.Net Mvc 四种过滤器

一.授权过滤器:AuthorizationFilters

二.动作过滤:ActionFilters

三.响应过滤:ResultFilters

四.异常过滤:ExceptionFilters

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一。授权过滤，这里以登陆账号密码，角色id不同进行过滤。

1.添加一个过滤类 ， 用于过滤掉和角色id不符合要求的账号。

 using Newtonsoft.Json;
 using Solution.Models;
 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Web;
 using System.Web.Mvc;
 using System.Web.Security;

 namespace Solution.Filter
 {
     public class UserAuthorize : AuthorizeAttribute
     {
         //允许的角色id集合
         public string[] x { get; set; }

         /// <summary>
         /// 请求授权时调用相关的参数
         /// </summary>
         /// <param name="filterContext"></param>
         public override void OnAuthorization(AuthorizationContext filterContext)
         {
             string[] str = Roles.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
             x = new string[str.Length];
             for (int i = ; i < str.Length; i++)
             {
                 x[i] = str[i];
             }
             base.OnAuthorization(filterContext);
         }

         protected override bool AuthorizeCore(HttpContextBase httpContext)
         {
             var thisUser = UserHelper.user;
             bool status = true;
             //判断是否登陆
             if (!HttpContext.Current.User.Identity.IsAuthenticated)
             {
                 return false;
             }

             //判断角色
             if (x.Count() >  && status==true)
             {
                 status = x.Contains(thisUser.role);
             }

             return status; 

         }
     }

 }

2.在Home控制器下添加对应的登陆和退出方法，登陆后跳转的页面。

创建LogDto类，用于封装登陆时需填写的属性

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;

 namespace Solution.Model
 {
    public class LogDto
     {
        public string Account { get; set; }

        public string PassWord { get; set; }
     }
 }

创建UserIdEntity类，用于封装存入cookie的票据信息

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace Solution.Models
{
    public class UserIdEntity
    {
        public string Account { get; set; }

        public string PassWord { get; set; }

        public string role { get; set; }
    }
}

创建ResponseMsg类，用于方法返回的结果信息

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;

 namespace Solution.Common
 {
     public class ResponseMsg
     {
         /// <summary>
         /// 默认构造函数
         /// </summary>
         public ResponseMsg()
         {
         }

         /// <summary>
         /// 设置初始值
         /// </summary>
         /// <param name="_Status"></param>
         public ResponseMsg(ActonState _Status)
         {
             _status = _Status;
         }

         public ActonState _status;

         public ActonState Status
         {
             get { return _status; }
             set { _status = value; }
         }

         public string Msg { get; set; }

         public string LoadUrl { get; set; }

         public object Data { get; set; }

     }

     public enum ActonState
     {
         Default = ,//默认

         Success = , //成功

         Failure = ,//失败

         ServerError = ,//服务错误

         Others =  //其它
     }
 }

在Home控制器下编写登陆方法

[HttpPost]//只允许post请求
        public ActionResult LogOn(LogDto logdto)
        {
            string name = logdto.Account;
            string pwd = logdto.PassWord;
            ResponseMsg response = new ResponseMsg() { Status = ActonState.Default };

            if ("Admin".Equals(name) && "".Equals(pwd))
            {
                UserIdEntity identity = new UserIdEntity() { Account = name, PassWord = pwd, role = "" };
                //创建Form票据
                FormsAuthenticationTicket ticket = new FormsAuthenticationTicket(, name, DateTime.Now, DateTime.Now.AddHours(), false, JsonConvert.SerializeObject(identity));
                //将票证转为字符串(加密)
                string str = FormsAuthentication.Encrypt(ticket);
                //将该票证存到cookie中
                //FormsAuthentication.SetAuthCookie(str,true);
                HttpCookie coo = new HttpCookie("DIQx", str); //cookie名称必须与配置中名称相同,否则读取不到userdata
                Response.Cookies.Add(coo);
                response.LoadUrl = "/Home/Main";
                response.Status = ActonState.Success;
            }
            else {
                response.Status = ActonState.Default;
            }
            return Json(response);
        }

要跳转的页面，这里只允许角色Id为（1，2，3）中的其中的一个进入。且[Roles=""]标记为固定写法

   [UserAuthorize(Roles="1,2,3")]
         public ActionResult Main()
         {
             return View();
         }

退出登陆

  [AllowAnonymous] //允许匿名
        public ActionResult OutLogon()
        {
            Session.Abandon();
            FormsAuthentication.SignOut();
            return RedirectToAction("Index","Home");
        }

在Web.config文件里  <system.web> 下添加配置如下，

<authentication mode="Forms">
<forms loginUrl="~/Home/Index" name="DIQx" timeout="2880" />
</authentication>

注：name="DIQx" 这个name值和登陆时把票据存入cookie时的cookie名称相同。

测试一下。

①什么也不填，直接地址栏输入要跳转的页面

②账号或密码输入错误的。

③角色id不是（1，2，3）中的一个

以上三种情况都会被阻止，并且跳转至刚才在WebConfig中配置的url地址

满足正确条件，返回Main页面

二。动作过滤  这里编写一个WebApi,对api方法进行加密。

编写过滤类，重写OnActionExecuting方法

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Web;

 using System.Net.Http;
 using Solution.Common;
 using System.Web.Http.Controllers;
 using System.Web.Http.Filters;
 namespace Solution.Filter
 {
     public class SecreKeyAttribute : ActionFilterAttribute
     {

         public override void OnActionExecuting(System.Web.Http.Controllers.HttpActionContext actionContext)
         {

