WSAAsyncSelect模型

这个模型跟窗口有关，它使用消息来进行通知的。如下是对话框客户端关键代码，连接的是一个echo服务端。

测试文件的传输，将文件发送出去，然后将读取的数据写入文件。

读写文件类WinFile参考： http://blog.csdn.net/tujiaw/article/details/17840823

Buffer类参考：http://blog.csdn.net/tujiaw/article/details/8872865

1. 自定义消息： #define WM_ASYNC_SELECT (WM_USER + 103)

2. 消息映射： ON_MESSAGE(WM_ASYNC_SELECT, &CSmallFileDlg::OnAsyncSelect)

afx_msg LRESULT CSmallFileDlg::OnAsyncSelect(WPARAM wParam, LPARAM lParam)
{
	switch (WSAGETSELECTEVENT(lParam))
	{
	case FD_CONNECT:
		if (WSAGETSELECTERROR(lParam))
		{
			MessageBox(GetErrorString(WSAGETSELECTERROR(lParam), L"FD_CONNECT"));
		}
		else
		{
			MessageBox(L"连接成功");
		}
		break;


	case FD_READ:
		{
			recvBuffer();
			static WinFile fr(L"C:\\Users\\jiaw\\Desktop\\2.flv", false);
			static size_t totalWritten = 0;
			size_t currentWritten;
			int ret = fr.write(m_input.peek(), m_input.readableBytes(), ¤tWritten);
			if (0 != ret) {
				MessageBox(GetErrorString(ret, L"FD_READ"));
				::shutdown(m_socket, SD_BOTH);
				::closesocket(wParam);
			} else {
				totalWritten += currentWritten;
				m_input.retrieve(currentWritten);
				fr.seek(totalWritten);
			}
		}
		break;


	case FD_WRITE:
		sendBuffer(); // send当网络缓冲区满的时候会产生WSAEWOULDBLOCK错误码，此时触发写事件继续写入
		break;


	case FD_CLOSE:
		if (WSAGETSELECTERROR(lParam))
		{
			MessageBox(GetErrorString(WSAGetLastError(), L"FD_CLOSE"));
		}
		::shutdown(m_socket, SD_BOTH);
		::closesocket(wParam);
		MessageBox(L"close");
		break;
	}


	return 0;
}


void CSmallFileDlg::OnBnClickedConnect()
{
	const char *ip = "192.168.239.150";
	unsigned short port = 5000;
	struct sockaddr_in sin;
	memset(&sin, 0, sizeof(sin));
	sin.sin_family = AF_INET;
	sin.sin_addr.S_un.S_addr = inet_addr(ip);
	sin.sin_port = htons(port);
	m_socket = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if (INVALID_SOCKET == m_socket) {
		MessageBox(GetErrorString(WSAGetLastError(), L"socket"));
		return;
	}

	// 会自动将socket设为非阻塞
	if (SOCKET_ERROR == WSAAsyncSelect(m_socket, m_hWnd, WM_ASYNC_SELECT, FD_READ | FD_WRITE | FD_CONNECT | FD_CLOSE)) {
		MessageBox(GetErrorString(WSAGetLastError(), L"WSAAsyncSelect"));
		::closesocket(m_socket);
	}


	if (SOCKET_ERROR == ::connect(m_socket, (sockaddr*)&sin, sizeof(sin))) {
		int errCode = WSAGetLastError();
		if (WSAEWOULDBLOCK != errCode) { // 非阻塞连接处理WSAEWOULDBLOCK
			MessageBox(GetErrorString(WSAGetLastError(), L"connect"));
			::closesocket(m_socket);
			return;
		}
	}
}

void CSmallFileDlg::OnBnClickedDisconnect()
{
	::shutdown(m_socket, SD_BOTH);
	::closesocket(m_socket);
}

void CSmallFileDlg::OnBnClickedSend()
{
	WinFile fr(L"C:\\Users\\jiaw\\Desktop\\1.flv", true);
	char buf[65536];
	size_t result;
	DWORD total = fr.size();
	DWORD nread = 0;
	while (nread != total) {
		int ret = fr.read(buf, sizeof(buf), &result);
		if (0 != ret) {
			MessageBox(GetErrorString(ret));
			break;
		}


		nread += result;
		fr.seek(nread); // 设置下次的读取位置，从0开始偏移


		m_output.append(buf, result);
		sendBuffer();
	}
}

void CSmallFileDlg::sendBuffer()
{
	int ret = ::send(m_socket, m_output.peek(), m_output.readableBytes(), 0);
	if (ret > 0)
	{
		m_output.retrieve(ret);
		m_sendNum += ret; // 发送消息计数
		UpdateData(FALSE);
	}
	else if (SOCKET_ERROR == ret)
	{
		int errCode = WSAGetLastError();
		if (WSAEWOULDBLOCK != errCode)
		{
			MessageBox(GetErrorString(errCode), L"send");
		}
	}
}

void CSmallFileDlg::recvBuffer()
{
	char buf[65536] = {0};
	int ret = ::recv(m_socket, buf, sizeof(buf) - 1, 0);
	if (ret > 0)
	{
		m_recvNum += ret; // 接收消息计数
		UpdateData(FALSE);
		m_input.append(buf, ret);
	}
	else if (0 == ret)
	{
		MessageBox(L"连接优雅的关闭");
	}
	else
	{
		MessageBox(GetErrorString(WSAGetLastError(), L"recv"));
	}
}

// 产生随机字符串
std::string BuildRandString(int num)
{
	static unsigned int s_add = 0;
	std::string ret;
	srand((unsigned int)time(NULL) + (s_add++));
	for (int i=0; i<num; )
	{
		char buf[17] = {0};
		_itoa_s(rand(), buf, 0x10);
		ret += buf;
		i += strlen(buf);
	}
	return ret.substr(0, num);
}

void DebugLog(const char *fmt, ...)
{
	va_list ap;
	va_start(ap, fmt);
	char buf[1024] = {0};
	vsnprintf_s(buf, sizeof(buf), fmt, ap);
	MessageBoxA(NULL, buf, "debug log", MB_OK);
	va_end(ap);
}