MQTT Client¶

Paho-Python¶

Here is an example of using the Paho-Python library to create an MQTT client. To run you need to install the dependencies first. After that you can create two scripts for the subscriber and publisher. Run the subscriber first and then the publisher. You should see the message received by the subscriber.

Subscriber¶

import paho.mqtt.client as mqtt

# Define the MQTT broker, topic, username, and password
broker_address = "8.222.194.160"  # Replace with your MQTT broker address
port = 1883 # Replace with your MQTT broker port
heartbeat_interval = 60  # The number of seconds until a heartbeat message is sent
topic = "csw-iot"
username = "cshwstem"  # Replace with your MQTT broker username
password = "88888888"  # Replace with your MQTT broker password

# Callback when the client connects to the broker
def on_connect(client, userdata, flags, rc):
    print("Connected with result code " + str(rc))
    # Subscribe to the topic when connected
    client.subscribe(topic)

# Callback when a message is received from the broker
def on_message(client, userdata, msg):
    print(f"Received message on topic {msg.topic}: {msg.payload.decode()}")

# Create an MQTT client instance
client = mqtt.Client()

# Set username and password
client.username_pw_set(username, password)

# Set callback functions
client.on_connect = on_connect
client.on_message = on_message

# Connect to the broker
client.connect(broker_address, port, heartbeat_interval)

# Start the loop to handle network communication, callbacks, and reconnecting
client.loop_start()

# Wait for the connection to be established
while not client.is_connected():
    pass

# Continue the program execution
try:
    # The client will subscribe to the topic in the on_connect callback
    while True:
        pass

except KeyboardInterrupt:
    # Disconnect from the broker when the program is interrupted
    client.disconnect()
    print("Disconnected from the broker")

Publisher¶

import paho.mqtt.client as mqtt

# Define the MQTT broker, topic, username, and password
broker_address = "8.222.194.160"  # Replace with your MQTT broker address
port = 1883 # Replace with your MQTT broker port
heartbeat_interval = 60  # The number of seconds until a heartbeat message is sent
topic = "csw-iot"
username = "cshwstem"  # Replace with your MQTT broker username
password = "88888888"  # Replace with your MQTT broker password

# Define the message to be sent
message = "Hello from Shuaiwen, MQTT!"

# Callback when the client connects to the broker
def on_connect(client, userdata, flags, rc):
    print("Connected with result code " + str(rc))
    # Publish the message when connected
    client.publish(topic, message)

# Callback when the message is published
def on_publish(client, userdata, mid):
    print("Message Published")

# Create an MQTT client instance
client = mqtt.Client()

# Set username and password
client.username_pw_set(username, password)

# Set callback functions
client.on_connect = on_connect
client.on_publish = on_publish

# Connect to the broker
client.connect(broker_address, port, heartbeat_interval)

# Start the loop to handle network communication, callbacks, and reconnecting
client.loop_start()

# Wait for the connection to be established
while not client.is_connected():
    pass

# Continue the program execution
try:
    # The client will publish the message in the on_connect callback
    while True:
        pass

except KeyboardInterrupt:
    # Disconnect from the broker when the program is interrupted
    client.disconnect()
    print("Disconnected from the broker")