serial callbacks in frontend

raspberry/roberto/Serial.py

@@ -62,3 +62,7 @@ class Serial(object):
 
     def add_callback(cmd, callback):
         self._callbacks[cmd] = callback
+
+    def del_callback(cmd, callback):
+        if cmd in self._callbacks:
+            del self._callbacks[cmd]

raspberry/roberto/views/websocket/routes.py

@@ -97,6 +97,8 @@ def disconnect():
     print("Received Disconnect message from %s" % sid)
     leave_room(ROOM)
     webrtccamera.disconnect_client(sid, ROOM)
+    from roberto import serial
+    serial.del_callback('B', display_battery)
 
 @socketio.on('connect', namespace='/webrtc')
 def connect():
@@ -104,6 +106,8 @@ def connect():
     print("Received Connect message from %s" % sid)
     join_room(ROOM)
     webrtccamera.connect_client(sid, ROOM)
+    from roberto import serial
+    serial.add_callback('B', display_battery)
 
 @socketio.on_error_default
 def default_error_handler(e):
@@ -113,3 +117,6 @@ def default_error_handler(e):
     keys.sort()
     for key in request:
         print('%s: %s' % (key, repr(request[key])))
+
+def display_battery(val):
+    socketio.emit('battery', data=val, room=ROOM, namespace='/webrtc')