سورس کد دانلود فایل از طریق Ftp (دلفی)

کد:
uses



  WinInet, ComCtrls;







function FtpDownloadFile(strHost, strUser, strPwd: string;



  Port: Integer; ftpDir, ftpFile, TargetFile: string;



  ProgressBar: TProgressBar): Boolean;







  function FmtFileSize(Size: Integer): string;



  begin



    if Size >= $F4240 then



      Result := Format('%.2f', [Size / $F4240]) + ' Mb'



    else



    if Size < 1000 then



      Result := IntToStr(Size) + ' bytes'



    else



      Result := Format('%.2f', [Size / 1000]) + ' Kb';



  end;







const



  READ_BUFFERSIZE = 4096;  // or 256, 512, ...



var



  hNet, hFTP, hFile: HINTERNET;



  buffer: array[0..READ_BUFFERSIZE - 1] of Char;



  bufsize, dwBytesRead, fileSize: DWORD;



  sRec: TWin32FindData;



  strStatus: string;



  LocalFile: file;



  bSuccess: Boolean;



begin



  Result := False;







  { Open an internet session }



  hNet := InternetOpen(



    'Program_Name', // Agent



    INTERNET_OPEN_TYPE_PRECONFIG, // AccessType



    nil,  // ProxyName



    nil,  // ProxyBypass



    0     // or INTERNET_FLAG_ASYNC / INTERNET_FLAG_OFFLINE



  );







  {



    Agent contains the name of the application or



    entity calling the Internet functions



  }







  { See if connection handle is valid }



  if hNet = nil then



  begin



    ShowMessage('Unable to get access to WinInet.Dll');



    Exit;



  end;







  { Connect to the FTP Server }



  hFTP := InternetConnect(



    hNet, // Handle from InternetOpen



    PChar(strHost), // FTP server



    port, // (INTERNET_DEFAULT_FTP_PORT),



    PChar(StrUser), // username



    PChar(strPwd),  // password



    INTERNET_SERVICE_FTP, // FTP, HTTP, or Gopher?



    0, // flag: 0 or INTERNET_FLAG_PASSIVE



    0  // User defined number for callback



  );







  if hFTP = nil then



  begin



    InternetCloseHandle(hNet);



    ShowMessage(Format('Host "%s" is not available',[strHost]));



    Exit;



  end;







  { Change directory }



  bSuccess := FtpSetCurrentDirectory(hFTP, PChar(ftpDir));







  if not bSuccess then



  begin



    InternetCloseHandle(hFTP);



    InternetCloseHandle(hNet);



    ShowMessage(Format('Cannot set directory to %s.',[ftpDir]));



    Exit;



  end;







  { Read size of file }



  if FtpFindFirstFile(hFTP, PChar(ftpFile), sRec, 0, 0) <> nil then



  begin



    fileSize := sRec.nFileSizeLow;



    // fileLastWritetime := sRec.lastWriteTime



  end else



  begin



    InternetCloseHandle(hFTP);



    InternetCloseHandle(hNet);



    ShowMessage(Format('Cannot find file ',[ftpFile]));



    Exit;



  end;







  { Open the file }



  hFile := FtpOpenFile(



    hFTP, // Handle to the ftp session



    PChar(ftpFile), // filename



    GENERIC_READ, // dwAccess



    FTP_TRANSFER_TYPE_BINARY, // dwFlags



    0 // This is the context used for callbacks.



  ); 







  if hFile = nil then



  begin



    InternetCloseHandle(hFTP);



    InternetCloseHandle(hNet);



    Exit;



  end;







  { Create a new local file }



  AssignFile(LocalFile, TargetFile);



  {$i-}



  Rewrite(LocalFile, 1);



  {$i+}







  if IOResult <> 0 then



  begin



    InternetCloseHandle(hFile);



    InternetCloseHandle(hFTP);



    InternetCloseHandle(hNet);



    Exit;



  end;







  dwBytesRead := 0;



  bufsize := READ_BUFFERSIZE;







  while (bufsize > 0) do



  begin



    Application.ProcessMessages;







    if not InternetReadFile(



      hFile,



      @buffer, // address of a buffer that receives the data



      READ_BUFFERSIZE, // number of bytes to read from the file



      bufsize // receives the actual number of bytes read



    ) then Break; 







    if (bufsize > 0) and (bufsize <= READ_BUFFERSIZE) then



      BlockWrite(LocalFile, buffer, bufsize);



    dwBytesRead := dwBytesRead + bufsize;







    { Show Progress }



    ProgressBar.Position := Round(dwBytesRead * 100 / fileSize);



    Form1.Label1.Caption := 



      Format(



        '%s of %s / %d %%',



        [



          FmtFileSize(dwBytesRead),



          FmtFileSize(fileSize), 



          ProgressBar.Position



        ]



      );



  end;







  CloseFile(LocalFile);







  InternetCloseHandle(hFile);



  InternetCloseHandle(hFTP);



  InternetCloseHandle(hNet);



  Result := True;



end;