Book Image

Hands-On MQTT Programming with Python

By : Gaston C. Hillar
Book Image

Hands-On MQTT Programming with Python

By: Gaston C. Hillar

Overview of this book

<p>MQTT is a lightweight messaging protocol for small sensors and mobile devices. This book explores the features of the latest versions of MQTT for IoT and M2M communications, how to use them with Python 3, and allow you to interact with sensors and actuators using Python.</p> <p>The book begins with the specific vocabulary of MQTT and its working modes, followed by installing a Mosquitto MQTT broker. You will use different utilities and diagrams to understand the most important concepts related to MQTT. You will learn to make all the necessary configuration to work with digital certificates for encrypting all data sent between the MQTT clients and the server. You will also work with the different Quality of Service levels and later analyze and compare their overheads.</p> <p>You will write Python 3.x code to control a vehicle with MQTT messages delivered through encrypted connections (TLS 1.2), and learn how leverage your knowledge of the MQTT protocol to build a solution based on requirements. Towards the end, you will write Python code to use the PubNub cloud-based real-time MQTT provider to monitor a surfing competition.</p> <p>In the end, you will have a solution that was built from scratch by analyzing the requirements and then write Python code that will run on water-proof IoT boards connected to multiple sensors in surfboards.</p>
Table of Contents (9 chapters)

Working with the network loop with Python

Now, we will use the previously coded functions in a __main__ method that will publish many commands included in the MQTT messages that the code that controls the vehicle will process. You have to add the next lines to the existing Python file. The following lines show the code for the __main__ method, that is, the main block of code. The code file for the sample is included in the mqtt_python_gaston_hillar_05_01 folder, in the file:

if __name__ == "__main__": 
    client = mqtt.Client(protocol=mqtt.MQTTv311) 
    client.on_connect = on_connect 
    client.on_subscribe = on_subscribe 
    client.on_message = on_message 
    client.tls_set(ca_certs = ca_certificate,