ft_irc: Internet Relay Chat Server

Overview

ft_irc is a complete implementation of an Internet Relay Chat (IRC) server, written in C++98. It is designed to demonstrate mastery of low-level networking, socket programming, and protocol parsing as defined in RFC 1459.

The system is built on a single-threaded, non-blocking I/O architecture using poll(). This design choice ensures the server handles multiple concurrent connections efficiently without the resource overhead of multi-threading, maintaining stability even under heavy load or partial data transmission.

Installation

Prerequisites

• C++ Compiler (g++ or clang++)
• make
• Any IRC Client (HexChat recommended)

Compilation

The project utilizes a custom Makefile to manage builds for both the server and the automated service agent (bot).

Command	Action
make	Compiles both the Server and the Bot.
make ircserv	Compiles only the Server.
make ircbot	Compiles only the Bot.
make fclean	Removes all object files and executables.

Usage

1. Start the Server

The server listens on a specified port and requires a password for incoming connections.

./ircserv <port> <password>

Example: ./ircserv 6667 securepass

2. Connect a Client

While raw TCP connections (nc) work, a dedicated client provides the best testing environment.

Recommended: HexChat

HexChat is highly recommended for testing channel modes and operator privileges visually.

1. Open HexChat and navigate to Network List (Ctrl+S).
2. Add a new network named ft_irc.
3. Edit the server details:
   • Server: localhost/6667 (or your port).
   • Password: The password used to launch the server.
   • SSL: Disabled.
4. Connect.

3. Launch the Bot (Optional)

The BravyBot is an autonomous agent that connects to the server to provide utility services.

./ircbot <ip> <port> <password>

Example: ./ircbot 127.0.0.1 6667 securepass

Features & Implementation

Technical Architecture

• I/O Multiplexing: Uses poll() to monitor all file descriptors (sockets) within a single event loop.
• Non-Blocking: All sockets are set to non-blocking mode via fcntl().
• Memory Safety: Strict RAII compliance (C++98) ensuring zero memory leaks.

Server Commands

The server supports the standard IRC lifecycle including:

• Auth: CAP, PASS, NICK, USER
• Operations: JOIN, PART, TOPIC, PRIVMSG, NOTICE
• Management: KICK, INVITE, QUIT, PING/PONG

Channel Modes

Operators can control channel behavior using the MODE command:

Flag	Description
i	Invite-only: Only invited users can join.
t	Protected Topic: Only operators can change the topic.
k	Key: Requires a password to join.
o	Operator: Grants/revokes operator status.
l	Limit: Sets a maximum number of users.

Automated Agent (Bot)

The BravyBot automatically joins #BravyBotChannel upon connection and interacts via private messages or channel chat.

Available Commands:

• !help : Displays available commands.
• !time / !date : Returns the current server time/date.
• !moment : Returns full timestamp.
• !add <cmd> <msg> : Dynamically teaches the bot a new custom command.
• !quit : Disconnects the bot.

Behaviors:

• Auto-Join: Automatically accepts invites to new channels.
• Greetings: Welcomes users when they join a channel.
• Farewells: Acknowledges users leaving a channel.