Super simple chat server.

cargo.toml

[package]
name = "chat-server"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
tokio = { version = "1.20.1", features = ["full"] }

main.rs

use tokio::{
    io::{AsyncBufReadExt, AsyncWriteExt, BufReader},
    net::TcpListener,
    sync::broadcast,
};

const PORT: i32 = 8080;

#[tokio::main]
async fn main() {
    let listener = TcpListener::bind(format!("localhost:{}", PORT))
        .await
        .expect("Port was occupied!");

    println!("Running chat server on port: {} 🚀", PORT);

    let (sender, _) = broadcast::channel(20);

    loop {
        let (mut socket, addr) = listener
            .accept()
            .await
            .expect("Could not accept new incomming connection.");

        let sender = sender.clone();
        let mut reciever = sender.subscribe();

        tokio::spawn(async move {
            let (read_half, mut writer) = socket.split();

            let mut reader = BufReader::new(read_half);
            let mut line = String::new();

            loop {
                tokio::select! {
                    result = reader.read_line(&mut line) => {
                        if let Ok(0) = result {
                            break;
                        }
                        sender.send((line.clone(), addr)).unwrap();
                        line.clear();
                    }
                    result = reciever.recv() => {
                       let (msg, new_addr) = result.unwrap();

                        if addr != new_addr {
                            writer.write_all(msg.as_bytes()).await.unwrap();
                        }
                    }
                }
            }
        });
    }
}