title: Modify JSON Object After Controller Returns
body: <p>I'm using C# with MVC and trying to add data to a JSON message after the controller returns, but before it gets to the client. </p>
  
  <p><em>Is there a C# framework/tool I can use for that?</em></p>
  
  <p><strong>Example</strong></p>
  
  <p>A controller returns order data for a particular order, which includes a date in Unix time (int representing seconds). </p>
  
  <p>The message is intercepted before being returned to the caller.</p>
  
  <p>Another field with Gregorian date/time converted from the Unix time is appended to the JSON message.</p>
  
  <p><strong>Is this possible?</strong></p>