ftp via Lnet example
lazarus / 38-Networking and Web Programming

----------------------------------------------------------------------
mirce.vladimirov · 2015-09-27 23:22

First I placed the Lnet's ftp-component on my form so an object was
created Code: [Select]FTP: TLFTPClientComponent;after that i coded
this, according to examples found :
Code: [Select]  ftp.Host:='myhost.com';
  ftp.Port:=word(21);
  ftp.Connect ;
//  ftp.Connect('myhost.com',21);
  ftp.Authenticate('myusername','mypwd') ;
  ftp.ChangeDirectory('public_ftp');
  ftp.Put('mypic.jpg');
  ftp.Disconnect(true);And the file was not sent. It is sending all
right if I use the synapse or the command-prompt ftp client. Obviously
I'm missing something but I cant see what is it.

----------------------------------------------------------------------
derek.john.evans · 2015-09-28 01:15

The example IFTPClient has this line:

Code: [Select]FCon.CallAction; // this needs to be called ASAP, in a
loop. It's the magic function which makes all the events work :)

EDIT: Personally, I prefer Indy because it comes with a stack of FTP
list parsers. This list is from the unit IdAllFTPListParsers.
Code: [Select]  IdFTPListParseAS400,
  IdFTPListParseBullGCOS7,
  IdFTPListParseBullGCOS8,
  IdFTPListParseChameleonNewt,
  IdFTPListParseCiscoIOS,
  IdFTPListParseDistinctTCPIP,
  IdFTPListParseEPLF,
  IdFTPListParseHellSoft,
  IdFTPListParseIEFTPGateway,
  IdFTPListParseKA9Q,
  IdFTPListParseMicrowareOS9,
  IdFTPListParseMPEiX,
  IdFTPListParseMusic,
  IdFTPListParseMVS,
  IdFTPListParseNCSAForDOS,
  IdFTPListParseNCSAForMACOS,
  IdFTPListParseNovellNetware,
  IdFTPListParseNovellNetwarePSU,
  IdFTPListParseOS2,
  IdFTPListParsePCNFSD,
  IdFTPListParsePCTCP,
  IdFTPListParseStercomOS390Exp,
  IdFTPListParseStercomUnixEnt,
  IdFTPListParseStratusVOS,
  IdFTPListParseSuperTCP,
  IdFTPListParseTandemGuardian,
  IdFTPListParseTOPS20,
  IdFTPListParseTSXPlus,
  IdFTPListParseUnisysClearPath,
  IdFTPListParseUnix,
  IdFTPListParseVM,
  IdFTPListParseVMS,
  IdFTPListParseVSE,
  IdFTPListParseVxWorks,
  IdFTPListParseWfFTP,
  IdFTPListParseWindowsNT,
  IdFTPListParseWinQVTNET,
  IdFTPListParseXecomMicroRTOS;

----------------------------------------------------------------------
Jurassic Pork · 2015-09-28 02:04

hello,
Geepster Callaction is only available in non-visual lNet
QuoteThe CallAction method of all “Connections” is a method which
“eventizes” the whole connection. It is valid only in non-visual lNet.
Whenever you call this method, all sockets of given connection are
checked for status updates (eg. if something can be received, if I can
send…) and appropriate callbacks are fired. You need to call this
method periodicly to assure functionality. You need to CallAction
periodicly if you want to know if you can receive. (get)
and mirce seems to be in a gui app :
QuoteFirst I placed the Lnet's ftp-component on my form so an object
was created
for me (Lazarus 1.4 Windows 7) lnet FTPclient works with the ftpclient
gui example but not with a project with simple mirce's code.
No event , No exception : strange thing.

----------------------------------------------------------------------
Jurassic Pork · 2015-09-28 03:31

mirce,
it seems that some procedures of the visual component
TLFTPClientComponent are non-blocking (ie Connect ) , then you must
check
status of the connexion between the procedure or event drive ( see
example) .  You cant' call procedure without delay between them.

----------------------------------------------------------------------
mirce.vladimirov · 2015-09-28 13:21

All right, got the point, thank you folks. Now I can upload, hooray.
Still, cant get the clue about downloading, do I have to use
FileStream ?  And if so, What is ftp.retrieve(s:string) in the example
? Do I have to invoke ftp.retrieve(string) and then onrecieve store it
to a FileStream ?

----------------------------------------------------------------------
mirce.vladimirov · 2015-09-28 14:03

QuoteStill, cant get the clue about downloading, do I have to use
FileStream ?The answer is yes, that is the way that the downloaded
data is saved.

QuoteDo I have to invoke ftp.retrieve(string) and then onrecieve store
it to a FileStream ?
And once again the answer is yes, invoke  ftp.retrieve(string) and do
coding to save it in the "onrecieve" procedure.

Thank to everybody.

EDIT:
here's the simple and short version :
Code: [Select]procedure TfLnet.button1Click(Sender: TObject);
begin
  ftp.ChangeDirectory('/public_ftp');
  ftp.Retrieve('slika1.jpg') ;
end;
and then:
Code: [Select]procedure TfLnet.FTPReceive(aSocket: TLSocket);
var
FFile: TFileStream;
s: string;
i: Integer;
newone:Boolean;
Buf: array[0..65535] of Byte;
begin
  newone:=true;
//  memo1.lines.Add('primiv bla blabla :' + FTP.GetDataMessage);
  if FTP.CurrentStatus = fsRetr then begin // getting file, save to
file
     i := FTP.GetData(Buf, 65535);
     if i > 0 then begin
       if newone=true then begin  // pri prviot takt da stvori nov
fajl
         FFile := TFileStream.Create(GetCurrentDir+'\'+'sl1.jpg',
fmCreate or fmOpenWrite);
         newone:=false;
       end;
       FFile.Write(Buf, i);
     end ;
     FreeAndNil(FFile);
  end;

end;
Once again, thanks everybody.