IHttpApplication::GetApplicationPhysicalPath Method

Article
03/09/2018

Retrieves the physical path of the application for the current request.

Syntax

virtual PCWSTR GetApplicationPhysicalPath(  
   VOID  
) const = 0;

Parameters

This method takes no parameters.

Return Value

A pointer to a string that contains the physical path for the application.

Remarks

The GetApplicationPhysicalPath method returns the physical path for the root folder of the application that is processing the current request. For example, requests for the default Web site on a server running IIS 7 will usually return the C:\Inetpub\Wwwroot location.

This path is not always the same folder path as the current request. For example, if a Web client requests both http://example.com/ and http://example.com/example/, these paths may be respectively located at C:\Inetpub\Wwwroot and C:\Inetpub\Wwwroot\Example. However, the GetApplicationPhysicalPath method will return only the C:\Inetpub\Wwwroot path for both requests if an application has not been created for the C:\Inetpub\Wwwroot\Example path.

Example

The following code example demonstrates how to use the GetApplicationPhysicalPath method to create an HTTP module that retrieves the physical path for the current request and returns the path to a Web client.

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

// 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;

        // Buffer to store the translated path.
        char* pszApplicationPhysicalPath;

        // Retrieve a pointer to the IHttpApplication class.
        IHttpApplication * pHttpApplication =
            pHttpContext->GetApplication();

        // Retrieve a pointer to the application configuration path.
        PCWSTR pwszApplicationPhysicalPath =
            pHttpApplication->GetApplicationPhysicalPath();

        // Test for an error.
        if (NULL != pwszApplicationPhysicalPath)
        {
            // Length of the returned path.
            DWORD cbApplicationPhysicalPath =
                (DWORD) wcslen(pwszApplicationPhysicalPath);
            // Allocate space to store the path.
            pszApplicationPhysicalPath =
                (PSTR) pHttpContext->AllocateRequestMemory
                (cbApplicationPhysicalPath + 1);
            // Test for an error.
            if (pszApplicationPhysicalPath==NULL)
            {
                // 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(pszApplicationPhysicalPath,
                pwszApplicationPhysicalPath,cbApplicationPhysicalPath);
            
            // 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);
            
            // Return the path information.
            WriteResponseMessage(pHttpContext,
                "Application physical path: ",pszApplicationPhysicalPath);

            // 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 );
    UNREFERENCED_PARAMETER( 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 Technical Preview
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

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