Asp.net identity get facebook information

Question

I have searched online on the following code for getting code information, but I have some questions

1) facebook.Options.Scope.Add("email") : How to determine what to put in email? For example what should I put if I need name or first name?

2) ext.Claims.First(x => x.Type.Contains("email")).Value; How do I determine the email here? Let's say I want first name, how do I know the first name is first_name of first-name of firstname

 var facebookOptions = new Microsoft.Owin.Security.Facebook.FacebookAuthenticationOptions()
            {
                AppId = "AppId",
                AppSecret = "AppSecret"
            };
            facebookOptions.Scope.Add("email");
            app.UseFacebookAuthentication(facebookOptions);

 ClaimsIdentity ext = await AuthenticationManager.GetExternalIdentityAsync(DefaultAuthenticationTypes.ExternalCookie);
            var email = ext.Claims.First(x => x.Type.Contains("email")).Value;

Answer 1

You can't directly get all of Facebook profile information from claims added through facebookOptions scope. You have to add scopes like below and use FacebookClient as explain.

var facebookOptions = new Microsoft.Owin.Security.Facebook.FacebookAuthenticationOptions()
            {
                AppId = "AppId",
                AppSecret = "AppSecret"
            };
            facebookOptions.Scope.Add("email");            
            facebookOptions.Scope.Add("public_profile");
            app.UseFacebookAuthentication(facebookOptions);

Then you can get Facebook user information using FacebookClient.

[Authorize]
public async Task<ActionResult> FacebookInfo()
{
    var claimsforUser = await UserManager.GetClaimsAsync(User.Identity.GetUserId());
    var access_token = claimsforUser.FirstOrDefault(x => x.Type == "FacebookAccessToken").Value;
    var fb = new FacebookClient(access_token);
    dynamic myInfo = fb.Get("/me"); **// Check this with Facebook api to get profile information.**

} 

Note that: If you only need to get Facebook user full name, then check your claims, you'll see user's full name is there.

More information

Hope this helps,