle_request(u'single "0"')