aws-mqtt-client

AWS MQTT Websocket Pub/Sub with AWS IoT based on MQTT.js. Recently AWS released support of WebSockets for IoT service. It is very easy to use as Pub/Sub message system for serverless web applications. You can post new messages from AWS lambda function via http post request and receive them as websocket messages on client.

Installing it

````bash npm i aws-mqtt-client --save ````

Basic usage

1. Create an IAM role and asign predefined AWSIoTDataAccess policy. (It is better to use AWS Cognito to provide temporary credentials for the front-end application, you can also customize policy to allow access only to user specific topics).
2. Run AWS CLI command aws iot describe-endpoint to get IoT endpoint url.
3. Create mqttClient with AWS credentials.

````js import AWSMqtt from "aws-mqtt-client";
const mqttClient = new AWSMqtt({ accessKeyId: AWSACCESSKEY, secretAccessKey: AWSSECRETACCESSKEY, sessionToken: AWSSESSIONTOKEN, endpointAddress: AWSIOTENDPOINTHOST, region: "us-east-1" }); ````

1. Connect and receive messages from your topic.

````js mqttClient.on("connect", () => { mqttClient.subscribe("test-topic"); console.log("connected to iot mqtt websocket"); }); mqttClient.on("message", (topic, message) => { console.log(message.toString()); }); ````

1. Publish a message.

````js mqttClient.publish(MQTTTOPIC, message); ````

Complete MQTT.js API

Credits

Based on Serverless JS-Webapp Pub/Sub with AWS IoT article by Stefan Siegl. This library is a wrapper around MQTT.js npm package.