GLOBAL_NOTIFICATION_STATUS Enumeration

Defines the return values for global-level notifications.

Syntax

typedef enum GLOBAL_NOTIFICATION_STATUS{  
   GL_NOTIFICATION_CONTINUE,  
   GL_NOTIFICATION_HANDLED  
};  

Members

Remarks

The members of the GLOBAL_NOTIFICATION_STATUS enumeration are used as return values from global-level notifications, and the members help to control process flow within the global-level notification processing pipeline. For example, returning GL_NOTIFICATION_CONTINUE from a global-level notification handler instructs IIS to continue processing additional global-level notifications, whereas returning GL_NOTIFICATION_HANDLED from a global-level notification handler informs IIS that global-level processing is complete and IIS should not process additional global-level notifications.

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 Enumerations
REQUEST_NOTIFICATION_STATUS Enumeration