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ICacheProvider Interface

IIS 7.0

Extends the IHttpEventProvider interface by adding support for retrieving cache information from a cache provider.

class ICacheProvider : public IHttpEventProvider

The following table lists the methods exposed by the ICacheProvider interface.

Name

Description

GetCacheKey

Returns the cache key for the cache provider.

GetCacheOperation

Returns the cache operation for the cache provider.

GetCacheRecord

Returns the cache record for the cache provider.

GetTraceContext

Returns the trace context for the cache provider.

SetCacheRecord

Sets the cache-specific data on the cache provider.

SetErrorStatus

(Inherited from IHttpEventProvider.)

This interface contains no derived classes.

CGlobalModule derived classes that register for GL_CACHE_OPERATION events receive an ICacheProvider pointer as a parameter on the CGlobalModule::OnGlobalCacheOperation virtual method.

The following code example demonstrates how to create a global module that listens for GL_CACHE_OPERATION and GL_CACHE_CLEANUP events and then writes the ICacheProvider information to the Event Viewer.

Caution noteCaution:

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.

#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;

#import "msxml6.dll"
using namespace MSXML2;

// 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 ToString method converts a HANDLE to a wstring.
    // h: the HANDLE to convert to a wstring.
    // return: the HANDLE as a wstring.
    static wstring ToString(HANDLE h)
    {
        // If the HANDLE is NULL, return the "NULL" string.
        if (NULL == h)
        {
            return L"NULL";
        }

        // If the HANDLE is not valid, return 
        // the INVALID_HANDLE_VALUE as a string.
        if (INVALID_HANDLE_VALUE == h)
        {
            return L"INVALID_HANDLE_VALUE";
        }

        // The HANDLE is valid.
        return L"valid";
    }

    // The ToString method converts a FILETIME pointer to a wstring.
    // fileTime: the FILETIME pointer to convert to a wstring.
    // return: the FILETIME pointer as a wstring.
    static wstring ToString(FILETIME* fileTime)
    {
        // If fileTime is NULL, return the empty string.
        if (NULL == fileTime)
        {
            return L"NULL";
        }

        // Convert the FILETIME to a local time, and 
        // then convert that local time to a wstring.
        SYSTEMTIME stUTC;
        SYSTEMTIME stLocal;
        FileTimeToSystemTime(fileTime, &stUTC);
        SystemTimeToTzSpecificLocalTime(NULL, &stUTC, &stLocal);        

        // Create a wstring to return.  Note: wsprintf 
        // can be also used. However, it is more difficult 
        // to handle both UNICODE and non-UNICODE correctly.
        wstring timeString =
            ToString(stLocal.wMonth) +
            wstring(L"/")            +
            ToString(stLocal.wDay)   +
            wstring(L"/")            +
            ToString(stLocal.wYear)  +
            wstring(L"  ")           +
            ToString(stLocal.wHour)  +
            wstring(L":")            +
            ToString(stLocal.wMinute);

        // Return the FILETIME data as a wstring.
        return timeString;
    }

    // The ToString method converts a 
    // ULARGE_INTEGER pointer to a wstring.
    // ui: the ULARGE_INTEGER pointer to convert to a string.
    // return: the ULARGE_INTEGER pointer as a string.
    static wstring ToString(ULARGE_INTEGER* ui)
    {
        // Return the empty string if the 
        // ULARGE_INTEGER pointer is NULL.
        if (NULL == ui)
        {
            return L"NULL";
        }

        // Return the low-order part to a wstring.
        return (ToString(ui->LowPart));
    }

    // The ToString method converts a PCSTR to a wstring.
    // pcstr: the PCSTR to convert to a wstring.
    // return: the PCSTR as a wstring.
    static wstring ToString(PCSTR pcstr)
    {
        // Return the empty string 
        // if the PCSTR is NULL.
        if (NULL == pcstr)
        {
            return L"NULL";
        }

        // Get the length of the string to copy.
        size_t length = strlen(pcstr);
        // Create a new double-byte character 
        // array of length plus 1.
        wchar_t* newText = new wchar_t[length+1];

        // Copy the source into the sink string.
        for (size_t i = 0; i < length; ++i)
        {
            newText[i] = pcstr[i];
        }

        // Terminate the string with the NULL character.
        newText[length] = '\0';
        // Get a wstring from the new double-byte string.
        wstring wText = newText;
        // Call delete on the newText pointer 
        // and set this pointer to NULL.
        delete[] newText;
        newText = NULL;

        // Return the wstring copy.
        return wText;
    }

    // The ToString method converts a long to a wstring.
    // l: the long value to convert to a wstring.
    // return: the long as a wstring.
    static wstring ToString(long l)
    {
        WCHAR str[256];
        str[0] = '\0';        
        _ltow_s(l, str, 256, 10);
        return str;
    }

    // The ToString method converts a DWORD to a wstring.
    // d: the DWORD value to convert to a wstring.
    // return: the DWORD as a wstring.
    static wstring ToString(DWORD d)
    {
        return ToString((long)d);
    }

    // The ToString method converts an LPCGUID to a wstring.
    // guid: the LPCGUID value to convert to a wstring.
    // return: The LPCGUID as a wstring; otherwise, L"" if
    // guid is NULL.
    static wstring ToString(LPCGUID guid)
    {
        // If the GUID is NULL, return the empty string.
        if (NULL == guid)
        {
            return L"NULL";
        }

        // Create a WCHAR array to write the GUID to.
        WCHAR guidString[256];
        // Initialize the zero-based index of the 
        // guidString to the null-terminating character 
        // because the StringFromGUID2 may fail.
        guidString[0] = '\0';
        // Convert the GUID to a string of the form "{...}".
        int characters = StringFromGUID2(*guid, guidString, 256);
        // Return the guidString as a wstring.
        return guidString;
    }

