CGlobalModule Class

Defines the base class for global-level HTTP modules.

Syntax

class CGlobalModule  

Methods

The following table lists the methods exposed by the CGlobalModule class.

Derived Classes

This class contains no derived classes.

Remarks

The CGlobalModule class is the base class for global-level HTTP modules. Global-level HTTP modules must contain a class that inherits from CGlobalModule. CGlobalModule defines the methods that IIS 7 calls to handle global-level notifications when global-level events occur. An HTTP module can register for specific events by defining a list of notifications in a module's exported RegisterModule function. When a global-level module has finished processing, the module should use the CGlobalModule::Terminate method to remove CGlobalModule instances from memory.

Example

The following code example demonstrates how to create a simple "Hello World" global-level HTTP module. The module defines an exported RegisterModule function that creates an instance of a class that is derived from CGlobalModule. If the class cannot be created, the function exits with an error code; otherwise, the function calls the IHttpModuleRegistrationInfo::SetRequestNotifications method to register for the GL_PRE_BEGIN_REQUEST notification.

When a GL_PRE_BEGIN_REQUEST notification occurs, IIS calls the module's CGlobalModule::OnGlobalPreBeginRequest method to process the notification. The method calls a private method to write an event to the application log of the Event Viewer, and then it returns GL_NOTIFICATION_CONTINUE to notify IIS to continue processing other notifications. When processing is complete, IIS calls the module's CGlobalModule::Terminate method to remove the class from memory.

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

// Create the module's global class.
class MyGlobalModule : public CGlobalModule
{
public:

    // Process a GL_APPLICATION_START notification.
    GLOBAL_NOTIFICATION_STATUS
    OnGlobalPreBeginRequest(
        IN IPreBeginRequestProvider * pProvider
    )
    {
        UNREFERENCED_PARAMETER( pProvider );
        WriteEventViewerLog( "Hello World!" );
        return GL_NOTIFICATION_CONTINUE;
    }

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

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

    ~MyGlobalModule()
    {
        // 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 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_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

Web Server Core Classes
Creating Native-Code HTTP Modules
CHttpModule Class