Book Image

MQTT Essentials - A Lightweight IoT Protocol

5 (1)
Book Image

MQTT Essentials - A Lightweight IoT Protocol

5 (1)

Overview of this book

This step-by-step guide will help you gain a deep understanding of the lightweight MQTT protocol. We’ll begin with the specific vocabulary of MQTT and its working modes, followed by installing a Mosquitto MQTT broker. Then, you will use best practices to secure the MQTT Mosquitto broker to ensure that only authorized clients are able to publish and receive messages. Once you have secured the broker with the appropriate configuration, you will develop a solution that controls a drone with Python. Further on, you will use Python on a Raspberry Pi 3 board to process commands and Python on Intel Boards (Joule, Edison and Galileo). You will then connect to the MQTT broker, subscribe to topics, send messages, and receive messages in Python. You will also develop a solution that interacts with sensors in Java by working with MQTT messages. Moving forward, you will work with an asynchronous API with callbacks to make the sensors interact with MQTT messages. Following the same process, you will develop an iOS app with Swift 3, build a website that uses WebSockets to connect to the MQTT broker, and control home automation devices with HTML5, JavaScript code, Node.js and MQTT messages
Table of Contents (16 chapters)
MQTT Essentials - A Lightweight IoT Protocol
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Creating a class to represent a drone

Now, we will write Python code that will run on the different IoT boards. Remember to copy the files we have created in the previous chapter to a directory in the computer or device that will represent the board that controls a drone and that we will use to run a Python script. We saved the files in a directory called certificates. Create a python_certificates directory in the computer or board you are going to use as the MQTT client for this example. Copy the following three files to this new directory:

  • ca.crt: Certificate authority certificate file

  • device001.crt: Client certificate file

  • device001.key: Client key

We will create the following two classes:

  • Drone: This class will represent a drone and provides methods that will be called whenever a command has to be processed. In order to keep the example simple, our methods will just print the actions that the drone executes after each method is called to the console output. A real-life class that represents...