Access email address in the OAuth ExternalLoginCallback from Facebook v2.4 API in ASP.NET MVC 5 [duplicate]

Answer 1

To resolve this I had to install the Facebook SDK for .NET from nuget and query the email address separately.

In the ExternalLoginCallback method, I added a conditional to populate the email address from the Facebook Graph API;

var loginInfo = await AuthenticationManager.GetExternalLoginInfoAsync();

if (loginInfo == null)
{
    return RedirectToAction("Login");
}

// added the following lines
if (loginInfo.Login.LoginProvider == "Facebook")
{
    var identity = AuthenticationManager.GetExternalIdentity(DefaultAuthenticationTypes.ExternalCookie);
    var access_token = identity.FindFirstValue("FacebookAccessToken");
    var fb = new FacebookClient(access_token);
    dynamic myInfo = fb.Get("/me?fields=email"); // specify the email field
    loginInfo.Email = myInfo.email;
}

And to get the FacebookAccessToken I extended ConfigureAuth;

app.UseFacebookAuthentication(new FacebookAuthenticationOptions
{
    AppId = "XXX",
    AppSecret = "XXX",
    Scope = { "email" },
    Provider = new FacebookAuthenticationProvider
    {
        OnAuthenticated = context =>
        {
            context.Identity.AddClaim(new System.Security.Claims.Claim("FacebookAccessToken", context.AccessToken));
            return Task.FromResult(true);
        }
    }
});

Answer 2

In MVC 6 (Asp.net Core 1.0), by configuring FacebookAuthentication in startup.cs like this:

         app.UseFacebookAuthentication(options =>
            {
                options.AppId = Configuration["Authentication:Facebook:AppId"];
                options.AppSecret = Configuration["Authentication:Facebook:AppSecret"];
                options.Scope.Add("email");
                options.UserInformationEndpoint = "https://graph.facebook.com/v2.4/me?fields=id,name,email,first_name,last_name";
            });

I could get the email. I.e:

   var info = await _signInManager.GetExternalLoginInfoAsync();
   var email = info.ExternalPrincipal.FindFirstValue(ClaimTypes.Email);