我可以从HTTPModule访问会话状态吗?

在街上发现的 ASP.NET forums :

using System;
using System.Web;
using System.Web.Security;
using System.Web.SessionState;
using System.Diagnostics;

// This code demonstrates how to make session state available in HttpModule,
// regardless of requested resource.
// author: Tomasz Jastrzebski

public class MyHttpModule : IHttpModule
{
   public void Init(HttpApplication application)
   {
      application.PostAcquireRequestState += new EventHandler(Application_PostAcquireRequestState);
      application.PostMapRequestHandler += new EventHandler(Application_PostMapRequestHandler);
   }

   void Application_PostMapRequestHandler(object source, EventArgs e)
   {
      HttpApplication app = (HttpApplication)source;

      if (app.Context.Handler is IReadOnlySessionState || app.Context.Handler is IRequiresSessionState) {
         // no need to replace the current handler
         return;
      }

      // swap the current handler
      app.Context.Handler = new MyHttpHandler(app.Context.Handler);
   }

   void Application_PostAcquireRequestState(object source, EventArgs e)
   {
      HttpApplication app = (HttpApplication)source;

      MyHttpHandler resourceHttpHandler = HttpContext.Current.Handler as MyHttpHandler;

      if (resourceHttpHandler != null) {
         // set the original handler back
         HttpContext.Current.Handler = resourceHttpHandler.OriginalHandler;
      }

      // -> at this point session state should be available

      Debug.Assert(app.Session != null, "it did not work :(");
   }

   public void Dispose()
   {

   }

   // a temp handler used to force the SessionStateModule to load session state
   public class MyHttpHandler : IHttpHandler, IRequiresSessionState
   {
      internal readonly IHttpHandler OriginalHandler;

      public MyHttpHandler(IHttpHandler originalHandler)
      {
         OriginalHandler = originalHandler;
      }

      public void ProcessRequest(HttpContext context)
      {
         // do not worry, ProcessRequest() will not be called, but let's be safe
         throw new InvalidOperationException("MyHttpHandler cannot process requests.");
      }

      public bool IsReusable
      {
         // IsReusable must be set to false since class has a member!
         get { return false; }
      }
   }
}

HttpContext.Current.Session pipeline events 在初始化会话状态之前发生的。。。

在注释中澄清后编辑:在处理 BeginRequest event ,会话对象实际上仍然是null/Nothing,因为它还没有被ASP.NET运行时初始化。要解决此问题,请将处理代码移动到发生在 PostAcquireRequestState PreRequestHandlerExecute 对于我自己来说,因为所有的低级工作都在这个阶段完成了,但是您仍然会抢占任何正常的处理。

访问 HttpContext.Current.Session IHttpModule 可以在 PreRequestHandlerExecute 处理程序。

PreRequestHandlerExecute :“发生在ASP.NET开始执行事件处理程序之前(例如,页面或XML Web服务)。”这意味着在服务“aspx”页面之前,此事件将被执行。“会话状态”可用,因此您可以将自己击倒。

例子:

public class SessionModule : IHttpModule 
    {
        public void Init(HttpApplication context)
        {
            context.BeginRequest += BeginTransaction;
            context.EndRequest += CommitAndCloseSession;
            context.PreRequestHandlerExecute += PreRequestHandlerExecute;
        }



        public void Dispose() { }

        public void PreRequestHandlerExecute(object sender, EventArgs e)
        {
            var context = ((HttpApplication)sender).Context;
            context.Session["some_sesion"] = new SomeObject();
        }
...
}

如果要在托管应用程序中编写一个普通的、基本的HttpModule,并希望通过页面或处理程序将其应用于asp.net请求,则只需确保在创建会话后在生命周期中使用事件即可。PreRequestHandlerExecute而不是Begin_请求通常是我要去的地方。mdb在他的编辑中有它的权利。

最初列出的回答问题的较长代码片段有效,但比初始问题复杂且范围更广。它将处理内容来自ASP.net处理程序不可用的情况,您可以在该处理程序中实现IRequiresessionState接口,从而触发会话机制使其可用。(就像磁盘上的静态gif文件)。它基本上是设置一个虚拟处理程序,然后实现该接口以使会话可用。

如果您只需要代码的会话,只需选择要在模块中处理的正确事件。

尝试:在MyHttpModule类中声明:

private HttpApplication contextapp;

public void Init(HttpApplication application)
{
     //Must be after AcquireRequestState - the session exist after RequestState
     application.PostAcquireRequestState += new EventHandler(MyNewEvent);
     this.contextapp=application;
}  

因此,在同一类中的另一个方法(事件)中:

public void MyNewEvent(object sender, EventArgs e)
{
    //A example...
    if(contextoapp.Context.Session != null)
    {
       this.contextapp.Context.Session.Timeout=30;
       System.Diagnostics.Debug.WriteLine("Timeout changed");
    }
}

自从.NET4.0以来,IHttpHandler的这种攻击就没有必要加载会话状态(就像大多数上浮答案中的一样)。有一种方法 HttpContext.SetSessionStateBehavior 如果所有请求集上都需要会话 runAllManagedModulesForAllRequests preCondition="managedHandler" 如果您不需要所有请求的会话。 对于未来的读者,这里有一个完整的示例:

<system.webServer>
    <modules runAllManagedModulesForAllRequests="true">
        <add name="ModuleWithSessionAccess" type="HttpModuleWithSessionAccess.ModuleWithSessionAccess, HttpModuleWithSessionAccess"/>
    </modules>
</system.webServer>

web.config声明-仅为托管请求调用HttpModule:

<system.webServer>
    <modules>
        <add name="ModuleWithSessionAccess" type="HttpModuleWithSessionAccess.ModuleWithSessionAccess, HttpModuleWithSessionAccess" preCondition="managedHandler"/>
    </modules>
</system.webServer>

IHTTP模块实现:

namespace HttpModuleWithSessionAccess
{
    public class ModuleWithSessionAccess : IHttpModule
    {
        public void Init(HttpApplication context)
        {
            context.BeginRequest += Context_BeginRequest;
            context.PreRequestHandlerExecute += Context_PreRequestHandlerExecute;
        }

        private void Context_BeginRequest(object sender, EventArgs e)
        {
            var app = (HttpApplication)sender;
            app.Context.SetSessionStateBehavior(System.Web.SessionState.SessionStateBehavior.Required);
        }
    
        private void Context_PreRequestHandlerExecute(object sender, EventArgs e)
        {
            var app = (HttpApplication)sender;
            if (app.Context.Session != null)
            {
                app.Context.Session["Random"] = $"Random value: {new Random().Next()}";
            }
        }

        public void Dispose()
        {
        }
    }
}