问题
I want to write an IHttpModule that has to be executed strictly after FormsAuthenticationModule, otherwise it will be useless.
There's HttpContext.Current.ApplicationInstance.Modules property that returns a collection of IHttpModules. I can check that my module is after FormsAuthenticationModule in this collection.
Will that be enough? Does that collection list IHttpModules in the order in which they are executed?
回答1:
Recall that modules can subscribe to different pipeline events. Within any given pipeline event, modules should run in the order in which they're specified in the Modules collection.
As a practical example, imagine a Modules collection which has these three modules registered:
- Module A, which subscribes to EndRequest
- Module B, which subscribes to BeginRequest and EndRequest
- Module C, which subscribes to AuthenticateRequest
The order of execution will be:
- Module B, BeginRequest
- Module C, AuthenticateRequest
- Module A, EndRequest
- Module B, EndRequest
Since the FormsAuthenticationModule subscribes to the AuthenticateRequest event, consider making your own module subscribe to the PostAuthenticateRequest event. That way you're guaranteed that if the FormsAuthenticationModule logic runs, it runs before your logic, regardless of the order in which they're registered in the Modules collection.
回答2:
I will try to answer it .
I do not think you should rely on HttpContext.Current.ApplicationInstance.Modules collection, because you do now in which order module will be executed.
Please note that I did't do any prototype, it's just my thought .
The dll Microsoft.Web.Infrastructure.dll has a method for register dynamically HTTP module
The dll is shipped with WebPages 1.0
Create helper class for registration
public static class RegisterHttpModuleHelper
{
public static void Start()
{
DynamicModuleUtility.RegisterModule(typeof(YourCustomModule));
}
}
FormsAuthenticationModule has event "Authenticate".
On hander of this event , try to dynamicaly register your Custom HttpModule using
public void FormsAuthentication_OnAuthenticate(object sender, FormsAuthenticationEventArgs args)
{
RegisterHttpModuleHelper.Start()
}
来源：https://stackoverflow.com/questions/14973667/can-i-be-sure-that-httpmodules-are-executed-in-the-order-in-which-they-are-liste