Identifying the logged in user from different browser tab in asp.net

Question

I have a website with login option in asp.net.

if i open website in two browser tabs and logged in with same user account and navigated to homescreen in both tabs , now i am logged out from one tab and again logged in same tab,after that i clicked on the second tab,

how can i discriminate that i am sending request from first tab or second tab from code behind?

If the request is from second tab i need to navigate the application to login screen.How can i do this?

in my home page i had added the logic like

if (Session["UserID"] == null)
{
   Response.Redirect("Login.aspx");
}

but the problem is that when i logout from first tab and login in again there, and after that second tab refreshed Session["UserID"] is not null so it will stay there.But i need to redirect login page .how can i achieve this??

A lot of browsers share cookies across tabs. Open a different browser (i.e. Internet Explorer and Chrome) to get a completely segregated session/cookie value. — Will, Jul 07 '15 at 15:46

score 7 · Accepted Answer · edited Jul 06 '15 at 18:04

7

May I suggest you to use JavaScript and Ajax Post for redirection. I use it for myself, and find it reliable, satisfying the need. I still think there may be far better ways to do this. But for now this will do your job.

Below code checks for tab focus/focus lost, and calls a Csharp code on Blur and focus.

    <script type="text/javascript">
        //divClearMessages
        $(window).on("blur focus", function (e) {
            var prevType = $(this).data("prevType");


            if (prevType != e.type) {   //  script for Please Come Back
                switch (e.type) {
                    case "blur":
                        // Use this if you want to check something after user changes tab
                    case "focus":
                        $.ajax({
                            type: "POST",
                            url: "main.aspx/CheckIfSessionIsNull", // Call here the Csharp method which checks the session and redirect user
                            contentType: "application/json; charset=utf-8",
                            dataType: "json",
                            success: function (retValue) {
                                // Do something with the return value from.Net method
                            }
                        });
                        break;
                }
            }

            $(this).data("prevType", e.type);
        })
    </script>

In Code behind add this method: (remember to add the [WebMethod] attribute)

    [System.Web.Services.WebMethod]
    public static void CheckIfSessionIsNull()
    {
       if (System.Web.HttpContext.Current.Session["UserId"] == null)
          HttpContext.Current.Response.Redirect("Login.aspx");
    }

edited Jul 06 '15 at 18:04

Stephen Kennedy

20,585
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answered Jul 04 '15 at 06:32

ThePravinDeshmukh

1,823
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i am trying to implement this concept.but this gives following error- An object reference is required for the non-static field, method, or property 'System.Web.UI.Page.Response.get'. Response.Redirect("Login.aspx"); is not possible to add inside a static method – AcAnanth Jul 06 '15 at 05:25
1

It is. Use this `HttpContext.Current.Response.Redirect("Login.aspx");` Also add reference to `System.Web;` – ThePravinDeshmukh Jul 06 '15 at 08:42
Any luck doing this bro? – ThePravinDeshmukh Jul 07 '15 at 05:11
This method is not triggering.blur or focus is not calling – AcAnanth Jul 07 '15 at 05:15
Can you place the debugger (or alert) in script to check, let me know where you reach – ThePravinDeshmukh Jul 07 '15 at 06:13
Uncaught ReferenceError: $ is not defined on this line $(window).on("blur focus", function(e) { – AcAnanth Jul 07 '15 at 06:31
Do you have jquery reference in your project? which version? Also remember to place code in head tag – ThePravinDeshmukh Jul 07 '15 at 06:33
sorry forgot to close the jquery ref tag(syntax error)...but it is not going inside the any of the method. I am using the iframes due to that??? – AcAnanth Jul 07 '15 at 06:49
1

Actually that shouldn't be the issue (i checked), Place script out side of iframe (in container) and change the tab to test.. (add some alert popup for that) – ThePravinDeshmukh Jul 07 '15 at 07:51

score 6 · Answer 2 · edited May 23 '17 at 12:09

Essentially your problem is that tabs belonging to the same browser process share cookies, so each tab is using the same Session and session cookie.

You can work around this by turning off session cookies as documented on MSDN:

<configuration>
  <system.web>
    <sessionState cookieless="true"
      regenerateExpiredSessionId="true" />
  </system.web>
</configuration>

ASP.NET maintains cookieless session state by automatically inserting a unique session ID into the page's URL.

Each new tab visit to a URL without a session ID in it will start a new session.

Alternatively, you could generate some unique ID in your initial page load event and store/retrieve your session variables by wrapping them in a class and storing an instance of that class under the new ID inside the session.

Credit and more information.

Identifying the logged in user from different browser tab in asp.net

2 Answers2