Re-fix #2516 - Make a new listing for final code of ch 20

carols10cents · carols10cents · commit 322899b375d0 · 2020-12-08T21:30:00.000-05:00
I was trying to reuse too much; we don't want the `take(2)` to be part
of the final code, but we do want it to be in the listing for the
example where we shut down gracefully after 2 requests.
diff --git a/listings/ch20-web-server/listing-20-25/src/bin/main.rs b/listings/ch20-web-server/listing-20-25/src/bin/main.rs
@@ -1,4 +1,3 @@
-// ANCHOR: all
 use hello::ThreadPool;
 use std::fs;
 use std::io::prelude::*;
@@ -12,7 +11,7 @@ fn main() {
     let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
     let pool = ThreadPool::new(4);
 
-    for stream in listener.incoming() {
+    for stream in listener.incoming().take(2) {
         let stream = stream.unwrap();
 
         pool.execute(|| {
@@ -47,4 +46,3 @@ fn handle_connection(mut stream: TcpStream) {
     stream.write(response.as_bytes()).unwrap();
     stream.flush().unwrap();
 }
-// ANCHOR_END: all
diff --git a/listings/ch20-web-server/no-listing-08-final-code/404.html b/listings/ch20-web-server/no-listing-08-final-code/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/listings/ch20-web-server/no-listing-08-final-code/Cargo.lock b/listings/ch20-web-server/no-listing-08-final-code/Cargo.lock
diff --git a/listings/ch20-web-server/no-listing-08-final-code/Cargo.toml b/listings/ch20-web-server/no-listing-08-final-code/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "hello"
+version = "0.1.0"
+authors = ["Your Name <you@example.com>"]
+edition = "2018"
+
+[dependencies]
diff --git a/listings/ch20-web-server/no-listing-08-final-code/hello.html b/listings/ch20-web-server/no-listing-08-final-code/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/listings/ch20-web-server/no-listing-08-final-code/src/bin/main.rs b/listings/ch20-web-server/no-listing-08-final-code/src/bin/main.rs
@@ -0,0 +1,46 @@
+use hello::ThreadPool;
+use std::fs;
+use std::io::prelude::*;
+use std::net::TcpListener;
+use std::net::TcpStream;
+use std::thread;
+use std::time::Duration;
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+
+    println!("Shutting down.");
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let mut buffer = [0; 1024];
+    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();
+}
diff --git a/listings/ch20-web-server/no-listing-08-final-code/src/lib.rs b/listings/ch20-web-server/no-listing-08-final-code/src/lib.rs
@@ -0,0 +1,101 @@
+use std::sync::mpsc;
+use std::sync::Arc;
+use std::sync::Mutex;
+use std::thread;
+
+pub struct ThreadPool {
+    workers: Vec<Worker>,
+    sender: mpsc::Sender<Message>,
+}
+
+type Job = Box<dyn FnOnce() + Send + 'static>;
+
+enum Message {
+    NewJob(Job),
+    Terminate,
+}
+
+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
+        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 &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();
+                }
+                Message::Terminate => {
+                    println!("Worker {} was told to terminate.", id);
+
+                    break;
+                }
+            }
+        });
+
+        Worker {
+            id,
+            thread: Some(thread),
+        }
+    }
+}
diff --git a/src/ch20-03-graceful-shutdown-and-cleanup.md b/src/ch20-03-graceful-shutdown-and-cleanup.md
@@ -256,13 +256,13 @@ Here’s the full code for reference:
 <span class="filename">Filename: src/bin/main.rs</span>
 
 ```rust,ignore
-{{#rustdoc_include ../listings/ch20-web-server/listing-20-25/src/bin/main.rs:all}}
+{{#rustdoc_include ../listings/ch20-web-server/no-listing-08-final-code/src/bin/main.rs}}
 ```
 
 <span class="filename">Filename: src/lib.rs</span>
 
 ```rust,noplayground
-{{#rustdoc_include ../listings/ch20-web-server/listing-20-25/src/lib.rs}}
+{{#rustdoc_include ../listings/ch20-web-server/no-listing-08-final-code/src/lib.rs}}
 ```
 
 We could do more here! If you want to continue enhancing this project, here are
