Comparing Native-Code and Managed-Code Notifications

Article
05/24/2022

Although the integrated request-processing pipeline in the IIS 7 Web server core enables native-code developers to write HTTP modules in C++, the event notifications that are available to native-code and managed-code developers are not identical. Developers who are migrating an HTTP module from a managed language such as C# to native code will have to address these differences when they create their new modules.

Global Notifications

With IIS 7, developers can now create native-code HTTP modules that process notifications at the global level. In previous versions of IIS, developers could create HTTP modules that processed notifications at only the request-level. HTTP modules that process notifications at the global level are used to process notifications for a variety of server-level events.

The following table lists the global notification methods that are available to native-code developers.

Event notification method	Description
OnGlobalApplicationResolveModules	Called when IIS resolves the registered modules.
OnGlobalApplicationStart	Called when IIS starts an application.
OnGlobalApplicationStop	Called when IIS exits an application.
OnGlobalCacheCleanup	Called when IIS clears the cache.
OnGlobalCacheOperation	Called when IIS performs a cache-related operation.
OnGlobalConfigurationChange	Called when a change is made to a configuration file.
OnGlobalCustomNotification	Called when a module raises a user-defined notification.
OnGlobalFileChange	Called when a file within a Web site is changed.
OnGlobalHealthCheck	Called when a health-related operation is executed.
OnGlobalPreBeginRequest	Called before a request enters the integrated request-processing pipeline.
OnGlobalRSCAQuery	Called when a Run-Time Status and Control query is executed.
OnGlobalStopListening	Called when IIS stops accepting new requests.
OnGlobalThreadCleanup	Called when IIS returns a thread to the thread pool.
OnGlobalTraceEvent	Called when a trace event is raised.

Comparing Request Notifications

Although request notification methods for native-code and managed-code HTTP modules are similar in many ways, they are not completely analogous. For example, the list of deterministic request notification methods is nearly identical for native-code and managed-code modules, yet the list of nondeterministic request notification methods differs greatly.

Native-Code Deterministic Request Notifications

The following table lists the deterministic request notification methods that are available to native-code developers.

Event notification method	Post-event notification method
OnBeginRequest	OnPostBeginRequest
OnAuthenticateRequest	OnPostAuthenticateRequest
OnAuthorizeRequest	OnPostAuthorizeRequest
OnResolveRequestCache	OnPostResolveRequestCache
OnMapRequestHandler	OnPostMapRequestHandler
OnAcquireRequestState	OnPostAcquireRequestState
OnPreExecuteRequestHandler	OnPostPreExecuteRequestHandler
OnExecuteRequestHandler	OnPostExecuteRequestHandler
OnReleaseRequestState	OnPostReleaseRequestState
OnUpdateRequestCache	OnPostUpdateRequestCache
OnLogRequest	OnPostLogRequest
OnEndRequest	OnPostEndRequest

Managed-Code Deterministic Request Notifications

The following table lists the deterministic request notification methods that are available to managed-code developers.

Event notification method	Post-event notification method
BeginRequest	(None)
AuthenticateRequest	PostAuthenticateRequest
AuthorizeRequest	PostAuthorizeRequest
ResolveRequestCache	PostResolveRequestCache
MapRequestHandler	PostMapRequestHandler
AcquireRequestState	PostAcquireRequestState
PreRequestHandlerExecute	(None)
RequestHandlerExecute	PostRequestHandlerExecute
ReleaseRequestState	PostReleaseRequestState
UpdateRequestCache	PostUpdateRequestCache
LogRequest	PostLogRequest
EndRequest	(None)

Native-Code Nondeterministic Request Notifications

The following table lists the nondeterministic request notification methods that are available to native-code developers.

Event notification method	Post-event notification method
OnAsyncCompletion	(None)
OnCustomRequestNotification	(None)
OnMapPath	(None)
OnReadEntity	(None)
OnSendResponse	(None)

Managed-Code Nondeterministic Request Notifications

The following table lists the nondeterministic request notification methods that are available to managed-code developers.

Event notification method	Post-event notification method
PreSendRequestHeaders	(None)
PreSendRequestContent	(None)

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