mvc Action Filter

mvc Action Filter中OnActionExecuting、OnActionExecuted、OnResultExecuting、OnResultExecuted的执行顺序

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

namespace MvcApp.ActionFilters
{
    public class SimpleFilterAttribute:ActionFilterAttribute
    {
        public int ID { get; set; }

        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            File.AppendAllText(@"D:\ActionFilterTest.log", "SimpleFilter " + this.ID + " OnActionExecuting! \r\n");
        }

        public override void OnActionExecuted(ActionExecutedContext filterContext)
        {
            File.AppendAllText(@"D:\ActionFilterTest.log", "SimpleFilter " + this.ID + " OnActionExecuted! \r\n");
        }

        public override void OnResultExecuting(ResultExecutingContext filterContext)
        {
            File.AppendAllText(@"D:\ActionFilterTest.log", "SimpleFilter " + this.ID + " OnResultExecuting! \r\n");
        }

        public override void OnResultExecuted(ResultExecutedContext filterContext)
        {
            File.AppendAllText(@"D:\ActionFilterTest.log", "SimpleFilter " + this.ID + " OnResultExecuted! \r\n");
        }
    }
}

　　   [SimpleFilter(ID = 1, Order = 1)]
        public ActionResult Index()
        {
            ViewData["Message"] = "Get the Filter Data!";
            return View();
        }

这样的执行的结果是

OnActionExecuted可以处理执行过程中的异常

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

namespace MvcApp.ActionFilters
{
    public class ErrorHandlingFilterAttribute:ActionFilterAttribute
    {
        public override void OnActionExecuted(ActionExecutedContext filterContext)
        {
            if (filterContext.Exception != null)
            {
                filterContext.ExceptionHandled = true;
                //Filter是Controllers的名称
                filterContext.Result = new RedirectToRouteResult("Filter", new RouteValueDictionary(new { action = "OnError" }));
            }
        }
    }
}

新建一个OnError的视图

public ActionResult OnError()
        {
            ViewData["Title"] = "OnError";
            ViewData["Message"] = "Error Page!";
            return View();
        }

        [ErrorHandlingFilter]
        public void RaiseError()
        {
            throw new Exception();
        }

OnResultExecuting可以用于服务器端的压缩和客户端缓存

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.IO.Compression;

namespace MvcApp.ActionFilters
{
    public class CompressFilterAttribute:ActionFilterAttribute
    {
        public override void OnResultExecuting(ResultExecutingContext filterContext)
        {
            string accpetEncoding = filterContext.HttpContext.Request.Headers["Accept-Encoding"];
            if (string.IsNullOrEmpty(accpetEncoding))
                return;
            var response = filterContext.HttpContext.Response;
            accpetEncoding=accpetEncoding.ToUpperInvariant();
            if (accpetEncoding.Contains("GZIP"))
            {
                response.AddHeader("content-encoding", "gzip");
                response.Filter = new GZipStream(response.Filter, CompressionMode.Compress);
            }
            else if (accpetEncoding.Contains("DEFLATE"))
            {
                response.AddHeader("content-encoding", "deflate");
                response.Filter = new DeflateStream(response.Filter, CompressionMode.Compress);
            }
            
        }
    }
}

新建一个Compress的视图，可以压缩前后的大小

　　　[CompressFilter]
        public ActionResult Compress()
        {
            return View();
        }

OnResultExecuting可以用于页面尾部输出信息和异常处理

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

namespace MvcApp.ActionFilters
{
    public class TraceFilterAttribute:ActionFilterAttribute
    {

        public override void OnResultExecuting(ResultExecutingContext filterContext)
        {
            filterContext.HttpContext.Items["Start"] = DateTime.Now;
        }

        public override void OnResultExecuted(ResultExecutedContext filterContext)
        {
            DateTime start = (DateTime)filterContext.HttpContext.Items["Start"];
            TimeSpan ts = DateTime.Now - start;
            filterContext.HttpContext.Response.Write("<hr />" + ts.ToString());
        }
    }
}

新建一个Timing的视图 

      [TraceFilter]
        public ActionResult Timing()
        {
            Random rdm = new Random(DateTime.Now.Millisecond);
            Thread.Sleep(rdm.Next(5) * 3000);
            return View();
        }