Add 'car/' from commit 'eee0e8dc445691e600680f4abc77f2814b20b054'

git-subtree-dir: car
git-subtree-mainline: 1d29a5526c
git-subtree-split: eee0e8dc44

car/Messaging/message_factory.py

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+import zmq
+
+
+class ZmqPubSubStreamer:
+    '''
+    Not thread-safe. Always get this inside the thread/process where you intend
+    to use it. 
+    '''
+
+    def __init__(self, port):
+        self._socket = zmq.Context.instance().socket(zmq.PUB)
+        print('Starting socket with address: ' + 'tcp://*:' + str(port))
+        self._socket.bind("tcp://*:" + str(port))
+        
+
+    def send_message(self, message):
+        '''
+        Args
+        ----
+        message: A message type that has the serialise() method.
+        '''
+        self.send_message_topic("", message)
+
+    def send_message_topic(self, topic, message):
+        self._socket.send_multipart([bytes(topic), message.serialise()])
+
+
+class BluetoothStreamer:
+    def __init__(self):
+        pass
+
+    def send_message(self, message_bytes):
+        pass
+
+class TestStreamer:
+    def __init__(self):
+        self._listeners = []
+
+    def send_message(self, message_bytes):
+        print('Got a message')
+
+    def send_message_topic(self, topic, message):
+        print('Got a message with topic: ' + str(topic))
+        self._fire_message_received(message)
+
+    def add_message_listener(self, listener):
+        self._listeners.append(listener)
+
+    def _fire_message_received(self, message):
+        for listener in self._listeners:
+            listener(message)
+
+def getZmqPubSubStreamer(port):
+    '''
+    Not thread-safe. Always get this inside the thread/process where you intend
+    to use it. 
+    '''
+    return ZmqPubSubStreamer(port)
+
+def getTestingStreamer():
+    return TestStreamer()
+
+# TODO: Create a general get method that will get the streamer based on an 
+# environment variable that is set. 

car/Messaging/messages.py

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+import umsgpack
+
+
+class Message():
+    def __init__(self, message=None):
+        self.message = message
+
+    def serialise(self):
+        raise NotImplementedError
+
+    def deserialise(self, message):
+        raise NotImplementedError
+
+
+class PackMessage(Message):
+
+    def serialise(self):
+        return umsgpack.packb(self.message)
+
+    def deserialise(self, message):
+        return PackMessage(umsgpack.unpackb(self.message))
+
+
+class ProtoMessage(Message):
+
+    def __init__(self, proto_type=None, message=None):
+        super().__init__(message)
+        self._type = proto_type
+
+    def serialise(self):
+        return self.message.SerializeToString()
+
+    def deserialise(self, message):
+        return ProtoMessage(self._type, self._type.ParseFromString(message))

car/Messaging/mqttsession.py

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+import paho.mqtt.client as mqtt
+
+"""
+Wrapper module for paho mqtt library, providing a singleton instance of the client to be used.
+Also adds some convenience functions such as having multiple connected callbacks,
+and managing whether the client is still connected. 
+"""
+
+
+client = mqtt.Client()
+host = None
+
+connect_callbacks = []
+disconnect_callbacks = []
+
+def on_connect(client, userdata, flags, rc):
+    print("Connected with result code " + str(rc))
+    if rc == 0:
+        global connected
+        connected = True
+
+    for callback in connect_callbacks:
+        callback()
+
+    client.subscribe('hello/test', qos=1)
+
+# Arguably not needed, just want to make the client static, but here anyway.
+def connect():
+    global client
+    if client is None or host is None:
+        print("Error: Client and/or host are not initialised.")
+    else:
+        client.connect(host, port=1883, keepalive=60, bind_address="")
+        client.loop_start()
+
+def add_connect_callback(callback):
+    global connect_callbacks
+    connect_callbacks += callback
+    connectted = True
+
+def add_disconnect_callback(callback):
+    global 
+
+def disconnect():
+    global client
+    if client is not None:
+        client.loop_stop()
+        client.disconnect()
+    else:
+        print("Error: Client is not initialised.")
+
+def on_disconnect(client, userdata, rc):
+    if rc != 0:
+        print("Unexpected disconnection.")
+
+    global connected
+    connected = False
+
+def Client():
+    global client
+    if client is None:
+        client =  mqtt.Client()
+
+    return client