Scoket异步套接字编程，在客户端实现数据的发送和接收

 

WSAAsyncSelect模型 实现socket客户端接收数据的例子

 

(1) h文件中声明网络事件响应函数

afx_msg void OnNetEvent(WPARAM wParam, LPARAM lParam);

(2)cpp文件中把NETWORK_EVENT事件映射到OnNetEvent()函数

BEGIN_MESSAGE_MAP(CInstrumentStatusView, CFormView)
    ON_MESSAGE(NETWORK_EVENT,OnNetEvent)
END_MESSAGE_MAP()

 

(3)OnNetEvent()函数体, 对FD_CONNECT, FD_CLOSE, FD_READ事件进行响应处理

void CInstrumentStatusView::OnNetEvent(WPARAM wParam, LPARAM lParam) {
    int iEvent = WSAGETSELECTEVENT(lParam);
    int error = WSAGETSELECTERROR(lParam); //if error!=0, it means failure
    SOCKET CurSock= (SOCKET)wParam;
    if(error)
    {
        AfxMessageBox("OnNetEvent()接收到错误消息");
        closesocket(wParam);
        return;
    }
    switch(iEvent){
    case FD_CONNECT:
             OnSockConnect(error); //void CInstrumentStatusView::OnSockConnect(int error);
        break;

    case FD_CLOSE:
             CloseCurrSockHandle();//void CInstrumentStatusView::CloseCurrSockHandle();
        break;

    case FD_READ:
             OnSockReceive();      //recv buffer and copy to m_pCurCommand->m_CommandBuffer
        break;

    }

}

 

(4)创建套接字, 并使用WSAAsyncSelect()为套接字m_sockClient注册事件

if(WSAAsyncSelect(m_sockClient,m_hWnd,NETWORK_EVENT,FD_CLOSE | FD_READ | FD_CONNECT) == SOCKET_ERROR)
{
    closesocket(m_sockClient);
    //MessageBox("CComWnd注册网络异步事件失败!");
    //WSACleanup();
    return 0;
}

 

(5)OnSockReceive()函数体, 收到FD_READ消息后, 执行此函数

void CInstrumentStatusView::OnSockReceive(){
    int ReadResults=0;
    BOOL Ready=FALSE;
    char tempChar;
    WSAAsyncSelect(m_sockClient,m_hWnd,NETWORK_EVENT,0); //关闭套接字事件m_sockClient上的事件
    //循环读,每次读一个字节
    //while(total!=m_pCurCommand->m_nExpectedBytes)
    while(!Ready) //当读到结束符时,Ready=TRUE
    {
        ReadResults=recv(m_sockClient,&tempChar,1,0);
        if(ReadResults == SOCKET_ERROR)//recv返回异常处理
        {
            if (WSAEWOULDBLOCK == WSAGetLastError())
            {
                continue; //如果异常是"阻塞异常", 继续下次循环
            }
            else //非WSAEWOULDBLOCK 异常的处理,可能是网络断开等
            {
                m_bConnected=FALSE;
                break;
            }
        }
        else if(ReadResults==0)
        {
            AfxMessageBox(_T("对端关闭了连接"));
        }
        else if(ReadResults==1)
        {
            if(m_pCurCommand->AddToReceiveBuffer(tempChar)) Ready=TRUE;
//AddToReceiveBuffer中判断tempChar是否是结束字符,如果是,返回TRUE, while循环条件Ready置为TRUE,退出循环
        }
    }
    WSAAsyncSelect(m_sockClient,m_hWnd,NETWORK_EVENT,FD_CLOSE | FD_READ | FD_CONNECT);//数据接收完成,恢复套接字m_sockClient的网络事件

}