CHttpModule::OnPostResolveRequestCache Method

Article
06/14/2022

Represents the method that will handle a ResolveRequestCache post-event, which occurs after IIS has resolved a request from the cache.

Syntax

virtual REQUEST_NOTIFICATION_STATUS OnPostResolveRequestCache(  
   IN IHttpContext* pHttpContext,  
   IN IHttpEventProvider* pProvider  
);

Parameters

pHttpContext
[IN] A pointer to an IHttpContext interface.

pProvider
[IN] A pointer to an IHttpEventProvider interface.

Return Value

A REQUEST_NOTIFICATION_STATUS value.

Remarks

When a request-level module is registered for the RQ_RESOLVE_REQUEST_CACHE notification, IIS will call the module's OnPostResolveRequestCache method after IIS has resolved a request from the cache.

Note

Request-level modules can register for the PostResolveRequestCache post-event notification by registering for RQ_RESOLVE_REQUEST_CACHE in the module's RegisterModule function.

Example

The following code example demonstrates how to create a request-level HTTP module that registers for the RQ_RESOLVE_REQUEST_CACHE event and post-event notifications. When IIS resolves a request from the cache, IIS will call the example module's OnResolveRequestCache and OnPostResolveRequestCache methods. Each method will write an entry in the application log of the Windows Event Viewer. When processing is complete, the module will exit.

#define _WINSOCKAPI_
#include <windows.h>
#include <sal.h>
#include <httpserv.h>

// Create the module class.
class MyHttpModule : public CHttpModule
{
public:

    // Process an RQ_RESOLVE_REQUEST_CACHE event.
    REQUEST_NOTIFICATION_STATUS
    OnResolveRequestCache(
        IN IHttpContext * pHttpContext,
        IN IHttpEventProvider * pProvider
    )
    {
        UNREFERENCED_PARAMETER( pHttpContext );
        UNREFERENCED_PARAMETER( pProvider );
        WriteEventViewerLog("OnResolveRequestCache");
        return RQ_NOTIFICATION_CONTINUE;
    }

    // Process an RQ_RESOLVE_REQUEST_CACHE post-event.
    REQUEST_NOTIFICATION_STATUS
    OnPostResolveRequestCache(
        IN IHttpContext * pHttpContext,
        IN IHttpEventProvider * pProvider
    )
    {
        UNREFERENCED_PARAMETER( pHttpContext );
        UNREFERENCED_PARAMETER( pProvider );
        WriteEventViewerLog("OnPostResolveRequestCache");
        return RQ_NOTIFICATION_CONTINUE;
    }

    MyHttpModule()
    {
        // Open a handle to the Event Viewer.
        m_hEventLog = RegisterEventSource( NULL,"IISADMIN" );
    }

    ~MyHttpModule()
    {
        // Test whether the handle for the Event Viewer is open.
        if (NULL != m_hEventLog)
        {
            // Close the handle to the Event Viewer.
            DeregisterEventSource( m_hEventLog );
            m_hEventLog = NULL;
        }
    }

private:

    // Create a handle for the event viewer.
    HANDLE m_hEventLog;

    // Define a method that writes to the Event Viewer.
    BOOL WriteEventViewerLog(LPCSTR szNotification)
    {
        // Test whether the handle for the Event Viewer is open.
        if (NULL != m_hEventLog)
        {
            // Write any strings to the Event Viewer and return.
            return ReportEvent(
                m_hEventLog,
                EVENTLOG_INFORMATION_TYPE, 0, 0,
                NULL, 1, 0, &szNotification, NULL );
        }
        return FALSE;
    }
};

// Create the module's class factory.
class MyHttpModuleFactory : public IHttpModuleFactory
{
public:
    HRESULT
    GetHttpModule(
        OUT CHttpModule ** ppModule, 
        IN IModuleAllocator * pAllocator
    )
    {
        UNREFERENCED_PARAMETER( pAllocator );

        // Create a new instance.
        MyHttpModule * pModule = new MyHttpModule;

        // Test for an error.
        if (!pModule)
        {
            // Return an error if the factory cannot create the instance.
            return HRESULT_FROM_WIN32( ERROR_NOT_ENOUGH_MEMORY );
        }
        else
        {
            // Return a pointer to the module.
            *ppModule = pModule;
            pModule = NULL;
            // Return a success status.
            return S_OK;
        }            
    }

    void Terminate()
    {
        // Remove the class from memory.
        delete this;
    }
};

// Create the module's exported registration function.
HRESULT
__stdcall
RegisterModule(
    DWORD dwServerVersion,
    IHttpModuleRegistrationInfo * pModuleInfo,
    IHttpServer * pGlobalInfo
)
{
    UNREFERENCED_PARAMETER( dwServerVersion );
    UNREFERENCED_PARAMETER( pGlobalInfo );

    // Set the request notifications and exit.
    return pModuleInfo->SetRequestNotifications(
        // Specify the class factory.
        new MyHttpModuleFactory,
        // Specify the event notifications.
        RQ_RESOLVE_REQUEST_CACHE,
        // Specify the post-event notifications.
        RQ_RESOLVE_REQUEST_CACHE
    );
}

Your module must export the RegisterModule function. You can export this function by creating a module definition (.def) file for your project, or you can compile the module by using the /EXPORT:RegisterModule switch. For more information, see Walkthrough: Creating a Request-Level HTTP Module By Using Native Code.

You can optionally compile the code by using the __stdcall (/Gz) calling convention instead of explicitly declaring the calling convention for each function.

Requirements

Type	Description
Client	- IIS 7.0 on Windows Vista - IIS 7.5 on Windows 7 - IIS 8.0 on Windows 8 - IIS 10.0 on Windows 10
Server	- IIS 7.0 on Windows Server 2008 - IIS 7.5 on Windows Server 2008 R2 - IIS 8.0 on Windows Server 2012 - IIS 8.5 on Windows Server 2012 R2 - IIS 10.0 on Windows Server 2016
Product	- IIS 7.0, IIS 7.5, IIS 8.0, IIS 8.5, IIS 10.0 - IIS Express 7.5, IIS Express 8.0, IIS Express 10.0
Header	Httpserv.h

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