platypush/platypush/backend/mqtt.py
2018-05-27 12:21:41 +02:00

61 lines
1.7 KiB
Python

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()
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