The SAM template deploys an Amazon API Gateway REST API endpoint that uses a Lambda Token Authorizer for access control.

• If the request to the endpoint does not include a 'authorizationToken' header, the Lambda Authorizer will not be invoked and API Gateway will return a 401 Forbidden.
• If the request to the endpoint includes a 'authorizationToken' header, the Lambda Authorizer will be invoked and its response will depend on the value of the 'authorizationToken' header.
• If the value of 'authorizationToken' header is 'unauthorized', API Gateway will return a 401 Unauthorized error.
• If the value of 'authorizationToken' header is 'Bearer deny', API Gateway will return a 403 error.
• Only if the value of 'authorizationToken' header is 'Bearer allow', API Gateway will successfully invoke the Lambda integration and return a 200.
• For any other case, API Gateway will return a 500 error.

Note: when deploying this pattern, CAPABILITY_IAM is required.

Learn more about this pattern at Serverless Land Patterns: https://serverlessland.com/patterns/apigw-lambda-authorizer

Important: this application uses various AWS services and there are costs associated with these services after the Free Tier usage - please see the AWS Pricing page for details. You are responsible for any AWS costs incurred. No warranty is implied in this example.

• Create an AWS account if you do not already have one and log in. The IAM user that you use must have sufficient permissions to make necessary AWS service calls and manage AWS resources.
• AWS CLI installed and configured
• Git Installed
• AWS Serverless Application Model (AWS SAM) installed

1. Create a new directory, navigate to that directory in a terminal and clone the GitHub repository:

   git clone https://github.com/aws-samples/serverless-patterns
   

2. Change directory to the pattern directory:

   cd apigw-lambda-authorizer
   

3. From the command line, use AWS SAM to deploy the AWS resources for the pattern as specified in the template.yml file:

   sam deploy -g
   

4. During the prompts:

   • Enter a stack name
   • Select the desired AWS Region
   • Allow SAM to create roles with the required permissions if needed.

   Once you have run guided mode once, you can use sam deploy in future to use these defaults.

5. Note the outputs from the SAM deployment process. These contain the resource names and/or ARNs which are used for testing.

The stack will output the api endpoint. Use curl to make a HTTP request to the API Gateway that includes a header with the authorization token to test the Resource Lambda Token Authorizer.

curl -i https://12345abcde.execute-api.{region}.amazonaws.com/Prod -H "authorizationToken: Bearer allow"

will successfully return a 200 HTTP code and the event object from the Lambda in the response body.

curl -i https://12345abcde.execute-api.{region}.amazonaws.com/Prod -H "authorizationToken: unauthorized"

will return a 401 Unauthorized error.

1. Delete the stack

   sam delete

2. Confirm the stack has been deleted

   aws cloudformation list-stacks --query "StackSummaries[?contains(StackName,'STACK_NAME')].StackStatus"

Copyright 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.

SPDX-License-Identifier: MIT-0