title: ASP.NET Web API with Facebook auth without OWIN
body: <p>I'm developing an ASP.NET Web API. The authentication used in this API does not use OWIN, and I need to make a method that authenticates a user by using their Facebook account.</p>
  
  <p>I only find examples on how to do this by using OWIN and OAuth. Is there another way to do this?</p>
  
  <p>Can someone post some link or explanation about this case?</p>
  
  <p>Thanks in advance!</p>