A sample of MQTT subscriber (QoS=0)

mqttsub.py

#!/usr/bin/env python2.7
from __future__ import print_function
import paho.mqtt.client as mqtt     # https://pypi.python.org/pypi/paho-mqtt/

topic = "foo/bar"

def on_connect(client, userdata, flags, respons_code):
    print('connect:status {0}'.format(respons_code))
    client.subscribe(topic)

def on_message(client, userdata, msg):
    print("recieve message %s:%s" % (msg.topic, str(msg.payload)))

if __name__ == '__main__':
    client = mqtt.Client(protocol=mqtt.MQTTv311)
    client.on_connect = on_connect
    client.on_message = on_message
    client.username_pw_set('subscriber', 'pass')
    client.connect('localhost')

    client.loop_forever()