• 设为首页
  • 点击收藏
  • 手机版
    手机扫一扫访问
    迪恩网络手机版
  • 关注官方公众号
    微信扫一扫关注
    公众号

ASP.NET——HttpModule

原作者: [db:作者] 来自: [db:来源] 收藏 邀请

ASP.NET模块——HttpModule[转]

HttpModule是如何工作的

当一个HTTP请求到达HttpModule时,整个ASP.NET Framework系统还并没有对这个HTTP请求做任何处理,也就是说此时对于HTTP请求来讲,HttpModule是一个HTTP请求的“必经之路”,所以可以在这个HTTP请求传递到真正的请求处理中心(HttpHandler)之前附加一些需要的信息在这个HTTP请求信息之上,或者针对截获的这个HTTP请求信息作一些额外的工作,或者在某些情况下干脆终止满足一些条件的HTTP请求,从而可以起到一个Filter过滤器的作用。

示例1:

 

using System;
using System.Collections.Generic;
using System.Text;
using System.Web;


namespace MyHttpModule
{
    /// <summary>
    /// 说明:用来实现自己的HttpModule类。
    /// </summary>
    public class MyFirstHttpModule : IHttpModule
    {
        private void Application_BeginRequest(object sender, EventArgs e)
        {
            HttpApplication application = (HttpApplication) sender;

            HttpContext context = application.Context;
            HttpRequest request = application.Request;
            HttpResponse response = application.Response;

            response.Write("我来自自定义HttpModule中的BeginRequest<br />");
        }


        private void Application_EndRequest(object sender, EventArgs e)
        {
            HttpApplication application = (HttpApplication) sender;

            HttpContext context = application.Context;
            HttpRequest request = application.Request;
            HttpResponse response = application.Response;

            response.Write("我来自自定义HttpModule中的EndRequest<br />");
        }

        #region IHttpModule 成员


        public void Dispose()
        {
        }

 

        public void Init(HttpApplication application)
        {
            application.BeginRequest += new EventHandler(Application_BeginRequest);
            application.EndRequest += new EventHandler(Application_EndRequest);
        }

        #endregion
    }
}

 

在Web.config进行如下配置

<add name="MyFirstHttpModule" type="MyHttpModule.MyFirstHttpModule,MyHttpModule"/>

深入了解HttpModule

一个HTTP请求在HttpModule容器的传递过程中,会在某一时刻(ResolveRequestCache事件)将这个HTTP请求传递给HttpHandler容器。在这个事件之后,HttpModule容器会建立一个HttpHandler的入口实例,但是此时并没有将HTTP请求控制权交出,而是继续触发AcquireRequestState事件以及PreRequestHandlerExcute事件。在PreRequestHandlerExcute事件之后,HttpModule窗口就会将控制权暂时交给HttpHandler容器,以便进行真正的HTTP请求处理工作。

而在HttpHandler容器内部会执行ProcessRequest方法来处理HTTP请求。在容器HttpHandler处理完毕整个HTTP请求之后,会将控制权交还给HttpModuleHttpModule则会继续对处理完毕的HTTP请求信息流进行层层的转交动作,直到返回到客户端为止。

图1:HttpModule生命周期示意图

示例2:验证HttpModule生命周期

 

 using System;
using System.Collections.Generic;
using System.Text;
using System.Web;

namespace MyHttpModule
{
    public class ValidaterHttpModule : IHttpModule
    {
        #region IHttpModule 成员

        public void Dispose()
        { }

        public void Init(HttpApplication application)
        {
            application.BeginRequest += new EventHandler(application_BeginRequest);

            application.EndRequest += new EventHandler(application_EndRequest);

            application.PreRequestHandlerExecute += new EventHandler(application_PreRequestHandlerExecute);

            application.PostRequestHandlerExecute += new EventHandler(application_PostRequestHandlerExecute);

            application.ReleaseRequestState += new EventHandler(application_ReleaseRequestState);

            application.AcquireRequestState += new EventHandler(application_AcquireRequestState);

            application.AuthenticateRequest += new EventHandler(application_AuthenticateRequest);

            application.AuthorizeRequest += new EventHandler(application_AuthorizeRequest);

            application.ResolveRequestCache += new EventHandler(application_ResolveRequestCache);

            application.PreSendRequestHeaders += new EventHandler(application_PreSendRequestHeaders);

            application.PreSendRequestContent += new EventHandler(application_PreSendRequestContent);
        }

        void application_PreSendRequestContent(object sender, EventArgs e)
        {
            HttpApplication application = (HttpApplication) sender;
            application.Context.Response.Write("application_PreSendRequestContent<br/>");
        }

