ISendResponseProvider::SetFlags Method

Article
03/09/2018

Configures the flags for the current HTTP response.

Syntax

virtual VOID SetFlags(  
   DWORD dwFlags  
) = 0;

Parameters

dwFlags
A DWORD that contains the response flags to set.

Return Value

VOID.

Remarks

You can use the SetFlags method to specify which response flags to use with the current response. These flags provide additional control over the HTTP behavior for IIS 7. The following flags are defined in the Http.h header file.

Name	Value	Description
HTTP_SEND_RESPONSE_FLAG_DISCONNECT	0x00000001	Disconnects the network connection immediately after the response is sent.
HTTP_SEND_RESPONSE_FLAG_MORE_DATA	0x00000002	Sends additional data in the response.
HTTP_SEND_RESPONSE_FLAG_BUFFER_DATA	0x00000004	Buffers the response before it is sent.
HTTP_SEND_RESPONSE_FLAG_ENABLE_NAGLING	0x00000008	Enables the Nagle algorithm to optimize TCP response packets.

Example

The following code example demonstrates how to use the SetFlags and GetFlags methods to create an HTTP module that sets the flags for the current response. The example then retrieves the modified flags and returns the response 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
    OnSendResponse(
        IN IHttpContext * pHttpContext,
        IN ISendResponseProvider * pProvider
    )
    {
        // Set the flags.
        pProvider->SetFlags( pProvider->GetFlags() | 
            HTTP_SEND_RESPONSE_FLAG_DISCONNECT |
            HTTP_SEND_RESPONSE_FLAG_BUFFER_DATA );

        // Retrieve the flags.
        DWORD dwFlags = pProvider->GetFlags();

        // 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);

        // Create a string buffer for the return message.
        char szBuffer[256];
        sprintf_s(szBuffer,255,"0x%x\n",dwFlags);

        // Test for the disconnect flag.
        if (dwFlags & HTTP_SEND_RESPONSE_FLAG_DISCONNECT)
            strcat_s(szBuffer,255,
            "\nHTTP_SEND_RESPONSE_FLAG_DISCONNECT");

        // Test for the more data flag.
        if (dwFlags & HTTP_SEND_RESPONSE_FLAG_MORE_DATA)
            strcat_s(szBuffer,255,
            "\nHTTP_SEND_RESPONSE_FLAG_MORE_DATA");

        // Test for the buffer data flag.
        if (dwFlags & HTTP_SEND_RESPONSE_FLAG_BUFFER_DATA)
            strcat_s(szBuffer,255,
            "\nHTTP_SEND_RESPONSE_FLAG_BUFFER_DATA");

        // Return the message to the Web client.
        WriteResponseMessage(pHttpContext,"\nFlags: ",szBuffer);

        // End additional processing.
        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 );
    UNREFERENCED_PARAMETER( pGlobalInfo );

    // Set the request notifications and exit.
    return pModuleInfo->SetRequestNotifications(
        new MyHttpModuleFactory,
        RQ_SEND_RESPONSE,
        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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