初探WinInet网络api

//必须的头文件，而且要链接wininet.lib
#include <WinInet.h>
#define UM_SOCKET (WM_USER + 1)

void CNetTimeDlg::OnBnClickedOk()
{
	// TODO:  在此添加控件通知处理程序代码
	// CDialogEx::OnOK();
	// 使用winsocket,获取国际标准时间并设置系统时间
	WSADATA WSAData = { 0 };
	int iError = 0;
	iError = WSAStartup(MAKEWORD(2, 2), &WSAData);//我这里成功了，但是加载的是2.0版本，WSAData.szDescription可以查看
	if (iError != 0)
	{
		MessageBoxA(m_hWnd, WSAData.szDescription, "WSAStartup", MB_OK);
		return;
	}
	SOCKET sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if (sock == INVALID_SOCKET)
	{
		MessageBoxA(m_hWnd, WSAData.szDescription, "socket", MB_OK);
		WSACleanup();
		return;
	}
	iError = WSAAsyncSelect(sock, m_hWnd, UM_SOCKET, FD_READ | FD_CONNECT);
	if (iError != 0)
	{
		MessageBoxA(m_hWnd, WSAData.szDescription, "WSAAsyncSelect", MB_OK);
		WSACleanup();
		return;
	}
	sockaddr_in sa = { 0 };
	sa.sin_family = AF_INET;
	sa.sin_port = htons(37);
	sa.sin_addr.S_un.S_addr = inet_addr("132.163.4.101");
	connect(sock, (SOCKADDR*)&sa, sizeof(sa));
	if (WSAEWOULDBLOCK != (iError = WSAGetLastError()))
	{
		MessageBoxA(m_hWnd, WSAData.szDescription, "WSAGetLastError", MB_OK);
		closesocket(sock);
		WSACleanup();
		return;
	}
}

LRESULT CNetTimeDlg::OnSocket(WPARAM wParam, LPARAM lParam)
{
	WORD wEvent = WSAGETSELECTEVENT(lParam);
	WORD wError = WSAGETSELECTERROR(lParam);
	SOCKET sock = wParam;
	SYSTEMTIME stNew = {1900,1,0,1,0,0,0,};
	FILETIME ftNew;//The FILETIME structure is a 64-bit value representing the number of 100-nanosecond intervals since January 1, 1601 (UTC). 
	unsigned long ultime = 0;
	int isize = 0;

	switch (wEvent)
	{
	case FD_CONNECT:
		//MSG_PEEK标记不删除缓冲区数据，所以下次recv仍可以读取这次读到的数据，这里是防止非阻塞下读不到完整的4字节数据
		isize = recv(sock, (char*)&ultime, 4, MSG_PEEK);
		break;
	case FD_READ:
		isize = recv(sock, (char*)&ultime, 4, 0);
		ultime = ntohl(ultime);
		SystemTimeToFileTime(&stNew, &ftNew);
		*(LONGLONG*)(&ftNew) += (LONGLONG)pow(10.0,9) / 100 * ultime;
		FileTimeToSystemTime(&ftNew, &stNew);
		SetSystemTime(&stNew);
		break;
	}
	return 0;
}

void CNetTimeDlg::OnBnClickedFtp()
{
	// TODO:  在此添加控件通知处理程序代码
	// 使用WinInet访问ftp服务器并下载文件
	char szError[64] = { 0 };
	char szDir[MAX_PATH] = { 0 };
	DWORD len = MAX_PATH;
	HINTERNET hInternet = InternetOpen(NULL, INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
	if (hInternet == NULL)
	{
		sprintf(szError, "InternetOpen error : %d", GetLastError());
		MessageBoxA(m_hWnd, szError, "error", MB_OK);
		return;
	}
	HINTERNET hFtpSession = InternetConnectA(hInternet, "192.168.3.95", INTERNET_DEFAULT_FTP_PORT, "admin", "admin", INTERNET_SERVICE_FTP, 0, 0);
	if (hFtpSession == NULL)
	{
		sprintf(szError, "InternetConnectA error : %d", GetLastError());
		MessageBoxA(m_hWnd, szError, "error", MB_OK);
		InternetCloseHandle(hInternet);
		return;
	}
	if (!FtpSetCurrentDirectoryA(hFtpSession, "/test"))
	{
		sprintf(szError, "FtpSetCurrentDirectoryA error : %d", GetLastError());
		MessageBoxA(m_hWnd, szError, "error", MB_OK);
		InternetCloseHandle(hFtpSession);
		InternetCloseHandle(hInternet);
		return;
	}
	WIN32_FIND_DATAA finddata;
	HINTERNET hFind = FtpFindFirstFileA(hFtpSession, "*.txt", &finddata, 0, 0);
	if (hFind == NULL)
	{
		MessageBoxA(m_hWnd, "no find file", "error", MB_OK);
		InternetCloseHandle(hFtpSession);
		InternetCloseHandle(hInternet);
		return;
	}
	do
	{
		FtpGetFileA(hFtpSession, finddata.cFileName, finddata.cFileName, TRUE, FILE_ATTRIBUTE_NORMAL, FTP_TRANSFER_TYPE_BINARY, 0);
	} while (InternetFindNextFileA(hFind, &finddata));
	InternetCloseHandle(hFind);
	InternetCloseHandle(hFtpSession);
	InternetCloseHandle(hInternet);
}