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add problem 03

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timeshifter
2026-07-11 17:36:35 +02:00
parent 48f8cd2bde
commit db8de55533
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problem03/Cargo.lock
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problem03/Cargo.toml
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[package]
name = "problem03"
version = "0.1.0"
edition = "2024"
[dependencies]
tokio = { version = "1", features = ["full"] }
anyhow = "1"
problem03/src/main.rs
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use std::sync::Arc;
use anyhow::bail;
use tokio::{
io::{AsyncReadExt, AsyncWriteExt, Result},
net::TcpStream,
sync::{Mutex, MutexGuard, broadcast::Sender},
};
#[tokio::main]
async fn main() -> Result<()> {
let listener = tokio::net::TcpListener::bind("0.0.0.0:10000").await?;
let room = Arc::new(Mutex::new(vec![]));
let (tx, _) = tokio::sync::broadcast::channel(100_000);
loop {
let (socket, _) = listener.accept().await?;
let the_room = room.clone();
let this_tx = tx.clone();
tokio::spawn(async move {
match handle_connection(socket, the_room, this_tx).await {
Ok(_) => (),
Err(err) => {
dbg!(err);
}
}
});
}
}
async fn handle_connection(
socket: TcpStream,
room: Arc<Mutex<Vec<String>>>,
tx: Sender<MessageType>,
) -> anyhow::Result<()> {
let (mut reader, mut writer) = tokio::io::split(socket);
writer
.write_all(b"Welcome to budgetchat! What shall I call you?\n")
.await?;
let mut read_buffer = Vec::with_capacity(1024);
read_to_buffer(&mut reader, &mut read_buffer).await?;
let newline = find_next_newline(&read_buffer).unwrap();
let before_newline = read_buffer.drain(0..=newline).collect();
let self_name = String::from_utf8(before_newline)?.trim().to_string();
let message = generate_room_contains_message(&room).await;
writer.write_all(&message.into_bytes()).await?;
let mut rx = {
let mut locked_room = room.lock().await;
deny_invalid_user(&self_name, &locked_room)?;
locked_room.push(self_name.clone());
let rx = tx.subscribe();
let message = MessageType::UserJoined(self_name.clone());
tx.send(message)?;
rx
};
loop {
tokio::select! {
read_amount = read_to_buffer(&mut reader, &mut read_buffer) => {
match read_amount {
Ok(_) => (),
Err(_) => {
tx.send(MessageType::UserQuit(self_name.clone()))?;
{
let mut the_room = room.lock().await;
let idx = the_room.iter().position(|name| *name == self_name).unwrap();
the_room.remove(idx);
}
return Ok(());
}
};
let newline = match find_next_newline(&read_buffer) {
Some(idx) => idx,
None => continue,
};
let before_newline = read_buffer.drain(0..=newline).collect();
let message = String::from_utf8(before_newline)?;
if !message.trim().is_empty() {
tx.send(MessageType::TextMessage(self_name.clone(), message.to_string()))?;
}
}
received = rx.recv() => {
match received? {
MessageType::UserJoined(user_name) => {
if user_name == self_name {
continue;
}
let message = format!("* {user_name} has entered the room\n");
writer.write_all(&message.into_bytes()).await?;
}
MessageType::UserQuit(user_name) => {
let message = format!("* {user_name} has left the room\n");
writer.write_all(&message.into_bytes()).await?;
}
MessageType::TextMessage(user_name, the_message) => {
if user_name == self_name {
continue;
}
let message = format!("[{user_name}] {}\n", the_message.trim());
writer.write_all(&message.into_bytes()).await?;
}
}
}
};
}
}
fn find_next_newline(read_buffer: &[u8]) -> Option<usize> {
read_buffer.iter().position(|c| *c == b'\n')
}
async fn read_to_buffer(
reader: &mut tokio::io::ReadHalf<TcpStream>,
read_buffer: &mut Vec<u8>,
) -> anyhow::Result<usize> {
let mut read_amount = 0;
while !read_buffer.contains(&b'\n') {
read_amount += reader.read_buf(read_buffer).await?;
if read_amount == 0 {
bail!("user disconnected");
}
}
Ok(read_amount)
}
fn deny_invalid_user(name: &str, room: &MutexGuard<'_, Vec<String>>) -> anyhow::Result<()> {
if name.is_empty()
|| !name.chars().all(|c| c.is_alphanumeric())
|| room.iter().any(|n| n == name)
{
bail!("user '{name}' is invalid or already exists");
}
Ok(())
}
async fn generate_room_contains_message(room: &Arc<Mutex<Vec<String>>>) -> String {
let the_room = room.lock().await;
let mut message = String::from("* The room contains: ");
let mut iter = the_room.iter().peekable();
while let Some(user) = iter.next() {
message.push_str(user.as_str());
if iter.peek().is_some() {
message.push_str(", ");
}
}
message.push('\n');
message
}
#[derive(Clone, Debug)]
enum MessageType {
UserJoined(String),
UserQuit(String),
TextMessage(String, String), // user, message
}