Library Management

Develop a library management system backend in Go that manages details of members, details of books, and borrowing transactions, without using an external database.

• System should allow creating, retrieving , and deleting members,books
• Members should have unique id like - (A000,A001…,AA999.. etc)
• Users should be able to borrow and return books, with functionalities like checking book is available and calculate the penalty if due date is passed
• Unit tests should be implemented

1. Data Structures

Member Struct:

• member_id: Unique identifier for members.
• name: Name of the member.
• email: Email address of the member.
• phone: Phone number of the member.
• date: Registration date of the member.
• unique_id: Custom unique identifier formatted like A000, A001, etc.

Book Struct:

• book_id: Unique identifier for books.
• title: Title of the book.
• author: Author of the book.
• category: Category or genre of the book.
• count: Number of copies available.

Book Transaction Struct:

• borrow_id: Unique identifier for each borrowing transaction.
• member_id: ID of the member borrowing the book.
• book_id: ID of the book being borrowed.
• borrow_date: Date when the book was borrowed.
• due_date: Due date for returning the book.
• return_date: Date when the book was returned (if returned).

2. Data Storage

The mock database (MockDB) is structured with slices to store: MockDB struct:

• Books: Slice of Book structs.
• Members: Slice of Member structs.
• BookTransactions: Slice of Transaction structs.

Service Design Pattern

The functionalities are divided into separate services:

Member Services:

• CreateMember(newMember *Member) error
• DeleteMember(member *Member) error
• GetMemberByID(id string) *Member

Book Services:

• FindBookByAuthor(author string)
• FindBookByCategory(category string)
• FindBookByPrefix(prefix string)
• CreateBook(newBook *Book)
• DeleteBook(book *Book)
• CheckBookAvailability(book *Book) bool

Book Transaction Services:

• BorrowBook(memberID string, bookID int)
• ReturnBook(memberID string, bookID int)

APIs

1. API Endpoint: POST - /api/members

Purpose

Create a new member in the system.

Request Body (JSON)

{
  "Name": "ASWINKRISHNA P",
  "Email": "[email protected]",
  "Phone": "9865272720"
}

Response Body (JSON)

{
  "ID": "A001",
  "Name": "ASWINKRISHNA P",
  "Email": "[email protected]",
  "Phone": "9865272720",
  "Date": "2024-01-01"
}

• responds with the newly created member details including a unique ID.

2. API Endpoint: GET - /api/members/:id

Purpose

Retrieve details of a specific member by their ID.

Request

• Endpoint: /api/members/:id
• Method: GET

Response Body (JSON)

{
  "Member_id": "A001",
  "Name": "ASWIN KRISHNA P",
  "Email": "[email protected]",
  "Phone": "123-456-7890",
  "Date": "2024-01-01"
}

3. API Endpoint: POST - /api/books

Purpose

Create a new book in the system.

Request Body (JSON)

{
  "Title": "Book 2",
  "Author": "Author1",
  "Category": "Fiction",
  "Count": 2
}

Response Body (JSON)

{
  "id": 1,
  "Title": "Book 2",
  "Author": "Author1",
  "Category": "Fiction",
  "Count": 2
}

• responds with the newly created book details including a unique ID (id).

4. API Endpoint: GET - /api/books?category=CATEGORY&author=AUTHORNAME&prefix=ANYPREFIX

Purpose

Retrieve a list of books based on optional filtering parameters.

Request

• Endpoint: /api/books
• Method: GET
• Query Parameters:
  • category: Optional, Filters books by category.
  • author: Optional, Filters books by author.
  • prefix: Optional, Filters books by title prefix.

Response Body (JSON)

[
  {
    "Book_id": 8,
    "Title": "The Hobbit",
    "Author": "J.R.R. Tolkien",
    "Category": "Fantasy",
    "Count": 8
  },
  {
    "Book_id": 20,
    "Title": "The Lord of the Rings",
    "Author": "J.R.R. Tolkien",
    "Category": "Fantasy",
    "Count": 7
  },
  {
    "Book_id": 36,
    "Title": "The Name of the Wind",
    "Author": "Patrick Rothfuss",
    "Category": "Fantasy",
    "Count": 5
  }
]

5. API Endpoint: POST - /api/borrow

Purpose

TO borrow Book

Request Body (JSON)

{
  "member_id": "A003",
  "book_id": 6
}

Response Body (JSON)

{
  "Borrow_id": 4,
  "Member": {
    "Member_id": "A003",
    "Name": "Charlie Brown",
    "Email": "[email protected]",
    "Phone": "345-678-9012",
    "Date": "15-07-2024"
  },
  "Book": {
    "Book_id": 4,
    "Title": "The Great Gatsby",
    "Author": "F. Scott Fitzgerald",
    "Category": "Classic",
    "Count": 5
  },
  "Borrow_date": "15-07-2024",
  "Due_date": "25-07-2024",
  "Return_date": ""
}

6. API Endpoint: PATCH - /api/return

Purpose

To return Book

Request Body (JSON)

{
  "member_id": "A003",
  "book_id": 6
}

Response Body (JSON)

{
  "Borrow_id": 2,
  "Member": {
    "Member_id": "A003",
    "Name": "Charlie Brown",
    "Email": "[email protected]",
    "Phone": "345-678-9012",
    "Date": "15-07-2024"
  },
  "Book": {
    "Book_id": 2,
    "Title": "1984",
    "Author": "George Orwell",
    "Category": "Science Fiction",
    "Count": 3
  },
  "Borrow_date": "15-07-2024",
  "Due_date": "25-07-2024",
  "Return_date": "15-07-2024",
  "Penalty": 0
}

7. API Endpoint: GET - /api/borrow/id

Purpose

To Get List of Books borrowed By a particular member

Request

• Endpoint: /api/members/:id
• Method: GET

Response Body (JSON)

[
  {
    "Book_id": 1,
    "Title": "To Kill a Mockingbird",
    "Author": "Harper Lee",
    "Category": "Fiction",
    "Count": 4
  },
  {
    "Book_id": 3,
    "Title": "Pride and Prejudice",
    "Author": "Jane Austen",
    "Category": "Romance",
    "Count": 3
  }
]