Move MPD message processing knowledge into the MPD module

mopidy/core.py

@@ -6,7 +6,7 @@ from mopidy import get_version, settings
 from mopidy.utils import get_class
 from mopidy.utils.log import setup_logging
 from mopidy.utils.path import get_or_create_folder, get_or_create_file
-from mopidy.utils.process import BaseProcess, unpickle_connection
+from mopidy.utils.process import BaseProcess
 from mopidy.utils.settings import list_settings_optparse_callback
 
 logger = logging.getLogger('mopidy.core')
@@ -67,19 +67,15 @@ class CoreProcess(BaseProcess):
         return get_class(settings.BACKENDS[0])(core_queue, output_queue)
 
     def setup_frontend(self, core_queue, backend):
-        frontend = get_class(settings.FRONTENDS[0])()
-        frontend.start_server(core_queue)
-        frontend.create_dispatcher(backend)
+        frontend = get_class(settings.FRONTENDS[0])(core_queue, backend)
+        frontend.start()
         return frontend
 
     def process_message(self, message):
         if message.get('to') == 'output':
             self.output_queue.put(message)
-        elif message['command'] == 'mpd_request':
-            response = self.frontend.dispatcher.handle_request(
-                message['request'])
-            connection = unpickle_connection(message['reply_to'])
-            connection.send(response)
+        elif message.get('to') == 'frontend':
+            self.frontend.process_message(message)
         elif message['command'] == 'end_of_track':
             self.backend.playback.on_end_of_track()
         elif message['command'] == 'stop_playback':

mopidy/frontends/mpd/__init__.py

@@ -1,5 +1,10 @@
+import logging
+
 from mopidy.frontends.mpd.dispatcher import MpdDispatcher
 from mopidy.frontends.mpd.process import MpdProcess
+from mopidy.utils.process import unpickle_connection
+
+logger = logging.getLogger('mopidy.frontends.mpd')
 
 class MpdFrontend(object):
     """
@@ -11,27 +16,28 @@ class MpdFrontend(object):
     - :attr:`mopidy.settings.MPD_SERVER_PORT`
     """
 
-    def __init__(self):
+    def __init__(self, core_queue, backend):
+        self.core_queue = core_queue
         self.process = None
-        self.dispatcher = None
+        self.dispatcher = MpdDispatcher(backend)
 
-    def start_server(self, core_queue):
-        """
-        Starts the MPD server.
-
-        :param core_queue: the core queue
-        :type core_queue: :class:`multiprocessing.Queue`
-        """
-        self.process = MpdProcess(core_queue)
+    def start(self):
+        """Starts the MPD server."""
+        self.process = MpdProcess(self.core_queue)
         self.process.start()
 
-    def create_dispatcher(self, backend):
+    def process_message(self, message):
         """
-        Creates a dispatcher for MPD requests.
+        Processes messages with the MPD frontend as destination.
 
-        :param backend: the backend
-        :type backend: :class:`mopidy.backends.base.BaseBackend`
-        :rtype: :class:`mopidy.frontends.mpd.dispatcher.MpdDispatcher`
+        :param message: the message
+        :type message: dict
         """
-        self.dispatcher = MpdDispatcher(backend)
-        return self.dispatcher
+        assert message['to'] == 'frontend', \
+            u'Message recipient must be "frontend".'
+        if message['command'] == 'mpd_request':
+            response = self.dispatcher.handle_request(message['request'])
+            connection = unpickle_connection(message['reply_to'])
+            connection.send(response)
+        else:
+            logger.warning(u'Cannot handle message: %s', message)

mopidy/frontends/mpd/session.py

@@ -48,6 +48,7 @@ class MpdSession(asynchat.async_chat):
         """Handle request by sending it to the MPD frontend."""
         my_end, other_end = multiprocessing.Pipe()
         self.core_queue.put({
+            'to': 'frontend',
             'command': 'mpd_request',
             'request': request,
             'reply_to': pickle_connection(other_end),