用Facebook C＃登录

Question

当我尝试使用我的网站上的facebook登录时，我有一个无限循环的刷新，
我在body标签之后声明了一个脚本

           <script>
                window.fbAsyncInit = function () {
                    FB.init({
                        appId: '337323336385***', // App ID
                        status: true, // check login status
                        cookie: true, // enable cookies to allow the server to access the session
                        xfbml: true  // parse XFBML
                    });

                    // Additional initialization code here
                    FB.Event.subscribe('auth.authResponseChange', function (response) {
                        if (response.status === 'connected') {
                            // the user is logged in and has authenticated your
                            // app, and response.authResponse supplies
                            // the user's ID, a valid access token, a signed
                            // request, and the time the access token 
                            // and signed request each expire
                            var uid = response.authResponse.userID;
                            var accessToken = response.authResponse.accessToken;

                            // TODO: Handle the access token
                            //alert("check");
                            // Do a post to the server to finish the logon
                            // This is a form post since we don't want to use AJAX
                            var form = document.createElement("form");
                            form.setAttribute("method", 'post');
                            form.setAttribute("action", '/FacebookLogin.ashx');

                            var field = document.createElement("input");
                            field.setAttribute("type", "hidden");
                            field.setAttribute("name", 'accessToken');
                            field.setAttribute("value", accessToken);
                            form.appendChild(field);

                            document.body.appendChild(form);
                            form.submit();
                        } else if (response.status === 'not_authorized') {
                            // the user is logged in to Facebook, 
                            // but has not authenticated your app
                            //alert("Please ");
                        } else {
                            // the user isn't logged in to Facebook.
                            //alert("jj");
                            alert("Please Sign into your account to access the site");
                        }
                    });
                };

                // Load the SDK Asynchronously
                (function (d) {
                    var js, id = 'facebook-jssdk', ref = d.getElementsByTagName('script')[0];
                    if (d.getElementById(id)) { return; }
                    js = d.createElement('script'); js.id = id; js.async = true;
                    js.src = "//connect.facebook.net/en_US/all.js";
                    ref.parentNode.insertBefore(js, ref);
                }(document));
            </script>

如您所见，此函数正在调用FacebookLogin.ashx文件中的C＃函数，该函数负责创建包含用户数据的Session变量

 public void ProcessRequest(HttpContext context)
 {

  var accessToken = context.Request["accessToken"];
  context.Session["AccessToken"] = accessToken;

  HttpCookie cookie = new HttpCookie("FB");

  string accessToken2 = context.Session["AccessToken"].ToString();
  Facebook.FacebookClient client = new Facebook.FacebookClient(accessToken2);
  dynamic result = client.Get("me", new { fields = "name,id,link,gender" });

  cookie["FBID"] = result.id;
  context.Response.Cookies.Add(cookie);

  context.Response.Redirect("/login.aspx");
}

之后，在页面加载中，我检查此会话变量是否存在

                string accessToken;
                FacebookClient client;
                dynamic result;
                if (Session["AccessToken"] != null)
                {
                    accessToken = Session["AccessToken"].ToString();
                    client = new FacebookClient(accessToken);
                    result = client.Get("me", new { fields = "name,id,link,gender" });

                    if (gb.CheckExistanceByFBID(result.id))
                    {
                        string FBID = result.id;
                        var userDetails = context.Users.Where(x => x.FBID == FBID).Select(x => x).First();

                        HttpCookie cookie = new HttpCookie("userData", userDetails.UserName);
                        cookie.Expires = DateTime.Now.AddMonths(2);

                        cookie["UserName"] = userDetails.UserName;
                        cookie["UserID"] = userDetails.UserID.ToString();
                        cookie["Password"] = userDetails.Password;
                        cookie["isAdmin"] = userDetails.Admin.ToString();
                        cookie["Name"] = userDetails.DisplayName;
                        cookie["FBID"] = userDetails.FBID;
                        Response.Cookies.Add(cookie);
                        System.Web.Security.FormsAuthentication.SetAuthCookie(userDetails.UserName, true);
                        System.Web.Security.FormsAuthentication.Timeout.Add(new TimeSpan(40, 0, 0, 0));
                        Response.Redirect("/Default.aspx");
                    }
                    else
                    {
                        //var accessToken = Session["AccessToken"].ToString();
                        //var client = new FacebookClient(accessToken);
                        //dynamic result = client.Get("me", new { fields = "name,id,link,gender" });

                        accessToken = Session["AccessToken"].ToString();
                        client = new FacebookClient(accessToken);
                        result = client.Get("me", new { fields = "name,id,link,gender" });

                        FBRegisterPanel.Visible = false;
                        MainRegisterPanel.Visible = true;
                        txtUserName.Text = result.name;
                    }
                }

单击Facebook登录按钮后，我的刷新无限循环的问题！

Answer 1

我有同样的问题。

加载login.aspx时，将执行JS，该JS将表单发布到FacebookLogin.ashx，该表单将重定向到login.aspx，这意味着JS将再次运行并继续循环。

（希望如此）通过执行以下操作，如果存储了OAuth令牌，则将if语句设为false，因此永远不会执行将表单提交给FacebookLogin.ashx的脚本。

FB.Event.subscribe('auth.authResponseChange', function (response) {
    if (response.status === 'connected' && "<%= Session["AccessToken"].ToString() %>" == "") { ... }

注意：即使没有要存储的访问令牌，也请确保Session [“ AccessToken”]包含空字符串，因为：

• JS在Session [“ AccessToken”]中寻找一个空字符串以使if语句为true。
• 如果为空，我认为<％= Session [“ AccessToken”]。ToString（）％>将引发空引用异常。

您可以通过在Page_Init上执行以下操作来做到这一点：

if (Session["AccessToken"] == null)
{
   Session["AccessToken"] = string.Empty;
}