FT_IRC - C++ IRC Server

)

Brief Overview

This project is a custom implementation of an Internet Relay Chat (IRC) server written in C++98. It is designed to be fully compliant with standard IRC clients (such as Irssi or Netcat) allowing users to connect, communicate, and manage channels. The server handles multiplexing using poll() for non-blocking I/O operations and enables multiple clients to chat and interact concurrently.

Key features include:

• Client authentication (PASS, NICK, USER).
• Channel management and operations (JOIN, PART, TOPIC, KICK, INVITE, MODE).
• Seamless non-blocking I/O multiplexing with poll().
• Built-in Bot behavior implementation.

What I Learned

During the development of this project, specifically while focusing on server initialization and IRC commands, I gained valuable insights into:

• Network Programming: Working efficiently with sockets, binding, listening, and managing client connections.
• I/O Multiplexing: Mastering the poll() function to handle multiple concurrent clients over a single-threaded architecture, ensuring smooth non-blocking operations.
• Protocol Implementation: Gaining a deep understanding of the IRC protocol, parsing line-based communication buffers, and properly formatting responses and numeric replies according to standards.
• String Parsing and Command Dispatching: Implementing robust algorithms for parsing incoming network buffers, handling partial reads/writes, and accurately mapping incoming text commands to their respective C++ handler functions.
• C++98 Standard: Adhering strictly to C++98 limits, improving my skills in object-oriented principles, memory management, and employing STL containers to manage state (like clients and channels).

How to Use

Prerequisites

• A UNIX-like environment (Linux/macOS)
• c++ compiler (e.g., g++ or clang++)
• make

Building the Server

Run the following command in the root directory to compile the project:

make

This will produce an executable named ircserv.

Running the Server

The executable requires two arguments: a listening port and a password that clients must use to authenticate.

./ircserv <port> <password>

Example:

./ircserv 6667 my_secure_password

Connecting as a Client

You can test the server using popular IRC clients such as irssi or standard tools like Netcat.

Using Netcat (nc):

nc 127.0.0.1 6667
PASS my_secure_password
NICK mynick
USER myuser 0 * :My Real Name

Using Irssi:

irssi -c 127.0.0.1 -p 6667 -w my_secure_password -n mynick

Supported Commands

Once connected, you can interact with the server using standard IRC commands:

• /JOIN <channel> - Join or create a channel
• /PRIVMSG <target> <message> - Send a private message to a specific user or a channel
• /KICK <channel> <user> - Kick a user from a channel
• /INVITE <user> <channel> - Invite a user to a channel
• /TOPIC <channel> [<topic>] - View or set the channel's topic
• /MODE <channel> <+|-mode> [params] - Modify channel modes (e.g., i for invite-only, t for topic restriction, k for passwords, o for operators, l for limits)
• /PART <channel> - Leave a channel
• /QUIT - Disconnect from the server

Useful Resources

Here are some excellent resources that helped in building this project, and will be valuable for anyone looking to understand IRC and socket programming:

• RFC 1459: Internet Relay Chat Protocol ⭐ (The most important and useful core documentation for understanding IRC commands and replies!)
• Article: Small IRC Server (ft_irc) Overview
• Guide/Video: Socket Programming Tutorial
• Guide/Video: Multiplexing with poll()
• Guide/Video: Networking in C++