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The managed API Gateway service on AWS is a great way to have your API up and running with minimal effort. One thing many tutorials around it leave out is authentication. You will likely need this, and AWS Cognito provides a robust solution. AWS Cognito offers user pools where you can create groups or identities to control access to your backend. You can customize the interface to match your branding and use Lambda code to implement additional request checks.
This article from Itsuki explains how to set this up from the AWS console and demonstrates an Infrastructure as Code (IaC) approach using the AWS Cloud Development Kit (CDK).
🔗 Read the full guide here: AWS Cognito For API Gateway (Lambda Proxy) Access Control
You Should Know:
1. Setting Up AWS Cognito User Pools
To create a Cognito User Pool via AWS CLI:
aws cognito-idp create-user-pool --pool-name MyUserPool --auto-verified-attributes email
2. Configuring API Gateway with Cognito Authorizer
Use the following AWS CLI command to add a Cognito authorizer to your API Gateway:
aws apigateway create-authorizer \ --rest-api-id YOUR_API_ID \ --name CognitoAuthorizer \ --type COGNITO_USER_POOLS \ --provider-arns "arn:aws:cognito-idp:REGION:ACCOUNT_ID:userpool/USER_POOL_ID" \ --identity-source "method.request.header.Authorization"
3. Lambda Integration for Custom Auth Logic
Here’s a sample Lambda function (Node.js) for additional request validation:
exports.handler = async (event) => {
const token = event.headers.Authorization;
if (!token) {
return { statusCode: 401, body: "Unauthorized" };
}
// Add custom validation logic
return { statusCode: 200, body: "Access Granted" };
};
4. Deploying with AWS CDK
A basic CDK stack to set up API Gateway with Cognito auth:
import as cdk from 'aws-cdk-lib';
import as apigateway from 'aws-cdk-lib/aws-apigateway';
import as cognito from 'aws-cdk-lib/aws-cognito';
export class AuthApiStack extends cdk.Stack {
constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
super(scope, id, props);
const userPool = new cognito.UserPool(this, 'MyUserPool');
const authorizer = new apigateway.CognitoUserPoolsAuthorizer(this, 'Authorizer', {
cognitoUserPools: [bash],
});
const api = new apigateway.RestApi(this, 'MyApi');
api.root.addMethod('GET', new apigateway.LambdaIntegration(lambdaFunction), {
authorizer,
});
}
}
5. Testing the Setup
Use `curl` to test your secured API endpoint:
curl -X GET https://YOUR_API_ID.execute-api.REGION.amazonaws.com/prod/ \ -H "Authorization: Bearer YOUR_COGNITO_TOKEN"
What Undercode Say
AWS Cognito simplifies API authentication by integrating seamlessly with API Gateway and Lambda. By leveraging user pools, custom Lambda authorizers, and AWS CDK, you can build a secure and scalable authentication system. Key takeaways:
– Use Cognito User Pools for identity management.
– Apply custom Lambda logic for advanced validation.
– Automate deployments using AWS CDK for Infrastructure as Code.
– Always test API security with tools like Postman or curl.
For further learning, explore AWS documentation on Cognito and API Gateway.
Expected Output:
A fully secured API Gateway with Cognito authentication, deployable via AWS CDK, and testable via REST clients.
References:
Reported By: Darryl Ruggles – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
