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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Go by Example 中文版: HTTP 服务端</title>
<link rel=stylesheet href="site.css">
</head>
<script>
onkeydown = (e) => {
if (e.key == "ArrowLeft") {
window.location.href = 'http-clients';
}
if (e.key == "ArrowRight") {
window.location.href = 'context';
}
}
</script>
<body>
<div class="example" id="http-servers">
<h2><a href="./">Go by Example 中文版</a>: HTTP 服务端</h2>
<table>
<tr>
<td class="docs">
<p>使用 <code>net/http</code> 包，我们可以轻松实现一个简单的 HTTP 服务器。</p>
</td>
<td class="code empty leading">
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<a href="https://play.studygolang.com/p/LUFfvmYCzXD"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
<pre class="chroma"><span class="kn">package</span> <span class="nx">main</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"><span class="kn">import</span> <span class="p">(</span>
<span class="s">"fmt"</span>
<span class="s">"net/http"</span>
<span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p><em>handlers</em> 是 <code>net/http</code> 服务器里面的一个基本概念。
handler 对象实现了 <code>http.Handler</code> 接口。
编写 handler 的常见方法是，在具有适当签名的函数上使用 <code>http.HandlerFunc</code> 适配器。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="kd">func</span> <span class="nf">hello</span><span class="p">(</span><span class="nx">w</span> <span class="nx">http</span><span class="p">.</span><span class="nx">ResponseWriter</span><span class="p">,</span> <span class="nx">req</span> <span class="o">*</span><span class="nx">http</span><span class="p">.</span><span class="nx">Request</span><span class="p">)</span> <span class="p">{</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>handler 函数有两个参数，<code>http.ResponseWriter</code> 和 <code>http.Request</code>。
response writer 被用于写入 HTTP 响应数据，这里我们简单的返回 “hello\n”。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Fprintf</span><span class="p">(</span><span class="nx">w</span><span class="p">,</span> <span class="s">"hello\n"</span><span class="p">)</span>
<span class="p">}</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"><span class="kd">func</span> <span class="nf">headers</span><span class="p">(</span><span class="nx">w</span> <span class="nx">http</span><span class="p">.</span><span class="nx">ResponseWriter</span><span class="p">,</span> <span class="nx">req</span> <span class="o">*</span><span class="nx">http</span><span class="p">.</span><span class="nx">Request</span><span class="p">)</span> <span class="p">{</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>这个 handler 稍微复杂一点，
我们需要读取的 HTTP 请求 header 中的所有内容，并将他们输出至 response body。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="k">for</span> <span class="nx">name</span><span class="p">,</span> <span class="nx">headers</span> <span class="o">:=</span> <span class="k">range</span> <span class="nx">req</span><span class="p">.</span><span class="nx">Header</span> <span class="p">{</span>
<span class="k">for</span> <span class="nx">_</span><span class="p">,</span> <span class="nx">h</span> <span class="o">:=</span> <span class="k">range</span> <span class="nx">headers</span> <span class="p">{</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Fprintf</span><span class="p">(</span><span class="nx">w</span><span class="p">,</span> <span class="s">"%v: %v\n"</span><span class="p">,</span> <span class="nx">name</span><span class="p">,</span> <span class="nx">h</span><span class="p">)</span>
<span class="p">}</span>
<span class="p">}</span>
<span class="p">}</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"><span class="kd">func</span> <span class="nf">main</span><span class="p">()</span> <span class="p">{</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>使用 <code>http.HandleFunc</code> 函数，可以方便的将我们的 handler 注册到服务器路由。
它是 <code>net/http</code> 包中的默认路由，接受一个函数作为参数。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">http</span><span class="p">.</span><span class="nf">HandleFunc</span><span class="p">(</span><span class="s">"/hello"</span><span class="p">,</span> <span class="nx">hello</span><span class="p">)</span>
<span class="nx">http</span><span class="p">.</span><span class="nf">HandleFunc</span><span class="p">(</span><span class="s">"/headers"</span><span class="p">,</span> <span class="nx">headers</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>最后，我们调用 <code>ListenAndServe</code> 并带上端口和 handler。
nil 表示使用我们刚刚设置的默认路由器。</p>
</td>
<td class="code">
<pre class="chroma">
<span class="nx">http</span><span class="p">.</span><span class="nf">ListenAndServe</span><span class="p">(</span><span class="s">":8090"</span><span class="p">,</span> <span class="kc">nil</span><span class="p">)</span>
<span class="p">}</span>
</pre>
</td>
</tr>
</table>
<table>
<tr>
<td class="docs">
<p>后台运行服务器。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="gp">$</span> go run http-servers.go &</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>访问 <code>/hello</code> 路由。</p>
</td>
<td class="code">
<pre class="chroma">
<span class="gp">$</span> curl localhost:8090/hello
<span class="go">hello</span></pre>
</td>
</tr>
</table>
<p class="next">
下一个例子: <a href="context.html">Context</a>
</p>
<p class="footer">
<a href="https://twitter.com/mmcgrana">@mmcgrana</a> 和<a href="https://eli.thegreenplace.net">Eli Bendersky</a>编写 | <a href="https://github.com/gobyexample-cn">gobyexample-cn</a> 翻译 | <a href="https://github.com/gobyexample-cn/gobyexample/issues">反馈</a> | <a href="https://github.com/gobyexample-cn/gobyexample">源码</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a> </p>
</p>
</div>
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</body>
</html>