🌐 ft_irc - RFC2812 Compliant IRC Server

A sophisticated Internet Relay Chat (IRC) server implementation in C++98, featuring advanced network programming, comprehensive protocol compliance, and production-quality architecture.

✨ Technical Highlights

🚀 Advanced Network Programming

• Non-blocking I/O with select() multiplexing for scalable concurrent client handling
• Socket programming with proper error handling and resource management
• Persistent connection management with graceful cleanup and disconnect detection
• Partial command buffering for robust network packet handling

🔐 Security & Access Control

• Multi-stage authentication (PASS → NICK → USER) with state validation
• Channel operator system with elevated privileges
• Comprehensive channel modes: +i (invite-only), +t (topic protection), +k (key), +o (operator), +l (limit)
• Invite-only channel management with sophisticated access control

⚡ Protocol Implementation

• Full RFC2812 compliance with proper IRC message formatting
• Complete numeric response codes (401, 403, 431, 432, 433, 442, etc.)
• Hostmask implementation (nick!user@host) in all messages
• Multi-channel operations with comma-separated JOIN commands

🎯 Core Features

IRC Commands Implemented

Command	Description	Advanced Features
PASS	Server authentication	Password validation
NICK	Nickname management	Conflict resolution with auto-modification
USER	User registration	Complete userinfo handling
JOIN	Channel joining	Multi-channel, key support, mode checking
PART	Channel leaving	Multi-channel departure
PRIVMSG	Messaging	Channel and private messages
TOPIC	Topic management	Operator restrictions, timestamps
MODE	Channel/user modes	All 5 IRC modes implemented
KICK	User removal	Operator privilege checking
INVITE	User invitation	Invite-only channel support
QUIT	Clean disconnection	Broadcast to common channels

Channel Management

• 🏗️ Dynamic channel creation - Channels created on first JOIN
• 👑 Automatic operator assignment - First user becomes operator
• 🧹 Smart cleanup - Empty channels automatically removed
• 📢 Efficient broadcasting - Optimized message distribution algorithms
• 🔄 Nickname propagation - Cross-channel nickname updates

🏗️ Architecture Overview

┌─────────────────┐    ┌─────────────────┐    ┌─────────────────┐
│     Server      │    │     Client      │    │    Channel      │
│   (Socket Mgmt) │◄──►│  (Auth State)   │◄──►│   (User Mgmt)   │
└─────────────────┘    └─────────────────┘    └─────────────────┘
         │                       │                       │
         ▼                       ▼                       ▼
┌─────────────────┐    ┌─────────────────┐    ┌─────────────────┐
│ CommandHandler  │    │ RFC2812Handler  │    │   Utilities     │
│ (Cmd Dispatch)  │    │ (Protocol Msgs) │    │  (Validation)   │
└─────────────────┘    └─────────────────┘    └─────────────────┘

Key Design Patterns

• Command Registry Pattern - Modular command dispatch system
• State Machine - Client authentication flow management
• Observer Pattern - Channel event broadcasting
• RAII - Resource management and cleanup

🚀 Quick Start

Prerequisites

• C++ compiler with C++98 support
• Make build system
• Unix-like environment (Linux/macOS)

Build & Run

# Clone and build
git clone https://github.com/lgeniaux/ft_irc
cd ft_irc
make

# Start the server
./ircserv <port> <password>

# Example
./ircserv 6667 mypassword

Connect with irssi

# Install irssi (if needed)
sudo apt install irssi  # Ubuntu/Debian
brew install irssi      # macOS

# Connect to your server
irssi
/connect localhost 6667 mypassword
/join #general
/msg #general Hello from my IRC server!

🔧 Advanced Usage

Multi-Channel Operations

/join #dev,#general,#random key1,key2
/part #dev,#general
/mode #channel +itk secretkey

Channel Management

/invite friend #private-channel
/kick #channel troublemaker
/topic #channel New topic here
/mode #channel +o friend

💻 Technical Implementation

Network Programming Approach

• Single-threaded design using select() for I/O multiplexing
• Non-blocking sockets to prevent server blocking on client operations
• Event-driven architecture for handling multiple simultaneous connections
• Graceful error handling with proper socket cleanup

Memory Management

• C++98 compliant memory management without modern smart pointers
• STL containers for efficient data structure management
• RAII principles for automatic resource cleanup
• No memory leaks - comprehensive resource management

Code Quality Features

• ✅ Strict compilation with -Wall -Wextra -Werror
• ✅ Modular architecture with clear separation of concerns
• ✅ Comprehensive error handling for network and protocol errors
• ✅ Professional build system with dependency tracking
• ✅ Signal handling for graceful server shutdown

📊 Performance Characteristics

• Scalable: Handles multiple concurrent clients efficiently
• Low latency: Direct message routing without unnecessary delays
• Memory efficient: Optimized data structures for minimal overhead
• Robust: Comprehensive error handling and recovery

🎓 Educational Value

This project demonstrates mastery of:

• Systems Programming - Low-level network programming in C++
• Protocol Implementation - Standards compliance and message formatting
• Concurrent Programming - Multi-client handling without threading
• Software Architecture - Clean, modular design patterns
• Resource Management - Memory and socket lifecycle management

🛠️ Development

Project Structure

ft_irc/
├── src/
│   ├── Server.cpp          # Core server implementation
│   ├── Client.cpp          # Client state management
│   ├── Channel.cpp         # Channel operations
│   ├── RFC2812Handler.cpp  # Protocol compliance
│   └── commands/           # Individual IRC commands
├── include/                # Header files
└── Makefile               # Build configuration

Build System

• Hierarchical Makefiles for modular compilation
• Automatic dependency tracking for efficient rebuilds
• Colored output for professional development experience

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Built with ❤️ and lots of ☕ at École 42

Showcasing advanced C++ systems programming and network protocol implementation