lib.rs

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

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 {
    
    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
            F: FnOnce() + Send + 'static
    {
        let job = Box::new(f);

        self.sender.send(Message::NewJob(job)).unwrap();
    }
}

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),
        }
    }
}

main.go

package main

import (
	"bytes"
	"fmt"
	"io/ioutil"
	"log"
	"net"
	"sync"
)

func main() {
	l, err := net.Listen("tcp", "0.0.0.0:8080")
	if err != nil {
		panic(err)
	}
	
	for {
		conn, _ := l.Accept()
		go handle(conn)
	}
}

var get []byte
var sleep []byte

func init() {
	get = []byte("GET / HTTP/1.1\r\n")
	sleep = []byte("GET /sleep HTTP/1.1\r\n")
}

func handle(conn net.Conn) {
	buffer := make([]byte, 500)
	conn.Read(buffer)
	var statusline, filename string
	if bytes.HasPrefix(buffer, get) {
		statusline, filename = "HTTP/1.1 200 OK\r\n\r\n", "hello.html"
	} else if bytes.HasPrefix(buffer, sleep) {
		statusline, filename = "HTTP/1.1 200 OK\r\n\r\n", "hello.html"
	} else {
		statusline, filename = "HTTP/1.1 404 NOT FOUND\r\n\r\n", "404.html"
	}

	content, _ := ioutil.ReadFile(filename)
	response := fmt.Sprintf("%s%s", statusline, content)
	conn.Write([]byte(response))
	conn.Close()
}

main.rs

use http_server::ThreadPool;

use std::env;
use std::io::prelude::*;
use std::net::TcpListener;
use std::net::TcpStream;
use std::fs;
use std::thread;
use std::time::Duration;

fn main() {

    let listener = TcpListener::bind("0.0.0.0:8080").unwrap();
    let pool = ThreadPool::new(n);

    for stream in listener.incoming() {
        let stream = stream.unwrap();

        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 sleep = b"GET /sleep 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 if buffer.starts_with(sleep) {
        thread::sleep(Duration::from_secs(5));
        ("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();
}