9e216da9ef
After go1.16, go will use module mode by default, even when the repository is checked out under GOPATH or in a one-off directory. Add go.mod, go.sum to keep this repo buildable without opting out of the module mode. > go mod init github.com/mmcgrana/gobyexample > go mod tidy > go mod vendor In module mode, the 'vendor' directory is special and its contents will be actively maintained by the go command. pygments aren't the dependency the go will know about, so it will delete the contents from vendor directory. Move it to `third_party` directory now. And, vendor the blackfriday package. Note: the tutorial contents are not affected by the change in go1.16 because all the examples in this tutorial ask users to run the go command with the explicit list of files to be compiled (e.g. `go run hello-world.go` or `go build command-line-arguments.go`). When the source list is provided, the go command does not have to compute the build list and whether it's running in GOPATH mode or module mode becomes irrelevant.
218 lines
8.7 KiB
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218 lines
8.7 KiB
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<!DOCTYPE html>
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<html>
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<head>
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<meta charset="utf-8">
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<title>Go by Example: HTTP Servers</title>
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<link rel=stylesheet href="site.css">
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</head>
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<script>
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onkeydown = (e) => {
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if (e.key == "ArrowLeft") {
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window.location.href = 'http-clients';
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}
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if (e.key == "ArrowRight") {
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window.location.href = 'context';
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}
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}
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</script>
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<body>
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<div class="example" id="http-servers">
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<h2><a href="./">Go by Example</a>: HTTP Servers</h2>
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<table>
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<tr>
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<td class="docs">
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<p>Writing a basic HTTP server is easy using the
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<code>net/http</code> package.</p>
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</td>
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<td class="code leading">
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<a href="http://play.golang.org/p/s3xMMt9Ytry"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
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<div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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</td>
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<td class="code leading">
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<div class="highlight"><pre><span class="kn">import</span> <span class="p">(</span>
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<span class="s">"fmt"</span>
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<span class="s">"net/http"</span>
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<span class="p">)</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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<p>A fundamental concept in <code>net/http</code> servers is
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<em>handlers</em>. A handler is an object implementing the
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<code>http.Handler</code> interface. A common way to write
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a handler is by using the <code>http.HandlerFunc</code> adapter
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on functions with the appropriate signature.</p>
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</td>
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<td class="code leading">
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<div class="highlight"><pre><span class="kd">func</span> <span class="nx">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>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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<p>Functions serving as handlers take a
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<code>http.ResponseWriter</code> and a <code>http.Request</code> as
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arguments. The response writer is used to fill in the
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HTTP response. Here our simple response is just
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“hello\n”.</p>
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</td>
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<td class="code leading">
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<div class="highlight"><pre> <span class="nx">fmt</span><span class="p">.</span><span class="nx">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>
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<span class="p">}</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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</td>
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<td class="code leading">
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<div class="highlight"><pre><span class="kd">func</span> <span class="nx">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>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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<p>This handler does something a little more
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sophisticated by reading all the HTTP request
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headers and echoing them into the response body.</p>
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</td>
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<td class="code leading">
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<div class="highlight"><pre> <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>
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<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>
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<span class="nx">fmt</span><span class="p">.</span><span class="nx">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>
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<span class="p">}</span>
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<span class="p">}</span>
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<span class="p">}</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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</td>
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<td class="code leading">
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<div class="highlight"><pre><span class="kd">func</span> <span class="nx">main</span><span class="p">()</span> <span class="p">{</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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<p>We register our handlers on server routes using the
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<code>http.HandleFunc</code> convenience function. It sets up
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the <em>default router</em> in the <code>net/http</code> package and
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takes a function as an argument.</p>
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</td>
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<td class="code leading">
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<div class="highlight"><pre> <span class="nx">http</span><span class="p">.</span><span class="nx">HandleFunc</span><span class="p">(</span><span class="s">"/hello"</span><span class="p">,</span> <span class="nx">hello</span><span class="p">)</span>
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<span class="nx">http</span><span class="p">.</span><span class="nx">HandleFunc</span><span class="p">(</span><span class="s">"/headers"</span><span class="p">,</span> <span class="nx">headers</span><span class="p">)</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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<p>Finally, we call the <code>ListenAndServe</code> with the port
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and a handler. <code>nil</code> tells it to use the default
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router we’ve just set up.</p>
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</td>
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<td class="code">
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<div class="highlight"><pre> <span class="nx">http</span><span class="p">.</span><span class="nx">ListenAndServe</span><span class="p">(</span><span class="s">":8090"</span><span class="p">,</span> <span class="kc">nil</span><span class="p">)</span>
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<span class="p">}</span>
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</pre></div>
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</td>
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</tr>
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</table>
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<table>
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<tr>
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<td class="docs">
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<p>Run the server in the background.</p>
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</td>
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<td class="code leading">
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<div class="highlight"><pre><span class="gp">$</span> go run http-servers.go <span class="p">&</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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<p>Access the <code>/hello</code> route.</p>
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</td>
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<td class="code">
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<div class="highlight"><pre><span class="gp">$</span> curl localhost:8090/hello
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<span class="go">hello</span>
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</pre></div>
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</td>
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</tr>
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</table>
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<p class="next">
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Next example: <a href="context">Context</a>.
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</p>
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<p class="footer">
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by <a href="https://markmcgranaghan.com">Mark McGranaghan</a> | <a href="https://github.com/mmcgrana/gobyexample/blob/master/examples/http-servers">source</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a>
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</p>
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</div>
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<script>
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var codeLines = [];
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codeLines.push('package main\u000A');codeLines.push('import (\u000A \"fmt\"\u000A \"net/http\"\u000A)\u000A');codeLines.push('func hello(w http.ResponseWriter, req *http.Request) {\u000A');codeLines.push(' fmt.Fprintf(w, \"hello\\n\")\u000A}\u000A');codeLines.push('func headers(w http.ResponseWriter, req *http.Request) {\u000A');codeLines.push(' for name, headers :\u003D range req.Header {\u000A for _, h :\u003D range headers {\u000A fmt.Fprintf(w, \"%v: %v\\n\", name, h)\u000A }\u000A }\u000A}\u000A');codeLines.push('func main() {\u000A');codeLines.push(' http.HandleFunc(\"/hello\", hello)\u000A http.HandleFunc(\"/headers\", headers)\u000A');codeLines.push(' http.ListenAndServe(\":8090\", nil)\u000A}\u000A');codeLines.push('');codeLines.push('');
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</script>
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<script src="site.js" async></script>
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</body>
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</html>
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