    // The ToString method converts a BOOL to a wstring.
    // b: the BOOL value to convert to a wstring.
    // return: L"true" for true; otherwise, L"false" for false.
    static wstring ToString(BOOL b)
    {
        return (b) ? L"true" : L"false";
    }

    // 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 ToString method converts a USHORT to a wstring.
    // u: the USHORT value to convert to a wstring.
    // return: the value of u as a wstring.
    static wstring ToString(USHORT u)
    {
        return (ToString((long)u));
    }

    // The ToString method converts a 
    // const BYTE pointer to a wstring.
    // bytes: the BYTE pointer to convert.
    // return: the value of bytes as a wstring.
    static wstring ToString(const BYTE* bytes)
    {
        return (ToString((PCSTR)bytes));    
    }

    // The ToString method converts 
    // a PCWSTR to a wstring.
    // pcwstr: the PCWSTR to convert.
    // return: L"NULL" if the pcwstr
    // parameter is NULL; otherwise, 
    // pcwstr converted to a wstring.
    static wstring ToString(PCWSTR pcwstr)
    {
        // If the pcwstr parameter
        // is NULL, return L"NULL".
        if (NULL == pcwstr)
        {
            return L"NULL";
        }

        // Implicitly convert the 
        // PCWSTR to a wstring.
        return pcwstr;
    }

    // The ToString method converts 
    // a character to a wstring.
    // c: the character to convert.
    // return: c as a wstring.
    static wstring ToString(char c)
    {
        wstring str;
        str += c;
        return str;
    }

    // The ToString method converts
    // a short to a wstring.
    // s: the short to convert.
    // return: s as a wstring.
    static wstring ToString(short s)
    {
        return (ToString((long)s));
    }
};

// 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 the content
    // of the XML document to the event log.
    // doc: the XML document to write.
    // return: true if the event log is written.
    BOOL ReportInfo(MSXML2::IXMLDOMDocument3Ptr doc)
    {
        MSXML2::IXMLDOMElementPtr documentElement = 
            doc->documentElement;
        // Get the XML as a BSTR and place this XML into a 
        // _bstr_t wrapper. The client of the XML document 
        // is responsible for deleting the returned BSTR from 
        // the property, which the _bstr_t wrapper will do
        // automatically.
        _bstr_t bstrXml = documentElement->xml;
        // Convert the _bstr_t to a wstring.
        wstring xmlString = bstrXml;
        // Write the XML to the event writer.
        return ReportInfo(xmlString);        
    }

    // 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);
    }

    // The ReportError method writes 
    // a wstring to the event log.
    // error: the wstring to write.
    // return: true if the event log is written.
    BOOL ReportError(const wstring& error)
    {
        return ReportEvent(EVENTLOG_ERROR_TYPE, error);
    }
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.
    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;
        }

        // The following code uses COM smart pointers. Wrap 
        // the code in one try/catch statement for _com_error
        // exceptions. Note: it is not necessary to call 
        // CoInitialize and CoUninitialize on this thread 
        // because IIS does this automatically.
        try
        {
            // Create an XML document in memory.
            MSXML2::IXMLDOMDocument3Ptr doc(__uuidof(MSXML2::DOMDocument60));

            // Create a cacheProvider root element and 
            // append this root element to the XML document.
            MSXML2::IXMLDOMElementPtr cacheProviderElement =
                doc->createElement(L"cacheProvider");
            doc->appendChild(cacheProviderElement);

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

            // Create an attribute for the cache operation and
            // add that attribute to the cacheProviderElement
            MSXML2::IXMLDOMAttributePtr cacheOperationAttribute =
                CreateAttribute(cacheOperation, doc);
            cacheProviderElement->setAttributeNode
                (cacheOperationAttribute);

            // Get the IHttpCacheKey pointer from the ICacheProvider 
            // pointer.
            IHttpCacheKey* cacheKey = pProvider->GetCacheKey();

            // Create an element for the cache key and add 
            // that element to the cacheProviderElement.
            MSXML2::IXMLDOMElementPtr cacheKeyElement =
                CreateElement(cacheKey, doc);
            cacheProviderElement->appendChild(cacheKeyElement);

            // Get the IHttpCacheSpecificData pointer 
            // from the ICacheProvider element.
            IHttpCacheSpecificData* cacheSpecificData = 
                pProvider->GetCacheRecord();

            // Create an element for the IHttpCacheSpecificData
            // pointer and add that element to the 
            // cacheProviderElement.
            MSXML2::IXMLDOMElementPtr recordElement =
                CreateElement(cacheSpecificData, doc);    
            cacheProviderElement->appendChild(recordElement);

            // Get the IHttpTraceContext pointer 
            // from the ICacheProvider pointer.
            IHttpTraceContext* traceContext = 
                pProvider->GetTraceContext();

            // Create an element for the IHttpTraceContext
            // pointer and add that element to the 
            // cacheProviderElement.
            MSXML2::IXMLDOMElementPtr traceElement =
                CreateElement(traceContext, doc);
            cacheProviderElement->appendChild(traceElement);

            // Write the XML using the writer.            
            m_eventWriter.ReportInfo(doc);    
        }
        // Catch any _com_error that occurs while you are 
        // writing to the XML document in memory.
        catch (_com_error& ce)
        {            
            // Get the description for the error.
            wstring description = ce.Description();
            // Write the error to the event writer.
            m_eventWriter.ReportError(description);
        }

        // 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.
    CGlobalCacheModule() : m_eventWriter(L"IISADMIN")
    {

