[易学易懂系列|rustlang语言|零基础|快速入门|（26）|实战3：Http服务器（多线程版本）]

[易学易懂系列|rustlang语言|零基础|快速入门|（26）|实战3：Http服务器（多线程版本）]

项目实战

实战3：Http服务器

我们今天来进一步开发我们的Http服务器，用多线程实现。

我们在原来工程h_server更新代码如下：

src/main.rs:

use h_server::*;
use std::fs;
use std::io::prelude::*;
use std::net::TcpListener;
use std::net::TcpStream;

fn main() {
    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
    let pool = ThreadPool::new(4);
    println!("multi-threads server is up!");
    for stream in listener.incoming() {
        let stream = stream.unwrap();
        println!("multi-threads server get request!");
        pool.execute(|| {
            handle_connection(stream);
        });
    }
}
fn handle_connection(mut stream: TcpStream) {
    let mut buffer = [0; 512];
    stream.read(&mut buffer).unwrap();

    let get = b"GET / HTTP/1.1\r\n";

    let (status_line, filename) = if buffer.starts_with(get) {
        ("HTTP/1.1 200 OK\r\n\r\n", "hello.html")
    } else {
        ("HTTP/1.1 404 NOT FOUND\r\n\r\n", "404.html")
    };

    let contents = fs::read_to_string(filename).unwrap();

    let response = format!("{}{}", status_line, contents);

    stream.write(response.as_bytes()).unwrap();
    stream.flush().unwrap();
}

src/lib.rs:

use std::sync::mpsc;
use std::sync::Arc;
use std::sync::Mutex;
use std::thread;

enum Message {
    NewJob(Job),
    Terminate,
}

pub struct ThreadPool {
    workers: Vec<Worker>,
    sender: mpsc::Sender<Message>,
}

trait FnBox {
    fn call_box(self: Box<Self>);
}

impl<F: FnOnce()> FnBox for F {
    fn call_box(self: Box<F>) {
        (*self)()
    }
}

type Job = Box<dyn FnBox + Send + 'static>;

impl ThreadPool {
    /// Create a new ThreadPool.
    ///
    /// The size is the number of threads in the pool.
    ///
    /// # Panics
    ///
    /// The `new` function will panic if the size is zero.
    pub fn new(size: usize) -> ThreadPool {
        assert!(size > 0);

        let (sender, receiver) = mpsc::channel();

        let receiver = Arc::new(Mutex::new(receiver));

        let mut workers = Vec::with_capacity(size);

        for id in 0..size {
            workers.push(Worker::new(id, Arc::clone(&receiver)));
        }

        ThreadPool { workers, sender }
    }

    pub fn execute<F>(&self, f: F)
    where
        //这里定义闭包，是FnOnce类型，代表一个线程只运行一次
        //Send类型，代表闭包可以在不同线程中传递
        //'static，代表闭包生命周期跟整个程序一样
        F: FnOnce() + Send + 'static,
    {
        let job = Box::new(f);

        self.sender.send(Message::NewJob(job)).unwrap();
    }
}
//实现Drop特征，用于处理资源释放相关逻辑
impl Drop for ThreadPool {
    fn drop(&mut self) {
        println!("Sending terminate message to all workers.");

        for _ in &mut self.workers {
            self.sender.send(Message::Terminate).unwrap();
        }

        println!("Shutting down all workers.");

        for worker in &mut self.workers {
            println!("Shutting down worker {}", worker.id);

            if let Some(thread) = worker.thread.take() {
                thread.join().unwrap();
            }
        }
    }
}

struct Worker {
    id: usize,
    thread: Option<thread::JoinHandle<()>>,
}

impl Worker {
    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Message>>>) -> Worker {
        let thread = thread::spawn(move || loop {
            let message = receiver.lock().unwrap().recv().unwrap();

            match message {
                Message::NewJob(job) => {
                    println!("Worker {} got a job; executing.", id);

                    job.call_box();
                }
                Message::Terminate => {
                    println!("Worker {} was told to terminate.", id);

                    break;
                }
            }
        });

        Worker {
            id,
            thread: Some(thread),
        }
    }
}

直接运行命令：

cargo run

启动服务器。

然后用浏览器访问：

http://127.0.0.1:7878/

页面显示：

Hello!

Hi from Rust

以上，希望对你有用。

如果遇到什么问题，欢迎加入：rust新手群，在这里我可以提供一些简单的帮助，加微信：360369487，注明：博客园+rust

参考文章：

https://doc.rust-lang.org/stable/book/ch20-02-multithreaded.html#creating-a-similar-interface-for-a-finite-number-of-threads