The Eclipse Paho JavaScript client provides:
Only a non-blocking (asynchronous) API.
Only a blocking (synchronous) API.
Both a blocking (synchronous) and a non-blocking (asynchronous) API.
In the Paho JavaScript API, the
Paho.MQTT.Client
object represents:The synchronous MQTT over WebSockets client.
The asynchronous MQTT over WebSockets client.
The asynchronous MQTT over TCP client (no WebSockets).
After the
Paho.MQTT.Client
instance establishes a connection with the MQTT server, the callback assigned to which of the following attributes of theconnectOptions
object passed as an argument to theconnect
function will be called?connectCallback
.onSuccess
.onConnect
.
After the
Paho.MQTT.Client
instance receives a message from one of the topic filters to which it has subscribed, the callback assigned to which of the following attributes of theconnectOptions
object passed as an argument to theconnect
function will be called?onMessageReceived
.messageReceivedCallback
.onMessageArrived...
MQTT Essentials - A Lightweight IoT Protocol
MQTT Essentials - A Lightweight IoT Protocol
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
Credits
About the Author
Acknowledgment
About the Reviewer
www.PacktPub.com
Customer Feedback
Dedication
Preface
Free Chapter
Lightweight Messaging with MQTT 3.1.1 and Mosquitto
Securing an MQTT Mosquitto Server
Controlling a Drone with Python
Interacting with Sensors in Java
Controlling Home Automation in JavaScript
Interacting with Actuators in Swift
Exersise Answers
Customer Reviews