    }

    // The AddAttribute creates a new attribute using 
    // the doc value, sets the new attribute's name and 
    // text, adds the new attribute to the element value 
    // and, finally, returns the attribute.
    // PRE: neither the element nor the doc 
    // parameters are NULL.
    // name: the name of the attribute.
    // text: the text of the attribute.
    // element: the element to add the new attribute to.
    // doc: the XML document for creating a new attribute.
    // return: the new IXMLDOMAttributePtr 
    // that is added to the element.
    // throws: a _com_error exception.
    static MSXML2::IXMLDOMAttributePtr AddAttribute
    (
        const wstring& name,
        const wstring& text,
        MSXML2::IXMLDOMElementPtr element,
        MSXML2::IXMLDOMDocument3Ptr doc
    ) throw (_com_error)
    {
        // Create an attribute with the name.
        MSXML2::IXMLDOMAttributePtr attribute = 
            doc->createAttribute(name.c_str());
        // Set the text of the attribute to the text value.
        attribute->text = text.c_str();
        // Add the attribute to the passed element.
        element->setAttributeNode(attribute);
        // Return the new attribute to the caller.
        return attribute;
    }

    // The CreateAttribute method converts a CACHE_OPERATION
    // enumeration to an XML attribute.
    // PRE: the doc parameter must not be NULL.
    // cacheOperation: the CACHE_OPERATION enumeration
    // to convert to an XML element.
    // doc: the XML document to 
    // use for creating attributes.
    // return: a new IXMLDOMAttributePtr attribute with 
    // the name of "cacheOperation" and text value of 
    // the cacheOperation parameter as a string.
    // throws: a _com_error exception.
    static MSXML2::IXMLDOMAttributePtr CreateAttribute
    (
        CACHE_OPERATION cacheOperation,
        MSXML2::IXMLDOMDocument3Ptr doc
    ) throw (_com_error)
    {
        // Create an attribute for the CACHE_OPERATION value.
        MSXML2::IXMLDOMAttributePtr cacheOperationAttribute =
            doc->createAttribute(L"cacheOperation");

        // 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;
            }
        }

        // Set the text value of the 
        // cacheOperationAttribute.
        cacheOperationAttribute->text = 
            cacheOperationString.c_str();

        // Return the new attribute to the caller.
        return cacheOperationAttribute;
    }

    // The CreateElement method converts an IHttpTokenKey 
    // pointer and its descendant data to an XML element.
    // PRE: the doc parameter must not be NULL.
    // tokenKey: the IHttpTokenKey pointer 
    // to convert to an XML element.
    // doc: the XML document used for creating a new element.
    // return: a new MSXML2::IXMLDOMElementPtr representing 
    // the data in the tokenKey parameter and its descendents.
    // throws: a _com_error exception.
    static MSXML2::IXMLDOMElementPtr CreateElement
    (
        IHttpTokenKey* tokenKey,
        MSXML2::IXMLDOMDocument3Ptr doc
    ) throw (_com_error)
    {
        // Create a new element to return.
        MSXML2::IXMLDOMElementPtr tokenKeyElement =
            doc->createElement(L"tokenKey");

        // If the tokenKey parameter is NULL, 
        // return the empty tokenKeyElement.
        if (NULL == tokenKey)
        {
            return tokenKeyElement;
        }

        // Get the user name from the 
        // IHttpTokenKey pointer.
        wstring userName = tokenKey->GetUserName();

        // Add a userName attribute to 
        // the tokenKeyElement.
        AddAttribute(L"userName", userName, 
                     tokenKeyElement, doc);

        // Get the password hash from 
        // the IHttpTokenKey pointer.
        wstring passwordHash = tokenKey->GetPasswordHash();

        // Add a passwordHash attribute 
        // to the tokenKeyElement.
        AddAttribute(L"passwordHash", passwordHash, 
                     tokenKeyElement, doc);

        // Get the logon method from the
        // IHttpTokenKey pointer.
        DWORD logonMethod = tokenKey->GetLogonMethod();
        // Convert the logonMethod to a wstring.
        wstring logonMethodString =
            CConvert::ToString(logonMethod);

        // Add a logon attribute to
        // the tokenKeyElement.
        AddAttribute(L"logon", logonMethodString,
                     tokenKeyElement, doc);

        // Return the tokenKeyElement to the caller.
        return tokenKeyElement;
    }

    // The CreateElement method converts an IFileKey pointer
    // and its decsendant data to an XML element.
    // PRE: the doc parameter must not be NULL.
    // POST: none.
    // fileKey: the IFileKey pointer to convert to an XML element.
    // return: a new MSXML2::IXMLDOMElementPtr representing 
    // the data in the fileKey parameter and its descendants.
    // throws: a _com_error exception.
    static MSXML2::IXMLDOMElementPtr CreateElement
    (
        IFileKey* fileKey,
        MSXML2::IXMLDOMDocument3Ptr doc
    ) throw (_com_error)
    {
        // Create a new element to return.
        MSXML2::IXMLDOMElementPtr fileKeyElement =
            doc->createElement(L"fileKey");

        // If the fileKey is empty return the fileKeyElement.
        if (NULL == fileKey)
        {
            return fileKeyElement;
        }

        // Get the path from the 
        // IFileKey pointer.
        wstring path = fileKey->GetPath();

        // Add a path attribute to the 
        // fileKeyElement.
        AddAttribute(L"path", path, fileKeyElement, doc);

        // Return the fileKeyElement to the caller.
        return fileKeyElement;
    }

    // The CreateElement method converts an IUriKey pointer 
    // and its descendant data into an XML element.
    // PRE: the doc parameter must not be NULL.    
    // uriKey: the IUriKey pointer to convert to an XML element.
    // return: a new MSXML2::IXMLDOMElementPtr representing 
    // the data in the uriKey parameter and its descendants.
    // throws: a _com_error exception.
    static MSXML2::IXMLDOMElementPtr CreateElement
    (
        IUriKey* uriKey,
        MSXML2::IXMLDOMDocument3Ptr doc
    ) throw (_com_error)
    {
        // Create a new element to return.
        MSXML2::IXMLDOMElementPtr uriKeyElement =
            doc->createElement(L"uriKey");

