Null Reference Exception in Global asax sharepoint

Question

I am overriding our global asax page where i want our users who are in a particular sharepoint list/ sharepoint group be redirected to the 2fa page (third party provided) every time the access sharepoint site. this is my code however i get a null reference exception error when i check the uls logs. this is a snippet of my code, this is the entry point:

public void Application_BeginRequest(object sender, EventArgs e)
        {
            //this.Context.Response.Redirect("https://www.google.com");
            if (SPContext.Current.Web.IsCurrentUserMemberOfGroup(Convert.ToInt32(WebConfigurationManager.AppSettings.Get("2FAAdminGroup"))))
            {
                if (this.Context.Session["jwt"] == null)
                {
                    this.Context.Session["jwt"] = "continue";
                    string text = SPContext.Current.Web.CurrentUser.LoginName;
                    if (text.Contains("\\"))
                    {
                        text = text.Substring(text.IndexOf("\\") + 1);
                    }
                    this.r1 = this.Status_Check(text);
                    if (string.IsNullOrEmpty(this.r1))
                    {
                        string url = this.Deregister_Check(text);
                        this.Context.Response.Redirect(url);
                    }
                    this.Context.Response.Redirect(this.r1);
                }
                else
                {
                    string a = this.Context.Session["jwt"].ToString();
                    if (a == "continue")
                    {
                        string text2 = HttpContext.Current.Request.QueryString["jwt"];
                        if (text2 != null && text2 != "")
                        {
                            this.Context.Session["jwt"] = text2;
                        }
                        else
                        {
                            this.Context.Session["jwt"] = "continue";
                            string text = SPContext.Current.Web.CurrentUser.LoginName;
                            if (text.Contains("\\"))
                            {
                                text = text.Substring(text.IndexOf("\\") + 1);
                            }
                            this.r1 = this.Status_Check(text);
                            if (string.IsNullOrEmpty(this.r1))
                            {
                                string url2 = this.Deregister_Check(text);
                                this.Context.Response.Redirect(url2);
                            }
                            this.Context.Response.Redirect(this.r1);
                        }
                    }
                }
            }     
        }

basically what it first does is it gets the data from the web config. but i am getting errors on that part i think here "SPContext.Current.Web.IsCurrentUserMemberOfGroup(Convert.ToInt32(WebConfigurationManager.AppSettings.Get("2FAAdminGroup")))"

i am new to this so can somebody shed some light on what method to use for this?

Answer 1

Can't init HttpContext.Current in Application_BeginRequest based on my testing.

You can get it in Application_PreRequestHandlerExecute.

Here is my test result(refer http://unabo.blogspot.com/2011/04/override-globalasax-in-sharepoint.html).

protected void Application_PreRequestHandlerExecute(Object sender, EventArgs e)
        {
            Microsoft.SharePoint.SPWeb contextWeb = Microsoft.SharePoint.WebControls.SPControl.GetContextWeb(HttpContext.Current);
            Microsoft.SharePoint.SPSecurity.RunWithElevatedPrivileges(delegate()
                {
                    Microsoft.SharePoint.SPSite site = null;
                    Microsoft.SharePoint.SPWeb web = null;
                    using (site = new Microsoft.SharePoint.SPSite(contextWeb.Site.Url))
                    {
                        web = site.OpenWeb();
                    }
                });
        }