simple_book_api.md

Task:

Write a Simple API that can:

• Create a user and register books that he/she owns
• Transfer book ownership

Requirements:

• Use AWS API Gateway with Lambda functions
• Use Dynamodb as the DB

Basic API requirements:

1. Initializing a user

Endpoint:

POST /users

Request Body:

{
    // list of book ids this owner owns
    "books": ["book_1", "book_2"]
}

Response:

{
    // generate a unique user id
    "user_id": "user_0001",
    "books": ["book_1", "book_2"],
}

Exception:

• User shouldn't be created if:
  • "book_ids" contains a book_id that is already owned by another user

2. Get User

Endpoint:

GET /users/<user_id>

Response:

{
    "user_id": "user_0001",
    "book": ["book_1", "book_2"],
}

3. Get all books

Endpoint:

GET /books

Response:

{
    "books": [
        {
            "id": "book_1",
            "owner": "user_001"
        },
        {
            "id": "book_2",
            "owner": "user_001"
        },
        {
            "id": "book_3",
            "owner": "user_002"
        }
    ]
}

4. Get a specific book

Endpoint:

GET /books/<book_id>

Response:

{
    "id": "book_1",
    "owner": "user_001"
}

5. Transfer book ownership

Endpoint:

POST /transfer

Request Body:

{
    "book_id": "book_1",
    "from": "user_001",
    "to": "user_002"
}

Response:

{
    "id": "book_1",
    "owner": "user_002"
}

Exception:

• Transfer should fail if:
  • book doesn't exist
  • from user_id doesn't match the correct owner
  • to == from
  • to user_id doesn't exist

Submission:

Submit the following

• github repository containing:
  • all the code for the lambda functions
  • script that creates two users and transfers books between them (more test scenarios can be added)
  • instructions on how to run the script
• please document your code appropriately