http: Working WebSockets which emits playback state changes

mopidy/frontends/http/__init__.py

@@ -5,9 +5,13 @@ import logging
 import pykka
 
 from mopidy import exceptions, settings
+from mopidy.core import CoreListener
 
 try:
     import cherrypy
+    from ws4py.server.cherrypyserver import WebSocketPlugin, WebSocketTool
+    from ws4py.websocket import WebSocket
+    from ws4py.messaging import TextMessage
 except ImportError as import_error:
     raise exceptions.OptionalDependencyError(import_error)
 
@@ -15,18 +19,34 @@ except ImportError as import_error:
 logger = logging.getLogger('mopidy.frontends.http')
 
 
-class HttpFrontend(pykka.ThreadingActor):
+class HttpFrontend(pykka.ThreadingActor, CoreListener):
     def __init__(self, core):
         super(HttpFrontend, self).__init__()
         self.core = core
+        self._setup_server()
+        self._setup_websocket_plugin()
+        app = self._create_app()
+        self._setup_logging(app)
+
+    def _setup_server(self):
         cherrypy.config.update({
             'engine.autoreload_on': False,
             'server.socket_host':
                 settings.HTTP_SERVER_HOSTNAME.encode('utf-8'),
             'server.socket_port': settings.HTTP_SERVER_PORT,
         })
-        app = cherrypy.tree.mount(Root(self.core), '/')
-        self._setup_logging(app)
+
+    def _setup_websocket_plugin(self):
+        WebSocketPlugin(cherrypy.engine).subscribe()
+        cherrypy.tools.websocket = WebSocketTool()
+
+    def _create_app(self):
+        return cherrypy.tree.mount(Root(self.core), '/', {
+            '/ws': {
+                'tools.websocket.on': True,
+                'tools.websocket.handler_cls': EventWebSocketHandler,
+            },
+        })
 
     def _setup_logging(self, app):
         cherrypy.log.access_log.setLevel(logging.NOTSET)
@@ -39,11 +59,36 @@ class HttpFrontend(pykka.ThreadingActor):
     def on_start(self):
         logger.debug(u'Starting HTTP server')
         cherrypy.engine.start()
-        logger.info(u'HTTP server running at %s',
-            cherrypy.server.base())
+        logger.info(u'HTTP server running at %s', cherrypy.server.base())
 
     def on_stop(self):
+        logger.debug(u'Stopping HTTP server')
         cherrypy.engine.stop()
+        logger.info(u'Stopped HTTP server')
+
+    def playback_state_changed(self, old_state, new_state):
+        cherrypy.engine.publish('websocket-broadcast',
+            TextMessage('playback_state_changed: %s -> %s' % (
+                old_state, new_state)))
+
+
+class EventWebSocketHandler(WebSocket):
+    def opened(self):
+        remote = cherrypy.request.remote
+        logger.debug(u'New WebSocket connection from %s:%d',
+            remote.ip, remote.port)
+
+    def closed(self, code, reason=None):
+        remote = cherrypy.request.remote
+        logger.debug(u'Closed WebSocket connection from %s:%d '
+            'with code %s and reason %r',
+            remote.ip, remote.port, code, reason)
+
+    def received_message(self, message):
+        remote = cherrypy.request.remote
+        logger.debug(u'Received WebSocket message from %s:%d: %s',
+            remote.ip, remote.port, message)
+        # This is where we would handle incoming messages from the clients
 
 
 class Root(object):
@@ -61,3 +106,7 @@ class Root(object):
             'playback_state': playback_state,
             'current_track': track,
         }
+
+    @cherrypy.expose
+    def ws(self):
+        logger.debug(u'WebSocket handler created')