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        <title>Structured Commons :: SCEP0105 - Standard <span class="caps">JSON</span> representation&nbsp;method </title>
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    <!--<h1>SCEP0105 – SCEP0105 - Standard <span class="caps">JSON</span> representation&nbsp;method</h1>-->

    <table class="docinfo"><col class="docinfo-name" /><col class="docinfo-content" />
    <tbody valign="top">
    <tr class="field"><th class="docinfo-name">SCEP:</th><td class="field-body">105</td></tr>
    <tr class="field"><th class="docinfo-name">Title:</th><td class="field-body">Standard <span class="caps">JSON</span> representation&nbsp;method</td></tr>
    <tr class="field"><th class="docinfo-name">Version:</th><td class="field-body">d761e41df9005076ab9540ce64fc614b0c15bb2d</td></tr>
    <tr class="field"><th class="docinfo-name">Last modified:</th><td class="field-body">2014-06-20 00:43:41 UTC (Fri, 20 June 2014)</td></tr>
    <tr class="field"><th class="docinfo-name">Author:</th><td class="field-body">Raphael ‘kena’ Poss</td></tr>
    <tr class="field"><th class="docinfo-name">Status:</th><td class="field-body">Draft</td></tr>
    <tr class="field"><th class="docinfo-name">Type:</th><td class="field-body">Standards Track</td></tr>
    <tr class="field"><th class="docinfo-name">Created:</th><td class="field-body">2014-06-20</td></tr>
    <tr class="field"><th class="docinfo-name">Source:</th><td class="field-body"><a href="scep0105.rst">scep0105.rst</a> (<tt>fp:XGG0y0ufgpBGRxzHbY76hYuc8ysaVo5CF7YZv5RA73COLw</tt>)</td></tr>
    </tbody></table>

    <p>The Structured Commons object model is defined semantically in <span class="caps">SCEP</span>
101 <a class="footnote-reference" href="#scep-101" id="id1">[1]</a>, independently from its particular representation in a
computer system. Conversely, there may exist multiple valid
representations for an&nbsp;object.</p>
<p>This <span class="caps">SCEP</span> defines the canonical representation of Structured
Commons objects as a <span class="caps">JSON</span> object, with method name &quot;<strong>json</strong>&quot;.</p>
<div class="section" id="overview">
<h2>Overview</h2>
<p>The <tt class="docutils literal">json</tt> representation maps objects to a <span class="caps">JSON</span> object <a class="footnote-reference" href="#json" id="id2">[2]</a>.</p>
<p>Object files are represented by <span class="caps">JSON</span> character&nbsp;strings.</p>
<p>Object dictionaries are represented by <span class="caps">JSON</span> associative&nbsp;arrays.</p>
<p>Dictionary names that map to objects are represented by
associative array entries that are the <span class="caps">JSON</span> representation
of the enclosed&nbsp;object.</p>
<p>Dictionary names that map to fingerprints are represented by a <span class="caps">JSON</span>
list containing one string entry containing the compact representation
of the&nbsp;fingerprint.</p>
</div>
<div class="section" id="example">
<h2>Example</h2>
<p>For example, the following Structured Commons&nbsp;object:</p>
<pre class="literal-block">
(root)
  |
  +-- hello.txt (file)
  |   hello, world!
