In this article, I want to create a python module which would connect to mosquitto server. We can connect a MQTT client as subscriber or publisher of message.
Mosquitto python module has been donated to Eclipse Paho project, which is open-source client implementations of MQTT. This module can be installed using pip command.
$ sudo pip install paho-mqtt
Subs.py – The code given below is subscribe module. You can look at comment to understand in detail.
#The line imports python mqtt module.
import paho.mqtt.client as mqtt
#Here we initilize variables used in the code.
server = "192.168.0.XXX"
port = 8883
keep_live = 45
topic = "msgTopic"
# Define routines to register.
# Client - The instance at the client side.
# userdata - Data to be passed by the user.
# flags - response flag sent by the server.
# rc - Return code, 0 is successful connection.
# mid - message id
# granted_qos - Quality of service granted by the server, default 0.
# payload - the message received on the topic.
def on_connect(client, userdata, flags, rc):
mqttc.subscribe(topic, 0)
def on_subscribe(client, userdata, mid, granted_qos):
print("Subscribed to: "+str(mid)+" "+str(granted_qos))
def on_message(client, userdata, msg):
print(msg.topic+" "+str(msg.qos)+" "+str(msg.payload))
# Initilize a client instance and ser password for the connection.
mqttc = mqtt.Client()
mqttc.username_pw_set(username="username",password="password")
# register the routines.
mqttc.on_message = on_message
mqttc.on_connect = on_connect
mqttc.on_subscribe = on_subscribe
# connect to the server and wait for message.
mqttc.connect(server, port, keep_live)
mqttc.loop_forever()
Pubs.py – The code given below is publisher module. You can look at comment to understand in detail.
#The line imports python mqtt module.
import paho.mqtt.client as mqtt
#Here we initilize variables used in the code.
server = "192.168.0.191"
port = 8883
keep_live = 45
topic = "msgTopic"
# Connect and publish modules
def on_connect(client, userdata, flags, rc):
mqttc.subscribe(topic, 0)
def on_publish(client, userdata, mid):
print "Message Published..."
# Initilize a client instance and ser password for the connection.
mqttc = mqtt.Client()
mqttc.username_pw_set(username="mqtt",password="mqtt")
# register the routines.
mqttc.on_publish = on_publish
mqttc.on_connect = on_connect
# Connect and publish the message on a topic.
mqttc.connect(server, port, keep_live)
mqttc.publish(topic,"Hello! How are you?")
mqttc.disconnect()
Output – Below is the Publish and Subscribe module in action on raspberry pi.
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