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base64-encoding
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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Go by Example: Base64 Encoding</title>
<link rel=stylesheet href="site.css">
</head>
<script>
onkeydown = (e) => {
if (e.key == "ArrowLeft") {
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<body>
<div class="example" id="base64-encoding">
<h2><a href="./">Go by Example</a>: Base64 Encoding</h2>
<table>
<tr>
<td class="docs">
<p>Go provides built-in support for <a href="http://en.wikipedia.org/wiki/Base64">base64
encoding/decoding</a>.</p>
</td>
<td class="code empty leading">
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<a href="http://play.golang.org/p/S7ff3UgzNlG"><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">
<p>This syntax imports the <code>encoding/base64</code> package with
the <code>b64</code> name instead of the default <code>base64</code>. It’ll
save us some space below.</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="kn">import</span> <span class="p">(</span>
<span class="nx">b64</span> <span class="s">"encoding/base64"</span>
<span class="s">"fmt"</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>Here’s the <code>string</code> we’ll encode/decode.</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">data</span> <span class="o">:=</span> <span class="s">"abc123!?$*&()'-=@~"</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>Go supports both standard and URL-compatible
base64. Here’s how to encode using the standard
encoder. The encoder requires a <code>[]byte</code> so we
convert our <code>string</code> to that type.</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">sEnc</span> <span class="o">:=</span> <span class="nx">b64</span><span class="p">.</span><span class="nx">StdEncoding</span><span class="p">.</span><span class="nf">EncodeToString</span><span class="p">([]</span><span class="nb">byte</span><span class="p">(</span><span class="nx">data</span><span class="p">))</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">sEnc</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>Decoding may return an error, which you can check
if you don’t already know the input to be
well-formed.</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">sDec</span><span class="p">,</span> <span class="nx">_</span> <span class="o">:=</span> <span class="nx">b64</span><span class="p">.</span><span class="nx">StdEncoding</span><span class="p">.</span><span class="nf">DecodeString</span><span class="p">(</span><span class="nx">sEnc</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nb">string</span><span class="p">(</span><span class="nx">sDec</span><span class="p">))</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">()</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>This encodes/decodes using a URL-compatible base64
format.</p>
</td>
<td class="code">
<pre class="chroma">
<span class="nx">uEnc</span> <span class="o">:=</span> <span class="nx">b64</span><span class="p">.</span><span class="nx">URLEncoding</span><span class="p">.</span><span class="nf">EncodeToString</span><span class="p">([]</span><span class="nb">byte</span><span class="p">(</span><span class="nx">data</span><span class="p">))</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">uEnc</span><span class="p">)</span>
<span class="nx">uDec</span><span class="p">,</span> <span class="nx">_</span> <span class="o">:=</span> <span class="nx">b64</span><span class="p">.</span><span class="nx">URLEncoding</span><span class="p">.</span><span class="nf">DecodeString</span><span class="p">(</span><span class="nx">uEnc</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nb">string</span><span class="p">(</span><span class="nx">uDec</span><span class="p">))</span>
<span class="p">}</span>
</pre>
</td>
</tr>
</table>
<table>
<tr>
<td class="docs">
<p>The string encodes to slightly different values with the
standard and URL base64 encoders (trailing <code>+</code> vs <code>-</code>)
but they both decode to the original string as desired.</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="gp">$</span> go run base64-encoding.go
<span class="go">YWJjMTIzIT8kKiYoKSctPUB+
</span><span class="go">abc123!?$*&()'-=@~</span></pre>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code">
<pre class="chroma"><span class="go">YWJjMTIzIT8kKiYoKSctPUB-
</span><span class="go">abc123!?$*&()'-=@~</span></pre>
</td>
</tr>
</table>
<p class="next">
Next example: <a href="reading-files">Reading Files</a>.
</p>
<p class="footer">
by <a href="https://markmcgranaghan.com">Mark McGranaghan</a> and <a href="https://eli.thegreenplace.net">Eli Bendersky</a> | <a href="https://github.com/mmcgrana/gobyexample">source</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a>
</p>
</div>
<script>
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