ASP.NET系统中默认的HttpModule：
DefaultAuthenticationModule 确保上下文中存在 Authentication 对象。无法继承此类。
FileAuthorizationModule 验证远程用户是否具有访问所请求文件的 NT 权限。无法继承此类。
FormsAuthenticationModule 启用 ASP.NET 应用程序以使用 Forms 身份验证。无法继承此类。
PassportAuthenticationModule 提供环绕,PassportAuthentication 服务的包装。无法继承此类。
SessionStateModule 为应用程序提供会话状态服务。
UrlAuthorizationModule 提供基于 URL 的授权服务以允许或拒绝对指定资源的访问。无法继承此类。
WindowsAuthenticationModule 启用 ASP.NET 应用程序以使用 Windows/IIS 身份验证。无法继承此类
这些系统默认的HttpModule是在文件machine.config中配置的，和我们开发时使用到的web.config的关系是：是在ASP.NET FRAMEWORK启动处理一个Http Request的时候，它会依次加载machine.config和请求页面所在目录的web.config文件，如果在machine中配置了一个自己的HttpModule，你仍然可以在所在页面的web.config文件中remove掉这个映射关系。
public class HelloWorldModule : IHttpModule
{
public HelloWorldModule()
{
}
public String ModuleName
{
get { return "HelloWorldModule"; }
}
// In the Init function, register for HttpApplication
// events by adding your handlers.
public void Init(HttpApplication application)
{
application.BeginRequest +=
(new EventHandler(this.Application_BeginRequest));
application.EndRequest +=
(new EventHandler(this.Application_EndRequest));
}
private void Application_BeginRequest(Object source,
EventArgs e)
{
// Create HttpApplication and HttpContext objects to access
// request and response properties.
HttpApplication application = (HttpApplication)source;
HttpContext context = application.Context;
context.Response.Write("<h1><font color=red> HelloWorldModule: Beginning of Request</font></h1><hr>");
}
private void Application_EndRequest(Object source, EventArgs e)
{
HttpApplication application = (HttpApplication)source;
HttpContext context = application.Context;
context.Response.Write("<hr><h1><font color=red>HelloWorldModule: End of Request</font></h1>");
}
public void Dispose()
{
}
}
<system.web>
<httpModules>
<add name="HelloWorldModule" type="HelloWorldModule"/>
</httpModules>
</system.web>
{
public HelloWorldModule()
{
}
public String ModuleName
{
get { return "HelloWorldModule"; }
}
// In the Init function, register for HttpApplication
// events by adding your handlers.
public void Init(HttpApplication application)
{
application.BeginRequest +=
(new EventHandler(this.Application_BeginRequest));
application.EndRequest +=
(new EventHandler(this.Application_EndRequest));
}
private void Application_BeginRequest(Object source,
EventArgs e)
{
// Create HttpApplication and HttpContext objects to access
// request and response properties.
HttpApplication application = (HttpApplication)source;
HttpContext context = application.Context;
context.Response.Write("<h1><font color=red> HelloWorldModule: Beginning of Request</font></h1><hr>");
}
private void Application_EndRequest(Object source, EventArgs e)
{
HttpApplication application = (HttpApplication)source;
HttpContext context = application.Context;
context.Response.Write("<hr><h1><font color=red>HelloWorldModule: End of Request</font></h1>");
}
public void Dispose()
{
}
}
<system.web>
<httpModules>
<add name="HelloWorldModule" type="HelloWorldModule"/>
</httpModules>
</system.web>