        // If uriKey is NULL, return the uriKeyElement.
        if (NULL == uriKey)
        {
            return uriKeyElement;
        }

        // Get the site identifier from 
        // the IUriKey pointer.
        DWORD siteIdDWORD = uriKey->GetSiteId();
        // Convert the siteId to a wstring.
        wstring siteId = 
            CConvert::ToString(siteIdDWORD);

        // Add a siteId attribute to
        // the uriKeyElement.
        AddAttribute(L"siteId", siteId, 
                     uriKeyElement, doc);

        // Get the site name from 
        // the IUriKey pointer.
        wstring siteName = uriKey->GetSiteName();

        // Add a siteName attribute to 
        // the uriKeyElement.
        AddAttribute(L"siteName", siteName, 
                     uriKeyElement, doc);

        // Get the URL from 
        // the IUriKey pointer.
        wstring url = uriKey->GetUrl();

        // Add a url attribute to
        // the uriKeyElement.
        AddAttribute(L"url", url, 
                     uriKeyElement, doc);

        // Return the uriKeyElement to the caller.
        return uriKeyElement;
    }

    // The CreateElement method converts an IHttpCacheKey 
    // pointer and its descendant data into an XML element.
    // PRE: the doc parameter must not be NULL.    
    // cacheKey: the IHttpCacheKey pointer 
    // to convert to an XML element.
    // return: a new MSXML2::IXMLDOMElementPtr representing 
    // the data in the cacheKey parameter and its descendants.
    // throws: a _com_error exception.
    static MSXML2::IXMLDOMElementPtr CreateElement
    (
        IHttpCacheKey* cacheKey,
        MSXML2::IXMLDOMDocument3Ptr doc
    ) throw (_com_error)
    {
        // Create a default cache key element to return.
        MSXML2::IXMLDOMElementPtr cacheKeyElement =
            doc->createElement(L"cacheKey");

        // If the cacheKey parameter is NULL 
        // return the empty cacheKeyElement.
        if (NULL == cacheKey)
        {            
            return cacheKeyElement;
        }

        // Get the cache name of the key. The name of this 
        // cache key indicates what interface extension to which
        // the IHttpCacheKey pointer can be safely downcast.
        wstring cacheName = cacheKey->GetCacheName();

        // If the cacheName is FILE_CACHE_NAME, it is safe to
        // downcast the cacheKey to an IFileKey pointer.
        if (FILE_CACHE_NAME == cacheName)
        {
            // Downcast the cacheKey to an IFileKey 
            // pointer for additional functionality.            
            IFileKey* fileKey =
                dynamic_cast<IFileKey*>(cacheKey);
            // Reset the cacheKeyElement to the new element.
            cacheKeyElement = CreateElement(fileKey, doc);
        }

        // If the cacheName is URI_CACHE_NAME, it is safe 
        // to downcast the cacheKey to an IUriKey pointer.
        if (URI_CACHE_NAME == cacheName)
        {
            // Downcast the cacheKey to an IUriKey 
            // pointer for additional functionality.            
            IUriKey* uriKey =
                dynamic_cast<IUriKey*>(cacheKey);
            // Reset the cacheKeyElement to the new element.
            cacheKeyElement = CreateElement(uriKey, doc);
        }

        // If cacheName is TOKEN_CACHE_NAME, it is safe to
        // downcast the cacheKey to an IHttpTokenKey pointer.
        if (TOKEN_CACHE_NAME == cacheName)
        {
            // Downcast the cacheKey to an IHttpTokenKey pointer.            
            IHttpTokenKey* tokenKey =
                dynamic_cast<IHttpTokenKey*>(cacheKey);
            // Reset the cacheKeyElement to the new element.
            cacheKeyElement = CreateElement(tokenKey, doc);
        }

        // Add an attribute to the cacheKeyElement 
        // for cache name information.
        AddAttribute(L"cacheName", cacheName, 
                     cacheKeyElement, doc);

        // Get the hash from the 
        // IHttpCacheKey pointer.
        DWORD hashDWORD = cacheKey->GetHash();
        // Convert the DWORD to a wstring.
        wstring hash = CConvert::ToString(hashDWORD);

        // Add an attribute to the 
        // cacheKeyElement for hash information.
        AddAttribute(L"hash", hash, 
                     cacheKeyElement, doc);

        // Get IsEqual information from the 
        // IHttpCacheKey pointer by comparing 
        // the current pointer.
        BOOL isEqualBOOL = 
            cacheKey->GetIsEqual(cacheKey);
        // Convert the Boolean to a wstring.
        wstring isEqual = CConvert::ToString(isEqualBOOL);

        // Add an attribute to the cacheKeyElement 
        // for equal information against itself.
        AddAttribute(L"isEqual", isEqual,                      
                     cacheKeyElement, doc);

        // Get GetIsPrefix information from 
        // the IHttpCacheKey pointer by comparing
        // the current pointer.
        BOOL isPrefixBOOL = 
            cacheKey->GetIsPrefix(cacheKey);
        // Convert the Boolean to a wstring.
        wstring isPrefix = CConvert::ToString(isPrefixBOOL);

        // Add an isPrefix attribute to
        // the cacheKeyElement.
        AddAttribute(L"isPrefix", isPrefix,                      
                     cacheKeyElement, doc);

        // Return the new cacheKeyElement to the caller.
        return cacheKeyElement;
    }

