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IHttpServer::GetConfigObject Method

  • Article

Retrieves the configuration object for the current context.

Syntax

virtual INativeConfigurationSystem* GetConfigObject(  
   VOID  
) const = 0;

Parameters

This method takes no parameters.

Return Value

A pointer to an INativeConfigurationSystem interface.

Remarks

The GetConfigObject method retrieves a configuration object that you can use to retrieve configuration settings from a configuration file. For example, the INativeConfigurationSystem::GetConfigSection method retrieves a INativeConfigurationElement interface, which is a container object for a section of the configuration settings for the current context. This container object contains several methods that you can use to retrieve or modify the configuration settings.

Example

The following code example demonstrates how to create an HTTP module that uses the IHttpContext::GetMetadata method to retrieve a pointer to an IMetadataInfo interface. The module completes the following steps:

  1. Uses the IMetadataInfo::GetMetaPath method to retrieve the configuration path for the current request.

  2. Uses the GetConfigObject method to retrieve a pointer to an INativeConfigurationSystem interface.

  3. Passes the configuration path for the current request to the INativeConfigurationSystem::GetConfigSection method.

  4. Retrieves an INativeConfigurationElement interface for the log settings for IIS.

  5. Uses the INativeConfigurationElement::GetBooleanProperty method to retrieve a value that indicates whether logging is enabled for the current request context.

  6. Returns this information to a Web client and then exits.

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

// Create a pointer for the global server interface.
IHttpServer * g_pHttpServer = NULL;

// Create the module class.
class MyHttpModule : public CHttpModule
{
public:
    REQUEST_NOTIFICATION_STATUS
    OnBeginRequest(
        IN IHttpContext * pHttpContext,
        IN IHttpEventProvider * pProvider
    )
    {
        UNREFERENCED_PARAMETER( pProvider );

        // Create an HRESULT to receive return values from methods.
        HRESULT hr;
        // Create a boolean variable for the configuration setting.
        BOOL fDoNotLog = FALSE;
        // Create pointers to configuration objects.
        INativeConfigurationSystem * pConfigSystem = NULL;
        INativeConfigurationElement * pConfigElement = NULL;

        // Retrieve a pointer to the IMetadataInfo interface.
        IMetadataInfo * pMetadataInfo = pHttpContext->GetMetadata();
        
        // Retrieve the configuration path.
        PCWSTR pwszConfigPath = pMetadataInfo->GetMetaPath();

        // Retrieve the configuration object.
        pConfigSystem = g_pHttpServer->GetConfigObject();

        // Test for an error.
        if (NULL != pConfigSystem)
        {        
            // Retrieve the HTTP logging configuration section.
            hr = pConfigSystem->GetConfigSection(
                L"system.webServer/httpLogging",
                pwszConfigPath,&pConfigElement,NULL,NULL);
        
            // Test for an error.
            if (SUCCEEDED(hr))
            {
                // Retrieve the log settings from the configuration section.
                hr = pConfigElement->GetBooleanProperty(
                    L"dontLog",&fDoNotLog,NULL);

                // Test for an error.
                if (SUCCEEDED(hr))
                {
                    // Clear the existing response.
                    pHttpContext->GetResponse()->Clear();
                    // Set the MIME type to plain text.
                    pHttpContext->GetResponse()->SetHeader(
                        HttpHeaderContentType,"text/plain",
                        (USHORT)strlen("text/plain"),TRUE);
                            
                    // Allocate space for the configuration path.
                    PSTR pszConfigPath =
                        (PSTR) pHttpContext->AllocateRequestMemory(
                        (DWORD) wcslen(pwszConfigPath) + 1 );

                    // Test for an error.
                    if (NULL == pszConfigPath)
                    {
                        // Set the error status.
                        hr = HRESULT_FROM_WIN32(ERROR_NOT_ENOUGH_MEMORY);
                        pProvider->SetErrorStatus( hr );
                        // End additional processing.
                        return RQ_NOTIFICATION_FINISH_REQUEST;
                    }

