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<ol class="chapter"><li class="chapter-item affix "><a href="../../about-book.html">关于本书</a></li><li class="chapter-item affix "><a href="../../into-rust.html">进入 Rust 编程世界</a></li><li class="chapter-item affix "><a href="../../first-try/sth-you-should-not-do.html">避免从入门到放弃</a></li><li class="chapter-item affix "><a href="../../community.html">社区和锈书</a></li><li class="spacer"></li><li class="chapter-item affix "><a href="../../some-thoughts.html">Xobserve: 一切皆可观测</a></li><li class="chapter-item affix "><a href="../../beat-ai.html">BeatAI: 工程师 AI 入门圣经</a></li><li class="chapter-item affix "><li class="part-title">Rust 语言基础学习</li><li class="spacer"></li><li class="chapter-item "><a href="../../first-try/intro.html"><strong aria-hidden="true">1.</strong> 寻找牛刀，以便小试</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../first-try/installation.html"><strong aria-hidden="true">1.1.</strong> 安装 Rust 环境</a></li><li class="chapter-item "><a href="../../first-try/editor.html"><strong aria-hidden="true">1.2.</strong> 墙推 VSCode!</a></li><li class="chapter-item "><a href="../../first-try/cargo.html"><strong aria-hidden="true">1.3.</strong> 认识 Cargo</a></li><li class="chapter-item "><a href="../../first-try/hello-world.html"><strong aria-hidden="true">1.4.</strong> 不仅仅是 Hello world</a></li><li class="chapter-item "><a href="../../first-try/slowly-downloading.html"><strong aria-hidden="true">1.5.</strong> 下载依赖太慢了？</a></li></ol></li><li class="chapter-item "><a href="../../basic/intro.html"><strong aria-hidden="true">2.</strong> Rust 基础入门</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/variable.html"><strong aria-hidden="true">2.1.</strong> 变量绑定与解构</a></li><li class="chapter-item "><a href="../../basic/base-type/index.html"><strong aria-hidden="true">2.2.</strong> 基本类型</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/base-type/numbers.html"><strong aria-hidden="true">2.2.1.</strong> 数值类型</a></li><li class="chapter-item "><a href="../../basic/base-type/char-bool.html"><strong aria-hidden="true">2.2.2.</strong> 字符、布尔、单元类型</a></li><li class="chapter-item "><a href="../../basic/base-type/statement-expression.html"><strong aria-hidden="true">2.2.3.</strong> 语句与表达式</a></li><li class="chapter-item "><a href="../../basic/base-type/function.html"><strong aria-hidden="true">2.2.4.</strong> 函数</a></li></ol></li><li class="chapter-item "><a href="../../basic/ownership/index.html"><strong aria-hidden="true">2.3.</strong> 所有权和借用</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/ownership/ownership.html"><strong aria-hidden="true">2.3.1.</strong> 所有权</a></li><li class="chapter-item "><a href="../../basic/ownership/borrowing.html"><strong aria-hidden="true">2.3.2.</strong> 引用与借用</a></li></ol></li><li class="chapter-item "><a href="../../basic/compound-type/intro.html"><strong aria-hidden="true">2.4.</strong> 复合类型</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/compound-type/string-slice.html"><strong aria-hidden="true">2.4.1.</strong> 字符串与切片</a></li><li class="chapter-item "><a href="../../basic/compound-type/tuple.html"><strong aria-hidden="true">2.4.2.</strong> 元组</a></li><li class="chapter-item "><a href="../../basic/compound-type/struct.html"><strong aria-hidden="true">2.4.3.</strong> 结构体</a></li><li class="chapter-item "><a href="../../basic/compound-type/enum.html"><strong aria-hidden="true">2.4.4.</strong> 枚举</a></li><li class="chapter-item "><a href="../../basic/compound-type/array.html"><strong aria-hidden="true">2.4.5.</strong> 数组</a></l
