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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Understanding the CocoaMQTT client in Swift 3

The CocoaMQTT client is very easy to use. First, it is necessary to import CocoaMQTT, create an instance of the CocoaMQTT class, specify the MQTT connection configuration values, and indicate an instance of a class that conforms to the CocoaMQTTDelegate protocol. We can call the methods for the created CocoaMQTT instance to subscribe to topics and publish messages.

Let's take a look at the code that declares the CocoaMQTTDelegate protocol:

@objc public protocol CocoaMQTTDelegate {
    func mqtt(_ mqtt: CocoaMQTT, didConnect host: String, port: Int)
    func mqtt(_ mqtt: CocoaMQTT, didConnectAck ack: CocoaMQTTConnAck)
    func mqtt(_ mqtt: CocoaMQTT, didPublishMessage message: CocoaMQTTMessage, id: UInt16)
    func mqtt(_ mqtt: CocoaMQTT, didPublishAck id: UInt16)
    func mqtt(_ mqtt: CocoaMQTT, didReceiveMessage message: CocoaMQTTMessage, id: UInt16 )
    func mqtt(_ mqtt: CocoaMQTT, didSubscribeTopic topic: String)
    func mqtt(_ mqtt: CocoaMQTT...