  |
  +-- link (fingerprint reference)
      (fp:0cYMtlAA_T4_vG2NBmtEeB7uh26b1tpzb-0qiDGHxGrIMw)
</pre>
<p>can be represented by the following <span class="caps">JSON</span>&nbsp;text:</p>
<pre class="code json literal-block">
<span class="p">{</span>
 <span class="nt">&quot;hello.txt&quot;</span> <span class="p">:</span> <span class="s2">&quot;hello, world!&quot;</span>
 <span class="s2">&quot;link&quot;</span> <span class="p">:</span> <span class="p">[</span><span class="s2">&quot;fp:0cYMtlAA_T4_vG2NBmtEeB7uh26b1tpzb-0qiDGHxGrIMw&quot;</span><span class="p">]</span>
<span class="p">}</span>
</pre>
</div>
<div class="section" id="alternate-representation">
<h2>Alternate&nbsp;representation</h2>
<p>When an object file contains many occurrences of byte codes outside of the
printable range, the &quot;direct&quot; <span class="caps">JSON</span> representation using Unicode escape sequences (&quot;<tt class="docutils literal">\uXXXX</tt>&quot;)
can incur a large space overhead, up to 500% of the length of the original byte&nbsp;string.</p>
<p>For applications where binary data is common, this specification provides an
<em>alternate</em>, mutually compatible encoding for file objects: a
<span class="caps">JSON</span> list containing one string containing the Base64 encoding
of the object (using the special <span class="caps">URL</span> safe alphabet defined in <a class="footnote-reference" href="#base" id="id3">[3]</a>).</p>
<p>With this alternate representation, the example above can be encoded
as&nbsp;follows:</p>
<pre class="code json literal-block">
<span class="p">{</span>
 <span class="nt">&quot;hello.txt&quot;</span> <span class="p">:</span> <span class="p">[</span><span class="s2">&quot;aGVsbG8sIHdvcmxkIQ==&quot;</span><span class="p">],</span>
 <span class="nt">&quot;link&quot;</span> <span class="p">:</span> <span class="p">[</span><span class="s2">&quot;fp:0cYMtlAA_T4_vG2NBmtEeB7uh26b1tpzb-0qiDGHxGrIMw&quot;</span><span class="p">]</span>
<span class="p">}</span>
</pre>
<p>The alternate encoding is not ambiguous with fingerprint references,
since the Base64 encoding of a file object can never start with the
three characters &quot;<tt class="docutils literal">fp:</tt>&quot;.</p>
</div>
<div class="section" id="example-reference-implementation">
<h2>Example/reference&nbsp;implementation</h2>
<p>Example code in Python is provided&nbsp;separately:</p>
<p><a class="reference external" href="https://github.com/structured-commons/tools">https://github.com/structured-commons/tools</a></p>
</div>
<div class="section" id="references">
<h2>References</h2>
<table class="docutils footnote" frame="void" id="scep-101" rules="none">
<colgroup><col class="label" /><col /></colgroup>
<tbody valign="top">
<tr><td class="label"><a class="fn-backref" href="#id1">[1]</a></td><td><span class="caps">SCEP</span> 101. &quot;Structured Commons Object Model and Fingerprints&quot;.
(<a class="reference external" href="http://www.structured-commons.org/scep0101.html">http://www.structured-commons.org/scep0101.html</a>)</td></tr>
</tbody>
</table>
<table class="docutils footnote" frame="void" id="json" rules="none">
<colgroup><col class="label" /><col /></colgroup>
<tbody valign="top">
<tr><td class="label"><a class="fn-backref" href="#id2">[2]</a></td><td><span class="caps">RFC</span> 7159. &quot;The JavaScript Object Notation (<span class="caps">JSON</span>) Data Interchange Format&quot;.
(<a class="reference external" href="https://tools.ietf.org/html/rfc7159">https://tools.ietf.org/html/rfc7159</a>)</td></tr>
</tbody>
</table>
<table class="docutils footnote" frame="void" id="base" rules="none">
<colgroup><col class="label" /><col /></colgroup>
<tbody valign="top">
<tr><td class="label"><a class="fn-backref" href="#id3">[3]</a></td><td><span class="caps">RFC</span> 4648. &quot;The Base16, Base32, and Base64 Data Encodings&quot;.
(<a class="reference external" href="https://tools.ietf.org/html/rfc4648">https://tools.ietf.org/html/rfc4648</a>)</td></tr>
</tbody>
</table>
</div>
<div class="section" id="copyright">
<h2>Copyright</h2>
<p>This document has been placed in the public&nbsp;domain.</p>
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