gobyexample/public/base64-encoding
Oleg Butuzov 646c8b39da bugfix (mmcgrana/gobyexample#294) sha1 sum calculator
This bugfix implements correct way to calculate source sha1 hash, before it will changed,
by propagation of unchanged sources.

This commit will also include regenerated static files and *.hash files.
2019-10-22 14:27:02 +03:00

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7.9 KiB
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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/S7ff3UgzNlG"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
<div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
</pre></div>
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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="p">(</span>
<span class="nx">b64</span> <span class="s">&quot;encoding/base64&quot;</span>
<span class="s">&quot;fmt&quot;</span>
<span class="p">)</span>
</pre></div>
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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>
</pre></div>
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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
convert 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>
</pre></div>
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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>
</pre></div>
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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>
</pre></div>
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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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<td class="code leading">
<div class="highlight"><pre><span class="gp">$</span> go run base64-encoding.go
<span class="go">YWJjMTIzIT8kKiYoKSctPUB+</span>
<span class="go">abc123!?$*&amp;()&#39;-=@~</span>
</pre></div>
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<div class="highlight"><pre><span class="go">YWJjMTIzIT8kKiYoKSctPUB-</span>
<span class="go">abc123!?$*&amp;()&#39;-=@~</span>
</pre></div>
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<p class="next">
Next example: <a href="reading-files">Reading Files</a>.
</p>
<p class="footer">
by <a href="https://markmcgranaghan.com">Mark McGranaghan</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>
</p>
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