Http 协议 请求 响应

 今天 在做.net mvc 项目中 关于权限限定模块 通过重载Controller 的OnActionExecuting方法 进行 action调用前的验证

 protected override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            base.OnActionExecuting(filterContext);

            #region 用户权限验证
                        String str =Request.Url.AbsoluteUri;
                        string[] strs = str.Split('/');
                       
                        if (strs.Count() >= 4)
                        {   
                            string skey = strs[3];

                            if (skey != "Login")
                            {
                                #region 用户登陆验证
                                if (Session["UserID"] == null || Session["current_user"] == null)
                                {
                                    Session["alertInformation"] = "页面已经过期，请重新登陆!";
                                    //filterContext.HttpContext.
                                    Response.Redirect("/Login/Index");
                                    //Response.Redirect("/LossCancel/Index");
                                    Response.End();
                                  return;
                                }
                                #endregion           
                                if (skey != "Welcome")
                                {
                                    Hashtable table = GetHashtable();
                                    foreach (DictionaryEntry de in table)
                                    {
                                        if (skey.Equals(de.Key))
                                        {
                                            bool permission = false;

                                            try
                                            {
                                                permission = new IsPermission().IsTrue(de.Value.ToString(), (string)Session["UserID"]);
                                            }
                                            catch (Exception ex)
                                            {
                                                logger.Error(ex);
                                                Session["alertInformation"] = "页面已经过期，请重新登陆!";
                                                Response.Redirect("/Login/Index");
                                                Response.End();  //此处语句执行后 服务器就给浏览器响应 但本线程继续往下执行

                                                                          //服务器接到响应302 立刻启动一个线程访问服务器（url：/Login/Index)

                                            }
                                            if (!permission)
                                            {
                                                Session["alertInfop"] = "对不起，您没有此权限！";
                                                Response.Redirect("/Login/Welcome");
                                                Response.End();
                                            }
                                        }
                                    }
                                }
    
                   }
                 }                    
                    
                 #endregion       

  对于 Http协议：每一次请求 对应一次响应 服务器每得到一次请求 就建立一个线程对其进行处理 并响应