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<div class="sect1" title="Prefilters">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="advanced.features.prefilters"></a>Prefilters</h2></div></div></div>
<p>
Template prefilters are PHP functions that your templates are ran through
<span class="emphasis"><em>before they are compiled</em></span>. This is good for preprocessing
your templates to remove unwanted comments, keeping an eye on what people are
putting in their templates, etc.
</p>
<p>
Prefilters can be either <a class="link" href="api.register.prefilter.html" title="register_prefilter()">registered</a> or loaded from
the <a class="link" href="variable.plugins.dir.html" title="$plugins_dir">plugins directory</a>
by using <a class="link" href="api.load.filter.html" title="load_filter()"><code class="varname">load_filter()</code></a> function or
by setting the <a class="link" href="variable.autoload.filters.html" title="$autoload_filters">
<em class="parameter"><code>$autoload_filters</code></em></a> variable.
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<p>
Smarty will pass the template source code as the first argument, and
expect the function to return the resulting template source code.
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<div class="example">
<a name="id3120942"></a><p class="title"><b>Example 15.2. Using a template prefilter</b></p>
<div class="example-contents">
<p>
This will remove all the html comments in the template source.
</p>
<pre class="programlisting">
<?php
// put this in your application
function remove_dw_comments($tpl_source, &$smarty)
{
return preg_replace("/<!--#.*-->/U",'',$tpl_source);
}
// register the prefilter
$smarty->register_prefilter('remove_dw_comments');
$smarty->display('index.tpl');
?>
</pre>
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<br class="example-break"><p>See also
<a class="link" href="api.register.prefilter.html" title="register_prefilter()"><code class="varname">register_prefilter()</code></a>,
<a class="link" href="advanced.features.postfilters.html" title="Postfilters">postfilters</a>
and
<a class="link" href="api.load.filter.html" title="load_filter()"><code class="varname">load_filter()</code></a>.
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