IIS 7.0: IHttpResponse::DisableKernelCache Method

Disables the kernel cache for this response.

virtual VOID DisableKernelCache(
   ULONG reason = 9
) = 0;

Parameters

reason: The optional reason for disabling the kernel cache.

Return Value

VOID.

Remarks

The DisableKernelCache method disables kernel caching for the current response.

You can optionally pass a reason parameter that contains a value defined in the IISCacheEvents::HTTPSYS_CACHEABLE::enumReason enumeration to indicate why you are disabling caching.

Note:
If you do not pass a reason parameter to the DisableKernelCache method, the default value of 9 (HANDLER_HTTPSYS_UNFRIENDLY) will be used.

Example

The following code example demonstrates how to use the DisableKernelCache method to disable kernel caching for the current request.

Note:
Combine this example module with the example module listed for the GetKernelCacheEnabled method if you want to return the current caching status.

Visual C++

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

// Create the module class.
class MyHttpModule : public CHttpModule
{
public:
    REQUEST_NOTIFICATION_STATUS
    OnBeginRequest(
        IN IHttpContext * pHttpContext,
        IN IHttpEventProvider * pProvider
    )
    {
        UNREFERENCED_PARAMETER( pProvider );

        // Retrieve a pointer to the response.
        IHttpResponse * pHttpResponse = pHttpContext->GetResponse();

        // Test for an error.
        if (pHttpResponse != NULL)
        {
            // Disable caching as HANDLER_HTTPSYS_UNFRIENDLY.
            pHttpResponse->DisableKernelCache(9);
        }

        // Return processing to the pipeline.
        return RQ_NOTIFICATION_CONTINUE;
    }
};

// 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(
        new MyHttpModuleFactory,
        RQ_BEGIN_REQUEST,
        0
    );
}

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 [IIS 7].

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	Requires IIS 7 on Windows Vista.
Server	Requires IIS 7 on Windows Vista.
Product	IIS 7
Header	Httpserv.h

Reference

IIS 7.0: IHttpResponse Interface

IIS 7.0: IHttpResponse::GetCachePolicy Method

IIS 7.0: IHttpResponse::GetKernelCacheEnabled Method

IIS 7.0: IHttpServer::FlushKernelCache Method