{ The following function shows how to connect to a ftp server and download a file. It uses the functions from wininet.dll. You need a ProgressBar to show the progress and a Label to show progress informations. } 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; //如果你只是找, 不想下載, 到這裹就可了 // 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) then Break; // receives the actual number of bytes read 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;
{ The following function shows how to connect to a ftp server
and download a file.
It uses the functions from wininet.dll. You need a ProgressBar to show the progress and a Label to show progress informations.
} 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; //如果你只是找, 不想下載, 到這裹就可了
// 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) then Break; // receives the actual number of bytes read 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;
这一句不知道怎么用的,起什么作用?