Since we're going to fix the url config parameters in another issue, this doesn't need to be fixed now, but there is a bug here. 

<code>request.url</code> contains the query parameters and <code>url.parse(request.url, true).search</code> has a question mark, so the result looks like this:
"/duck/?threejs/2Irjbo71OZdEshw9??threejs/"
instead of:
"/duck/2Irjbo71OZdEshw9?threejs/"