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

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:
Startup.Auth.cs
app.UseFacebookAuthentication(
appId: "x",
appSecret: "y");
app.UseGoogleAuthentication();
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 });
}
}

Answer 2

You need to explicitly configure the FacebookAuthenticationOptions to get the email address from the authenticated user.
In your MVC5 project, add these lines in the Startup.Auth.cs
var options = new FacebookAuthenticationOptions() {
AppId = "xxxxxxxx",
AppSecret = "xxxxxxxxx"
};
options.Scope.Add("email");
app.UseFacebookAuthentication(options);
Update
Reduced my sample code to the absolute minimum. Your updated code works fine by the way, I have also tried it with both Facebook and Google.

Answer 3

In ASP.NET Core Facebook authentication the Facebook middleware seems to no longer pass in the email, even if you add it to the scope. You can work around it by using Facebook's Graph Api to request the email.
You can use any Facebook Graph Api client or roll your own, and use it to invoke the Graph api as follows:
app.UseFacebookAuthentication(options =>
{
options.AppId = Configuration["Authentication:Facebook:AppId"];
options.AppSecret = Configuration["Authentication:Facebook:AppSecret"];
options.Scope.Add("public_profile");
options.Scope.Add("email");
options.Events = new OAuthEvents
{
OnCreatingTicket = context => {
// Use the Facebook Graph Api to get the user's email address
// and add it to the email claim
var client = new FacebookClient(context.AccessToken);
dynamic info = client.Get("me", new { fields = "name,id,email" });
context.Identity.AddClaim(new Claim(ClaimTypes.Email, info.email));
return Task.FromResult(0);
}
};
});
You can find a more detailed example about how to use it here: http://zainrizvi.io/2016/03/24/create-site-with-facebook-login-using-asp.net-core/#getting-the-email-address-from-facebook