Create DELETE API

In this step, we will add the DELETE method to allow the frontend to delete books by ID via the book_delete Lambda function.

The DELETE endpoint uses a path parameter (/books/{id}), which is already defined by the BookDeleteApiResource resource. Like the previous POST step, adding a new method requires re-creating the API deployment in two phases.

We also add a BookApiDeleteOptions resource (MOCK integration) to support browser preflight CORS requests for this endpoint.

Phase 1 — Remove old Deployment

1. Open the template.yaml file in the fcaj-book-shop folder.

2. Comment out the BookApiDeployment block and the DeploymentId line inside BookApiStage:

   # BookApiDeployment:
   #   Type: AWS::ApiGateway::Deployment
   #   Properties:
   #     RestApiId: !Ref BookApi
   #   DependsOn:
   #     - BookApiGet
   #     - BookApiCreate
   
   BookApiStage:
     Type: AWS::ApiGateway::Stage
     Properties:
       RestApiId: !Ref BookApi
       StageName: !Ref stage
       # DeploymentId: !Ref BookApiDeployment
   

   

3. Run the commands to validate, build, and deploy:

   sam validate
   sam build
   

   

   sam deploy
   

   The changeset shows:

   • Modify BookApiStage
   • Delete BookApiDeployment

   Enter y to confirm.

   

4. Wait for the deployment to complete.

   

Phase 2 — Add DELETE Method and Redeploy

5. Add the BookApiDelete method resource. Note that ResourceId references BookDeleteApiResource (the /{id} path), not BookApiResource:

   BookApiDelete:
     Type: AWS::ApiGateway::Method
     Properties:
       HttpMethod: DELETE
       RestApiId: !Ref BookApi
       ResourceId: !Ref BookDeleteApiResource
       AuthorizationType: NONE
       Integration:
         Type: AWS_PROXY
         IntegrationHttpMethod: POST # For Lambda integrations, you must set the integration method to POST
         Uri: !Sub >-
           arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${BookDelete.Arn}/invocations
       MethodResponses:
         - StatusCode: "200"
           ResponseParameters:
             method.response.header.Access-Control-Allow-Origin: true
             method.response.header.Access-Control-Allow-Methods: true
             method.response.header.Access-Control-Allow-Headers: true
   

   

6. Add BookApiDeleteOptions (MOCK integration for CORS preflight) and BookApiDeleteInvokePermission:

   BookApiDeleteOptions:
     Type: AWS::ApiGateway::Method
     Properties:
       HttpMethod: OPTIONS
       RestApiId: !Ref BookApi
       ResourceId: !Ref BookDeleteApiResource
       AuthorizationType: NONE
       Integration:
         Type: MOCK
         RequestTemplates:
           application/json: '{"statusCode": 200}'
         IntegrationResponses:
           - StatusCode: "200"
             ResponseParameters:
               method.response.header.Access-Control-Allow-Origin: "'*'"
               method.response.header.Access-Control-Allow-Methods: "'GET,POST,OPTIONS,DELETE'"
               method.response.header.Access-Control-Allow-Headers: "'Content-Type,X-Amz-Date,Authorization,X-Api-Key,X-Amz-Security-Token'"
       MethodResponses:
         - StatusCode: "200"
           ResponseParameters:
             method.response.header.Access-Control-Allow-Origin: true
             method.response.header.Access-Control-Allow-Methods: true
             method.response.header.Access-Control-Allow-Headers: true
   
   BookApiDeleteInvokePermission:
     Type: AWS::Lambda::Permission
     Properties:
       FunctionName: !Ref BookDelete
       Action: lambda:InvokeFunction
       Principal: apigateway.amazonaws.com
       SourceAccount: !Ref "AWS::AccountId"
   

   

7. Uncomment the BookApiDeployment block and DeploymentId. Update DependsOn to include all three methods — BookApiGet, BookApiCreate, and BookApiDelete:

   BookApiDeployment:
     Type: AWS::ApiGateway::Deployment
     Properties:
       RestApiId: !Ref BookApi
     DependsOn:
       - BookApiGet
       - BookApiCreate
       - BookApiDelete
   
   BookApiStage:
     Type: AWS::ApiGateway::Stage
     Properties:
       RestApiId: !Ref BookApi
       StageName: !Ref stage
       DeploymentId: !Ref BookApiDeployment
   

   

8. Run the commands again to build and deploy:

   sam validate
   sam build
   

   

   sam deploy
   

   The changeset shows new resources being added:

   • Add BookApiDelete (AWS::ApiGateway::Method)
   • Add BookApiDeleteOptions (AWS::ApiGateway::Method)
   • Add BookApiDeployment (AWS::ApiGateway::Deployment)
   • Add BookApiDeleteInvokePermission (AWS::Lambda::Permission)
   • Modify BookApiStage (AWS::ApiGateway::Stage)

   Enter y to confirm.

   

9. Wait for the deployment to complete. You should see Successfully created/updated stack - fcaj-book-shop in ap-southeast-1.

   

Verify on AWS Console

10. Open the AWS API Gateway console. Click on the fcaj-serverless-api REST API.

    

11. At the fcaj-serverless-api page:

    • Click Resources in the left menu.
    • Expand /books → /{id} → select DELETE.
    • Click the Lambda integration tooltip — confirm the integrated function is book_delete.

    

12. Click Stages in the left menu.

    • Expand staging → /books → /{id} → select DELETE.
    • Copy and save the Invoke URL.

    Example: https://1bupjnr42d.execute-api.ap-southeast-1.amazonaws.com/staging/books/{id}