winhttp API 獲取服務器文件大小(更新時間)等

#include <Windows.h>
#include <winhttp.h>
#pragma comment(lib,"Winhttp.lib")

//這裏要獲取下面的URL的文件的大小
//http://www.test.com/test.txt
#define HTTP_URL   L"www.test.com"
#define  HTTP_PORT 80
#define HTTP_RES   L"test.txt"
int _tmain(int argc, _TCHAR* argv[])
{
    DWORD dwSize = 0;
    LPVOID lpOutBuffer = NULL;
    BOOL  bResults = FALSE;
    HINTERNET hSession = NULL,
        hConnect = NULL,
        hRequest = NULL;

    // Use WinHttpOpen to obtain a session handle.
    hSession = WinHttpOpen(  L"A WinHTTP Example Program/1.0",//這裏可以隨便寫，不要也行
        WINHTTP_ACCESS_TYPE_DEFAULT_PROXY,
        WINHTTP_NO_PROXY_NAME,
        WINHTTP_NO_PROXY_BYPASS, 0);

    // Specify an HTTP server."
    if (hSession)
        hConnect = WinHttpConnect( hSession,HTTP_URL,
        HTTP_PORT, 0);

    // Create an HTTP request handle.
    if (hConnect)
        hRequest = WinHttpOpenRequest( hConnect, L"GET",HTTP_RES,
        NULL, WINHTTP_NO_REFERER,
        WINHTTP_DEFAULT_ACCEPT_TYPES,
        0);

    // Send a request.
    if (hRequest)
        bResults = WinHttpSendRequest( hRequest,
        WINHTTP_NO_ADDITIONAL_HEADERS,
        0, WINHTTP_NO_REQUEST_DATA, 0,
        0, 0);

    // End the request.
    if (bResults)
        bResults = WinHttpReceiveResponse( hRequest, NULL);

    // First, use WinHttpQueryHeaders to obtain the size of the buffer.
    if (bResults)
    {
        WinHttpQueryHeaders( hRequest,  WINHTTP_QUERY_RAW_HEADERS_CRLF,
            WINHTTP_HEADER_NAME_BY_INDEX, NULL,
            &dwSize, WINHTTP_NO_HEADER_INDEX);

        // Allocate memory for the buffer.
        if( GetLastError( ) == ERROR_INSUFFICIENT_BUFFER )
        {
            lpOutBuffer = new WCHAR[dwSize/sizeof(WCHAR)];

            // Now, use WinHttpQueryHeaders to retrieve the header.

            bResults = WinHttpQueryHeaders( hRequest,
                //這裏放入需要查詢的參數  可參考參數說明  http://www.yfvb.com/help/winhttp/index.htm?page=query_info_flags.htm
                WINHTTP_QUERY_CONTENT_LENGTH ,   //  WINHTTP_QUERY_LAST_MODIFIED  WINHTTP_QUERY_CONTENT_LENGTH
                WINHTTP_HEADER_NAME_BY_INDEX,
                lpOutBuffer, &dwSize,
                WINHTTP_NO_HEADER_INDEX);
        }
    }

    // Print the header contents.  這裏是結果
    if (bResults)
        printf("Header contents: \n%S",lpOutBuffer);

    // Free the allocated memory.
    delete [] lpOutBuffer;

    // Report any errors.
    if (!bResults)
        printf("Error %d has occurred.\n",GetLastError());

    // Close any open handles.
    if (hRequest) WinHttpCloseHandle(hRequest);
    if (hConnect) WinHttpCloseHandle(hConnect);
    if (hSession) WinHttpCloseHandle(hSession);
	return 0;
}