        void application_PreSendRequestHeaders(object sender, EventArgs e)
        {
            HttpApplication application = (HttpApplication) sender;
            application.Context.Response.Write("application_PreSendRequestHeaders<br/>");
        }

        void application_ResolveRequestCache(object sender, EventArgs e)
        {
            HttpApplication application = (HttpApplication) sender;
            application.Context.Response.Write("application_ResolveRequestCache<br/>");
        }

        void application_AuthorizeRequest(object sender, EventArgs e)
        {
            HttpApplication application = (HttpApplication) sender;
            application.Context.Response.Write("application_AuthorizeRequest<br/>");
        }

        void application_AuthenticateRequest(object sender, EventArgs e)
        {
            HttpApplication application = (HttpApplication) sender;
            application.Context.Response.Write("application_AuthenticateRequest<br/>");
        }

        void application_AcquireRequestState(object sender, EventArgs e)
        {
            HttpApplication application = (HttpApplication) sender;
            application.Context.Response.Write("application_AcquireRequestState<br/>");
        }

        void application_ReleaseRequestState(object sender, EventArgs e)
        {
            HttpApplication application = (HttpApplication) sender;
            application.Context.Response.Write("application_ReleaseRequestState<br/>");
        }

        void application_PostRequestHandlerExecute(object sender, EventArgs e)
        {
            HttpApplication application = (HttpApplication) sender;
            application.Context.Response.Write("application_PostRequestHandlerExecute<br/>");
        }

        void application_PreRequestHandlerExecute(object sender, EventArgs e)
        {
            HttpApplication application = (HttpApplication) sender;
            application.Context.Response.Write("application_PreRequestHandlerExecute<br/>");
        }

        void application_EndRequest(object sender, EventArgs e)
        {
            HttpApplication application = (HttpApplication) sender;
            application.Context.Response.Write("application_EndRequest<br/>");
        }

        void application_BeginRequest(object sender, EventArgs e)
        {
            HttpApplication application = (HttpApplication) sender;
            application.Context.Response.Write("application_BeginRequest<br/>");
        }

        #endregion
    }
}

 

多个自定义的Http Module的运作

从运行结果可以看到,在web.config文件中引入自定义HttpModule的顺序就决定了多个自定义HttpModule在处理一个HTTP请求的接管顺序。注:系统默认那几个HttpModule是最先衩ASP.NET Framework所加载上去的。

示例3:(代码类同示例2)

在HttpModule中终止此次的HTTP请求

可以利用HttpModule通过调用HttpApplication.CompleteRequest()方法实现当满足某一个条件时终止此次的HTTP请求。

需要注意的是,即使调用了HttpApplication.CompleteRequest()方法终止了一个HTTP请求,ASP.NET Framework仍然会触发HttpApplication后面的这3个事件:EndRequest事件、PreSendRequestHeaders事件、PreSendRequestContent事件。

如果存在多个自定义的HttpModule的话,当Module1终止了一个HTTP请求,这个HTTP请求将不会再触发Module2中相应的事件了,但Module2的最后三个事件仍会被触发。

示例4:

 

 using System;

using System.Collections.Generic;

using System.Text;
using System.Web;

namespace MyHttpModule
{
    public class CompleteRequestHttpModule : IHttpModule
    {
        #region IHttpModule 成员

        public void Dispose()
        { }

        public void Init(HttpApplication application)
        {
            application.BeginRequest += new EventHandler(Application_BeginRequest);
        }

        void Application_BeginRequest(object sender, EventArgs e)
        {
            HttpApplication application = (HttpApplication) sender;
            application.CompleteRequest();
            application.Context.Response.Write("请求被终止。");
        }

        #endregion
    }
}

 

 


鲜花

握手

雷人

路过

鸡蛋
该文章已有0人参与评论

请发表评论

全部评论

专题导读
上一篇:
[转载]ASP.NET应用程序设计的10大技巧发布时间:2022-07-10
下一篇:
在IIS6ASP.NET4.0安装最常遇到的四个问题发布时间:2022-07-10
热门推荐
热门话题
阅读排行榜

扫描微信二维码

查看手机版网站

随时了解更新最新资讯

139-2527-9053

在线客服(服务时间 9:00~18:00)

在线QQ客服
地址:深圳市南山区西丽大学城创智工业园
电邮:jeky_zhao#qq.com
移动电话:139-2527-9053

Powered by 互联科技 X3.4© 2001-2213 极客世界.|Sitemap