📚 Library Management & Borrowing System

A comprehensive Library Management System built with Django REST Framework featuring user authentication, book borrowing/returning, inventory management, and penalty tracking system.

Features

• 🔐 User Authentication

  • JWT-based login/register using Simple-JWT
  • Custom user model with penalty points tracking

• 📖 Book Management

  • Admins ➝ Full CRUD operations for books, authors, and categories
  • Users ➝ Browse books with advanced filtering (author, category)
  • Real-time inventory tracking with atomic updates

• 📋 Borrowing System

  • Smart borrowing limits (max 3 books per user)
  • Automated due date calculation (14 days)
  • Early return support
  • Late return penalty system (1 point per day late)

• 📊 Inventory Management

  • Multiple copies per book tracking
  • Atomic inventory updates during borrow/return
  • Real-time availability checking

• 📘 API Documentation

  • Swagger & ReDoc support for live testing via drf_yasg

Tech Stack

• Django, Django REST Framework
• SimpleJWT for JWT authentication
• drf_yasg for Swagger API Documentation
• django_extensions for ER Diagram generation

📄 API Documentation (Swagger)

Access the interactive API documentation:

http://localhost:8000/api/docs/   # Swagger UI
http://localhost:8000/api/redoc/  # ReDoc UI 

🪪 Authorization

Click "Authorize" in Swagger UI and paste your JWT token:

Bearer <your_access_token>

🗄️ Database Models

Core Models

• User: Extended with penalty_points field
• Author: name, bio
• Category: name
• Book: title, description, author (FK), category (FK), total_copies, available_copies
• Borrow: user (FK), book (FK), borrow_date, due_date, return_date (nullable)

📁 Project Structure

The project follows a modular and scalable architecture:

backend/
├── core/               # Project-level configuration
│   ├── settings.py     # Django settings
│   ├── urls.py         # Main URL routing
│   └── wsgi.py         # WSGI configuration
├── apps/               # Modular app structure
│   ├── borrow/         # Borrowing and returning related APIs
│   ├── catalog/        # Books, authors, categories related APIs  
│   └── users/          # Authentication, registration, and penalty APIs
└── manage.py

App Responsibilities:

• core/: Project-level settings, URL routing, and configuration
• apps/borrow/: Borrowing and returning logic
• apps/catalog/: Book, author, and category management
• apps/users/: Authentication, user registration, and penalty tracking

🔐 API Endpoints & Usage

👤 Authentication

Register

POST /api/register/

{
  "username": "johndoe",
  "email": "[email protected]", 
  "password": "securepass123"
}

Login (JWT)

POST /api/login/

{
  "username": "johndoe",
  "password": "securepass123"
}

📚 Books & Metadata

Browse Books

GET /api/books/

• Query params: ?author=<author_name>&category=<category_name>

Book Details

GET /api/books/{id}/

Admin-Only Book Management

POST /api/books/          # Create book (admin only)
PUT /api/books/{id}/      # Update book (admin only)
DELETE /api/books/{id}/   # Delete book (admin only)

Note: Admin permissions required. Create superuser via python manage.py createsuperuser

Authors & Categories

GET /api/authors/         # List authors
POST /api/authors/        # Create author (admin only)
GET /api/categories/      # List categories  
POST /api/categories/     # Create category (admin only)

Note: Admin permissions required for POST operations

📋 Borrowing Operations

Borrow a Book

POST /api/borrow/

{
  "book_id": 1
}

Validation Logic:

• ✅ User has < 3 active borrows
• ✅ Book has available copies (available_copies > 0)
• ✅ Atomically decrements available_copies
• ✅ Sets due_date = borrow_date + 14 days

View Active Borrows

GET /api/borrow/

Return a Book

POST /api/return/

{
  "borrow_id": 1
}

Return Logic:

• ✅ Updates return_date to current timestamp
• ✅ Atomically increments available_copies
• ✅ Calculates late days if past due_date
• ✅ Adds penalty points (1 point per day late)

Check Penalty Points

GET /api/users/{id}/penalties/

• Accessible by admin and the user themselves

🧮 Business Logic

Borrowing System

1. Limit Enforcement: Users cannot borrow more than 3 books simultaneously
2. Inventory Validation: Only books with available_copies > 0 can be borrowed
3. Atomic Updates: All inventory changes use database transactions to prevent race conditions
4. Due Date Calculation: Automatically set to 14 days from borrow date

Penalty System

• Late Return Detection: Compares return_date with due_date
• Penalty Calculation: 1 penalty point per day late
• Accumulative: Penalty points accumulate across multiple late returns
• Admin Oversight: Admins can view all user penalties

Inventory Management

• Real-time Tracking: available_copies updated instantly on borrow/return
• Data Integrity: Uses Django's select_for_update() for atomic operations
• Validation: Prevents borrowing when no copies available

🚀 Setup & Installation

✅ Clone the repository

git clone https://github.com/shemanto27/Django-Library-Management-Borrowing-System.git
cd Django-Library-Management-Borrowing-System

✅ Navigate to backend directory

cd backend

✅ Install dependencies using uv || NO NEED FOR requirements.txt FILE, USE uv sync COMMAND

uv sync

✅ Activate Virtual Environment

source .venv/bin/activate  

✅ Apply migrations

python manage.py migrate

✅ Create superuser for admin operations

python manage.py createsuperuser

✅ Run the development server

python manage.py runserver

✅ Access API Documentation

http://localhost:8000/api/docs/

🔄 Testing Workflow

For Regular Users:

1. Create User ➝ POST /api/register/
2. Login ➝ POST /api/login/ (get JWT token)
3. Authorize ➝ Use token in Swagger UI
4. Browse Books ➝ GET /api/books/
5. Borrow Book ➝ POST /api/borrow/
6. Check Borrows ➝ GET /api/borrow/
7. Return Book ➝ POST /api/return/

For Admin Operations:

1. Create Superuser ➝ python manage.py createsuperuser (in terminal)
2. Login with Admin ➝ POST /api/login/ (use superuser credentials)
3. Authorize ➝ Use admin JWT token in Swagger UI
4. Admin Operations ➝ Create/Update/Delete books, authors, categories

ℹ️ Notes

• This project uses uv for modern Python package management, NO NEED FOR requirements.txt FILE, USE uv sync COMMAND
• Authentication uses Simple-JWT for stateless JWT tokens
• API documentation generated with drf_yasg
• Database operations use atomic transactions for data integrity
• Admin interface available at /admin/ for manual data management
• Project follows Django best practices with modular app structure