title: Header set with query_string
body: <p>I am runing apache and I am trying to set a header Foo=bar only when the request has a variable "q" on the query string. I would like something like this in my htaccess:</p>
  
  <pre><code>&lt;RequestUri "q="&gt;
      Header set Foor "bar"
  &lt;/RequestUri&gt;
  </code></pre>
  
  <p>Of course it does not work. I already tried using "Location" and "LocationMatch" but those are not allowed inside the htaccess. So how can I do that?</p>