5.1. Library API

Creating the Library API

• For practice, lets take a look at how we might actually create the REST API for our library
• A base repository can be found here

Identify Resources in the Library System

1. Books (/books)

   • Each book in the library, identified by a unique ID.
   • Attributes:
     • id
     • title
     • author
     • yearPublished
     • availableCopies

2. Users (/users)

   • Library members, identified by a unique ID.
   • Attributes:
     • id
     • name
     • email
     • borrowedBooks (list of books borrowed by the user)

Operations on Resources

1. Books Resource (/books)

   • GET /books: Retrieve all books in the library.
     • Response: List of all books with details like title, author, availability, etc.
   • GET /books/:id: Retrieve details about a specific book by ID.
   • POST /books: Add a new book to the library.
     • Request Body: JSON with book details (e.g., title, author, yearPublished, etc.).
   • PUT /books/:id: Update details about a specific book.
     • Request Body: JSON with updated book details.
   • DELETE /books/:id: Remove a book from the library by ID.

2. Users Resource (/users)

   • GET /users: Retrieve all users registered in the library.
   • GET /users/:id: Retrieve details of a specific user by ID.
   • POST /users: Add a new user to the library system.
     • Request Body: JSON with user details (name, email).
   • PUT /users/:id: Update a user’s information.
   • DELETE /users/:id: Remove a user from the system by ID.

3. Borrowing a Book (/users/:id/books/:bookId)

   • POST /users/:id/books/:bookId: Let a user borrow a book from the library.
     • Response: Updates the book’s availability and adds it to the user’s borrowedBooks list.
   • DELETE /users/:id/books/:bookId: Let a user return a book.
     • Response: Updates the book’s availability and removes it from the user’s borrowedBooks list.

Example Endpoints

1. GET /books:

   • Retrieves the entire collection of books available in the library.
   • Sample Response:

     [
       { "id": 1, "title": "1984", "author": "George Orwell", "availableCopies": 3 },
       { "id": 2, "title": "Brave New World", "author": "Aldous Huxley", "availableCopies": 5 }
     ]

2. POST /books:

   • Adds a new book to the library.
   • Request:

     { "title": "Fahrenheit 451", "author": "Ray Bradbury", "yearPublished": 1953, "availableCopies": 2 }

3. POST /users/:id/books/:bookId:

   • A user borrows a book from the library.
   • Example: POST /users/1/books/2 (user with ID 1 borrows the book with ID 2).

4. DELETE /users/:id/books/:bookId:

   • A user returns a borrowed book to the library.