lambda-trigger-custom-message-sign-up.js - AWS Code Sample


/* Copyright, Inc. or its affiliates. All Rights Reserved. SPDX-License-Identifier: Apache-2.0 ABOUT THIS NODE.JS EXAMPLE: This example works with AWS SDK for JavaScript version 3 (v3), which is pending release. The preview version of the SDK is available at This example is in the 'AWS SDK for JavaScript v3 Developer Guide' at Purpose: node lambda-trigger-custom-message-sign-up.js is invoked to customize an email or SMS message when the service requires an app to send a verification code to the user. Running the code: 1. On the AWS Lambda service dashboard, choose Create function. 2. On the Create function page, name the function, and choose Create function. 3. Copy and paste the code into the index.js file in the editor, and save the function. 4. Open the Amazon Cognito service. 5. Choose Manage user pools. 6. Choose the user pool you want to add the trigger to. (If you don't have a user pool, create one.) 7. In General Settings, choose Triggers. 8. In the Pre Token Generation pane, select the Lambda function. */ exports.handler = async (event, context) => { try { if (event.userPoolId === "theSpecialUserPool") { // Identify why this function was invoked if (event.triggerSource === "CustomMessage_SignUp") { // Ensure that your message contains event.request.codeParameter. This is the placeholder for code that will be sent. event.response.smsMessage = "Welcome to the service. Your confirmation code is " + event.request.codeParameter; event.response.emailSubject = "Welcome to the service"; event.response.emailMessage = "Thank you for signing up. " + event.request.codeParameter + " is your verification code"; } // Create custom message for other events // Customize messages for other user pools } } catch (err) { // Return to Amazon Cognito return null; } };