                    // Convert the WCHAR string to a CHAR string.
                    wcstombs(pszConfigPath,
                        pwszConfigPath,wcslen(pwszConfigPath));

                    // Return the configuration path.
                    WriteResponseMessage(pHttpContext,
                        "\nConfiguration path:\t",pszConfigPath);

                    // Return the configuration setting.
                    WriteResponseMessage(pHttpContext,"\nLogging enabled:\t",
                        (FALSE == fDoNotLog) ? "Yes" : "No");

                    // End additional processing.
                    return RQ_NOTIFICATION_FINISH_REQUEST;
                }
            }
        }

        // Return processing to the pipeline.
        return RQ_NOTIFICATION_CONTINUE;
    }

private:

    // Create a utility method that inserts a name/value pair into the response.
    HRESULT WriteResponseMessage(
        IHttpContext * pHttpContext,
        PCSTR pszName,
        PCSTR pszValue
    )
    {
        // Create an HRESULT to receive return values from methods.
        HRESULT hr;
        
        // Create a data chunk.
        HTTP_DATA_CHUNK dataChunk;
        // Set the chunk to a chunk in memory.
        dataChunk.DataChunkType = HttpDataChunkFromMemory;
        // Buffer for bytes written of data chunk.
        DWORD cbSent;

        // Set the chunk to the first buffer.
        dataChunk.FromMemory.pBuffer =
            (PVOID) pszName;
        // Set the chunk size to the first buffer size.
        dataChunk.FromMemory.BufferLength =
            (USHORT) strlen(pszName);
        // Insert the data chunk into the response.
        hr = pHttpContext->GetResponse()->WriteEntityChunks(
            &dataChunk,1,FALSE,TRUE,&cbSent);
        // Test for an error.
        if (FAILED(hr))
        {
            // Return the error status.
            return hr;
        }

        // Set the chunk to the second buffer.
        dataChunk.FromMemory.pBuffer =
            (PVOID) pszValue;
        // Set the chunk size to the second buffer size.
        dataChunk.FromMemory.BufferLength =
            (USHORT) strlen(pszValue);
        // Insert the data chunk into the response.
        hr = pHttpContext->GetResponse()->WriteEntityChunks(
            &dataChunk,1,FALSE,TRUE,&cbSent);
        // Test for an error.
        if (FAILED(hr))
        {
            // Return the error status.
            return hr;
        }

        // Return a success status.
        return S_OK;
    }
};

// Create the module's class factory.
class MyHttpModuleFactory : public IHttpModuleFactory
{
public:
    HRESULT
    GetHttpModule(
        OUT CHttpModule ** ppModule, 
        IN IModuleAllocator * pAllocator
    )
    {
        UNREFERENCED_PARAMETER( pAllocator );

        // Create a new instance.
        MyHttpModule * pModule = new MyHttpModule;

        // Test for an error.
        if (!pModule)
        {
            // Return an error if the factory cannot create the instance.
            return HRESULT_FROM_WIN32( ERROR_NOT_ENOUGH_MEMORY );
        }
        else
        {
            // Return a pointer to the module.
            *ppModule = pModule;
            pModule = NULL;
            // Return a success status.
            return S_OK;
        }            
    }

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

// Create the module's exported registration function.
HRESULT
__stdcall
RegisterModule(
    DWORD dwServerVersion,
    IHttpModuleRegistrationInfo * pModuleInfo,
    IHttpServer * pGlobalInfo
)
{
    UNREFERENCED_PARAMETER( dwServerVersion );

    // Store the pointer for the global server interface.
    g_pHttpServer = pGlobalInfo;

    // Set the request notifications and exit.
    return pModuleInfo->SetRequestNotifications(
        new MyHttpModuleFactory,
        RQ_BEGIN_REQUEST,
        0
    );
}

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 Request-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

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

IHttpServer Interface