title: Symfony2 - How to check if we are being called from a mobile device
body: <p>Using Symfony2, I need to check in the controller wether I am being called from a mobile device or from a desktop web browser.</p>
  
  <p>Depending on the origin of the request, render different twig templates according to the screen sizes and conditions.</p>
  
  <p>What would be a good approach to do this? What do we have in the Controller to check this?</p>