<?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 JSON, it's important to also set the
        appropriate response header. The JSON view helper does exactly that. In
        addition, by default, it disables layouts (if currently enabled), as
        layouts generally aren't used with JSON responses.
    </para>

    <para>
        The JSON helper sets the following header:
    </para>

    <programlisting role="text"><![CDATA[
Content-Type: application/json
]]></programlisting>

    <para>
        Most AJAX libraries look for this header when parsing responses to
        determine how to handle the content.
    </para>

    <para>
        Usage of the JSON helper is very straightforward:
    </para>

    <programlisting role="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 JSON 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
            <classname>Zend_Json::encode()</classname> and used internally to encode data.
        </para>

        <para>
            To keep layouts, the second parameter needs to be boolean
            <code>true</code>. When the second parameter is an array, keeping
            layouts can be achieved by including a <code>keepLayouts</code> key
            with a value of a boolean <code>true</code>.
        </para>

        <programlisting role="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 JSON
            expressions using <classname>Zend_Json_Expr</classname> objects. This option
            is disabled by default.  To enable this option, pass a boolean
            <code>true</code> to the <code>enableJsonExprFinder</code> key of
            the options array:
        </para>

        <programlisting role="php"><![CDATA[
<?php echo $this->json($this->data, array(
    'enableJsonExprFinder' => true,
    'keepLayouts'          => true,
)) ?>
]]></programlisting>
    </note>
</sect3>
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