MQTT Tutorial With Python

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Install paho-mqtt Plugin ✈️

pip install paho-mqtt

pip3 install paho-mqtt

Check paho-mqtt Plugin ✈️

C:\>pip list ↩️
Package    Version
---------- -------
paho-mqtt  1.6.1  ⬅️ Successfully installed paho-mqtt-1.6.1
pip        22.3.1
setuptools 65.5.0

Use a free MQTT server

test.mosquitto.org
ports : 1884
username : rw
password : readwrite

import paho.mqtt.client as mqtt


# The callback function that will be executed 
# when connecting to the MQTT server
def on_connect(client, userdata, flags, rc):
    print("Connected with result code " + str(rc))

    # Subscriptions can be set in on_connet, 
    # and will be re-subscribed if the connection
    # is lost or reconnected
    client.subscribe("$SYS/#")


# The callback function to be performed 
# when receiving a message sent from the MQTT server
def on_message(client, userdata, msg):
    # Convert encoding to utf-8 or not
    print(msg.topic + " " +
          str(msg.payload.decode("utf-8")))


# Initialize the my_client
my_client = mqtt.Client()

# Set the callback function after connection
my_client.on_connect = on_connect

# Set the callback function after receiving
my_client.on_message = on_message

# Set login account and password
my_client.username_pw_set("rw", "readwrite")

# Set connection parameters (IP, Port, connection time)
my_client.connect("test.mosquitto.org", 1884, 60)

# Start the connection, execute the set action 
# and loop_forever can handle the reconnection problem
# You can also manually use other loop functions to connect
my_client.loop_forever()

Results

Connected with result code 0
$SYS/broker/bytes/received 1534092578435
$SYS/broker/bytes/sent 32330049071821
$SYS/broker/clients/active 3489
$SYS/broker/clients/connected 3489
$SYS/broker/clients/disconnected 102900
$SYS/broker/clients/inactive 102900
$SYS/broker/clients/total 106389
$SYS/broker/connection/31d8cf14464a.famous/state 1
$SYS/broker/connection/31d8cf14464a.renningen/state 1
$SYS/broker/connection/4de57af3c5ab.mosquitto-bridge/state 0

First, execute the following “subscribe” code.

import paho.mqtt.client as mqtt


def on_connect(client, userdata, flags, rc):
    client.subscribe("mqtt_topic/#")


def on_message(client, userdata, msg):
    print("From > " + msg.topic + " : " +
          str(msg.payload.decode("utf-8")))


my_client = mqtt.Client()

my_client.on_connect = on_connect

my_client.on_message = on_message

my_client.username_pw_set("rw", "readwrite")

my_client.connect("test.mosquitto.org", 1884, 60)

my_client.loop_forever()

Then execute the following “publish” code.

import paho.mqtt.client as mqtt
import json


msg = "Hello World"

my_client = mqtt.Client()

my_client.username_pw_set("rw", "readwrite")

my_client.connect("test.mosquitto.org", 1884, 60)

# The topic and content to publish
my_client.publish("mqtt_topic", json.dumps(msg))

You will see the following output in the subscribed terminal.