Real-time Chat Application

A real-time chat application built with Node.js, Express, MongoDB, and Socket.IO. This application provides instant messaging functionality with user authentication and real-time message delivery.

Features

• User authentication (Register/Login)
• Real-time messaging
• Online/Offline status
• Message history
• Secure password hashing
• JWT-based authentication
• CORS enabled for cross-origin requests

Tech Stack

Backend

• Node.js - JavaScript runtime
• Express - Web framework
• MongoDB - Database
• Mongoose - MongoDB object modeling
• Socket.IO - Real-time communication
• JWT - JSON Web Tokens for authentication
• bcryptjs - Password hashing
• dotenv - Environment variables

Prerequisites

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

Getting Started

1. Clone the repository

   git clone <repository-url>
   cd chat-app/backend

2. Install dependencies

   npm install

3. Set up environment variables Create a .env file in the backend directory with the following variables:

   PORT=5000
   MONGO_URI=your_mongodb_connection_string
   JWT_SECRET=your_jwt_secret_key
   JWT_EXPIRE=30d
   

4. Start the development server

   npm run dev

   The server will start on http://localhost:5000

API Endpoints

Authentication

• POST /api/auth/register - Register a new user
• POST /api/auth/login - Login user
• GET /api/auth/me - Get current user (protected)
• GET /api/auth/logout - Logout user

Users

• GET /api/users - Get all users (protected)

Messages

• GET /api/messages - Get all messages (protected)
• POST /api/messages - Send a new message (protected)

WebSocket Events

Client to Server

• sendMessage - Send a new message
• typing - Notify when user is typing
• stopTyping - Notify when user stops typing

Server to Client

• message - Receive a new message
• userTyping - Notify that a user is typing
• userStopTyping - Notify that a user stopped typing
• userOnline - Notify when a user comes online
• userOffline - Notify when a user goes offline

Environment Variables

• PORT - Server port (default: 5000)
• MONGO_URI - MongoDB connection string
• JWT_SECRET - Secret key for JWT
• JWT_EXPIRE - JWT expiration time (e.g., 30d)

Contributing

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

Acknowledgments

• Built with ❤️ using modern JavaScript technologies

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Happy Coding! 🚀