如何在MVC中使用Facebook C＃SDK获得生日（和其他字段）的权限

Question

I am building an MVC 4 website that allows users to login via Facebook. All this works like a charm out-of-the-box.

But now I am stuck at getting the user's birthday from Facebook. I have installed the latest version of the Facebook C# SDK (6.1.4) from Nuget. I have set up my app in Facebook to request permission for user_birthday. When I look at the Login Dialog Preview birthday is in the list of permissions.

When I run my MVC application and login via my own facebook account I get my birthday in the response, but as soon as I login using a different account, no birthday is passed back and there is also no Login Dialog where the user can grant my app permission to use the birthday field. Below is the complete code of my ExternalLoginCallback() action:

[AllowAnonymous]
public ActionResult ExternalLoginCallback(string returnUrl)
{
    AuthenticationResult result = OAuthWebSecurity.VerifyAuthentication(Url.Action("ExternalLoginCallback", new { ReturnUrl = returnUrl }));

    if (!result.IsSuccessful)
    {
        return RedirectToAction("ExternalLoginFailure");
    }

    // Get the Facebook access token
    if (result.ExtraData.Keys.Contains("accesstoken"))
    {
        Session["facebooktoken"] = result.ExtraData["accesstoken"];
    }

    if (OAuthWebSecurity.Login(result.Provider, result.ProviderUserId, createPersistentCookie: false))
    {
        return RedirectToLocal(returnUrl);
    }

    if (User.Identity.IsAuthenticated)
    {
        // If the current user is logged in add the new account
        OAuthWebSecurity.CreateOrUpdateAccount(result.Provider, result.ProviderUserId, User.Identity.Name);

        return RedirectToLocal(returnUrl);
    }
    else
    {
        // User is new, ask for their desired membership name
        string loginData = OAuthWebSecurity.SerializeProviderUserId(result.Provider, result.ProviderUserId);

        ViewBag.ProviderDisplayName = OAuthWebSecurity.GetOAuthClientData(result.Provider).DisplayName;

        ViewBag.ReturnUrl = returnUrl;

        var client = new FacebookClient(Session["facebooktoken"].ToString());

        dynamic response = client.Get("me", new { fields = "gender, birthday" });

        return View("ExternalLoginConfirmation", 
            new RegisterExternalLoginModel 
            { 
                UserName = result.UserName, 
                FullName = result.ExtraData["name"], 
                DateOfBirth = DateTime.ParseExact(response["birthday"], "MM/dd/yyyy", CultureInfo.InvariantCulture), 
                ExternalLoginData = loginData 
            });
    }
}

I hope somebody can tell me what I am doing wrong here. I have Googled for two days no but somehow I haven't been able to find the right answer. Or maybe I am just to dumb to understand it.

Any help would be greatly appreciated.

Erwin

Answer 1

You have to make sure that you add the birthday to the scope! Default it is not grapped by the facebookAuthenticationvar fbAuthOpt = new FacebookAuthenticationOptions();

        fbAuthOpt.Scope.Add("email");
        fbAuthOpt.Scope.Add("user_birthday");
        fbAuthOpt.AppId = "";
        fbAuthOpt.AppSecret = "";
        fbAuthOpt.SignInAsAuthenticationType = DefaultAuthenticationTypes.ExternalCookie;
        fbAuthOpt.Provider = new FacebookAuthenticationProvider
        {
            OnAuthenticated = async context =>
            {
                context.Identity.AddClaim(new System.Security.Claims.Claim("FacebookAccessToken", context.AccessToken));

                foreach (var claim in context.User)
                {
                    var claimType = string.Format("urn:facebook:{0}", claim.Key);
                    var claimValue = claim.Value.ToString();

                    if (!context.Identity.HasClaim(claimType, claimValue))
                        context.Identity.AddClaim(new System.Security.Claims.Claim(claimType, claimValue, "XmlSchemaString", "Facebook"));
                }

            }
        };

        app.UseFacebookAuthentication(fbAuthOpt);

Later on I grap this with "urn:facebook:birthday".

Answer 2

This post has a fix that worked great for me! He created a custom facebook provider, there you can create your scope requesting permissions and then the querystring to get the info.

http://savvydev.com/authenticating-facebook-users-with-mvc-4-oauth-and-obtaining-scope-permissions/