ftp断点继传

梨华5345

　　导语:  如果ftp server支持REST指令(可以通过ftp client登入，然后输入REST 100，然后检查服务端响应)，则上传或下载失败后，下次连接成功后可以从断点开始继续传输数据;
　　
　　下面是基于Delphi7的组件IdFTP的示例代码，比自己用指令实现方便。
　　
　　断点上传：

procedure TFtpThread.Execute;
var
AFileStream: TFileStream;
sFileName: string;
begin
sFileName := ExtractFileName(AFileName);
AFileStream := TFileStream.Create(AFileName, fmOpenRead);
try
with frmMain.IdFTP2 do
try
if Connected then
Disconnect; //重新连接
Username := 'zzzz';
Password := 'yyyyyy';
Host := 'xx.xx.xx.xx';
Port := 21;
Passive := mypassive;
Connect;
except
on e: Exception do
begin
frmMain.StatusBar1.Panels[0].Text := '出错,异常:' + E.Message;
frmMain.WriteLog(E.Message);
AFileStream.Free;
exit;
end;
end;
// 获取断点
finishedSize := frmMain.IdFTP2.Size(sFileName);
AFileStream.Seek(finishedSize, soFromBeginning);
// 开始断点续传
BytesToTransfer := AFileStream.Size;
frmMain.ProgressBar1.Max :=  BytesToTransfer div 1024;
AFileStream.Position := finishedSize;
try
{while (not Terminated) and (AFileStream.Position < AFileStream.Size) do
begin
frmMain.IdFTP2.Put(AFileStream, sFileName, true);
end;
AMemStream.Free; }
frmMain.IdFTP2.Put(AFileStream, sFileName, true);
except
on e: Exception do
begin
frmMain.StatusBar1.Panels[0].Text := '出错,异常:' + E.Message;
frmMain.WriteLog(E.Message);
AFileStream.Free;
exit;
end;
end;
// 判断是否上传完毕
if AFileStream.Position = AFileStream.Size then
frmMain.StatusBar1.Panels[0].Text := '上传完毕!'
else
frmMain.StatusBar1.Panels[0].Text := '未完成上传，点击上传继续传输！';
AFileStream.Free;
except
on e: Exception do
begin
frmMain.StatusBar1.Panels[0].Text := '出错,异常:' + E.Message;
frmMain.WriteLog(E.Message);
AFileStream.Free;
exit;
end;
end;
end;
　　
　　断点下载:
　　

procedure TfrmMain.FtpDownLoad(aURL, aFile: string);
var
tStream: TFileStream;
sName, sPass, sHost, sPort, sDir,sFile: string;
bResume: Boolean;
begin //ftp方式下载
if FileExists(aFile) then //建立文件流
tStream := TFileStream.Create(aFile, fmOpenWrite)
else
tStream := TFileStream.Create(aFile, fmCreate);
GetFTPParams(aURL, sName, sPass, sHost, sPort, sDir,sFile);
with IdFTP1 do
try
if Connected then
Disconnect; //重新连接
Username := sName;
Password := sPass;
Host := sHost;
Port := StrToInt(sPort);
Passive := mypassive;
Connect;
except
on e: Exception do
begin
Application.MessageBox(PChar(E.Message), 'error', 16);
WriteLog(E.Message);
exit;
end;
end;
IdFTP1.ChangeDir(sDir); //改变目录
BytesToTransfer := IdFTP1.Size(sFile);
ProgressBar1.Max := BytesToTransfer div 1024;
if FileExists(aFile) then
bResume := true
else
bResume := false;
try
if bResume then //续传
begin
//ProgressBar1.Position := tStream.Size div 1024;
finishedSize := tStream.Size;
tStream.Position := tStream.Size;
IdFTP1.Get(sFile, tStream, True);
end
else begin
IdFTP1.Get(sFile, tStream, False);
end;
if tStream.Position = BytesToTransfer then
begin
StatusBar1.Panels[0].Text := '下载完成';
end;
finally
tStream.Free;
end;
end;
//ftp://user:pwd@foolish.6600.org:2003/soft/list.mp4
procedure TfrmMain.GetFTPParams(var aURL, sName, sPass, sHost, sPort,
sDir,sFile: String);
var
URI: TIdURI;
begin
URI := TIdURI.Create(aURL); //建立
try
sHost := URI.Host; //主机
sPort := URI.Port;
sName := URI.Username;
sPass := URI.Password;
sDir := URI.Path;
sFile := URI.Document;
finally
URI.Free;
end;
end;