    // The CreateElement method converts an IHttpStoredContext
    // pointer and its descendant data to an XML element.
    // PRE: the doc parameter must not be NULL.    
    // storedContext: the IHttpStoredContext 
    // pointer to convert to an XML element.
    // doc: the XML document for creating elements.
    // return: a new MSXML2::IXMLDOMElementPtr representing the 
    // data in the storedContext parameter and its descendants.
    // throws: a _com_error exception.
    static MSXML2::IXMLDOMElementPtr CreateElement
    (
        IHttpStoredContext* storedContext,
        MSXML2::IXMLDOMDocument3Ptr doc
    ) throw (_com_error)
    {
        // Create a new element to return.
        MSXML2::IXMLDOMElementPtr storedContextElement =
            doc->createElement(L"storedContext");

        // If the storedContext pointer is NULL, 
        // return the storedContextElement.
        if (NULL == storedContext)
        {
            return storedContextElement;
        }

        // Return the storedContextElement to the caller.
        return storedContextElement;
    }

    // The CreateElement method converts an IHttpModuleContextContainer
    // and its descendant data into an XML element.
    // PRE: the doc parameter must not be NULL.    
    // contextContainer: the IHttpModuleContextContainer 
    // pointer to convert to an XML element.
    // doc: the XML document used for creating elements.
    // return: a new MSXML2::IXMLDOMElementPtr representing the 
    // data in the contextContainer parameter and its descendants.
    // throws: a _com_error exception.
    static MSXML2::IXMLDOMElementPtr CreateElement
    (
        IHttpModuleContextContainer* contextContainer,
        MSXML2::IXMLDOMDocument3Ptr doc
    ) throw (_com_error)
    {
        // Create a new element to return.
        MSXML2::IXMLDOMElementPtr contextContainerElement =
            doc->createElement(L"contextContainer");

        // If the contextContainer pointer is NULL, return the 
        // contextContainerElement.
        if (NULL == contextContainer)
        {
            return contextContainerElement;
        }

        // Get the IHttpStoredContext pointer from 
        // the IHttpModuleContextContainer pointer.
        IHttpStoredContext* storedContext = 
            contextContainer->GetModuleContext(NULL);

        // Add a new element from the IHttpStoredContext 
        // pointer to the contextContainerElement.
        MSXML2::IXMLDOMElementPtr storedContextElement = 
            CreateElement(storedContext, doc);
        contextContainerElement->appendChild(storedContextElement);

        // Return the contextContainerElement.
        return contextContainerElement;
    }

    // The CreateElement method converts an IHttpTokenEntry 
    // pointer and its descendant data into an XML element.
    // PRE: the doc parameter must not be NULL.    
    // tokenEntry: the IHttpTokenEntry 
    // pointer to convert to an XML element.
    // doc: the XML document used for creating elements.
    // return: a new MSXML2::IXMLDOMElementPtr representing the 
    // data in the tokenEntry parameter and its descendants.
    // throws: a _com_error exception.
    static MSXML2::IXMLDOMElementPtr CreateElement
    (
        IHttpTokenEntry* tokenEntry,
        MSXML2::IXMLDOMDocument3Ptr doc
    ) throw (_com_error)
    {
        // Create a new element to return.
        MSXML2::IXMLDOMElementPtr tokenEntryElement =
            doc->createElement(L"tokenEntry");

        // If the tokenEntry parameter is NULL, 
        // return the empty tokenEntryElement.
        if (NULL == tokenEntry)
        {
            return tokenEntryElement;
        }

        // Get the impersonation token from
        // the IHttpTokenEntry pointer.
        HANDLE impersonationTokenHANDLE =
            tokenEntry->GetImpersonationToken();
        // Convert the token to a wstring.
        wstring impersonationToken =
            CConvert::ToString(impersonationTokenHANDLE);

        // Add an impersonationToken attribute
        // to the tokenEntryElement.
        AddAttribute(L"impersonationToken", impersonationToken,                      
                     tokenEntryElement, doc);

        // Get the primary token from the
        // IHttpTokenEntry pointer.
        HANDLE primaryTokenHANDLE =
            tokenEntry->GetPrimaryToken();
        // Convert the primary token to
        // a wstring.
        wstring primaryToken =
            CConvert::ToString(primaryTokenHANDLE);

        // Add a primaryToken attribute to
        // the tokenEntryElement.
        AddAttribute(L"primaryToken", primaryToken,                     
                     tokenEntryElement, doc);

        // Get the SID from the 
        // IHttpTokenEntry pointer.
        PSID sidPSID = tokenEntry->GetSid();
        // Convert the SID to a wstring.
        wstring sid = CConvert::ToString(sidPSID);

        // Add an attribute to the tokenEntryElement 
        // for the SID.
        AddAttribute(L"sid", sid,                      
                     tokenEntryElement, doc);

        // Return the tokenEntryElement to the caller.
        return tokenEntryElement;
    }

    // The CreateElement method converts an IHttpFileInfo
    // pointer and its descendant data into an XML element.
    // PRE: the doc parameter must not be NULL.
    // fileInfo: the IHttpFileInfo pointer 
    // to convert to an XML element.
    // return: a new MSXML2::IXMLDOMElementPtr representing 
    // the data in the fileInfo parameter and its descendants.
    // throws: a _com_error exception.
    static MSXML2::IXMLDOMElementPtr CreateElement
    (
        IHttpFileInfo* fileInfo,
        MSXML2::IXMLDOMDocument3Ptr doc
    ) throw (_com_error)
    {
        // Create a new element to return.
        MSXML2::IXMLDOMElementPtr fileInfoElement =
            doc->createElement(L"fileInfo");

        // If the fileInfo pointer is NULL, 
        // return the empty fileInfoElement.
        if (NULL == fileInfo)
        {
            return fileInfoElement;
        }

        // Get file-changed information from
        // the IHttpFileInfo pointer.
        BOOL changedBOOL = 
            fileInfo->CheckIfFileHasChanged(NULL);
        // Covert the Boolean to a wstring.
        wstring changed = CConvert::ToString(changedBOOL);

