IHttpRequest::InsertEntityBody Method

Inserts a new entity body into the existing HTTP request body.

Syntax

virtual HRESULT InsertEntityBody(  
   IN VOID* pvBuffer,  
   IN DWORD cbBuffer  
) = 0;  

Parameters

pvBuffer
[IN] A pointer to a VOID buffer that contains the request entity body.

cbBuffer
[IN] A DWORD that contains the size, in bytes, of the buffer.

Return Value

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

Remarks

The InsertEntityBody method inserts the entity body that is pointed to by the pvBuffer parameter into the HTTP request entity body.

Example

The following code example demonstrates how create an HTTP module that calls the IHttpContext::AllocateRequestMemory method to allocate a 1-KB buffer. The module then copies the string "Hello World" into the buffer. Finally, the module calls the InsertEntityBody method to replace the preloaded HTTP request entity body with the buffer and then exits.

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

// NOTE - Data needs to be passed to this module, e.g. a POST request, or it will not appear to return anything.

// Create the module class.
class MyHttpModule : public CHttpModule
{
public:
    REQUEST_NOTIFICATION_STATUS
    OnBeginRequest(
        IN IHttpContext * pHttpContext,
        IN IHttpEventProvider * pProvider
    )
    {
        // Create an HRESULT to receive return values from methods.
        HRESULT hr;

        // Allocate a 1K buffer.
        DWORD cbBuffer = 1024;
        void * pvBuffer = pHttpContext->AllocateRequestMemory(cbBuffer);
        
        // Test for an error.
        if (NULL == pvBuffer)
        {
            // Set the error status.
            pProvider->SetErrorStatus(
                HRESULT_FROM_WIN32(ERROR_NOT_ENOUGH_MEMORY));
            // End additional processing.
            return RQ_NOTIFICATION_FINISH_REQUEST;
        }
        
        // Copy a string into the buffer.
        strcpy_s((char*)pvBuffer,cbBuffer,"Hello world!");
        // Insert the entity body into the buffer.
        hr = pHttpContext->GetRequest()->InsertEntityBody(
            pvBuffer,(DWORD)strlen((char*)pvBuffer));

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

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

// 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

See Also

IHttpRequest Interface