xform

      <ol>

        <li>Caching must be enabled for this URL. See the <code class="directive"><a href="./mod/mod_cache.html#cacheenable">CacheEnable</a></code> and <code class="directive"><a href="./mod/mod_cache.html#cachedisable">CacheDisable</a></code> directives.</li>

        <li>The response must have a HTTP status code of 200, 203, 300, 301 or

        410.</li>

        <li>If the response has an HTTP status code other than 200, 203, 300, 

        301 or 410 it must also specify an "Expires" or "Cache-Control" header.

        </li>

        <li>The request must be a HTTP GET request.</li>