When developing a video, voice communication, or message chat system using the AWS Chime SDK, user authentication is a crucial part. One way to securely authenticate users is by using JSON Web Tokens (JWT). In this blog post, we will explore how to implement JWT-based login for AWS Chime SDK in Node.js, walking through the necessary setup and the provided code.

Prerequisites

Before we begin, ensure that you have the following:

• AWS Account with access to Chime SDK

• Basic knowledge of JWT and its usage

• Node.js environment installed on your local machine

• AWS SDK for JavaScript installed in your project

Setting Up AWS Chime SDK

1. Install AWS SDK and Chime SDK

   First, you need to install the required AWS SDK in your Node.js project.

     npm install aws-sdk uuid
   

   The aws-sdk package allows us to interact with AWS services, including AWS Chime. The uuid package is used for generating unique tokens for AWS API requests.

2. Set Up Environment Variables

   You will also need to set some environment variables that are used in the application:

    USER_ROLE_ARN=arn:aws:iam::xxxxxxxx:role/YourUserRole
    CHIME_APP_INSTANCE_ARN=arn:aws:chime:us-east-1:xxxxxxxx:app-instance/YourChimeAppInstance
   

   These values can be found in your AWS IAM roles and AWS Chime SDK settings.

JWT-Based User Login in AWS Chime SDK

The provided code implements a login system where users are authenticated using JWT tokens, and AWS Chime SDK is used to create or retrieve the necessary credentials for communication.

Step-by-Step Breakdown of the Code

Let’s break down the code and explain how it works:

typescriptCopy codeasync userSignIn(userData: any) {
  const { id, full_name } = userData;

  // Step 1: Create a user object that contains the UUID and display name
  const user: any = {
    uuid: id,
    displayName: full_name,
    metadata: null
  };

  // Step 2: Assume a role using AWS Security Token Service (STS) to obtain temporary credentials
  const creds = await this.assumeRole(user);

  // Step 3: Either create a new Chime user or get the existing user's ARN
  const userArn = await this.createOrGetChimeUserArn(user);

  // Step 4: Return the necessary Chime credentials to the frontend
  return {
    ChimeAppInstanceUserArn: userArn,
    ChimeUserId: user.uuid,
    ChimeCredentials: creds,
    ChimeDisplayName: user.displayName
  };
}

Explanation:

• userSignIn function: This function takes user data (including id and full_name), creates a user object, and assumes a role via AWS STS to get temporary credentials. It then creates or retrieves the Chime App Instance User's ARN and returns the required credentials to the frontend.

Assuming Role with AWS STS

typescriptCopy codeasync assumeRole(user: any) {
  const USER_ROLE_ARN = process.env.USER_ROLE_ARN || '';

  const assumedRoleResponse = await sts
    .assumeRole({
      RoleArn: USER_ROLE_ARN,
      RoleSessionName: `chime_${user.uuid}`,
      DurationSeconds: 3600,
      Tags: [
        {
          Key: 'UserUUID',
          Value: user.uuid.toString()
        }
      ]
    })
    .promise();
  return assumedRoleResponse.Credentials;
}

• AssumeRole function: This function interacts with AWS Security Token Service (STS) to assume a role specified in the environment variable USER_ROLE_ARN. It tags the session with the user’s UUID and returns the temporary credentials.

Creating or Getting Chime User ARN

typescriptCopy codeasync createOrGetChimeUserArn(user: AwsChimeUserData) {
  const createUserResponse = await chimeIdentity
    .createAppInstanceUser({
      AppInstanceArn: appConfig.appInstanceArn,
      AppInstanceUserId: user.uuid.toString(),
      ClientRequestToken: uuid(),
      Name: user.displayName
    })
    .promise();

  return createUserResponse.AppInstanceUserArn;
}

• createOrGetChimeUserArn function: This function either creates a new App Instance User or retrieves an existing user using the AWS Chime SDK. It requires the AppInstanceArn (set via environment variables), user ID, and display name.

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Conclusion

By combining JWT authentication with the AWS Chime SDK, you can provide secure access to meetings, video conferences, and chat functionality. In this guide, we walked through the code that performs the following tasks:

1. Authenticates users with JWT tokens.

2. Assumes roles via AWS STS for temporary credentials.

3. Creates or retrieves AWS Chime App Instance User ARN for each user.

This setup ensures that your application’s communication system is both secure and scalable.

Next Steps:

• Expand this implementation with JWT token validation for additional security.

• Implement token expiration handling to reauthenticate users as needed.