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<main>
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<h1 id="一个实践项目-web-服务器"><a class="header" href="#一个实践项目-web-服务器">一个实践项目: Web 服务器</a></h1>
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<p>知识学得再多，不实际应用也是纸上谈兵，不是忘掉就是废掉，对于技术学习尤为如此。在之前章节中，我们已经学习了 <code>Async Rust</code> 的方方面面，现在来将这些知识融会贯通，最终实现一个并发 Web 服务器。</p>
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<h2 id="多线程版本的-web-服务器"><a class="header" href="#多线程版本的-web-服务器">多线程版本的 Web 服务器</a></h2>
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<p>在正式开始前，先来看一个单线程版本的 <code>Web</code> 服务器，该例子来源于 <a href="https://doc.rust-lang.org/book/ch20-01-single-threaded.html"><code>Rust Book</code></a> 一书。</p>
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<p><code>src/main.rs</code>:</p>
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<pre><pre class="playground"><code class="language-rust edition2021">use std::fs;
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use std::io::prelude::*;
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use std::net::TcpListener;
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use std::net::TcpStream;
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fn main() {
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// 监听本地端口 7878 ，等待 TCP 连接的建立
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let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
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// 阻塞等待请求的进入
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for stream in listener.incoming() {
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let stream = stream.unwrap();
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handle_connection(stream);
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}
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}
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fn handle_connection(mut stream: TcpStream) {
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// 从连接中顺序读取 1024 字节数据
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let mut buffer = [0; 1024];
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stream.read(&mut buffer).unwrap();
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let get = b"GET / HTTP/1.1\r\n";
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|
// 处理HTTP协议头，若不符合则返回404和对应的 `html` 文件
|
|
|
|
|
|
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();
|
|
|
|
|
|
|
|
|
|
|
|
// 将回复内容写入连接缓存中
|
|
|
|
|
|
let response = format!("{status_line}{contents}");
|
|
|
|
|
|
stream.write_all(response.as_bytes()).unwrap();
|
|
|
|
|
|
// 使用 flush 将缓存中的内容发送到客户端
|
|
|
|
|
|
stream.flush().unwrap();
|
|
|
|
|
|
}</code></pre></pre>
|
|
|
|
|
|
<p><code>hello.html</code>:</p>
|
|
|
|
|
|
<pre><code class="language-html"><!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>
|
|
|
|
|
|
</code></pre>
|
|
|
|
|
|
<p><code>404.html</code>:</p>
|
|
|
|
|
|
<pre><code class="language-html"><!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>
|
|
|
|
|
|
</code></pre>
|
|
|
|
