Implemented MQTT backend and plugin, see issue #56

platypush/backend/mqtt.py

@@ -0,0 +1,61 @@
+import logging
+import json
+
+import paho.mqtt.client as mqtt
+import paho.mqtt.publish as publisher
+
+from platypush.backend import Backend
+from platypush.message import Message
+
+
+class MqttBackend(Backend):
+    """
+    Backend that reads messages from a configured MQTT topic
+    (default: `platypush_bus_mq/<device_id>`) and posts them to the application bus.
+    """
+
+    def __init__(self, host, port=1883, topic='platypush_bus_mq', *args, **kwargs):
+        """
+        Params:
+            host -- MQTT broker host
+            port -- MQTT broker port (default: 1883)
+            topic -- Topic to read messages from (default: platypush_bus_mq/<device_id>)
+        """
+        super().__init__(*args, **kwargs)
+
+        self.host = host
+        self.port = port
+        self.topic = '{}/{}'.format(topic, self.device_id)
+
+
+    def send_message(self, msg):
+        publisher.single(self.topic, str(msg), hostname=self.host, port=self.port)
+
+
+    def run(self):
+        def on_connect(client, userdata, flags, rc):
+            client.subscribe(self.topic)
+
+        def on_message(client, userdata, msg):
+            msg = msg.payload.decode('utf-8')
+            try:
+                msg = Message.build(json.loads(msg))
+            except:
+                pass
+
+            logging.info('Received message on the MQTT backend: {}'.format(msg))
+            self.bus.post(msg)
+
+        super().run()
+        client = mqtt.Client()
+        client.on_connect = on_connect
+        client.on_message = on_message
+        client.connect(self.host, self.port, 60)
+        logging.info('Initialized MQTT backend on host {}:{}, topic {}'.
+                     format(self.host, self.port, self.topic))
+
+        client.loop_forever()
+
+
+# vim:sw=4:ts=4:et:
+

platypush/plugins/mqtt.py

@@ -0,0 +1,16 @@
+import logging
+
+import paho.mqtt.publish as publisher
+
+from platypush.message.response import Response
+from platypush.plugins import Plugin
+
+
+class MqttPlugin(Plugin):
+    def send_message(self, topic, msg, host, port=1883, *args, **kwargs):
+        publisher.single(topic, str(msg), hostname=host, port=port)
+        return Response(output={'state': 'ok'})
+
+
+# vim:sw=4:ts=4:et:
+