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<h1 class="refname">json_decode</h1>
<p class="verinfo">(PHP 5 >= 5.2.0, PECL json >= 1.2.0)</p><p class="refpurpose"><span class="refname">json_decode</span> — <span class="dc-title">Decodes a JSON string</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.json-decode-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <span class="methodname"><strong>json_decode</strong></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$json</code></span>
[, <span class="methodparam"><span class="type">bool</span> <code class="parameter">$assoc</code><span class="initializer"> = false</span></span>
[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$depth</code><span class="initializer"> = 512</span></span>
[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$options</code><span class="initializer"> = 0</span></span>
]]] )</div>
<p class="para rdfs-comment">
Takes a JSON encoded string and converts it into a PHP variable.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.json-decode-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">json</code></em></span>
<dd>
<p class="para">
The <em><code class="parameter">json</code></em> <span class="type"><a href="language.types.string.html" class="type string">string</a></span> being decoded.
</p>
<p class="para">
This function only works with UTF-8 encoded strings.
</p>
<blockquote class="note"><p><strong class="note">Note</strong>: <p class="para">PHP implements a superset of
JSON - it will also encode and decode scalar types and <strong><code>NULL</code></strong>. The JSON standard
only supports these values when they are nested inside an array or an object.
</p></p></blockquote>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">assoc</code></em></span>
<dd>
<p class="para">
When <strong><code>TRUE</code></strong>, returned <span class="type"><a href="language.types.object.html" class="type object">object</a></span>s will be converted into
associative <span class="type"><a href="language.types.array.html" class="type array">array</a></span>s.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">depth</code></em></span>
<dd>
<p class="para">
User specified recursion depth.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">options</code></em></span>
<dd>
<p class="para">
Bitmask of JSON decode options. Currently only
<strong><code>JSON_BIGINT_AS_STRING</code></strong>
is supported (default is to cast large integers as floats)
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.json-decode-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns the value encoded in <em><code class="parameter">json</code></em> in appropriate
PHP type. Values <em>true</em>, <em>false</em> and
<em>null</em> (case-insensitive) are returned as <strong><code>TRUE</code></strong>, <strong><code>FALSE</code></strong>
and <strong><code>NULL</code></strong> respectively. <strong><code>NULL</code></strong> is returned if the
<em><code class="parameter">json</code></em> cannot be decoded or if the encoded
data is deeper than the recursion limit.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.json-decode-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-3755">
<p><strong>Example #1 <span class="function"><strong>json_decode()</strong></span> examples</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$json </span><span style="color: #007700">= </span><span style="color: #DD0000">'{"a":1,"b":2,"c":3,"d":4,"e":5}'</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">json_decode</span><span style="color: #007700">(</span><span style="color: #0000BB">$json</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">json_decode</span><span style="color: #007700">(</span><span style="color: #0000BB">$json</span><span style="color: #007700">, </span><span style="color: #0000BB">true</span><span style="color: #007700">));<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
object(stdClass)#1 (5) {
["a"] => int(1)
["b"] => int(2)
["c"] => int(3)
["d"] => int(4)
["e"] => int(5)
}
array(5) {
["a"] => int(1)
["b"] => int(2)
["c"] => int(3)
["d"] => int(4)
["e"] => int(5)
}
</pre></div>
</div>
</div>
<div class="example" id="example-3756">
<p><strong>Example #2 Accessing invalid object properties</strong></p>
<div class="example-contents"><p>
Accessing elements within an object that contain characters not
permitted under PHP's naming convention (e.g. the hyphen) can be
accomplished by encapsulating the element name within braces and the apostrophe.
</p></div>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />$json </span><span style="color: #007700">= </span><span style="color: #DD0000">'{"foo-bar": 12345}'</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$obj </span><span style="color: #007700">= </span><span style="color: #0000BB">json_decode</span><span style="color: #007700">(</span><span style="color: #0000BB">$json</span><span style="color: #007700">);<br />print </span><span style="color: #0000BB">$obj</span><span style="color: #007700">->{</span><span style="color: #DD0000">'foo-bar'</span><span style="color: #007700">}; </span><span style="color: #FF8000">// 12345<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
<div class="example" id="example-3757">
<p><strong>Example #3 common mistakes using <span class="function"><strong>json_decode()</strong></span></strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br /></span><span style="color: #FF8000">// the following strings are valid JavaScript but not valid JSON<br /><br />// the name and value must be enclosed in double quotes<br />// single quotes are not valid <br /></span><span style="color: #0000BB">$bad_json </span><span style="color: #007700">= </span><span style="color: #DD0000">"{ 'bar': 'baz' }"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">json_decode</span><span style="color: #007700">(</span><span style="color: #0000BB">$bad_json</span><span style="color: #007700">); </span><span style="color: #FF8000">// null<br /><br />// the name must be enclosed in double quotes<br /></span><span style="color: #0000BB">$bad_json </span><span style="color: #007700">= </span><span style="color: #DD0000">'{ bar: "baz" }'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">json_decode</span><span style="color: #007700">(</span><span style="color: #0000BB">$bad_json</span><span style="color: #007700">); </span><span style="color: #FF8000">// null<br /><br />// trailing commas are not allowed<br /></span><span style="color: #0000BB">$bad_json </span><span style="color: #007700">= </span><span style="color: #DD0000">'{ bar: "baz", }'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">json_decode</span><span style="color: #007700">(</span><span style="color: #0000BB">$bad_json</span><span style="color: #007700">); </span><span style="color: #FF8000">// null<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
