Return 401 Unauthorized Response when using Lambda Authorizer with API Gateway

Hi , You can try official docs help or

import { Handler, APIGatewayAuthorizerResult } from 'aws-lambda';

export const handler: Handler = async (event, context, callback): Promise<APIGatewayAuthorizerResult> => {
    try {
        // 1. Your authorization logic (using awaited Promises if needed)
        const token = event.authorizationToken; 
        if (!token || !await isValidToken(token)) {
            return { 
                principalId: 'user', // Arbitrary value
                policyDocument: {
                    Version: '2012-10-17',
                    Statement: [{
                        Action: 'execute-api:Invoke',
                        Effect: 'Deny',
                        Resource: event.methodArn 
                    }]
                }
            }; 
        }

        // 2. Successful authorization - Return an Allow policy
        return { 
            principalId: 'user', // Identify the user 
            policyDocument: {
                Version: '2012-10-17',
                Statement: [{
                    Action: 'execute-api:Invoke',
                    Effect: 'Allow',
                    Resource: event.methodArn 
                }]
            }
        }; 

    } catch (error) {
        console.error('Authorization error:', error);
        // For simplicity, handle errors as Unauthorized
        callback('Unauthorized'); 
    }
};

// Helper function for your token validation logic
async function isValidToken(token: string): Promise<boolean> {
    // Your token validation logic here
    // ...
}

Authorization Logic: Replace isValidToken with your actual token validation logic (which can now be asynchronous using await). Deny Policy: If authorization fails, return an IAM policy document with a 'Deny' effect. Ensure the Resource matches the method ARN of your API Gateway method. Allow Policy: If authorization succeeds, return an IAM policy document with an 'Allow' effect. Error Handling: Wrap your logic in a try...catch block. For simplicity, we log the error and then return an 'Unauthorized' string. You can adjust error handling for more specific responses, if desired.

i used content from aws docs that i found on github and some from huggingface...hope it helps

You could look into this guide for general troubleshooting: https://repost.aws/knowledge-center/api-gateway-401-error-lambda-authorizer.

From your description could be that you need to “block” those asynchronous processes by awaiting them inside the lambda handler.