        // Add a changed attribute to
        // the fileInfoElement.
        AddAttribute(L"changed", changed,                      
                     fileInfoElement, doc);

        // Get attribute information from
        // the IHttpFileInfo pointer.
        DWORD attributesDWORD =
            fileInfo->GetAttributes();
        // Convert the attributes to a wstring.
        wstring attributes = 
            CConvert::ToString(attributesDWORD);

        // Add an attributes attribute to
        // the fileInfoElement.
        AddAttribute(L"attributes", attributes, 
                     fileInfoElement, doc);

        // Get eTag information from the
        // IHttpFileInfo pointer.
        PCSTR eTagPCSTR = fileInfo->GetETag();
        // Convert the eTag to a wstring.
        wstring eTag = CConvert::ToString(eTagPCSTR);

        // Add an eTag attribute to 
        // the fileInfoElement.
        AddAttribute(L"eTag", eTag,                     
                     fileInfoElement, doc);

        // Get the file buffer as a raw BYTE 
        // pointer from the IHttpFileInfo pointer.
        const BYTE* fileBuffer = fileInfo->GetFileBuffer();
        // Convert the buffer to a string.
        wstring buffer = 
            CConvert::ToString(NULL != fileBuffer);

        // Add a buffer attribute to
        // the fileInfoElement.
        AddAttribute(L"buffer", buffer,                      
                     fileInfoElement, doc);

        // Get the file HANDLE from the
        // IHttpFileInfo pointer.
        HANDLE handleHANDLE =
            fileInfo->GetFileHandle();
        // Convert the HANDLE to a wstring.
        wstring handle = CConvert::ToString(handleHANDLE);

        // Add an attribute to the fileInfoElement 
        // for file handle information.
        AddAttribute(L"handle", handle,                     
                     fileInfoElement, doc);

        // Get the path from the 
        // IHttpFileInfo pointer.
        wstring path = fileInfo->GetFilePath();

        // Add a path attribute to
        // the fileInfoElement.
        AddAttribute(L"path", path, 
                     fileInfoElement, doc);

        // Declare a DWORD for seconds to live.
        DWORD secondsToLiveDWORD = 0;

        // Get cache allowed information from the
        // IHttpFileInfo pointer.
        BOOL cacheAllowedBOOL =
            fileInfo->GetHttpCacheAllowed(&secondsToLiveDWORD);
        // Convert the Boolean to a wstring.
        wstring cacheAllowed = 
            CConvert::ToString(cacheAllowedBOOL);
        // Convert the seconds-to-live
        // to a wstring.
        wstring secondsToLive = 
            CConvert::ToString(secondsToLiveDWORD);

        // Add an attribute to the fileInfoElement
        // indicating if caching is allowed.
        AddAttribute(L"cacheAllowed", cacheAllowed, 
                     fileInfoElement, doc);

        // Add an attribute to the fileInfoElement
        // for the number of seconds to live.
        AddAttribute(L"secondsToLive", secondsToLive,
                     fileInfoElement, doc);

        // Get last modified information from
        // the IHttpFileInfo pointer.
        PCSTR lastModifiedPCSTR =
            fileInfo->GetLastModifiedString();
        // Convert the PCSTR string to
        // a wstring.
        wstring lastModifiedString =
            CConvert::ToString(lastModifiedPCSTR);

        // Add an attribute to the fileInfoElement 
        // for last-modified information.
        AddAttribute(L"lastModifiedString", lastModifiedString,                    
                     fileInfoElement, doc);

        // Get the last modified time from
        // the IHttpFileInfo pointer.
        FILETIME lastModifiedTimeFILETIME;
        fileInfo->GetLastModifiedTime(&lastModifiedTimeFILETIME);
        // Convert the last modified time
        // to a wstring.
        wstring lastModifiedTime =
            CConvert::ToString(&lastModifiedTime);

        // Add a lastModifiedTime attribute to
        // the fileInfoElement.
        AddAttribute(L"lastModifiedTime", lastModifiedTime,                     
                     fileInfoElement, doc);

        // Get the IHttpModuleContextContainer pointer
        // from the IHttpFileInfo pointer.
        IHttpModuleContextContainer* contextContainer = 
            fileInfo->GetModuleContextContainer();

        // Add a container element to the
        // fileInfoElement element.
        MSXML2::IXMLDOMElementPtr contextContainerElement =
            CreateElement(contextContainer, doc);
        fileInfoElement->appendChild(contextContainerElement);

        // Get the file size from the
        // IHttpFileInfo pointer.
        ULARGE_INTEGER fileSizeInt;
        fileInfo->GetSize(&fileSizeInt);
        // Convert the ULARGE_INTEGER to
        // a wstring.
        wstring size = CConvert::ToString(&fileSizeInt);

        // Add a size attribute to 
        // the fileInfoElement.
        AddAttribute(L"size", size, 
                     fileInfoElement, doc);

        // Get the VR path from the 
        // IHttpFileInfo pointer.
        wstring vrPath = fileInfo->GetVrPath();

        // Add a vrPath attribute to 
        // the fileInfoElement.
        AddAttribute(L"vrPath", vrPath, 
                     fileInfoElement, doc);

        // Get the VR token from the
        // IHttpFileInfo pointer.
        HANDLE vrTokenHANDLE =
            fileInfo->GetVrToken();
        // Convert the HANDLE to
        // a wstring.
        wstring vrToken = CConvert::ToString(vrTokenHANDLE);

        // A a vrToken attribute to
        // the fileInfoElement.
        AddAttribute(L"vrToken", vrToken,                      
                     fileInfoElement, doc);

