title: DotNetOpenAuth programmatically without redirection
body: <p>I'm doing a simple project that consists of two separate parts:</p>
  
  <ol>
  <li>Backend app in C# (ASP MVC) that server as business logic layer and
  exposes public controlers/actions with JSON responses</li>
  <li>Frontend app in PHP that serves as an interface to the backend app</li>
  </ol>
  
  <p>I have implemented Forms authentication with custom MembershipProvider which stores user details in Entity Framework model and SQL Server.</p>
  
  <p>The next step would be to enable OpenID authentication. What I need to do is:</p>
  
  <ol>
  <li>In my frontend get user OpenID credentials (probably Facebook and
  Google)</li>
  <li>Forward those to my backend controler via POST request</li>
  <li>Authenticate user with OpenID provider in my backend, storing their data (email only) in my model</li>
  <li>Inform the frontend that user is authenticated</li>
  </ol>
  
  <p>I've been going through different DotNetOpenAuth documents and samples, but I just can't figure out the point 3. in my list.</p>