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 multiple calls to the loop method

The following lines declare the process_incoming_commands method that is part of the VehicleCommandProcessor class. You have to add these lines to the existing Python file. The code file for the sample is included in the mqtt_python_gaston_hillar_04_01 folder, in the file:

    def process_incoming_commands(self):

The process_incoming_commands method calls the loop method for the MQTT client and ensures communication with the MQTT server is carried out. Think about the call to the loop method as synchronizing your mailbox. Any pending messages to be published in the outgoing box will be sent, any incoming messages will arrive to the inbox, and the events that we have previously analyzed will be fired. This way, the vehicle command processor will receive messages...