IGlobalRSCAQueryProvider::GetFunctionParameters Method

Returns the parameters of the dynamic function call that caused the event.

Syntax

virtual PCWSTR GetFunctionParameters(  
   VOID  
) const = 0;  

Parameters

This method takes no parameters.

Return Value

A pointer to a constant null-terminated Unicode string that contains the parameters of the dynamic function call that caused the event.

Remarks

CGlobalModule derived classes that register for GL_RSCA_QUERY events receive an IGlobalRscaQueryProvider pointer as a parameter on the CGlobalModule::OnGlobalRSCAQueryvirtual method. You can then retrieve the parameters of the function by calling the GetFunctionParameters method on the IGlobalRSCAQueryProvider pointer.

The return value of the GetFunctionParameters method depends on implementation. You should use the following information as a guideline, but it may not be correct in all scenarios:

• The default implementer of the IProtocolManager, IPmCustomActions, IPmHealthAndIdleMonitor, and IPmListenerChannelManager interfaces raises events when you call the IRSCA_WorkerProcess::EnumerateAppDomains and IRSCA_AppDomain::Unload methods. These methods map to the PMH_App_Domain_Enum_V1 and PMH_App_Domain_Unload_V1 values, respectively, which are returned when you call the GetFunctionName method. The parameters of this function are, in turn, returned when you call GetFunctionParameters.

• The IGlobalRSCAQueryProvider implementer receives the function name and function parameter values as strings when either of the IRSCA_AppDomain events is raised, and the implementer holds references to these strings. If a string is NULL, GetFunctionParameters returns the empty string. Otherwise, GetFunctionParameters returns a pointer to this shared string.

Notes for Implementers

IGlobalRSCAQueryProvider implementers are responsible for memory management with this data; therefore, IGlobalRSCAQueryProvider implementers that use dynamic memory allocation must release or call delete on the PCWSTR pointer when it is no longer needed.

Notes for Callers

IGlobalRSCAQueryProvider implementers are responsible for memory management with this data; therefore, IGlobalRSCAQueryProvider clients must not release or call delete on the returned PCWSTR pointer when this data is no longer needed. Furthermore, clients must not cast this data to a pointer that is not a const or change the state of the memory referenced by this PCWSTR, because either an access violation will be thrown or the data will become invalid.

Example

The following code example demonstrates how to create a global module that listens for GL_RSCA_QUERY events and then writes the function parameter information to the Event Viewer.

Caution

IIS 7 generates a large number of events in the Event Viewer. To avoid a log overflow error in a production environment, you should generally avoid writing cache information to the event log. For demonstration purposes, this code example writes an entry to the Event Viewer in debug mode only.

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

#include <string>
using namespace std;

// The CConvert class mirrors the Convert class that is 
// defined in the .NET Framework. It converts primitives 
// and other data types to wstring types.
class CConvert
{
public:
    // The ToByteString converts a double-byte 
    // character string to a single-byte string.
    // str: the double-byte string to convert.
    // return: a single-byte string copied from str.
    static string ToByteString(const wstring& str)
    {
        // Get the length of the 
        // double-byte string.
        size_t length = str.length();

        // Create a temporary char pointer.
        char* byteChar = new char[length+1];
        byteChar[0] = '\0';
        // Copy the double-byte character string
        // into the single-byte string.        
        size_t charsReturned = 0;
        wcstombs_s(&charsReturned, byteChar, 
                   length+1, str.c_str(), length+1);
        // Create a string to return.
        string retString = byteChar;
        // Delete the temporary string and
        // set that string to NULL.
        delete[] byteChar;
        byteChar = NULL;

        // Return the single-byte string.
        return retString;
    }
};

// The CEventWriter class writes XML 
// documents and strings to the event log.
class CEventWriter
{
public:
    // Creates the CEventWriter class.
    // name: the name of the 
    // event log to open.
    CEventWriter(const wstring& name)
    {                
        #ifdef UNICODE
        m_eventLog = RegisterEventSource(NULL, name.c_str());
        #else
        string multiName = CConvert::ToByteString(name);
        m_eventLog = RegisterEventSource(NULL, multiName.c_str());
        #endif        
    }

    // Creates the destructor for the 
    // CEventWriter class. This destructor
    // closes the HANDLE to the event 
    // log if that HANDLE is open.
    virtual ~CEventWriter()
    {
        // If the HANDLE to the event 
        // log is open, close it.
        if (NULL != m_eventLog)
        {
            // Deregister the event log HANDLE.
            DeregisterEventSource(m_eventLog);
            // Set the HANDLE to NULL.
            m_eventLog = NULL;
        }
    }

    // The ReportInfo method writes 
    // a wstring to the event log.
    // info: the wstring to write.
    // return: true if the event log is written.
    BOOL ReportInfo(const wstring& info)
    {
        return ReportEvent(EVENTLOG_INFORMATION_TYPE, info);
    }
protected:
    // The ReportEvent method accepts an event type
    // and a wstring, and attempts to write that 
    // event to the event log.
    // type: the type of the event.
    // data: the wstring to write to the event log.
    // return: true if the event log is written;
    // otherwise, false.
    BOOL ReportEvent(WORD type, const wstring& data)
    {
        // If the m_eventLog HANDLE 
        // is NULL, return false.
        if (NULL == m_eventLog)
        {
            return FALSE;
        }

        #ifndef _DEBUG
        // If the current build is not debug,
        // return so the event log is not written.
        return TRUE;
        #endif

