IHttpContext：：IndicateCompletion 方法

指示异步工作完成，并请求 IIS 在调用线程上恢复执行。

语法

virtual VOID IndicateCompletion(  
   IN REQUEST_NOTIFICATION_STATUS notificationStatus  
) = 0;  

parameters

notificationStatus
[IN]异步操作的通知状态。

返回值

VOID.

注解

HTTP 模块可以使用 IndicateCompletion 方法指示异步操作已完成，并请求 IIS 在调用线程上恢复处理。 此行为与 PostCompletion 方法的行为不同，后者将执行排入线程池。

如果 参数指定的 notificationStatus 状态未 REQUEST_NOTIFICATION_PENDING，则请求状态计算机将继续运行，而不会重新输入原始通知入口点。

示例

下面的代码示例演示如何创建使用 IndicateCompletion 方法指示异步操作已完成的 HTTP 模块。

#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;

        // Create a string to return to a Web client.
        PCSTR pszBuffer = "Hello World!";
        
        // 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 data chunk. (Defined in the Http.h file.)
        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 completion expected flag to false.
        BOOL pfCompletionExpected = FALSE;

        // Set the chunk to the buffer.
        dataChunk.FromMemory.pBuffer = (PVOID) pszBuffer;
        // Set the chunk size to the buffer size.
        dataChunk.FromMemory.BufferLength = (USHORT) strlen(pszBuffer);
        // Insert the data chunk into the response.
        hr = pHttpContext->GetResponse()->WriteEntityChunks(
            &dataChunk,1,TRUE,TRUE,&cbSent,&pfCompletionExpected);

        // Test for an error.
        if (FAILED(hr))
        {
            // Return the error status and exit.
            pProvider->SetErrorStatus(hr);
            return RQ_NOTIFICATION_FINISH_REQUEST;
        }

        if (TRUE == pfCompletionExpected)
        {
            // Notify IIS that an asynchronous completion is expected.
            return RQ_NOTIFICATION_PENDING;
        }

        // Flush the response to the client.
        hr = pHttpContext->GetResponse()->Flush(TRUE,FALSE,&cbSent,&pfCompletionExpected);
        
        // Test for an error.
        if (FAILED(hr))
        {
            // Return the error status and exit.
            pProvider->SetErrorStatus(hr);
            return RQ_NOTIFICATION_FINISH_REQUEST;
        }

        if (TRUE == pfCompletionExpected)
        {
            // Notify IIS that an asynchronous completion is expected.
            return RQ_NOTIFICATION_PENDING;
        }

        // End additional processing.
        return RQ_NOTIFICATION_FINISH_REQUEST;
    }
    
    REQUEST_NOTIFICATION_STATUS OnAsyncCompletion(
        IN IHttpContext* pHttpContext,
        IN DWORD dwNotification,
        IN BOOL fPostNotification,
        IN OUT IHttpEventProvider* pProvider,
        IN IHttpCompletionInfo* pCompletionInfo
    )
    {
        // Indicate completion for the operation.
        pHttpContext->IndicateCompletion(RQ_NOTIFICATION_CONTINUE);
        // Return processing to the pipeline.
        return RQ_NOTIFICATION_PENDING;
    }
};

// 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 we 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
    );
}

模块必须导出 RegisterModule 函数。 可以通过为项目创建模块定义 (.def) 文件导出此函数，也可以使用 开关编译模块 /EXPORT:RegisterModule 。 有关详细信息，请参阅 演练：使用本机代码创建Request-Level HTTP 模块。

可以选择使用调用约定编译代码， __stdcall (/Gz) 而不是为每个函数显式声明调用约定。

要求

类型	说明
客户端	- Windows Vista 上的 IIS 7.0 - Windows 7 上的 IIS 7.5 - Windows 8 上的 IIS 8.0 - Windows 10 上的 IIS 10.0
服务器	- Windows Server 2008 上的 IIS 7.0 - Windows Server 2008 R2 上的 IIS 7.5 - Windows Server 2012 上的 IIS 8.0 - Windows Server 2012 R2 上的 IIS 8.5 - Windows Server 2016 上的 IIS 10.0
产品	- 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

另请参阅

IHttpContext 接口
IHttpContext：:P ostCompletion 方法