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 retained last will messages

Now, we will check what happens when the MQTT client that controls the vehicle disconnects unexpectedly from the MQTT server and our vehicle remote control application disconnects unexpectedly, too. Pay attention to all the steps because we will manually interrupt the execution of both programs to understand a specific problem that we will solve by taking advantage of the last will and testament feature combined with the retained flag value.

You will have to be quick to run the next steps. Hence, make sure you read all the steps and then execute them.

Execute the following line to start the vehicle remote control example on any computer or device that you want to use as the MQTT client and uses Linux or macOS:


In Windows, you must execute the following line:

    python vehicle_mqtt_remote_control...