        #ifdef UNICODE
        // The unicode version of the ReportEvent
        // method requires double-byte strings.
        PCWSTR arr[1];
        arr[0] = data.c_str();
        return ::ReportEvent(m_eventLog,
                             type,
                             0, 0, NULL, 1, 
                             0, arr, (void*)arr);
        #else
        // The non-unicode version of the ReportEvent
        // method requires single-byte strings.
        string multiByte = 
            CConvert::ToByteString(data);
        LPCSTR arr[1];
        arr[0] = multiByte.c_str();
        return ::ReportEvent(m_eventLog,
                             type,
                             0, 0, NULL, 1,
                             0, arr, (void*)arr);
        #endif
    }
private:
    // Specify the HANDLE to the 
    // event log for writing.
    HANDLE m_eventLog;
};

// The CRSCAGlobalModule class creates the CGlobalModule 
// class and registers for GL_RSCA_QUERY and events.
class CRSCAGlobalModule : public CGlobalModule
{
public:
    // Creates the destructor for the 
    // CGlobalCacheModule class.
    virtual ~CRSCAGlobalModule()
    {

    }

    // The RegisterGlobalModule method creates and registers 
    // a new CRSCAGlobalModule for GL_RSCA_QUERY events.
    // dwServerVersion: the current server version.
    // pModuleInfo: the current IHttpModuleRegistrationInfo pointer.
    // pGlobalInfo: the current IHttpServer pointer.
    // return: E_INVALIDARG if the IHttpServer pointer
    // is NULL; ERROR_NOT_ENOUGH_MEMORY if the heap is out of 
    // memory; otherwise, the value from the call to the 
    // SetGlobalNotifications method on the pModuleInfo pointer.
    static HRESULT RegisterGlobalModule
    (
        DWORD dwServerVersion,
        IHttpModuleRegistrationInfo* pModuleInfo,
        IHttpServer* pGlobalInfo
    )
    {        
        // The pGlobalInfo parmeter must be 
        // non-NULL because the constructor 
        // for the CGlobalCacheModule class 
        // requires a non-NULL pointer to a 
        // valid IHttpServer pointer.
        if (NULL == pGlobalInfo)
        {
            return E_INVALIDARG;
        }

        // Create a new CGlobalCacheModule pointer.
        CRSCAGlobalModule* rscaModule = 
            new CRSCAGlobalModule();

        // Return an out-of-memory error 
        // if the traceModule is NULL 
        // after the call to the new operator.
        if (NULL == rscaModule)
        {            
            return HRESULT_FROM_WIN32(ERROR_NOT_ENOUGH_MEMORY);
        }        

        // Attempt to set global notification 
        // for GL_RSCA_QUERY events by using 
        // the rscaModule as a listener.
        HRESULT hr = pModuleInfo->SetGlobalNotifications
            (rscaModule, GL_RSCA_QUERY);

        // Return the HRESULT from the call to 
        // the SetGlobalNotifications method.
        return hr;
    }

    // The OnGlobalRSCAQuery method is the event 
    // handler method for the GL_RSCA_QUERY event.
    // pProvider: the IGlobalRSCAQueryProvider pointer.
    // return: GL_NOTIFICATION_CONTINUE.
    virtual GLOBAL_NOTIFICATION_STATUS OnGlobalRSCAQuery
    (
        IN IGlobalRSCAQueryProvider* pProvider
    )
    {
        // Return GL_NOTIFICATION_CONTINUE if the
        // IGlobalRSCAQueryProvider pointer is NULL.
        if (NULL == pProvider)
        {
            return GL_NOTIFICATION_CONTINUE;
        }

        // Get the parameters from the 
        // IGlobalRSCAQueryProvider pointer.
        wstring parameters = 
            pProvider->GetFunctionParameters();

        // Write the parameter information
        // to the event writer.
        m_eventWriter.ReportInfo
            (L"Parameters:  " + parameters);

        // Return GL_NOTIFICATION_CONTINUE so
        // other listeners will receive this event.
        return GL_NOTIFICATION_CONTINUE;
    }

    // The Terminate method is a pure virtual 
    // method that all non-abstract CGlobalModule
    // classes must implement. Calls delete on this.
    virtual VOID Terminate(VOID)
    {
        delete this;
    }
protected:
    // Creates the CRSCAGlobalModule class.
    // Initializes the CEventWriter to write
    // to the event log using the IISADMIN key.
    CRSCAGlobalModule() : m_eventWriter(L"IISADMIN")
    {

    }
private:
    // Specify the CEventWriter writer.
    CEventWriter m_eventWriter;
};

// The RegisterModule method is the 
// main entry point for the DLL.
// dwServerVersion: the current server version.
// pModuleInfo: the current 
// IHttpModuleRegistrationInfo pointer.
// pGlobalInfo: the current IHttpServer pointer.
// return: the value returned by calling the
// CRSCAGlobalModule::RegisterGlobalModule
// method.
HRESULT
__stdcall
RegisterModule(
    DWORD dwServerVersion,
    IHttpModuleRegistrationInfo* pModuleInfo,
    IHttpServer* pGlobalInfo
)
{        
    // Call the static method for initialization.
    return CRSCAGlobalModule::RegisterGlobalModule            
        (dwServerVersion, 
         pModuleInfo, 
         pGlobalInfo);             
}

For more information on how to create and deploy a native DLL module, see Walkthrough: Creating a Request-Level HTTP Module By Using Native Code.

The above code writes an event to the application log of the Event Viewer, where the Data box contains a string similar to the following:

Parameters:  

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

See Also

IGlobalRSCAQueryProvider Interface