TCP Chat Application

A simple real-time chat application built with Node.js TCP sockets. Users can connect to a central server and exchange messages with all connected clients.

Features

• Real-time messaging between multiple clients
• User join/leave notifications
• Anti-spam protection with automatic kick
• Connection timeout handling (30 seconds)
• Clean terminal UI with message alignment
• Graceful shutdown handling

Prerequisites

• Node.js (v14 or higher recommended)
• npm or yarn

Installation

1. Clone the repository
2. Install dependencies:

npm install

3. Create a .env file in the root directory:

NODE_ENV=development
PORT=your.port.number
DEV_IP_ADDRESS=0.0.0.0
PROD_IP_ADDRESS=your.production.ip

Usage

Starting the Server

node --env-file=.env --watch server.js

The server will start listening on the configured host and port (default: 0.0.0.0:${PORT}).

Connecting as a Client

Open a new terminal window and run:

node client.js

You can open multiple terminals to simulate multiple users chatting.

Chat Commands

• Type your message and press Enter to send
• Type .exit to disconnect gracefully
• Press Ctrl+C to force quit

Project Structure

├── server.js       # TCP server handling multiple client connections
├── client.js       # TCP client with interactive chat interface
├── globals.js      # Shared constants (delimiter, message limit)
├── spammer.js      # Test script for spam detection
├── .env            # Environment configuration
└── .gitignore      # Git ignore rules

Technical Details

Message Protocol

Messages are delimited using a custom delimiter {[$#%#$]} to handle TCP streaming and chunk reassembly.

Spam Protection

• Maximum message buffer size: 1024 bytes (1 KB)
• Clients exceeding this limit without sending the delimiter are automatically kicked
• Test spam behavior using node spammer.js

Connection Management

• Each client receives a unique ID upon connection
• Server broadcasts join/leave/disconnect notifications to all clients
• Automatic cleanup on timeout (30 seconds of inactivity)

Security Considerations

This is a basic implementation intended for educational purposes. For production use, consider adding:

• Authentication and authorization
• Message encryption (TLS/SSL)
• Rate limiting per client
• Input sanitization
• Message size validation
• IPv6 support

License

MIT

Contributing

Feel free to submit issues or pull requests for improvements.