        // Return the fileInfoElement.
        return fileInfoElement;
    }

    // The CreateElement method converts an IHttpCacheSpecificData
    // and its descendant data into an XML element.
    // PRE: the doc parameter must not be NULL.    
    // cacheSpecificData: the IHttpCacheSpecificData 
    // pointer to convert to an XML element.
    // doc: the XML document to use for creating elements.
    // return: a new MSXML2::IXMLDOMElementPtr.
    // throws: a _com_error exception.
    static MSXML2::IXMLDOMElementPtr CreateElement
    (
        IHttpCacheSpecificData* cacheSpecificData,
        MSXML2::IXMLDOMDocument3Ptr doc
    ) throw (_com_error)
    {
        // Create a default cacheSpecificData element.
        MSXML2::IXMLDOMElementPtr cacheSpecificDataElement =
            doc->createElement(L"cacheSpecificData");

        // If the cacheSpecificData is NULL, 
        // return the empty cacheSpecificDataElement.
        if (NULL == cacheSpecificData)
        {
            return cacheSpecificDataElement;
        }

        // Increment the reference count on the cache data.
        cacheSpecificData->ReferenceCacheData();

        // Get the IHttpCacheKey pointer from the 
        // IHttpCacheSpecificData pointer.
        IHttpCacheKey* cacheKey = 
            cacheSpecificData->GetCacheKey();

        // If the cacheKey is non-NULL, get its name.
        // This may allow downcasting to a more specific 
        // IHttpCacheSpecificData pointer type.
        if (NULL != cacheKey)
        {
            // Get the cache name from the cacheKey.
            wstring cacheKeyName = cacheKey->GetCacheName();

            // If the cacheKeyName is FILE_CACHE_NAME, the
            // IHttpCacheSpecificData pointer can be downcast 
            // to an IHttpFileInfo pointer.
            if (FILE_CACHE_NAME == cacheKeyName)
            {
                // Attempt to cast the IHttpCacheSpecificData 
                // pointer to an IHttpFileInfo pointer.                
                IHttpFileInfo* fileInfo =
                    dynamic_cast<IHttpFileInfo*>(cacheSpecificData);
                // Reset the cacheSpecificDataElement 
                // to the new element.
                cacheSpecificDataElement = 
                    CreateElement(fileInfo, doc);
            }

            // If the cacheKeyName is TOKEN_CACHE_NAME, the
            // IHttpCacheSpecificData pointer can be 
            // downcast to an IHttpTokenEntry pointer.
            if (TOKEN_CACHE_NAME == cacheKeyName)
            {
                // Attempt to cast the IHttpCacheSpecificData 
                // pointer to an IHttpTokenEntry pointer.                
                IHttpTokenEntry* tokenEntry =
                    dynamic_cast<IHttpTokenEntry*>(cacheSpecificData);
                // Reset the cacheSpecificDataElement 
                // to the new element.
                cacheSpecificDataElement = 
                    CreateElement(tokenEntry, doc);
            }
        }

        // Add an element to the cacheSpecificDataElement 
        // for the cacheKey pointer.
        MSXML2::IXMLDOMElementPtr cacheKeyElement =
            CreateElement(cacheKey, doc);
        cacheSpecificDataElement->appendChild(cacheKeyElement);

        // Get flushed information from the
        // IHttpCacheSpecificData pointer.
        BOOL flushedBOOL =
            cacheSpecificData->GetFlushed();
        // Convert the Boolean to
        // a wstring.
        wstring flushed = CConvert::ToString(flushedBOOL);

        // Add a flushed attribute to the
        // cacheSpecificDataElement.
        AddAttribute(L"flushed", flushed,                      
                     cacheSpecificDataElement, doc);    

        // Decrement the reference count 
        // on the IHttpCacheSpecificData pointer.
        cacheSpecificData->DereferenceCacheData();

        // Return the new cacheSpecificDataElement to the caller.
        return cacheSpecificDataElement;
    }

    // The CreateElement method converts an HTTP_TRACE_CONFIGURATION
    // pointer and its data into an XML element.
    // PRE: the doc parameter must not be NULL.    
    // traceConfiguration: the HTTP_TRACE_CONFIGURATION 
    // pointer to convert to an XML element.
    // hr: the HRESULT returned from retrieving 
    // the HTTP_TRACE_CONFIGURATION data.
    // doc: the MSXML2::IXMLDOMDocument3Ptr to 
    // use for creating a new element.    
    // return: a new MSXML2::IXMLDOMElementPtr.
    // throws: a _com_error exception.
    static MSXML2::IXMLDOMElementPtr CreateElement
    (
        HTTP_TRACE_CONFIGURATION* traceConfiguration,
        HRESULT hr,
        MSXML2::IXMLDOMDocument3Ptr doc        
    ) throw (_com_error)
    {
        // Create a default cacheSpecificData element to return.
        MSXML2::IXMLDOMElementPtr traceConfigurationElement =
            doc->createElement(L"traceConfiguration");

        // If the HTTP_TRACE_CONFIGURATION data is 
        // NULL or the HRESULT from getting the data 
        // is not S_OK, return the new empty element.
        if ((NULL == traceConfiguration) ||
            (FAILED(hr)))
        {
            return traceConfigurationElement;
        }

        // Get provider GUID information from
        // the HTTP_TRACE_CONFIGURATION pointer.
        LPCGUID providerGuidLPCGUID =
            traceConfiguration->pProviderGuid;
        // Convert the GUID to a wstring.
        wstring providerGuid =
            CConvert::ToString(providerGuidLPCGUID);

        // Add a providerGuid attribute to
        // the traceConfigurationElement.
        AddAttribute(L"providerGuid", providerGuid,                      
                     traceConfigurationElement, doc);

