Chat server: Difference between revisions

</lang>

=={{header|Rust}}==

<lang rust>

use std::collections::HashMap;

use std::io;

use std::io::prelude::*;

use std::io::BufReader;

use std::net::{TcpListener, TcpStream};

use std::sync::{Arc, RwLock};

use std::thread;

type Username = String;

/// Sends a message to all clients except the sending client.

fn broadcast_message(

user: &str,

clients: &mut HashMap<String, TcpStream>,

message: &str,

) -> io::Result<()> {

for (client, stream) in clients.iter_mut() {

if client != user {

writeln!(stream, "{}", message)?;

}

}

Ok(())

}

fn chat_loop(listener: &TcpListener) -> io::Result<()> {

let local_clients: Arc<RwLock<HashMap<Username, TcpStream>>> =

Arc::new(RwLock::new(HashMap::new()));

println!("Accepting connections on {}", listener.local_addr()?.port());

for stream in listener.incoming() {

match stream {

Ok(stream) => {

let client_clients = Arc::clone(&local_clients);

thread::spawn(move || -> io::Result<()> {

let mut reader = BufReader::new(stream.try_clone()?);

let mut writer = stream;

let mut name = String::new();

loop {

write!(writer, "Please enter a username: ")?;

reader.read_line(&mut name)?;

name = name.trim().to_owned();

let clients = client_clients.read().unwrap();

if !clients.contains_key(&name) {

writeln!(writer, "Welcome, {}!", &name)?;

break;

}

writeln!(writer, "That username is taken.")?;

name.clear();

}

{

let mut clients = client_clients.write().unwrap();

clients.insert(name.clone(), writer);

broadcast_message(

&name,

&mut *clients,

&format!("{} has joined the chat room.", &name),

)?;

}

for line in reader.lines() {

let mut clients = client_clients.write().unwrap();

broadcast_message(&name, &mut *clients, &format!("{}: {}", &name, line?))?;

}

{

let mut clients = client_clients.write().unwrap();

clients.remove(&name);

broadcast_message(

&name,

&mut *clients,

&format!("{} has left the chat room.", &name),

)?;

}

Ok(())

});

}

Err(e) => {

println!("Connection failed: {}", e);

}

}

}

Ok(())

}

fn main() {

let listener = TcpListener::bind(("localhost", 7000)).unwrap();

chat_loop(&listener).unwrap();

}