Test APIs by Postman

In this step, we will test operation of the APIs using Postman tool.

Test the Listing API (GET)

1. Open Postman and create a new tab:

   • Select GET method

   • Enter Invoke URL of the GET API from the previous step (e.g., https://<api-id>.execute-api.ap-southeast-1.amazonaws.com/staging/books)

   • Click Send

   • Check the returned result (200 OK) with all data from Books table

Test the Writing API (POST)

2. Create a new tab:

   • Select POST method

   • Enter Invoke URL of the POST API

   • In Body section, select raw and JSON

   • Enter the JSON content:

   {
       "id": "5",
       "rv_id": 0,
       "name": "Amazon Web Services in Action 2nd Edition",
       "author": "Andreas Wittig",
       "price": "59.99",
       "category": "IT",
       "description": "Amazon Web Services in Action, Second Edition is a comprehensive introduction to computing, storing, and networking in the AWS cloud. You'll find clear, relevant coverage of all the essential AWS services you to know, emphasizing best practices for security, high availability and scalability.",
       "image": "https://book-image-resize-store.s3.ap-southeast-2.amazonaws.com/aws.jpg"
   }
   

   • Click Send and check the returned result (200 OK)

3. Open Books table in DynamoDB console to check data. New item with id=5 has been added

Test the Deleting API (DELETE)

Since the delete Lambda function deletes the image uploaded by the user, we manually upload the image to the S3 bucket so the API can run properly.

4. Open Amazon S3 console, select bucket book-image-stores-tranvix and click Upload

5. Click Add files

6. Download the image below and select it to upload to S3: aws.jpg

7. Select file aws.jpg and click Upload

8. Upload successful

9. Switch to bucket book-image-resize-stores-tranvix to check. The image has been resized by Lambda function resize_image

10. Go back to API Gateway to get Invoke URL for DELETE method

11. Back to Postman, add a new tab to call the delete API:

    • Select DELETE method

    • Enter Invoke URL of the DELETE API, replace {id} with 5 (e.g., https://<api-id>.execute-api.ap-southeast-1.amazonaws.com/staging/books/5)

    • Click Send

    • Check the returned result (200 OK) with message “Book deleted successfully”

12. Open bucket book-image-resize-stores-tranvix to check result. The aws.jpg image has been deleted

So we have successfully tested all APIs: GET, POST and DELETE.