<div class="example" id="example-3758">
<p><strong>Example #4 <em><code class="parameter">depth</code></em> errors</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// Encode the data.<br /></span><span style="color: #0000BB">$json </span><span style="color: #007700">= </span><span style="color: #0000BB">json_encode</span><span style="color: #007700">(<br /> array(<br /> </span><span style="color: #0000BB">1 </span><span style="color: #007700">=> array(<br /> </span><span style="color: #DD0000">'English' </span><span style="color: #007700">=> array(<br /> </span><span style="color: #DD0000">'One'</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">'January'<br /> </span><span style="color: #007700">),<br /> </span><span style="color: #DD0000">'French' </span><span style="color: #007700">=> array(<br /> </span><span style="color: #DD0000">'Une'</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">'Janvier'<br /> </span><span style="color: #007700">)<br /> )<br /> )<br />);<br /><br /></span><span style="color: #FF8000">// Define the errors.<br /></span><span style="color: #0000BB">$constants </span><span style="color: #007700">= </span><span style="color: #0000BB">get_defined_constants</span><span style="color: #007700">(</span><span style="color: #0000BB">true</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$json_errors </span><span style="color: #007700">= array();<br />foreach (</span><span style="color: #0000BB">$constants</span><span style="color: #007700">[</span><span style="color: #DD0000">"json"</span><span style="color: #007700">] as </span><span style="color: #0000BB">$name </span><span style="color: #007700">=> </span><span style="color: #0000BB">$value</span><span style="color: #007700">) {<br /> if (!</span><span style="color: #0000BB">strncmp</span><span style="color: #007700">(</span><span style="color: #0000BB">$name</span><span style="color: #007700">, </span><span style="color: #DD0000">"JSON_ERROR_"</span><span style="color: #007700">, </span><span style="color: #0000BB">11</span><span style="color: #007700">)) {<br /> </span><span style="color: #0000BB">$json_errors</span><span style="color: #007700">[</span><span style="color: #0000BB">$value</span><span style="color: #007700">] = </span><span style="color: #0000BB">$name</span><span style="color: #007700">;<br /> }<br />}<br /><br /></span><span style="color: #FF8000">// Show the errors for different depths.<br /></span><span style="color: #007700">foreach (</span><span style="color: #0000BB">range</span><span style="color: #007700">(</span><span style="color: #0000BB">4</span><span style="color: #007700">, </span><span style="color: #0000BB">3</span><span style="color: #007700">, -</span><span style="color: #0000BB">1</span><span style="color: #007700">) as </span><span style="color: #0000BB">$depth</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">json_decode</span><span style="color: #007700">(</span><span style="color: #0000BB">$json</span><span style="color: #007700">, </span><span style="color: #0000BB">true</span><span style="color: #007700">, </span><span style="color: #0000BB">$depth</span><span style="color: #007700">));<br /> echo </span><span style="color: #DD0000">'Last error: '</span><span style="color: #007700">, </span><span style="color: #0000BB">$json_errors</span><span style="color: #007700">[</span><span style="color: #0000BB">json_last_error</span><span style="color: #007700">()], </span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">, </span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
array(1) {
[1]=>
array(2) {
["English"]=>
array(2) {
[0]=>
string(3) "One"
[1]=>
string(7) "January"
}
["French"]=>
array(2) {
[0]=>
string(3) "Une"
[1]=>
string(7) "Janvier"
}
}
}
Last error: JSON_ERROR_NONE
NULL
Last error: JSON_ERROR_DEPTH
</pre></div>
</div>
</div>
<div class="example" id="example-3759">
<p><strong>Example #5 <span class="function"><strong>json_decode()</strong></span> of large integers</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$json </span><span style="color: #007700">= </span><span style="color: #DD0000">'{"number": 12345678901234567890}'</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">json_decode</span><span style="color: #007700">(</span><span style="color: #0000BB">$json</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">json_decode</span><span style="color: #007700">(</span><span style="color: #0000BB">$json</span><span style="color: #007700">, </span><span style="color: #0000BB">false</span><span style="color: #007700">, </span><span style="color: #0000BB">512</span><span style="color: #007700">, </span><span style="color: #0000BB">JSON_BIGINT_AS_STRING</span><span style="color: #007700">));<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
object(stdClass)#1 (1) {
["number"]=>
float(1.2345678901235E+19)
}
object(stdClass)#1 (1) {
["number"]=>
string(20) "12345678901234567890"
}
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 notes" id="refsect1-function.json-decode-notes">
<h3 class="title">Notes</h3>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
The JSON spec is not JavaScript, but a subset of JavaScript.
</p>
</p></blockquote>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
In the event of a failure to decode, <span class="function"><a href="function.json-last-error.html" class="function">json_last_error()</a></span>
can be used to determine the exact nature of the error.
</p>
</p></blockquote>
</div>
<div class="refsect1 changelog" id="refsect1-function.json-decode-changelog">
<h3 class="title">Changelog</h3>
<p class="para">
<table class="doctable informaltable">
<thead>
<tr>
<th>Version</th>
<th>Description</th>
</tr>
</thead>
<tbody class="tbody">
<tr>
<td>5.4.0</td>
<td>
The <em><code class="parameter">options</code></em> parameter was added.
</td>
</tr>
<tr>
<td>5.3.0</td>
<td>Added the optional <em><code class="parameter">depth</code></em>. The default recursion depth was increased from 128 to 512</td>
</tr>
<tr>
<td>5.2.3</td>
<td>The nesting limit was increased from 20 to 128</td>
</tr>
<tr>
<td>5.2.1</td>
<td>
Added support for JSON decoding of basic types.
</td>
</tr>
</tbody>
</table>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.json-decode-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.json-encode.html" class="function" rel="rdfs-seeAlso">json_encode()</a> - Returns the JSON representation of a value</span></li>
<li class="member"> <span class="function"><a href="function.json-last-error.html" class="function" rel="rdfs-seeAlso">json_last_error()</a> - Returns the last error occurred</span></li>
</ul>
</p>
</div>
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