mahmoudxyz / cognito-pre-sign-up-lambda

Cognito Pre-sign-up Lambda

This AWS Lambda function, CognitoPreSignUpHandler, is designed to handle pre-sign-up events in an AWS Cognito user pool. It ensures seamless user registration and linkage for both email-password and social sign-up methods like Google or Facebook.

Overview

When a pre-sign-up event is triggered in the Cognito user pool, this Lambda function intercepts the event and executes a series of actions:

1. Checks if the trigger source is an external provider.
2. Creates a new user if one does not exist.
3. Changes the user's status to password confirmed.
4. Links users if necessary.

Usage

Configuration

Before using this Lambda function, ensure the following environment variables are set:

• ACCESS_KEY_ID: AWS access key ID.
• ACCESS_KEY_SECRET: AWS secret access key.
• USER_POOL_ID: ID of the Cognito user pool.
• REGION_NAME: AWS region name.

Trigger

This Lambda function is triggered by pre-sign-up events in the Cognito user pool.

Dependencies

This Lambda function relies on the AWS SDK for Java to interact with the Cognito Identity Provider.

Deployment

To deploy this Lambda function, package the code along with its dependencies using Maven and the Maven Shade plugin. Then, upload the deployment package to AWS Lambda.

Execution

When a pre-sign-up event occurs, AWS Cognito invokes this Lambda function. The function processes the event, performs the necessary actions, and returns the modified event.

Code Structure

• CognitoPreSignUpHandler: Main class representing the Lambda function.
• handleWRequest: Method to handle pre-sign-up events.
• getAWSCognitoIdentityProvider: Method to retrieve the AWS Cognito Identity Provider client.
• createUser: Method to create a user in the Cognito user pool.
• changeToPasswordConfirmed: Method to change a user's status to password confirmed.
• generatePassword: Method to generate a random password for the user.
• listUsers: Method to list users in the Cognito user pool based on email.
• getUserTypeIfExistNativeUser: Method to retrieve user types if native users exist in the user pool.
• linkUser: Method to link users in the Cognito user pool.

Conclusion

This Lambda function simplifies the process of handling pre-sign-up events in AWS Cognito, ensuring a seamless user registration and linkage experience for both email-password and social sign-up methods. It enhances the functionality of AWS Cognito, making it more versatile and developer-friendly.