title: How to get back the data parameter of the Request Dialog?
body: <p>I need to use Facebook's Request Dialog to let user invite their friends. I have a doubt regarding the <code>data</code> paramenter of the request dialog.</p>
  
  <p><a href="https://developers.facebook.com/docs/reference/dialogs/requests/" rel="nofollow">https://developers.facebook.com/docs/reference/dialogs/requests/</a></p>
  
  <p><strong>data:</strong> Optional, additional data you may pass for tracking. This will be stored as part of the request objects created. The maximum length is 255 characters.</p>
  
  <p>If I set this paramenter with an id like 1234, How can I get back this value (1234) when the user authorize the application clicking on the link in the invitation message?</p>
  
  <p>Thank you!</p>