title: Custom ActionFilter to check the existence of the parametre in Database
body: <p>Hi there I am looking for a solution to solve this problem.I am building an Web app with Asp.net mvc3.
  I want to make a custom Action Filter ([KeyAuthorization]) so that only authorized key will access the controllers. </p>
  
  <p>This is my default Route</p>
  
  <pre><code>routes.MapRoute(
                  "Default", // Route name
                 "{guid}/{controller}/{action}", // URL with parameters
                 new { guid = UrlParameter.Optional, controller = "Home", action = "Index", }
  </code></pre>
  
  <p>So let say someone access the  <strong>www.example.com/34safd-234s/home/index</strong></p>
  
  <p>if key:34safd-234s is correct (authorized) than the user will see the content otherwise the web app will throw an 404. </p>
  
  <p>How can achieve this?</p>
  
  <p>Thank you,</p>
  
  <p>How can I build and action filter that checkes that guid parametre exist in the </p>