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<title>Go by Example: Base64 Encoding</title>
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<div class="example" id="base64-encoding">
<h2><a href="./">Go by Example</a>: Base64 Encoding</h2>
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<p>Go provides built-in support for <a href="http://en.wikipedia.org/wiki/Base64">base64
encoding/decoding</a>.</p>
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<a href="http://play.golang.org/p/t6rFm2x4Yr"><img title="Run code" src="play.png" class="run" /></a>
<div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
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<p>This syntax imports the <code>encoding/base64</code> package with
the <code>b64</code> name instead of the default <code>base64</code>. It&rsquo;ll
save us some space below.</p>
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<div class="highlight"><pre><span class="kn">import</span> <span class="nx">b64</span> <span class="s">&quot;encoding/base64&quot;</span>
<span class="kn">import</span> <span class="s">&quot;fmt&quot;</span>
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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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<p>Here&rsquo;s the <code>string</code> we&rsquo;ll encode/decode.</p>
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<div class="highlight"><pre> <span class="nx">data</span> <span class="o">:=</span> <span class="s">&quot;abc123!?$*&amp;()&#39;-=@~&quot;</span>
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<p>Go supports both standard and URL-compatible
base64. Here&rsquo;s how to encode using the standard
encoder. The encoder requires a <code>[]byte</code> so we
cast our <code>string</code> to that type.</p>
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<div class="highlight"><pre> <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="nx">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="nx">Println</span><span class="p">(</span><span class="nx">sEnc</span><span class="p">)</span>
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<p>Decoding may return an error, which you can check
if you don&rsquo;t already know the input to be
well-formed.</p>
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<div class="highlight"><pre> <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="nx">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="nx">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="nx">Println</span><span class="p">()</span>
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<p>This encodes/decodes using a URL-compatible base64
format.</p>
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<div class="highlight"><pre> <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="nx">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="nx">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="nx">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="nx">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>
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<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>
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<div class="highlight"><pre><span class="gp">$</span> go run base64-encoding.go
<span class="go">YWJjMTIzIT8kKiYoKSctPUB+</span>
<span class="go">abc123!?$*&amp;()&#39;-=@~</span>
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<div class="highlight"><pre><span class="go">YWJjMTIzIT8kKiYoKSctPUB-</span>
<span class="go">abc123!?$*&amp;()&#39;-=@~</span>
</pre></div>
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<p class="next">
Next example: <a href="reading-files">Reading Files</a>.
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<p class="footer">
by <a href="https://twitter.com/mmcgrana">@mmcgrana</a> | <a href="mailto:mmcgrana@gmail.com">feedback</a> | <a href="https://github.com/mmcgrana/gobyexample/blob/master/examples/base64-encoding">source</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a>
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