asp.net mvc 5 - Getting the email from external providers Google and Facebook during account association step in a default MVC5 app

Question

Apparently you can do this with the Facebook provider by adding scopes to the FacebookAuthenticationOptions object in Startup.Auth.cs:

http://blogs.msdn.com/b/webdev/archive/2013/10/16/get-more-information-from-social-providers-used-in-the-vs-2013-project-templates.aspx

List<string> scope = new List<string>() { "email" };
var x = new FacebookAuthenticationOptions();
x.Scope.Add("email");
...
app.UseFacebookAuthentication(x);

How to do the same with Google provider? There isn't a x.Scope property for the GoogleAuthenticationOptions class/object!

Answer 1

PLEASE SEE UPDATES AT THE BOTTOM OF THIS POST!

The following works for me for Facebook:

StartupAuth.cs:

var facebookAuthenticationOptions = new FacebookAuthenticationOptions()
{
    AppId = "x",
    AppSecret = "y"
};
facebookAuthenticationOptions.Scope.Add("email");
app.UseFacebookAuthentication(facebookAuthenticationOptions);

ExternalLoginCallback method:

var externalIdentity = HttpContext.GetOwinContext().Authentication.GetExternalIdentityAsync(DefaultAuthenticationTypes.ExternalCookie);
var emailClaim = externalIdentity.Result.Claims.FirstOrDefault(c => c.Type == ClaimTypes.Email);
var email = emailClaim.Value;

And for Google:

StartupAuth.cs

app.UseGoogleAuthentication();

ExternalLoginCallback method (same as for facebook):

var externalIdentity = HttpContext.GetOwinContext().Authentication.GetExternalIdentityAsync(DefaultAuthenticationTypes.ExternalCookie);
var emailClaim = externalIdentity.Result.Claims.FirstOrDefault(c => c.Type == ClaimTypes.Email);
var email = emailClaim.Value;

If I set a breakpoint here:

var email = emailClaim.Value;

I see the email address for both Facebook and Google in the debugger.

Update 1: The old answer had me confused so I updated it with the code I have in my own project that I just debugged and I know works.

Update 2: With the new ASP.NET Identity 2.0 RTM version you no longer need any of the code in this post. The proper way to get the email is by simply doing the following:

1. Startup.Auth.cs

       app.UseFacebookAuthentication(
          appId: "x",
          appSecret: "y");
   
       app.UseGoogleAuthentication();
   

2. AccountController.cs

   //
   // GET: /Account/ExternalLoginCallback
   [AllowAnonymous]
   public async Task<ActionResult> ExternalLoginCallback(string returnUrl)
   {
       var loginInfo = await AuthenticationManager.GetExternalLoginInfoAsync();
       if (loginInfo == null)
       {
           return RedirectToAction("Login");
       }
   
       // Sign in the user with this external login provider if the user already has a login
       var result = await SignInHelper.ExternalSignIn(loginInfo, isPersistent: false);
       switch (result)
       {
           case SignInStatus.Success:
               return RedirectToLocal(returnUrl);
           case SignInStatus.LockedOut:
               return View("Lockout");
           case SignInStatus.RequiresTwoFactorAuthentication:
               return RedirectToAction("SendCode", new { ReturnUrl = returnUrl });
           case SignInStatus.Failure:
           default:
               // If the user does not have an account, then prompt the user to create an account
               ViewBag.ReturnUrl = returnUrl;
               ViewBag.LoginProvider = loginInfo.Login.LoginProvider;
               return View("ExternalLoginConfirmation", new ExternalLoginConfirmationViewModel { Email = loginInfo.Email });
       }
   }