利用Action Filter 防止重复提交

1、原文：http://15815850410.blog.163.com/blog/static/11499607920135742231644/

 public class NoResubmitAttribute : ActionFilterAttribute
    {
        private static readonly string HttpMehotdPost = "POST";
        private static readonly string prefix = "postFlag";
        private string nameWithRoute;

        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            var controllerContext = filterContext.Controller.ControllerContext;
            if (!controllerContext.IsChildAction)
            {
                var request = controllerContext.HttpContext.Request;
                var session = controllerContext.HttpContext.Session;
                nameWithRoute = generateNameWithRoute(controllerContext);
                int sessionFlag = session[nameWithRoute] == null ? 0 : (int)session[nameWithRoute];
                int requestFlag = string.IsNullOrEmpty(request.Form[nameWithRoute]) ? 0 : int.Parse(request.Form[nameWithRoute]);
                // get or normal post: true;    
                bool isValid = !IsPost(filterContext) || sessionFlag == requestFlag;
                if (sessionFlag == int.MaxValue)
                {
                    sessionFlag = -1;
                }
                session[nameWithRoute] = ++sessionFlag;
                if (!isValid)
                {
                    filterContext.Result = new RedirectResult(GenerateUrlWithTimeStamp(request.RawUrl));
                    return;
                }
            }
            base.OnActionExecuting(filterContext);
        }

        private string GenerateUrlWithTimeStamp(string url)
        {
            return string.Format("{0}{1}timeStamp={2}", url, url.Contains("?") ? "&" : "?", (DateTime.Now - DateTime.Parse("2010/01/01")).Ticks);
        }

        private bool IsPost(ActionExecutingContext filterContext)
        {
            return filterContext.HttpContext.Request.HttpMethod == HttpMehotdPost;
        }

        private string generateNameWithRoute(ControllerContext controllerContext)
        {
            StringBuilder sb = new StringBuilder(prefix);
            foreach (object routeValue in controllerContext.RouteData.Values.Values)
            {
                sb.AppendFormat("_{0}", routeValue);
            }
            return sb.ToString();
        }

        public override void OnResultExecuted(ResultExecutedContext filterContext)
        {
            base.OnResultExecuted(filterContext);
            if (!filterContext.IsChildAction && !(filterContext.Result is RedirectResult))
            {
                //string format = "<script type='text/javascript'>$(function () [[ $('form').each(function()[[$('<input type=hidden id={0} name={0} value={1} />').appendTo($(this));]])]]); </script>";
                string format = "<script type='text/javascript'> var forms = document.getElementsByTagName('form'); for(var i = 0; i<forms.length; i++)[[var ele = document.createElement('input'); ele.type='hidden'; ele.id=ele.name='{0}'; ele.value='{1}'; forms[i].appendChild(ele);]] </script>";
                string script = string.Format(format, nameWithRoute, filterContext.HttpContext.Session[nameWithRoute]).Replace("[[", "{").Replace("]]", "}");
                filterContext.HttpContext.Response.Write(script);
            }
        }
    }



        [HttpGet]
        [NoResubmit]
        public ActionResult Index()
        {
            return View();
        }

        [HttpPost]
        [NoResubmit]
        public ActionResult Index(int id)
        {
            return View();
        }

        [NoResubmit]
        public ActionResult About()
        {
            return View();
        }        

2、原文：http://www.kuiyu.net/art-15.html

public class PreventSpamAttribute : ActionFilterAttribute
{
      //处理请求之间的延迟
      public int DelayRequest = 10;
      //防止多次请求时的错误提示信息
      public string ErrorMessage = "Excessive Request Attempts Detected.";
      //出错时URL重定向
      public string RedirectURL;

      public override void OnActionExecuting(ActionExecutingContext filterContext)
      {
             base.OnActionExecuting(filterContext);
      }
}

public override void  OnActionExecuting(ActionExecutingContext filterContext)
{
      //存储 HttpContext 
      var request = filterContext.HttpContext.Request;

      //获取IP请求者的IP地址
      var originationInfo = request.ServerVariables["HTTP_X_FORWARDED_FOR"] ?? request.UserHostAddress;

      //Append the User Agent
      originationInfo += request.UserAgent;

      //目标URL信息
      var targetInfo = request.RawUrl + request.QueryString;

      base.OnActionExecuting(filterContext);
}

public override void  OnActionExecuting(ActionExecutingContext filterContext)
{
      //Store our HttpContext 
      var request = filterContext.HttpContext.Request;
      //Store our HttpContext.Cache 
      var cache = filterContext.HttpContext.Cache;

      //Grab the IP Address from the originating Request 
      var originationInfo = request.ServerVariables["HTTP_X_FORWARDED_FOR"] ?? request.UserHostAddress;

      //Append the User Agent
      originationInfo += request.UserAgent;

      //目标URL信息
      var targetInfo = request.RawUrl + request.QueryString;

      //创建希哈值
      var hashValue = string.Join("", MD5.Create().ComputeHash(Encoding.ASCII.GetBytes(originationInfo + targetInfo)).Select(s => s.ToString("x2")));

      //如果希哈值在缓存中,(重复提交)
      if (cache[hashValue] != null)
      {
              //添加错误信息
              filterContext.Controller.ViewData.ModelState.AddModelError("ExcessiveRequests", ErrorMessage);
      }
      else
      {
              //使用希哈值的key添加一个空对象到缓存中(决定是否过期)
              //if the Request is valid or not
              cache.Add(hashValue, hashValue, null, DateTime.Now.AddSeconds(DelayRequest), Cache.NoSlidingExpiration, CacheItemPriority.Default, null);
      }
      base.OnActionExecuting(filterContext);
}

应用
//Displays your form initially
public ActionResult YourPage()
{
      return View(new TestModel());
}

[HttpPost]
[PreventSpam]
public ActionResult YourPage(TestModel yourModel)
{
      //If your Model was valid - output that it was successful!
      if (ModelState.IsValid)
      {
             return Content("Success!");
      }
      //Otherwise return the model to the View
      else
      {
             return View(yourModel);
      }
}


//This action can only be accessed every 60 seconds and any additional requests within that timespan will 
//notify the user with a custom message. 
[PreventSpam(DelayRequest=60,ErrorMessage="You can only create a new widget every 60 seconds.")]
public ActionResult YourActionName(YourModel model)
{
      //Your Code Here
}  

还可以用 使用Post/Redirect/Get实现Asp.net防止表单重复提交 就是Http-Post完后，马上做Redirect操作，接下来那个页面是Get。这时用户强制按F5刷新也没有用了。

原文：http://www.cnblogs.com/wintersun/archive/2012/03/24/2415349.html