title: Routing to different controllers depending on authentication
body: <p>In rewriting an app using Symfony2, I'm attempting to preserve some legacy behaviour and am looking for a clean solution.</p>
  
  <p>My goal is to have the URI "/" display a splash page if the user is not logged in, and the same URI display a per-user dashboard if they are logged in.</p>
  
  <p>The solution also needs to be scalable - there are several pages on the "public" site which have different representations on the "private" site (i.e. the index, support, about, contact, etc) - because of this I can't simply use a catch-all route and forward to the correct controller myself.</p>
  
  <p>I have one potential solution, which I will post as an answer, but I'm looking for advice on better approaches.</p>