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<?xml version="1.0" encoding="UTF-8"?>
<!-- Reviewed: no -->
<sect3 id="zend.view.helpers.initial.json">
<title>JSON Helper</title>
<para>
When creating views that return <acronym>JSON</acronym>, it's important to also set the
appropriate response header. The <acronym>JSON</acronym> view helper does exactly that. In
addition, by default, it disables layouts (if currently enabled), as
layouts generally aren't used with <acronym>JSON</acronym> responses.
</para>
<para>
The <acronym>JSON</acronym> helper sets the following header:
</para>
<programlisting language="text"><![CDATA[
Content-Type: application/json
]]></programlisting>
<para>
Most <acronym>AJAX</acronym> libraries look for this header when parsing responses to
determine how to handle the content.
</para>
<para>
Usage of the <acronym>JSON</acronym> helper is very straightforward:
</para>
<programlisting language="php"><![CDATA[
<?php echo $this->json($this->data) ?>
]]></programlisting>
<note>
<title>Keeping layouts and enabling encoding using Zend_Json_Expr</title>
<para>
Each method in the <acronym>JSON</acronym> helper accepts a second, optional argument.
This second argument can be a boolean flag to enable or disable
layouts, or an array of options that will be passed to
<methodname>Zend_Json::encode()</methodname> and used internally to encode data.
</para>
<para>
To keep layouts, the second parameter needs to be boolean
<constant>TRUE</constant>. When the second parameter is an array, keeping
layouts can be achieved by including a <property>keepLayouts</property> key
with a value of a boolean <constant>TRUE</constant>.
</para>
<programlisting language="php"><![CDATA[
// Boolean true as second argument enables layouts:
echo $this->json($this->data, true);
// Or boolean true as "keepLayouts" key:
echo $this->json($this->data, array('keepLayouts' => true));
]]></programlisting>
<para>
<classname>Zend_Json::encode</classname> allows the encoding of native
<acronym>JSON</acronym> expressions using <classname>Zend_Json_Expr</classname> objects.
This option is disabled by default. To enable this option, pass a boolean
<constant>TRUE</constant> to the <property>enableJsonExprFinder</property> key of
the options array:
</para>
<programlisting language="php"><![CDATA[
<?php echo $this->json($this->data, array(
'enableJsonExprFinder' => true,
'keepLayouts' => true,
)) ?>
]]></programlisting>
</note>
<note>
<title>Sending pre-encoded JSON</title>
<para>
By default, the <acronym>JSON</acronym> helper will JSON-encode the
data provided to the helper's first parameter. If you wish to pass
in data which has already been encoded into <acronym>JSON</acronym>,
the third parameter needs to be set to boolean <constant>FALSE</constant>.
When the second parameter is an array, disabling <acronym>JSON</acronym>
encoding can be achived by including a <property>encodeData</property>
key with the value of boolean <constant>FALSE</constant>:
</para>
<programlisting language="php"><![CDATA[
// Boolean false as third argument disables internal JSON encoding of data
echo $this->json($this->data, false, false);
// Or boolean false as "encodeData" key:
echo $this->json($this->data, array('encodeData' => false));
]]></programlisting>
</note>
</sect3>
<!--
vim:se ts=4 sw=4 et:
-->
|
