Question

I'm trying to get user name and user email from facebook. I read a lot of information on this topic and this is my final code that works for some reason only on my facebook app admin account:

public partial class Startup
{
    public void ConfigureAuth(IAppBuilder app)
    {

        /*Other external login options*/

         var FacebookOptions = new FacebookAuthenticationOptions()
                {
                    AppId = "My App Id",
                    AppSecret = "My App Secret",
                    SignInAsAuthenticationType = DefaultAuthenticationTypes.ExternalCookie,
                    BackchannelHttpHandler = new FacebookBackChannelHandler(),
                    UserInformationEndpoint = "https://graph.facebook.com/v2.7/me?fields=id,name,email"
                };


    }
}
public class FacebookBackChannelHandler : HttpClientHandler
{
    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken)
    {
        if (!request.RequestUri.AbsolutePath.Contains("/oauth"))
        {
            request.RequestUri = new Uri(request.RequestUri.AbsoluteUri.Replace("?access_token", "&access_token"));
        }

        return await base.SendAsync(request, cancellationToken);
    }
}
public class AccountController : Controller
{
    public async Task<ActionResult> ExternalLoginCallback(string returnUrl)
    {
        var loginInfo = await AuthenticationManager.GetExternalLoginInfoAsync();
        /*my sign in code that works on my facebook app admin account*/
    }  
}

On every over account I get loginInfo.Email is equal to null.

In developers.facebook.com I have:

When someone clicks on "Login with Facebook" he gets this message:

If I click "Review the info you provide" i get:

What am I missing? Why doesn't it work?

Answer 1

终于找到了答案！所有需要做的就是将Scope = { "email" }添加到FacebookOptions，这就解决了问题！

我的代码现在：

public partial class Startup
{
    public void ConfigureAuth(IAppBuilder app)
    {

        /*Other external login options*/

         var FacebookOptions = new FacebookAuthenticationOptions()
                {
                    AppId = "My App Id",
                    AppSecret = "My App Secret",
                    SignInAsAuthenticationType = DefaultAuthenticationTypes.ExternalCookie,
                    BackchannelHttpHandler = new FacebookBackChannelHandler(),
                    Scope = { "email" },
                    UserInformationEndpoint = "https://graph.facebook.com/v2.7/me?fields=id,name,email"
                };
    }
}

其余代码保持不变。如果此问题返回，我只为案例添加了错误页面：

public class AccountController : Controller
{
    public async Task<ActionResult> ExternalLoginCallback(string returnUrl)
    {
        var loginInfo = await AuthenticationManager.GetExternalLoginInfoAsync();
        if(loginInfo.Email == null)
        {
             return RedirectToAction("FacebookError", "Account");
        }
        /*my sign in code*/
    }  
}

Answer 2

Facebook让人们可以完全控制他们授予应用的权限。该控件超出了他们看到登录对话框的程度。他们可以选择在登录过程中不授予某些权限。他们还可以随时撤消其Facebook隐私设置中的权限。在尝试执行API调用之前，应用应检查权限的有效性。例如，在尝试发布Open Graph故事之前，仍然会检查该电子邮件操作是否已被授予。 facebook提供了一个图形API端点来检索已授予权限的列表：

GET /{user-id}/permissions

必须使用用户访问令牌或应用访问令牌进行调用。该调用将返回一个JSON字符串，其中包含已授予应用程序的权限名称及其状态：

{
  "data": [
    {
      "permission": "public_profile",
      "status": "granted"
    },
    {
      "permission": "publish_actions",
      "status": "granted"
    },
    {
      "permission": "user_friends",
      "status": "declined"
    }
  ]
}

通过使用它，您可以检测是否可以获取所需的信息。希望这有帮助。

参考：https://developers.facebook.com/docs/facebook-login/permissions/requesting-and-revoking

Get user email from facebook in asp net

2 个答案: