ICacheProvider::GetCacheOperation-Methode

Gibt den Cachevorgang für den Cacheanbieter zurück.

Syntax

virtual CACHE_OPERATION GetCacheOperation(  
   VOID  
) const = 0;  

Parameter

Diese Methode nimmt zwei Parameter entgegen.

Rückgabewert

Eine CACHE_OPERATION-Enumeration für den ICacheProvider-Zeiger .

Bemerkungen

Von CGlobalModule abgeleitete Klassen, die sich für GL_CACHE_OPERATION Ereignisse registrieren, erhalten einen ICacheProvider-Zeiger als Parameter für die CGlobalModule::OnGlobalCacheOperation-Methodevirtual . Sie können eine CACHE_OPERATION Enumeration abrufen, indem Sie die GetCacheOperation -Methode für den ICacheProvider Zeiger aufrufen.

Beispiel

Im folgenden Codebeispiel wird veranschaulicht, wie ein globales Modul erstellt wird, das auf GL_CACHE_OPERATION Ereignisse lauscht und GL_CACHE_CLEANUP und dann die ICacheProvider Informationen in die Ereignisanzeige schreibt.

Achtung

IIS 7 generiert eine große Anzahl von Ereignissen im Ereignisanzeige. Um einen Protokollüberlauffehler in einer Produktionsumgebung zu vermeiden, sollten Sie im Allgemeinen das Schreiben von Cacheinformationen in das Ereignisprotokoll vermeiden. Zu Demonstrationszwecken schreibt dieses Codebeispiel nur im Debugmodus einen Eintrag in die Ereignisanzeige.

#pragma warning( disable : 4290 )
#pragma warning( disable : 4530 )

#define _WINSOCKAPI_
#include <windows.h>
#include <sal.h>
#include <tchar.h>
#include <initguid.h>
#include <httptrace.h>
#include <httpserv.h>
#include <httpcach.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 CEventException class is 
// an exception that can be thrown 
// when writing an event fails.
class CEventException
{
public:
    // Creates the CEventException class.
    // str: the wstring that could 
    // not be written to a log.
    CEventException(const wstring& str)
        : m_string(str)
    {
        
    }

    // Creates the destructor for 
    // the CEventException class.
    virtual ~CEventException()
    {

    }

private:
    // Specify the wstring that could
    // not be written to an event viewer.
    wstring m_string;
};

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

    }

    // The RegisterGlobalModule method creates and registers 
    // a new CGlobalCacheModule for GL_CACHE_OPERATION and 
    // GL_CACHE_CLEANUP events.
    // dwServerVersion: the current server version.
    // pModuleInfo: the current IHttpModuleRegistrationInfo pointer.
    // pGlobalInfo: the current IHttpServer pointer.
    // return: 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.
        CGlobalCacheModule* traceModule = 
            new CGlobalCacheModule();

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

        // Attempt to set global notification for both 
        // GL_CACHE_OPERATION and GL_CACHE_CLEANUP events 
        // by using the traceModule as a listener.
        HRESULT hr = pModuleInfo->SetGlobalNotifications
            (traceModule, GL_CACHE_OPERATION | GL_CACHE_CLEANUP);

        // If the SetGlobalNotifications method 
        // fails, return the HRESULT.
        if (FAILED(hr))
        {
            return hr;
        }

        // Set the priority to PRIORITY_ALIAS_FIRST, 
        // which will populate the data as much as possible.
        hr = pModuleInfo->SetPriorityForGlobalNotification(
            GL_CACHE_OPERATION, PRIORITY_ALIAS_FIRST);

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

    // The OnGlobalCacheOperation method is called 
    // when GL_CACHE_OPERATION operations occur.
    // pProvider: the current ICacheProvider pointer.
    // return: GL_NOTIFICATION_CONTINUE if the event
    // log is written; otherwise, GL_NOTIFICATION_HANDLED.
    virtual GLOBAL_NOTIFICATION_STATUS OnGlobalCacheOperation
    (
        IN ICacheProvider* pProvider
    )
    {
        // The OnGlobalCacheOperation must return if the 
        // pProvider parameter is NULL because this pointer 
        // is needed for data to write to the event log.
        if (NULL == pProvider)
        {
            return GL_NOTIFICATION_CONTINUE;
        }

        try
        {
            // Get the CACHE_OPERATION 
            // from the provider pointer.        
            CACHE_OPERATION cacheOperation =
                pProvider->GetCacheOperation();

            // Write the cacheOperation 
            // to the event log.
            Write(cacheOperation);            
        }
        // A CEventException is thrown 
        // if any Write method cannot 
        // write to the event log.
        catch (CEventException)
        {
            return GL_NOTIFICATION_HANDLED;
        }

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

    // The OnGlobalCacheCleanup method is called 
    // when GL_CACHE_CLEANUP events occur.
    // return: GL_NOTIFICATION_CONTINUE.
    virtual GLOBAL_NOTIFICATION_STATUS OnGlobalCacheCleanup(VOID)
    {
        // Return GL_NOTIFICATION_CONTINUE so that 
        // other listeners will receive this event.
        return GL_NOTIFICATION_CONTINUE;
    }

    // PRE: none.
    // POST: the Terminate method calls delete on 
    // this, which releases the memory for the current 
    // CGlobalCacheModule pointer on the heap.
    virtual VOID Terminate(VOID)
    {
        delete this;
    }
protected:
    // Creates the constructor for 
    // the CGlobalCacheModule class.
    // The constructor initializes the 
    // private m_eventWriter to write 
    // to the IISADMIN event log.
    CGlobalCacheModule() : m_eventWriter(L"IISADMIN")
    {

    }

    // The ReportInfo method writes the 
    // formatted name and value of a method 
    // call to the event log.
    // name: the name of the method or property.
    // value: the value of the 
    // method or the property.
    // throws: a CEventException exception.
    void ReportInfo
    (
        const wstring& name,
        const wstring& value
    ) throw (CEventException)
    {
        // Create a formatted string to
        // write to the event log.
        wstring infoString =
            name + wstring(L":  ") + value;
        // Attempt to write the formatted 
        // string to the event log. If the 
        // ReportInfo method call fails,
        // throw a CEventException exception.
        if (!m_eventWriter.ReportInfo(infoString))
        {
            throw CEventException(infoString);
        }        
    }

    // The Write method writes CACHE_OPERATION
    // information to the event log.
    // cacheOperation: the CACHE_OPERATION 
    // data to write.
    // throws: a CEventException exception.
    void Write
    (
        CACHE_OPERATION cacheOperation    
    ) throw (CEventException)
    {    
        // Declare a wstring to set as a 
        // value of the cacheOperation.
        wstring cacheOperationString;
        
        // Convert the value of the cacheOperation 
        // parameter to a string and assign this string 
        // to the text on the cacheOperationAttribute.
        switch (cacheOperation)
        {
            case CACHE_OPERATION_RETRIEVE :
            {
                cacheOperationString = 
                    L"CACHE_OPERATION_RETRIEVE";                
                break;            
            }

            case CACHE_OPERATION_ADD :
            {
                cacheOperationString = 
                    L"CACHE_OPERATION_ADD";
                break;
            }
            case CACHE_OPERATION_DELETE :
            {
                cacheOperationString = 
                    L"CACHE_OPERATION_DELETE";
                break;        
            }
            case CACHE_OPERATION_FLUSH_PREFIX :
            {
                cacheOperationString = 
                    L"CACHE_OPERATION_FLUSH_PREFIX";
                break;                
            }
            case CACHE_OPERATION_ENUM:
            {
                cacheOperationString = 
                    L"CACHE_OPERATION_ENUM";
                break;    
            }
            default:
            {
                cacheOperationString = 
                    L"ERROR";
                break;
            }
        }
        
        // Write the cache operation
        // information to the event log.
        ReportInfo(L"GetCacheOperation", 
                   cacheOperationString);        
    }    
private:
    // Specify the event 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
// CGlobalCacheModule::RegisterGlobalModule
// method.
HRESULT
__stdcall
RegisterModule(
    DWORD dwServerVersion,
    IHttpModuleRegistrationInfo* pModuleInfo,
    IHttpServer* pGlobalInfo
)
{        
    // Call the static method for initialization.
    return CGlobalCacheModule::RegisterGlobalModule            
        (dwServerVersion, 
         pModuleInfo, 
         pGlobalInfo);             
}

Weitere Informationen zum Erstellen und Bereitstellen eines nativen DLL-Moduls finden Sie unter Exemplarische Vorgehensweise: Erstellen eines Request-Level HTTP-Moduls mithilfe von nativem Code.

Der obige Code schreibt ein neues Ereignis in das Anwendungsprotokoll der Ereignisanzeige, wobei das Feld Daten eine Zeichenfolge ähnlich der folgenden enthält.

GetCacheOperation: CACHE_OPERATION_RETRIEVE  

Sie können den Code optional kompilieren, indem Sie die __-stdcall (/Gz) Aufrufkonvention verwenden, anstatt die Aufrufkonvention für jede Funktion explizit zu deklarieren.

Anforderungen

type	BESCHREIBUNG
Client	– IIS 7.0 unter Windows Vista – IIS 7.5 unter Windows 7 – IIS 8.0 unter Windows 8 – IIS 10.0 unter Windows 10
Server	– IIS 7.0 unter Windows Server 2008 – IIS 7.5 unter Windows Server 2008 R2 – IIS 8.0 unter Windows Server 2012 – IIS 8.5 unter Windows Server 2012 R2 – IIS 10.0 unter Windows Server 2016
Produkt	– 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

Weitere Informationen

ICacheProvider-Schnittstelle