        // Get dwAreas information from
        // the HTTP_TRACE_CONFIGURATION pointer.
        DWORD areasDWORD =
            traceConfiguration->dwAreas;
        // Convert the DWORD to a wstring.
        wstring areas = CConvert::ToString(areasDWORD);

        // Add an areas attribute to
        // the traceConfigurationElement.
        AddAttribute(L"areas", areas,                      
                     traceConfigurationElement, doc);    

        // Get verbosity information from
        // the HTTP_TRACE_CONFIGURATION pointer.
        DWORD verbosityDWORD =
            traceConfiguration->dwVerbosity;
        // Convert the DWORD to a wstring.
        wstring verbosity =
            CConvert::ToString(verbosityDWORD);

        // Add a verbosity attribute to
        // the traceConfigurationElement.
        AddAttribute(L"verbosity", verbosity,
                     traceConfigurationElement, doc);

        // Get enabled information from the
        // HTTP_TRACE_CONFIGURATION pointer.
        BOOL providerEnabledBOOL =
            traceConfiguration->fProviderEnabled;
        // Convert the Boolean to a wstring.
        wstring providerEnabled = 
            CConvert::ToString(providerEnabledBOOL);

        // Add an attribute to the traceConfigurationElement 
        // for provider-enabled information.
        AddAttribute(L"providerEnabled", providerEnabled,                     
                     traceConfigurationElement, doc);

        // Return the traceConfigurationElement to the caller.
        return traceConfigurationElement;
    }

    // The CreateElement method converts an IHttpTraceContext
    // pointer and its descendant data into an XML element.
    // PRE: the doc parameter must not be NULL.    
    // traceContext: the IHttpTraceContext 
    // pointer to convert to an XML element.
    // doc: the MSXML2::IXMLDOMDocument3Ptr to 
    // use for creating a new element.    
    // return: a new MSXML2::IXMLDOMElementPtr.
    // throws: a _com_error exception.
    static MSXML2::IXMLDOMElementPtr CreateElement
    (
        IHttpTraceContext* traceContext,
        MSXML2::IXMLDOMDocument3Ptr doc
    ) throw (_com_error)
    {
        // Create a default cacheSpecificData element.
        MSXML2::IXMLDOMElementPtr traceContextElement =
            doc->createElement(L"traceContext");

        // Return the traceContext element if the IHttpTraceContext 
        // pointer data is NULL.
        if (NULL == traceContext)
        {
            return traceContextElement;
        }

        // Get trace configuration information 
        // from the IHttpTraceContext pointer.
        HTTP_TRACE_CONFIGURATION traceConfig;
        traceConfig.dwAreas = 0;
        traceConfig.dwVerbosity = 0;
        traceConfig.fProviderEnabled = FALSE;
        traceConfig.pProviderGuid = NULL;        
        HRESULT hr = 
            traceContext->GetTraceConfiguration(&traceConfig);

        // Create a trace configuration element
        // and append it to the traceContextElement.
        MSXML2::IXMLDOMElementPtr traceConfigElement =
            CreateElement(&traceConfig, hr, doc);
        traceContextElement->appendChild(traceConfigElement);

        // Get the activity identifier from
        // the IHttpTraceContext pointer.
        LPCGUID activityIdLPCGUID =
            traceContext->GetTraceActivityId();
        // Convert the activity identifier 
        // to a wstring.
        wstring activityId = 
            CConvert::ToString(activityIdLPCGUID);

        // Add an attribute to the traceContextElement 
        // for the activity identifier.
        AddAttribute(L"activityId", activityId,                     
                     traceContextElement, doc);

        // Return the traceContextElement.
        return traceContextElement;
    }
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);             
}


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 a new event to the application log of the Event Viewer, where the Data box contains XML similar to the following.

<cacheProvider cacheOperation="CACHE_OPERATION_RETRIEVE">
    <fileKey 
        path="D:\INETPUB\WWWROOT" 
        cacheName="FILE" 
        hash="-711969814" 
        isEqual="true" 
        isPrefix="true"/>
    <fileInfo 
        changed="false" 
        attributes="32" 
        eTag="1234567890abcde:0" 
        buffer="true" 
        path="C:\INETPUB\WWWROOT\DEFAULT.HTM" 
        handle="INVALID_HANDLE_VALUE" 
        cacheAllowed="true" 
        secondsToLive="-1" 
        lastModifiedString="Tue, 13 Dec 2005 10:57:41 GMT" 
        lastModifiedTime="12/13/2005 02:57" 
        size="50" 
        vrPath="NULL" 
        vrToken="NULL">
        <fileKey 
            path="C:\INETPUB\WWWROOT\DEFAULT.HTM" 
            cacheName="FILE" 
            hash="-711969814" 
            isEqual="true" 
            isPrefix="true" />
        <contextContainer>
            <storedContext />
        </contextContainer>
    </fileInfo>
    <traceContext 
        activityId="{00000000-0000-0000-3400-0080000000FF}">
        <traceConfiguration 
            providerGuid="" 
            areas="0" 
            verbosity="0" 
            providerEnabled="false"/>
    </traceContext>
</cacheProvider>

You can optionally compile the code by using the __stdcall (/Gz) calling convention instead of explicitly declaring the calling convention for each function.

Type

Description

Client

  • IIS 7.0 on Windows Vista

  • IIS 7.5 on Windows 7

  • IIS Express 7.5 on Windows XP, Windows Vista, Windows 7

  • IIS 8.0 on Windows 8 Client

Server

  • IIS 7.0 on Windows Server 2008

  • IIS 7.5 on Windows Server 2008 R2

  • IIS Express 7.5 on Windows Server 2003, Windows Server 2008, Windows Server 2008 R2

  • IIS 8.0 on Windows Server 2012

Product

IIS 7.0, IIS 7.5, IIS Express 7.5, IIS 8.0

Header

Httpserv.h

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