For example, if the user input the url like "http://site.com/controller.php", I want it has the same result as he input "http://site.com/controller".
List of examples with equivalent url:
1. /controller.php <-> /controller
2. /controller/action.html <-> /controller/action
3. /controller/action.asp <-> /controller/action
4. /controller/action/id.aspx <-> /controller/action/id
Is there an elegant way to achieve it?