Update: This article now also exists as a git repository.
I played around with MQTT and Python for an upcoming project of mine.
Here are some notes and a simple example code for a subscriber.
Requires Mosquitto to be installed.
On Linux with the apt-get package manager:
sudo apt-get install mosquitto sudo apt-get install mosquitto-clients
mosquitto-clients is to get the mosquitto_pub to make it simple to try stuff from the command line.
Also install virtualenv if you want to use it (recommended):
sudo apt-get install python-virtualenv
The use of virtualenv is optional but recommended for playing around with this example code.
mkdir mqtt-mosquitto-example cd mqtt-mosquitto-example virtualenv . source bin/activate pip install paho-mqtt
import paho.mqtt.client as paho def on_message(mosq, obj, msg): print "%-20s %d %s" % (msg.topic, msg.qos, msg.payload) mosq.publish('pong', 'ack', 0) def on_publish(mosq, obj, mid): pass if __name__ == '__main__': client = paho.Client() client.on_message = on_message client.on_publish = on_publish #client.tls_set('root.ca', certfile='c1.crt', keyfile='c1.key') client.connect("127.0.0.1", 1883, 60) client.subscribe("kids/yolo", 0) client.subscribe("adult/#", 0) while client.loop() == 0: pass # vi: set fileencoding=utf-8 :
Test the subscriber example
First start the subscriber which will enter a loop waiting for new messages: ::bash ./subscriber.py
Then open a new terminal and send a message:
mosquitto_pub -d -h localhost -q 0 -t adult/pics -m "can i haz moar kittenz"
This should generate a message in the terminal running the subscriber.
See mosquitto-tls on how to generate certificates and keys.
Once created you need to adjust /etc/mosquitto/mosquitto.conf and subscriber.py accordingly and then use mosquitto_pub with cert and key:
mosquitto_pub -d -h localhost --cafile root.ca --cert c1.crt --key c1.key -q 0 -t adult/pics -m "can i haz moar kittenz"
* http://jpmens.net/2013/02/25/lots-of-messages-mqtt-pub-sub-and-the-mosquitto-broker/ * https://www.justinribeiro.com/chronicle/2012/11/08/securing-mqtt-communication-between-ardruino-and-mosquitto/ * http://www.instructables.com/id/USB-RFID-Python-Pub-Sub-MQTT/ * http://mosquitto.org/documentation/python/ * https://pypi.python.org/pypi/paho-mqtt