💬 Chat application using AWS IoT platform via MQTT over the WebSocket protocol
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This is a React application demonstrating how to use the AWS IoT platform via MQTT over the WebSocket protocol to build a live chat application. The sample application serves as a starting point for users to build serverless projects with Amazon Cognito, AWS Lambda and Amazon DynamoDB. The project showcases the solution to common user questions such as how to authenticate IoT devices with Amazon Cognito.
Please note that this project has only been tested on macOS. Windows users may need to update some of the scripts. Pull requests are welcome to add Windows support.
outputformat to be
$ git clone https://github.com/aws-samples/aws-iot-chat-example.git
If you would like to enable login with Facebook and/or Google, please follow the Social Logins guide.
$ cd api $ sudo npm install -g serverless $ npm install $ serverless deploy
The Serverless Framework is a tool for deploying serverless architectures. The stack including Lambda functions and CloudFormation resources are defined in
After deploying the serverless application, two scripts are invoked by means of a lifecycle hook. The first,
api/scripts/attachConfirmUserTrigger.shis used to attach a Lambda function to the PreSignUp trigger on the Cognito User Pool.
The second script in
client/scripts/setup.shuses the AWS CLI to query the Cloudformation template output variables and stores them in the file
client/src/config/config.json. This auto-generated file is then imported by
client/src/config/index.jsand used within the client side application.
$ cd ../client $ npm install $ npm start
It is important to run the setup script so that the client knows the destination of the AWS IoT endpoint, API Gateway endpoint and other coniguration variables generated by
http://localhost:3000and try it out!
To tear down the stack, use the command
Try the app on the Demo website
Register a user using Amazon Cognito User Pools. You can use user pools to add user registration and sign-in features to your apps.
Login a user using Amazon Cognito User Pools.
Alternatively, you can use Amazon Cognito Federated Identities to create unique identities for your users and federate them with identity providers such as Facebook and Google.
Displays the list of available rooms to join. If you are subscribed to a room, there will be an icon indication. The number of unread messages to subscribed rooms is also displayed. Lastly, on this screen you can create a room. The application will generate an appropriate topic name to publish on if your room name contains illegal characters.
All HTTP API endpoints are AWS Lambda functions invoked through Amazon API Gateway.
This is the main chat page where the real-time messaging is displayed. You will still be subscribed to other rooms as indicated by the unread message counters that increment when a message is received. Sending a message will dispatch a message to AWS IoT which in turn is responsible for fanning out the messages to all the subscribers of the room.
api/serverless.ymlfile, functions, events, resources and services are defined which Serverless uses to deploy the appropriate Lambda functions, API Gateway services and additional CloudFormation resources.
MQTT (Message Queue Telemetry Transport) protocol uses a hierarchical structure to describe the topic space. Multi-level
#wildcards and single-level
+wildcards can be used in addition to topic level separators
In this application, topics are subscribed to using the form:
This matches topics such as:
room/public/room/abc room/public/another-room/123 room/public/another-room/us-west-2:7f86d9a8-b9f4-439e-bcf3-9756e4d2bbdf
Note the last example topic because this is the topic that users will publish to.
Based on the MQTT specification, a receiving client does not know who published the message without either including the message author in the message payload itself or by encoding the message author in the message topic.
This application opted for the second option by appending the cognito identity id to the end of the publishing topic. To prevent users from publishing to other user's topics, the AWS Lambda function
AttachPublicPublishcreates a dynamic IoT policy that allows only that one identity to publish messages to their unique topic.
In both the
npm run testcan be used to run unit tests using jest