|
|
<p>运行以上代码，并从浏览器访问 <code>127.0.0.1:7878</code> 你将看到一条来自 <code>Ferris</code> 的问候。</p>
|
|
|
|
|
|
<p>在回忆了单线程版本该如何实现后，我们也将进入正题，一起来实现一个基于 <code>async</code> 的异步 Web 服务器。</p>
|
|
|
|
|
|
<h2 id="运行异步代码"><a class="header" href="#运行异步代码">运行异步代码</a></h2>
|
|
|
|
|
|
<p>一个 Web 服务器必须要能并发的处理大量来自用户的请求，也就是我们不能在处理完上一个用户的请求后，再处理下一个用户的请求。上面的单线程版本可以修改为多线程甚至于线程池来实现并发处理，但是线程还是太重了，使用 <code>async</code> 实现 <code>Web</code> 服务器才是最适合的。</p>
|
|
|
|
|
|
<p>首先将 <code>handle_connection</code> 修改为 <code>async</code> 实现:</p>
|
|
|
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
|
|
|
</span><span class="boring">fn main() {
|
|
|
|
|
|
</span>async fn handle_connection(mut stream: TcpStream) {
|
|
|
|
|
|
//<-- snip -->
|
|
|
|
|
|
}
|
|
|
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
|
|
|
<p>该修改会将函数的返回值从 <code>()</code> 变成 <code>Future<Output=()></code> ，因此直接运行将不再有任何效果，只用通过 <code>.await</code> 或执行器的 <code>poll</code> 调用后才能获取 <code>Future</code> 的结果。</p>
|
|
|
|
|
|
<p>在之前的代码中，我们使用了自己实现的简单的执行器来进行 <code>.await</code> 或 <code>poll</code> ，实际上这只是为了学习原理，<strong>在实际项目中，需要选择一个三方的 <code>async</code> 运行时来实现相关的功能</strong>。 具体的选择我们将在下一章节进行讲解，现在先选择 <code>async-std</code> ，该包的最大优点就是跟标准库的 API 类似，相对来说更简单易用。</p>
|
|
|
|
|
|
<h4 id="使用-async-std-作为异步运行时"><a class="header" href="#使用-async-std-作为异步运行时">使用 <code>async-std</code> 作为异步运行时</a></h4>
|
|
|
|
|
|
<p>下面的例子将演示如何使用一个异步运行时 <code>async-std</code> 来让之前的 <code>async fn</code> 函数运行起来，该运行时允许使用属性 <code>#[async_std::main]</code> 将我们的 <code>fn main</code> 函数变成 <code>async fn main</code> ，这样就可以在 <code>main</code> 函数中直接调用其它 <code>async</code> 函数，否则你得用之前章节的 <code>block_on</code> 方法来让 <code>main</code> 去阻塞等待异步函数的完成，但是这种简单粗暴的阻塞等待方式并不灵活。</p>
|
|
|
|
|
|
<p>修改 <code>Cargo.toml</code> 添加 <code>async-std</code> 包并开启相应的属性:</p>
|
|
|
|
|
|
<pre><code class="language-toml">[dependencies]
|
|
|
|
|
|
futures = "0.3"
|
|
|
|
|
|
|
|
|
|
|
|
[dependencies.async-std]
|
|
|
|
|
|
version = "1.6"
|
|
|
|
|
|
features = ["attributes"]
|
|
|
|
|
|
</code></pre>
|
|
|
|
|
|
<p>下面将 <code>main</code> 函数修改为异步的，并在其中调用前面修改的异步版本 <code>handle_connection</code> :</p>
|
|
|
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021">#[async_std::main]
|
|
|
|
|
|
async fn main() {
|
|
|
|
|
|
let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
|
|
|
|
|
|
for stream in listener.incoming() {
|
|
|
|
|
|
let stream = stream.unwrap();
|
|
|
|
|
|
// 警告，这里无法并发
|
|
|
|
|
|
handle_connection(stream).await;
|
|
|
|
|
|
}
|
|
|
|
|
|
}</code></pre></pre>
|
|
|
|
|
|
<p><strong>上面的代码虽然已经是异步的，实际上它还无法并发</strong>，原因我们后面会解释，先来模拟一下慢请求:</p>
|
|
|
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
|
|
|
</span><span class="boring">fn main() {
|
|
|
|
|
|
</span>use std::time::Duration;
|
|
|
|
|
|
use async_std::task;
|
|
|
|
|
|
|
|
|
|
|
|
async 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) {
|
|
|
|
|
|
task::sleep(Duration::from_secs(5)).await;
|
|
|
|
|
|
("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();
|
|
|
|
|
|
}
|
|
|
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
|
|
|
<p>上面是全新实现的 <code>handle_connection</code> ，它会在内部睡眠 5 秒，模拟一次用户慢请求，需要注意的是，我们并没有使用 <code>std::thread::sleep</code> 进行睡眠，原因是该函数是阻塞的，它会让当前线程陷入睡眠中，导致其它任务无法继续运行！因此我们需要一个睡眠函数 <code>async_std::task::sleep</code>，它仅会让当前的任务陷入睡眠，然后该任务会让出线程的控制权，这样线程就可以继续运行其它任务。</p>
|
|
|
|
|
|
