IHttpServer::GetManagedType Method

 

Retrieves the managed type for a specific site and Uniform Resource Identifier (URI).

Syntax

virtual HRESULT GetManagedType(  
   IN DWORD dwSiteId,  
   IN PCWSTR pszVirtualPath,  
   __out PWSTR pszManagedType,  
   IN OUT DWORD* pcchManagedType  
) = 0;  

Parameters

dwSiteId
[IN] The site identifier for the URI in pszVirtualPath.

pszVirtualPath
[IN] A pointer to a string that contains a URI.

pszManagedType
[__out] A pointer to a preallocated string buffer.

pcchManagedType
[IN][OUT] The length, in bytes, of the pszManagedType buffer.

Return Value

An HRESULT. Possible values include, but are not limited to, those in the following table.

Value Description
S_OK Indicates that the operation was successful.
E_INVALIDARG Indicates that an invalid value was passed in one of the parameters (for example, one of the pointers is set to NULL).
E_OUTOFMEMORY Indicates that there is not enough available memory to perform the operation.
ERROR_INVALID_PARAMETER Indicates that an invalid value was passed in one of the parameters.
ERROR_INSUFFICIENT_BUFFER Indicates that there is not enough buffer space to perform the operation.

Remarks

The GetManagedType method retrieves the type attribute for request handler that will process a specific virtual path that is specified by the dwSiteId and pszVirtualPath parameters. The method then returns this information in the buffer that is specified by the pszManagedType parameter.

Important

The caller must allocate the buffer for pszManagedType. If the caller passes NULL for this parameter, the method will return E_INVALIDARG.

The type attribute for a request handler is located in the <handlers> section of the ApplicationHost.config file. This attribute contains a list of the .NET Framework namespaces for a request handler. For example, the "TraceHandler-Integrated" request handler has a type attribute of "System.Web.Handlers.TraceHandler" by default.

The IHttpServer::GetManagedType method differs from the IScriptMapInfo::GetManagedType method in that the IHttpServer::GetManagedType method can retrieve the type attribute for any virtual path, whereas the IScriptMapInfo::GetManagedType method will retrieve only the type attribute for the IScriptMapInfo interface.

Example

The following code example demonstrates how to use the GetManagedType method to create an HTTP module that retrieves the managed type for the /default.aspx URI.

The module completes the following steps:

  1. Retrieves the site identifier for the current request.

  2. Retrieves the length needed to retrieve the managed type for the request.

  3. Allocates a buffer for the managed type.

  4. Retrieves the managed type.

  5. Returns the result 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;

        // Retrieve the site ID.
        DWORD dwSiteId = pHttpContext->GetSite()->GetSiteId();

        // Create buffers to store the managed type.
        PWSTR pwszManagedType =
            (PWSTR) pHttpContext->AllocateRequestMemory( 1 );
        char* pszManagedType = NULL;
        DWORD cchManagedType = 0;

        // Test for an error.
        if (NULL != pwszManagedType)
        {
            // Retrieve the size of the managed type.
            hr = g_pHttpServer->GetManagedType(
                dwSiteId,L"/default.aspx",
                pwszManagedType,&cchManagedType);
            // Test for an error.
            if ((HRESULT_CODE(hr)==ERROR_INSUFFICIENT_BUFFER) && (cchManagedType>0))
            {
                // Allocate space for the managed type.
                pwszManagedType =
                    (PWSTR) pHttpContext->AllocateRequestMemory(
                    (cchManagedType*2)+1 );
                // Test for an error.
                if (NULL == pwszManagedType)
                {
                    // Set the error status.
                    hr = HRESULT_FROM_WIN32(ERROR_NOT_ENOUGH_MEMORY);
                    pProvider->SetErrorStatus( hr );
                }
                else
                {
                    // Retrieve the managed type.
                    hr = g_pHttpServer->GetManagedType(
                        dwSiteId,L"/default.aspx",
                        pwszManagedType,&cchManagedType);
                    // 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 managed type.
                        pszManagedType =
                            (char*) pHttpContext->AllocateRequestMemory(
                            (DWORD) wcslen(pwszManagedType)+1 );
                        // Test for an error.
                        if (NULL == pszManagedType)
                        {
                            // Set the error status.
                            hr = HRESULT_FROM_WIN32(ERROR_NOT_ENOUGH_MEMORY);
                            pProvider->SetErrorStatus( hr );
                        }
                        else
                        {
                            // Convert the WCHAR string to a CHAR string.
                            wcstombs(pszManagedType,
                                pwszManagedType,wcslen(pwszManagedType));
                            // Return the managed type to the client.
                            WriteResponseMessage(pHttpContext,"Managed type: ",
                                (cchManagedType>1) ? pszManagedType : "n/a");
                        }
                        // End additional processing.
                        return RQ_NOTIFICATION_FINISH_REQUEST;
                    }
                }
            }
        }

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

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 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

See Also

IHttpServer Interface
IScriptMapInfo::GetManagedType Method