             ResponseMsg response = new ResponseMsg() { Status = ActonState.Default };

             //var Ticket = actionContext.ActionArguments["Ticket"];//get请求时带的参数

             var Ticket = System.Web.HttpContext.Current.Request["Ticket"];

             if (Ticket == null)
             {
                 response.Msg = "请传入密钥！";
                 actionContext.Response = actionContext.Request.CreateResponse(System.Net.HttpStatusCode.OK, response);
             }
             else
             {
                 string SecrtetKey = Ticket.ToString();
                 if (!SecrtetKey.Equals(""))
                 {
                     response.Msg = "密钥错误！";
                     actionContext.Response = actionContext.Request.CreateResponse(System.Net.HttpStatusCode.OK, response);
                 }
             }
             base.OnActionExecuting(actionContext);

         }

         public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
         {

             base.OnActionExecuted(actionExecutedContext);
         }

     }
 }

编写WebApiConfig配置文件，

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Web;
 using System.Web.Http;

 namespace Solution.Models
 {
     public class WebApiConfig
     {
         public static void Register(HttpConfiguration config)
         {
             //config.MapHttpAttributeRoutes();

             config.Routes.MapHttpRoute(
                 name: "DefaultApi",//默认请求api地址
                 routeTemplate: "api/{controller}/{action}/{id}", //例如：
 http://localhost:41464/api/ScreateKey/GetInfo
                 defaults: new { id = RouteParameter.Optional });
         }
     }
 }

在Golba.asax中Application_Start()方法下加入刚才的WebApi文件配置

WebApiConfig.Register(GlobalConfiguration.Configuration);

创建对应的api方法，并加入 [SecreKey]标签

 using Solution.Common;
 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Web;
 using System.Web.Http;

 using System.Net;
 using System.Net.Http;
 using Solution.Filter;

 namespace Solution.Controllers
 {
     public class ScreateKeyController : ApiController
     {

         // GET: ScreateKey
         [SecreKey]
         [HttpPost]
         public ResponseMsg GetInfo([FromBody]string Ticket)
         {
             ResponseMsg response = new ResponseMsg() { Status = ActonState.Default };
             response.Msg = "密钥正确时，会返回这个结果";
             return response;
         }
     }
 }

注：这里用的是post请求。 参数必须带上这个[FromBody]，不然请求不到。而且这个[FromBody]只能用一次，如果有多个参数就只能封装到一个类里面。

测试一下。正确密钥 “8888888”

密钥错误：

密钥正确：

三。结果过滤

添加一个过滤特性类

 using Solution.Common;
 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Web;
 using System.Web.Mvc;

 namespace Solution.Filter
 {
     public class ResultAttribute : ActionFilterAttribute
     {
         public override void OnResultExecuting(ResultExecutingContext resultContext)
         {
             ResponseMsg response = new ResponseMsg() { Status = ActonState.Default };
             resultContext.HttpContext.Response.Write("<br/> 结果返回之前执行");
             base.OnResultExecuting(resultContext);
         }

         public override void OnResultExecuted(ResultExecutedContext resultContext)
         {
             ResponseMsg response = new ResponseMsg() { Status = ActonState.Default };
             resultContext.HttpContext.Response.Write("<br/> 结果返回之后执行");
             base.OnResultExecuted(resultContext);
         }
     }
 }

在Home控制器添加一个视图，并添加[Result]标签

 [Result]
         public ActionResult FunResult()
         {
             return View();
         }

在FunResult.cshtml页面加入如下代码：

@{
Response.Write("<br/> 返回的结果");
}

测试一下，得到结果如下图：

四。异常过滤

创建一个发生错误时跳转的页面

添加一个异常过滤特性类

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Web;

 using System.Web.Mvc;

 namespace Solution.Filter
 {
     //异常过滤器
     public class HandErrorAttribute :HandleErrorAttribute
     {
         //程序中任何一个地方发生异常都会处理
         public override void OnException(ExceptionContext filterContext)
         {
             //获取异常对象
             Exception ex = filterContext.Exception;

             //记录日志

             //发生错误后，跳转的页面
             filterContext.Result = new RedirectResult("/Home/Error");

             //告知异常已被处理。如果没有则按照系统正常的异常处理流程走！
             filterContext.ExceptionHandled = true;

         }
     }
 }

在App_Start文件夹下创建FilterConfig文件

 using Solution.Filter;
 using System.Web;
 using System.Web.Mvc;

 namespace Solution
 {
     public class FilterConfig
     {
         public static void RegisterGlobalFilters(GlobalFilterCollection filters)
         {
             filters.Add(new HandErrorAttribute());
         }
     }
 }

在Glabal.asa文件Application_Start()方法下添加刚才的筛选配置

FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);