<p>因此，光把函数变成 <code>async</code> 往往是不够的，还需要将它内部的代码也都变成异步兼容的，阻塞线程绝对是不可行的。</p>
|
|
|
|
|
|
<p>现在运行服务器，并访问 <code>127.0.0.1:7878/sleep</code>， 你会发现只有在完成第一个用户请求(5 秒后)，才能开始处理第二个用户请求。现在再来看看该如何解决这个问题，让请求并发起来。</p>
|
|
|
|
|
|
<h2 id="并发地处理连接"><a class="header" href="#并发地处理连接">并发地处理连接</a></h2>
|
|
|
|
|
|
<p>上面代码最大的问题是 <code>listener.incoming()</code> 是阻塞的迭代器。当 <code>listener</code> 在等待连接时，执行器是无法执行其它 <code>Future</code> 的，而且只有在我们处理完已有的连接后，才能接收新的连接。</p>
|
|
|
|
|
|
<p>解决方法是将 <code>listener.incoming()</code> 从一个阻塞的迭代器变成一个非阻塞的 <code>Stream</code>， 后者在前面章节有过专门介绍：</p>
|
|
|
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021">use async_std::net::TcpListener;
|
|
|
|
|
|
use async_std::net::TcpStream;
|
|
|
|
|
|
use futures::stream::StreamExt;
|
|
|
|
|
|
|
|
|
|
|
|
#[async_std::main]
|
|
|
|
|
|
async fn main() {
|
|
|
|
|
|
let listener = TcpListener::bind("127.0.0.1:7878").await.unwrap();
|
|
|
|
|
|
listener
|
|
|
|
|
|
.incoming()
|
|
|
|
|
|
.for_each_concurrent(/* limit */ None, |tcpstream| async move {
|
|
|
|
|
|
let tcpstream = tcpstream.unwrap();
|
|
|
|
|
|
handle_connection(tcpstream).await;
|
|
|
|
|
|
})
|
|
|
|
|
|
.await;
|
|
|
|
|
|
}</code></pre></pre>
|
|
|
|
|
|
<p>异步版本的 <code>TcpListener</code> 为 <code>listener.incoming()</code> 实现了 <code>Stream</code> 特征，以上修改有两个好处:</p>
|
|
|
|
|
|
<ul>
|
|
|
|
|
|
<li><code>listener.incoming()</code> 不再阻塞</li>
|
|
|
|
|
|
<li>使用 <code>for_each_concurrent</code> 并发地处理从 <code>Stream</code> 获取的元素</li>
|
|
|
|
|
|
</ul>
|
|
|
|
|
|
<p>现在上面的实现的关键在于 <code>handle_connection</code> 不能再阻塞:</p>
|
|
|
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
|
|
|
</span><span class="boring">fn main() {
|
|
|
|
|
|
</span>use async_std::prelude::*;
|
|
|
|
|
|
|
|
|
|
|
|
async fn handle_connection(mut stream: TcpStream) {
|
|
|
|
|
|
let mut buffer = [0; 1024];
|
|
|
|
|
|
stream.read(&mut buffer).await.unwrap();
|
|
|
|
|
|
|
|
|
|
|
|
//<-- snip -->
|
|
|
|
|
|
stream.write(response.as_bytes()).await.unwrap();
|
|
|
|
|
|
stream.flush().await.unwrap();
|
|
|
|
|
|
}
|
|
|
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
|
|
|
<p>在将数据读写改造成异步后，现在该函数也彻底变成了异步的版本，因此一次慢请求不再会阻止其它请求的运行。</p>
|
|
|
|
|
|
<h2 id="使用多线程并行处理请求"><a class="header" href="#使用多线程并行处理请求">使用多线程并行处理请求</a></h2>
|
|
|
|
|
|
<p>聪明的读者不知道有没有发现，之前的例子有一个致命的缺陷：只能使用一个线程并发的处理用户请求。是的，这样也可以实现并发，一秒处理几千次请求问题不大，但是这毕竟没有利用上 CPU 的多核并行能力，无法实现性能最大化。</p>
|
|
|
|
|
|
<p><code>async</code> 并发和多线程其实并不冲突，而 <code>async-std</code> 包也允许我们使用多个线程去处理，由于 <code>handle_connection</code> 实现了 <code>Send</code> 特征且不会阻塞，因此使用 <code>async_std::task::spawn</code> 是非常安全的:</p>
|
|
|
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021">use async_std::task::spawn;
|
|
|
|
|
|
|
|
|
|
|
|
#[async_std::main]
|
|
|
|
|
|
async fn main() {
|
|
|
|
|
|
let listener = TcpListener::bind("127.0.0.1:7878").await.unwrap();
|
|
|
|
|
|
listener
|
|
|
|
|
|
.incoming()
|
|
|
|
|
|
.for_each_concurrent(/* limit */ None, |stream| async move {
|
|
|
|
|
|
let stream = stream.unwrap();
|
|
|
|
|
|
spawn(handle_connection(stream));
|
|
|
|
|
|
})
|
|
|
|
|
|
.await;
|
|
|
|
|
|
}</code></pre></pre>
|
|
|
|
|
|
<p>至此，我们实现了同时使用并行(多线程)和并发( <code>async</code> )来同时处理多个请求！</p>
|
|
|
|
|
|
<h2 id="测试-handle_connection-函数"><a class="header" href="#测试-handle_connection-函数">测试 <code>handle_connection</code> 函数</a></h2>
|
|
|
|
|
|
