Unlocking the Power of Keycloak Rest API via Lambda AWS: A Step-by-Step Guide

Are you tired of dealing with authentication and authorization headaches in your application? Do you want to leverage the power of Keycloak’s Rest API to secure your application without breaking the bank? Look no further! In this comprehensive guide, we’ll show you how to call Keycloak Rest API via Lambda AWS, and take your application’s security to the next level.

What is Keycloak?

Before we dive into the nitty-gritty of calling Keycloak Rest API via Lambda AWS, let’s take a quick peek at what Keycloak is. Keycloak is an open-source identity and access management solution that provides a robust and scalable way to manage authentication, authorization, and identity management for your application.

Keycloak provides a wide range of features, including:

• User authentication and authorization
• Single sign-on (SSO) and single logout (SLO)
• OAuth 2.0 and OpenID Connect protocols
• Identity brokering and social login
• Extensive customization and integration options

What is AWS Lambda?

AWS Lambda is a serverless compute service provided by Amazon Web Services (AWS). It allows you to run code without provisioning or managing servers, making it an ideal choice for applications that require real-time processing, event-driven architecture, and scalable computing.

With AWS Lambda, you can focus on writing code without worrying about the underlying infrastructure, and let AWS handle the heavy lifting for you.

Why Call Keycloak Rest API via Lambda AWS?

So, why would you want to call Keycloak Rest API via Lambda AWS? Here are some compelling reasons:

• Serverless architecture: By using AWS Lambda, you can offload authentication and authorization logic to a serverless function, reducing the load on your application and improving overall performance.
• Scalability: AWS Lambda provides automatic scaling, ensuring that your Keycloak Rest API calls are handled efficiently, even during peak traffic periods.
• Cost-effective: With AWS Lambda, you only pay for the compute time consumed by your function, making it a cost-effective solution for calling Keycloak Rest API.
• Enhanced security: By using AWS Lambda, you can implement an additional layer of security between your application and Keycloak, reducing the attack surface and improving overall security posture.

Prerequisites

Before we get started, make sure you have the following prerequisites in place:

• A Keycloak instance with Rest API enabled
• An AWS account with Lambda and API Gateway enabled
• A basic understanding of Node.js, AWS Lambda, and Keycloak Rest API

Step 1: Create a Lambda Function

Login to your AWS account and navigate to the AWS Lambda dashboard. Click on “Create function” and choose “Author from scratch”. Choose Node.js as the runtime and give your function a name, e.g., “KeycloakAuthLambda”.

exports.handler = async (event) => {
  // TO DO: Implement Keycloak Rest API call logic
};

Step 2: Install Required Dependencies

In your Lambda function, install the required dependencies using npm or yarn. You’ll need the following packages:

• axios (for making HTTP requests to Keycloak Rest API)
• json-web-token (for verifying and generating JSON Web Tokens)

npm install axios jsonwebtoken

Step 3: Implement Keycloak Rest API Call Logic

In your Lambda function, implement the logic to call the Keycloak Rest API. You can use the axios package to make HTTP requests to Keycloak.

const axios = require('axios');
const jwt = require('jsonwebtoken');

exports.handler = async (event) => {
  const keycloakUrl = 'https://your-keycloak-instance.com/auth/realms/your-realm/protocol/openid-connect/token';
  const clientId = 'your-client-id';
  const clientSecret = 'your-client-secret';

  const tokenConfig = {
    method: 'post',
    url: keycloakUrl,
    headers: {
      'Content-Type': 'application/x-www-form-urlencoded'
    },
    data: `grant_type=client_credentials&client_id=${clientId}&client_secret=${clientSecret}`
  };

  try {
    const response = await axios(tokenConfig);
    const token = response.data.access_token;
    console.log(`Received token: ${token}`);

    // TO DO: Implement authentication and authorization logic using the received token
  } catch (error) {
    console.error(error);
  }
};

Step 4: Implement Authentication and Authorization Logic

Using the received token, implement authentication and authorization logic to validate the user’s credentials and permissions.

const userConfig = {
  method: 'get',
  url: 'https://your-keycloak-instance.com/auth/admin/realms/your-realm/users',
  headers: {
    'Authorization': `Bearer ${token}`
  }
};

try {
  const userResponse = await axios(userConfig);
  const user = userResponse.data;

  if (user.roles.includes('your-expected-role')) {
    console.log(`User authenticated and authorized`);
    // TO DO: Implement business logic for authorized users
  } else {
    console.log(`User not authorized`);
    // TO DO: Implement error handling for unauthorized users
  }
} catch (error) {
  console.error(error);
}

Step 5: Configure API Gateway

Create an API Gateway REST API and configure it to trigger your Lambda function.

Resource	Method	Integration Request	Integration Response
/auth	POST	Lambda Function	200 OK

Step 6: Test Your Implementation

Test your implementation by sending a POST request to your API Gateway URL with the required credentials.

curl -X POST \
  https://your-api-gateway-url.execute-api.us-east-1.amazonaws.com/dev/auth \
  -H 'Content-Type: application/json' \
  -d '{"username": "your-username", "password": "your-password"}'

If everything is configured correctly, you should receive a successful response with an authentication token.

Conclusion

In this comprehensive guide, we’ve demonstrated how to call Keycloak Rest API via Lambda AWS, unlocking the power of serverless authentication and authorization for your application. By following these step-by-step instructions, you can leverage the benefits of Keycloak and AWS Lambda to build a robust, scalable, and secure application.

Remember to follow best practices for security, testing, and deployment to ensure a smooth and successful implementation.

Further Reading

If you’re interested in learning more about Keycloak, AWS Lambda, and serverless architecture, check out the following resources:

• Keycloak Documentation: https://www.keycloak.org/documentation
• AWS Lambda Documentation: https://docs.aws.amazon.com/lambda/latest/dg/welcome.html
• Serverless Architecture Guide: https://aws.amazon.com/whitepapers/serverless-architecture-guide/

Happy coding!

Frequently Asked Question

Lambda AWS and Keycloak REST API – a match made in heaven! But, we know you’ve got some burning questions. Allow us to put your mind at ease with our top 5 FAQs on calling Keycloak REST API via Lambda AWS.