Migration Lambda from Basic Auth to Cognito

migrate.js

const { Client } = require('pg');
const AmazonCognitoIdentity = require('amazon-cognito-identity-js');

exports.handler = async (event) => {
    const { username, password } = JSON.parse(event.body);

    // Validate credentials against PostgreSQL database
    const postgresClient = new Client({
        host: process.env.RDS_HOST,
        user: process.env.RDS_USER,
        password: process.env.RDS_PASSWORD,
        database: process.env.RDS_DATABASE,
        port: process.env.RDS_PORT
    });

    return new Promise((resolve, reject) => {
        // Validate credentials against PostgreSQL database
        postgresClient.connect();
        const postgresQuery = 'SELECT * FROM users WHERE username = $1 AND password = $2';
        const postgresValues = [username, password];

        postgresClient.query(postgresQuery, postgresValues, (postgresError, postgresResults) => {
            // Add basic auth code of choice (must match your old password checking code)
            // ON FAILURE DO NOTHING
            
            // ON SUCCESS, UPDATE COGNITO USER
            // Configuration for Amazon Cognito User Pool
            const poolData = {
                UserPoolId: process.env.COGNITO_USER_POOL_ID,
                ClientId: process.env.COGNITO_CLIENT_ID
            };

            const userPool = new AmazonCognitoIdentity.CognitoUserPool(poolData);
            
                const authenticationDetails = new AmazonCognitoIdentity.AuthenticationDetails(authenticationData);

                const userData = {
                    Username: username,
                    Pool: userPool
                };

                const cognitoUser = new AmazonCognitoIdentity.CognitoUser(userData);

                cognitoUser.authenticateUser(authenticationDetails, {
                    onSuccess: (session) => {
                        // Update password in Cognito to match the database password
                        cognitoUser.changePassword(password, password, (cognitoChangePasswordError, result) => {
                            if (cognitoChangePasswordError) {
                                resolve({
                                    statusCode: 500,
                                    body: JSON.stringify({ message: 'Error updating password in Cognito' })
                                });
                            } else {
                                resolve({
                                    statusCode: 200,
                                    body: JSON.stringify({ message: 'Login successful. Password updated in Cognito.' })
                                });
                            }
                        });
                    },
                    onFailure: (cognitoError) => {
                        resolve({
                            statusCode: 401,
                            body: JSON.stringify({ message: 'Invalid credentials or user not found in Cognito' })
                        });
                    }
                });
            } else {
                resolve({
                    statusCode: 401,
                    body: JSON.stringify({ message: 'Invalid credentials' })
                });
            }
        });
    });
};