hod-desc">
<dt>Description:</dt>
<dd>
<p>
 Shortcut for header("user-agent"). 
</p>

<pre><code>user_agent()</code></pre>

</dd>
</dl>

<h2 id="caution" class="section-head">Caution</h2>

<p>
Several restrictions are introduced to avoid misconfiguration when using <code>acl</code> method.
<ul>
<li><code>acl</code> method can be called only once in each handler configuration</li>
<li>If <code>acl</code> method is used, the handler returned by the configuration directive must be the one returned by the <code>