<p>对于测试 Web 服务器，使用集成测试往往是最简单的，但是在本例子中，将使用单元测试来测试连接处理函数的正确性。</p>
|
|
|
|
|
|
<p>为了保证单元测试的隔离性和确定性，我们使用 <code>MockTcpStream</code> 来替代 <code>TcpStream</code> 。首先，修改 <code>handle_connection</code> 的函数签名让测试更简单，之所以可以修改签名，原因在于 <code>async_std::net::TcpStream</code> 实际上并不是必须的，只要任何结构体实现了 <code>async_std::io::Read</code>, <code>async_std::io::Write</code> 和 <code>marker::Unpin</code> 就可以替代它：</p>
|
|
|
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
|
|
|
</span><span class="boring">fn main() {
|
|
|
|
|
|
</span>use std::marker::Unpin;
|
|
|
|
|
|
use async_std::io::{Read, Write};
|
|
|
|
|
|
|
|
|
|
|
|
async fn handle_connection(mut stream: impl Read + Write + Unpin) {
|
|
|
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
|
|
|
<p>下面，来构建一个 mock 的 <code>TcpStream</code> 并实现了上面这些特征，它包含一些数据，这些数据将被拷贝到 <code>read</code> 缓存中, 然后返回 <code>Poll::Ready</code> 说明 <code>read</code> 已经结束：</p>
|
|
|
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
|
|
|
</span><span class="boring">fn main() {
|
|
|
|
|
|
</span>use super::*;
|
|
|
|
|
|
use futures::io::Error;
|
|
|
|
|
|
use futures::task::{Context, Poll};
|
|
|
|
|
|
|
|
|
|
|
|
use std::cmp::min;
|
|
|
|
|
|
use std::pin::Pin;
|
|
|
|
|
|
|
|
|
|
|
|
struct MockTcpStream {
|
|
|
|
|
|
read_data: Vec<u8>,
|
|
|
|
|
|
write_data: Vec<u8>,
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
impl Read for MockTcpStream {
|
|
|
|
|
|
fn poll_read(
|
|
|
|
|
|
self: Pin<&mut Self>,
|
|
|
|
|
|
_: &mut Context,
|
|
|
|
|
|
buf: &mut [u8],
|
|
|
|
|
|
) -> Poll<Result<usize, Error>> {
|
|
|
|
|
|
let size: usize = min(self.read_data.len(), buf.len());
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buf[..size].copy_from_slice(&self.read_data[..size]);
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Poll::Ready(Ok(size))
|
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}
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}
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<span class="boring">}</span></code></pre></pre>
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<p><code>Write</code>的实现也类似，需要实现三个方法 : <code>poll_write</code>, <code>poll_flush</code>, 与 <code>poll_close</code>。 <code>poll_write</code> 会拷贝输入数据到 mock 的 <code>TcpStream</code> 中，当完成后返回 <code>Poll::Ready</code>。由于 <code>TcpStream</code> 无需 <code>flush</code> 和 <code>close</code>，因此另两个方法直接返回 <code>Poll::Ready</code> 即可。</p>
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<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
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</span><span class="boring">fn main() {
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</span>impl Write for MockTcpStream {
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fn poll_write(
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mut self: Pin<&mut Self>,
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_: &mut Context,
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|
buf: &[u8],
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|
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|
) -> Poll<Result<usize, Error>> {
|
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|
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|
|
self.write_data = Vec::from(buf);
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Poll::Ready(Ok(buf.len()))
