How do I use the Paho MQTT library?

How do I use the Paho MQTT library?

The Paho MQTT library is a popular choice for implementing MQTT clients in various programming languages. What specific language are you using?

I'm using Python. Can you give me a basic example?

Sure! First, install the library using pip install paho-mqtt. Then, you can create a simple client like this:

import paho.mqtt.client as mqtt

# Callback when the client receives a CONNACK response from the server
def on_connect(client, userdata, flags, rc):
    print('Connected with result code ' + str(rc))
    client.subscribe('test/topic')

# Callback when a message is published
def on_message(client, userdata, msg):
    print(msg.topic + ' ' + str(msg.payload))

client = mqtt.Client()
client.on_connect = on_connect
client.on_message = on_message

client.connect('mqtt.eclipse.org', 1883, 60)
client.loop_forever()

This connects to a public MQTT broker and subscribes to a topic.

What if I want to publish a message?

You can publish a message using the publish method. Here's how you can do it:

client.publish('test/topic', 'Hello, MQTT!')

Just call this after connecting to the broker, and it will send the message to the specified topic.