title: How to filter requests for access code in Play 2.1
body: <p>I'd like to add a (per method / global) filter to requests, that simply rejects (404/403 page) any request that doesn't have a specific URL parameter.</p>
  
  <p>I know Play has one-two mechanism to do this (e.g. register on <code>Global.onRouteRequest()</code>), so don't just send me a link to the documentation unless it contains a code sample that covers this question. I tried playing with the API but got a bit stuck.</p>