CGlobalModule::OnGlobalFileChange Method

Represents the method that will handle a GlobalFileChange event, which occurs when a file within a Web site is changed.

Syntax

virtual GLOBAL_NOTIFICATION_STATUS OnGlobalFileChange(  
   IN IGlobalFileChangeProvider* pProvider  
);  

Parameters

pProvider
[IN] A pointer to an IGlobalFileChangeProvider interface.

Return Value

A GLOBAL_NOTIFICATION_STATUS value.

Remarks

When a global module has registered for the GL_FILE_CHANGE event notification, IIS will call the module's OnGlobalFileChange method when a file within the scope of a Web site is changed.

IIS creates an IGlobalFileChangeProvider interface and passes the interface to a module's OnGlobalFileChange method. Developers can use this interface to retrieve information about the file that was changed.

Example

The following code example demonstrates how to create a global-level HTTP module that uses the IGlobalFileChangeProvider::GetFileName method to retrieve the path to a file that has been modified. The module then writes the path of the file to a log entry in the Event Viewer.

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

// Create the module's global class.
class MyGlobalModule : public CGlobalModule
{
public:
    GLOBAL_NOTIFICATION_STATUS
    OnGlobalFileChange(
        IN IGlobalFileChangeProvider * pProvider
    )
    {
        // Test for an error.
        if (NULL != m_pHttpContext)
        {
            // Retrieve the file name.
            PCWSTR pwszFileName = pProvider->GetFileName();
            // Test for an error.
            if (NULL != pwszFileName)
            {
                // Allocate storage for the file name.
                char * pszFileName =
                    (char *) m_pHttpContext->AllocateRequestMemory(
                    (DWORD) wcslen(pwszFileName)+1 );
                // Test for an error.
                if (NULL != pszFileName)
                {
                    // Convert the file name.
                    wcstombs(pszFileName,pwszFileName,
                        wcslen(pwszFileName));
                    // Create an array of strings.
                    LPCSTR szBuffer[2] = {"File Name"};
                    // Store the file name.
                    szBuffer[1] = pszFileName;
                    // Write the strings to the Event Viewer.
                    WriteEventViewerLog(szBuffer,2);
                }
            }
        }
        // Return processing to the pipeline.
        return GL_NOTIFICATION_CONTINUE;
    }

    GLOBAL_NOTIFICATION_STATUS
    OnGlobalPreBeginRequest(
        IN IPreBeginRequestProvider * pProvider
    )
    {
        // Retrieve a pointer to the context.
        m_pHttpContext = pProvider->GetHttpContext();
        // Return processing to the pipeline.
        return GL_NOTIFICATION_CONTINUE;
    }

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

    MyGlobalModule()
    {
        // Open a handle to the Event Viewer.
        MyGlobalModule::m_hEventLog = RegisterEventSource( NULL,"IISADMIN" );
        // Initialize the context pointer to NULL.
        MyGlobalModule::m_pHttpContext = NULL;
    }

    ~MyGlobalModule()
    {
        // Test whether the handle for the Event Viewer is open.
        if (NULL != MyGlobalModule::m_hEventLog)
        {
            DeregisterEventSource( MyGlobalModule::m_hEventLog );
            MyGlobalModule::m_hEventLog = NULL;
            MyGlobalModule::m_pHttpContext = NULL;
        }
    }

private:

    // Create a handle for the event viewer.
    HANDLE m_hEventLog;
    // Create a pointer for the module context.
    IHttpContext * m_pHttpContext;

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

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

    // Create an instance of the global module class.
    MyGlobalModule * pGlobalModule = new MyGlobalModule;
    // Test for an error.
    if (NULL == pGlobalModule)
    {
        return HRESULT_FROM_WIN32(ERROR_NOT_ENOUGH_MEMORY);
    }
    // Set the global notifications and exit.
    return pModuleInfo->SetGlobalNotifications(
        pGlobalModule, GL_FILE_CHANGE | GL_PRE_BEGIN_REQUEST );
}

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 Global-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

See Also

CGlobalModule Class