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|
}
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fn poll_flush(self: Pin<&mut Self>, _: &mut Context) -> Poll<Result<(), Error>> {
|
|
|
|
|
|
Poll::Ready(Ok(()))
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|
|
|
|
|
}
|
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|
|
fn poll_close(self: Pin<&mut Self>, _: &mut Context) -> Poll<Result<(), Error>> {
|
|
|
|
|
|
Poll::Ready(Ok(()))
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|
|
|
|
|
}
|
|
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|
|
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}
|
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|
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<span class="boring">}</span></code></pre></pre>
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|
<p>最后，我们的 mock 需要实现 <code>Unpin</code> 特征，表示它可以在内存中安全的移动，具体内容在<a href="https://course.rs/advance/async/pin-unpin.html">前面章节</a>有讲。</p>
|
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|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
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|
|
|
</span><span class="boring">fn main() {
|
|
|
|
|
|
</span>use std::marker::Unpin;
|
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|
|
impl Unpin for MockTcpStream {}
|
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|
|
|
|
<span class="boring">}</span></code></pre></pre>
|
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|
<p>现在可以准备开始测试了，在使用初始化数据设置好 <code>MockTcpStream</code> 后，我们可以使用 <code>#[async_std::test]</code> 来运行 <code>handle_connection</code> 函数，该函数跟 <code>#[async_std::main]</code> 的作用类似。为了确保 <code>handle_connection</code> 函数正确工作，需要根据初始化数据检查正确的数据被写入到 <code>MockTcpStream</code> 中。</p>
|
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|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
|
|
|
</span><span class="boring">fn main() {
|
|
|
|
|
|
</span>use std::fs;
|
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|
|
|
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|
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|
|
#[async_std::test]
|
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|
|
|
async fn test_handle_connection() {
|
|
|
|
|
|
let input_bytes = b"GET / HTTP/1.1\r\n";
|
|
|
|
|
|
let mut contents = vec![0u8; 1024];
|
|
|
|
|
|
contents[..input_bytes.len()].clone_from_slice(input_bytes);
|
|
|
|
|
|
let mut stream = MockTcpStream {
|
|
|
|
|
|
read_data: contents,
|
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|
|
|
|
write_data: Vec::new(),
|
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|
|
|
|
};
|
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|
|
|
|
|
|
|
|
|
|
handle_connection(&mut stream).await;
|
|
|
|
|
|
let mut buf = [0u8; 1024];
|
|
|
|
|
|
stream.read(&mut buf).await.unwrap();
|
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|
|
|
|
|
|
|
|
|
let expected_contents = fs::read_to_string("hello.html").unwrap();
|
|
|
|
|
|
let expected_response = format!("HTTP/1.1 200 OK\r\n\r\n{}", expected_contents);
|
|
|
|
|
|
assert!(stream.write_data.starts_with(expected_response.as_bytes()));
|
|
|
|
|
|
}
|
|
|
|
|
|
<span class="boring">}</span></code></pre></pre>
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