📝 Todo List API

A RESTful API for managing todo lists with user authentication, built with Node.js, Express, and MongoDB.

✨ Features

• 🔐 User Authentication - JWT-based authentication with registration and login
• 📋 CRUD Operations - Create, read, update, and delete todos
• 🔒 Authorization - Users can only access their own todos
• 📄 Pagination - Get todos with pagination support
• 🔍 Search & Filter - Search todos by title and sort by various fields
• ✅ Data Validation - Comprehensive input validation and error handling
• 🛡️ Security - Password hashing, JWT tokens, and secure endpoints

🚀 Tech Stack

• Backend: Node.js, Express.js
• Database: MongoDB with Mongoose ODM
• Authentication: JSON Web Tokens (JWT)
• Security: bcrypt for password hashing
• Environment: dotenv for configuration

📋 API Endpoints

Authentication

Method	Endpoint	Description	Body
POST	/api/auth/register	Register a new user	{ "name": "John Doe", "email": "john@example.com", "password": "password123" }
POST	/api/auth/login	Login user	{ "email": "john@example.com", "password": "password123" }

Todos (Protected Routes)

Method	Endpoint	Description	Headers
GET	/api/todos	Get all todos with pagination	Authorization: Bearer <token>
POST	/api/todos	Create a new todo	Authorization: Bearer <token>
PUT	/api/todos/:id	Update a todo	Authorization: Bearer <token>
DELETE	/api/todos/:id	Delete a todo	Authorization: Bearer <token>

Query Parameters for GET /api/todos

• page (optional): Page number (default: 1)
• limit (optional): Items per page (default: 10)
• search (optional): Search by title
• sort (optional): Sort field (default: createdAt)
• order (optional): Sort order - asc/desc (default: desc)

🛠️ Installation & Setup

Prerequisites

• Node.js (v14 or higher)
• MongoDB (local or Atlas)
• npm or yarn

1. Clone the Repository

git clone <your-repo-url>
cd todo-api

2. Install Dependencies

npm install

3. Environment Configuration

Create a .env file in the root directory:

# Server Configuration
PORT=5000
NODE_ENV=development

# Database Configuration
MONGO_URL=mongodb://127.0.0.1:27017/todo-api
# OR for MongoDB Atlas:
# MONGO_URL=mongodb+srv://username:password@cluster.mongodb.net/todo-api

# JWT Configuration
JWT_SECRET=your-super-secret-jwt-key-change-this-in-production
JWT_EXPIRES_IN=1h

4. Database Setup

Option A: MongoDB Atlas (Recommended)

1. Go to MongoDB Atlas
2. Create a free account and cluster
3. Create a database user
4. Whitelist your IP address
5. Get your connection string and update MONGO_URL in .env

Option B: Local MongoDB

1. Download and install MongoDB Community Server
2. Start MongoDB service
3. The default connection string should work: mongodb://127.0.0.1:27017/todo-api

Option C: Docker

docker run -d -p 27017:27017 --name mongodb mongo:latest

5. Start the Server

# Development mode (with auto-restart)
npm run dev

# Production mode
npm start

# Start without database (for testing)
npm run start-fallback

🧪 Testing the API

1. Health Check

curl http://localhost:5000/

2. Register a User

curl -X POST http://localhost:5000/api/auth/register \
  -H "Content-Type: application/json" \
  -d '{
    "name": "John Doe",
    "email": "john@example.com",
    "password": "password123"
  }'

3. Login

curl -X POST http://localhost:5000/api/auth/login \
  -H "Content-Type: application/json" \
  -d '{
    "email": "john@example.com",
    "password": "password123"
  }'

4. Create a Todo

curl -X POST http://localhost:5000/api/todos \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer <your-jwt-token>" \
  -d '{
    "title": "Buy groceries",
    "description": "Buy milk, eggs, and bread"
  }'

5. Get Todos

curl -X GET "http://localhost:5000/api/todos?page=1&limit=10" \
  -H "Authorization: Bearer <your-jwt-token>"

📊 Response Examples

Successful Registration/Login

{
  "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."
}

Todo Creation

{
  "id": "64f1c2a7e4b0f2a1c9d3b7e8",
  "title": "Buy groceries",
  "description": "Buy milk, eggs, and bread",
  "completed": false,
  "createdAt": "2023-09-01T10:00:00.000Z"
}

Get Todos with Pagination

{
  "data": [
    {
      "id": "64f1c2a7e4b0f2a1c9d3b7e8",
      "title": "Buy groceries",
      "description": "Buy milk, eggs, and bread",
      "completed": false,
      "createdAt": "2023-09-01T10:00:00.000Z"
    }
  ],
  "page": 1,
  "limit": 10,
  "total": 1
}

🔧 Available Scripts

# Start production server
npm start

# Start development server with auto-restart
npm run dev

# Start server without database (for testing)
npm run start-fallback

# Test MongoDB connection
npm run check-db

# Troubleshoot MongoDB Atlas connection
npm run troubleshoot

🏗️ Project Structure

todo-api/
├── controllers/
│   ├── auth.js          # Authentication logic
│   └── todoController.js # Todo CRUD operations
├── middlewares/
│   ├── auth.js          # JWT authentication middleware
│   └── errorMiddleware.js # Error handling
├── models/
│   ├── User.js          # User schema
│   └── Todo.js          # Todo schema
├── routes/
│   ├── authRoutes.js    # Authentication routes
│   └── todoRoutes.js    # Todo routes
├── app.js               # Express app configuration
├── index.js             # Server entry point
└── package.json         # Dependencies and scripts

🔒 Security Features

• Password Hashing: Uses bcrypt with salt rounds
• JWT Authentication: Secure token-based authentication
• Input Validation: Comprehensive validation for all inputs
• Authorization: Users can only access their own data
• Error Handling: Secure error messages without sensitive data

🚨 Error Handling

The API returns appropriate HTTP status codes and error messages:

• 400 - Bad Request (validation errors)
• 401 - Unauthorized (invalid/missing token)
• 403 - Forbidden (insufficient permissions)
• 404 - Not Found (resource doesn't exist)
• 500 - Internal Server Error

📝 Data Models

User Model

{
  name: String (required, 2-50 characters),
  email: String (required, unique, valid email),
  password: String (required, min 6 characters),
  createdAt: Date,
  updatedAt: Date
}

Todo Model

{
  title: String (required, max 200 characters),
  description: String (optional, max 1000 characters),
  completed: Boolean (default: false),
  user: ObjectId (reference to User),
  createdAt: Date,
  updatedAt: Date
}

🤝 Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

📄 License

This project is licensed under the ISC License.

🆘 Troubleshooting

Common Issues

1. MongoDB Connection Error

   • Check if MongoDB is running
   • Verify connection string in .env
   • Ensure IP is whitelisted (for Atlas)

2. JWT Token Issues

   • Check if JWT_SECRET is set in .env
   • Verify token format in Authorization header

3. Port Already in Use

   • Change PORT in .env file
   • Kill existing processes on the port

Getting Help

• Check the terminal output for specific error messages
• Verify your .env configuration
• Test MongoDB connection with npm run check-db

🎯 Future Enhancements

• Email verification for registration
• Password reset functionality
• Todo categories and tags
• File uploads for todo attachments
• Real-time updates with WebSockets
• API rate limiting
• Comprehensive API documentation with Swagger

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Happy coding! 🚀