HttpModule是如何工作的 當一個HTTP請求到達HttpModule時，整個ASP.NET Framework系統還并沒有對這個HTTP請求做任何處理，也就是說此時對于HTTP請求來講，HttpModule是一個HTTP請求的“必經之路”，是以可以在這個HTTP請求傳遞到真正的請求進行中心（HttpHandler）之前附加一些需要的資訊在這個HTTP請求資訊之上，或者針對截獲的這個HTTP請求資訊作一些額外的工作，或者在某些情況下幹脆終止滿足一些條件的HTTP請求，進而可以起到一個Filter過濾器的作用。 示例1： using System; using System.Collections.Generic; using System.Text; using System.Web; namespace MyHttpModule { ///<summary> /// 說明：用來實作自己的HttpModule類。 /// 作者：文野 /// 聯系：[email protected] ///</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(" 我來自自定義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(" 我來自自定義HttpModule中的EndRequest<br />" ); } #region IHttpModule 成員 public void Dispose() {} public void Init(HttpApplication application) { application.BeginRequest += new EventHandler(Application_BeginRequest); application.EndRequest += new EventHandler(Application_EndRequest); } #endregion } } 在Web.config進行如下配置 < add name = "MyFirstHttpModule"type="MyHttpModule.MyFirstHttpModule,MyHttpModule"/>
深入了解 HttpModule 一個HTTP請求在HttpModule容器的傳遞過程中，會在某一時刻（ResolveRequestCache事件）将這個HTTP請求傳遞給HttpHandler容器。在這個事件之後，HttpModule容器會建立一個HttpHandler的入口執行個體，但是此時并沒有将HTTP請求控制權交出，而是繼續觸發AcquireRequestState事件以及PreRequestHandlerExcute事件。在PreRequestHandlerExcute事件之後，HttpModule視窗就會将控制權暫時交給HttpHandler容器，以便進行真正的HTTP請求處理工作。 而在HttpHandler容器内部會執行ProcessRequest方法來處理HTTP請求。在容器HttpHandler處理完畢整個HTTP請求之後，會将控制權交還給HttpModule，HttpModule則會繼續對處理完畢的HTTP請求資訊流進行層層的轉交動作，直到傳回到用戶端為止。
圖1：HttpModule生命周期示意圖 示例2：驗證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 成員 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 } }