Assuming you are already successfully authenticating against Identity Server 3, you should be all set already. If you look in the CallApiController you'll find this method
// GET: CallApi/UserCredentials
public async Task<ActionResult> UserCredentials()
{
var user = User as ClaimsPrincipal;
var token = user.FindFirst("access_token").Value;
var result = await CallApi(token);
ViewBag.Json = result;
return View("ShowApiResult");
}
the user variable should already contain claims for the user's name, Id and such. So
var id = user.FindFirst(Constants.ClaimTypes.Subject).Value;
var firstName = user.FindFirst(Constants.ClaimTypes.GivenName).Value;
var middleName = user.FindFirst(Constants.ClaimTypes.MiddleName).Value;
var lastName = user.FindFirst(Constants.ClaimTypes.LastName).Value;
Of course, that all assumes that you've got that information in your store of user information and I'm not checking for the errors that will occur if they are not there.