Rust 异步编程

第一步 安装tokio库

cargo add tokio --features full

use tokio::io::{AsyncReadExt, AsyncWriteExt};
use tokio::net::{TcpListener, TcpStream};
use std::error::Error;

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    // 绑定到本地地址的8080端口
    let listener = TcpListener::bind("127.0.0.1:8080").await?;
    println!("服务器正在监听 127.0.0.1:8080");

    loop {
        // 等待新的连接
        let (socket, addr) = listener.accept().await?;
        println!("接收到来自 {} 的新连接", addr);

        // 为每个连接生成一个新任务
        tokio::spawn(async move {
            if let Err(e) = handle_connection(socket).await {
                println!("处理连接时出错: {}", e);
            }
        });
    }
}

async fn handle_connection(mut socket: TcpStream) -> Result<(), Box<dyn Error>> {
    // 创建一个缓冲区来存储数据
    let mut buf = [0; 1024];

    loop {
        // 读取数据
        let size = match socket.read(&mut buf).await {
            // 客户端关闭了连接
            Ok(size) if size == 0 => return Ok(()),
            Ok(size) => size,
            Err(e) => {
                return Err(e.into());
            }
        };

        let data = &buf[..size];
        let received = String::from_utf8_lossy(data);
        println!("Received data: {}", received);
        // 检查是否是telnet的断开命令（IAC IP）
        if size >= 3 && buf[0] == 255 && buf[1] == 244 {
            println!("Detected telnet disconnect command (IAC IP)");
             //显示关闭连接并且传播异常
            socket.shutdown().await?;
            //这个也能退出事件循环 关闭连接
            return Ok(());
        }
        
        // 检查普通ASCII的CTRL+C (3)
        if buf[..size].contains(&3) {
            println!("Detected CTRL+C, closing connection");
            //显示关闭连接并且传播异常
            socket.shutdown().await?;
            //这个也能退出事件循环 关闭连接
            return Ok(());
        }

        println!("接收到 {} 字节数据", size);

        // 将数据写回客户端
        if let Err(e) = socket.write_all(&buf[0..size]).await {
            return Err(e.into());
        }
    }
}