(SOLVED) FTP download in memory
lazarus / 38-Networking and Web Programming

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xinyiman · 2016-06-06 09:39

Hello guys, does anyone have an example of an FTP download with
synapse but that does not create the file but rather charge me the
downloaded image directly into a TPicture? In short working only in
RAM to be faster. Thank you

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balazsszekely · 2016-06-06 10:11

With Indy you can. There is an overloaded version of IdFTP.Get method
which accepts as parameter a stream:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
Get(const ASourceFile: string; ADest: TStream; AResume: Boolean =
false); overload;Looking at the synapse code, I see the FtpGetFile
function, which internally use the RetriveFile then the DataRead
method. DataRead accepts a stream parameter, so in theory it's
possible but you have to do a little work.

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rvk · 2016-06-06 10:15

Just set DirectFile to false. It will use the FDataStream
(TMemoryStream) to read the file in memory.

You'll have to do something like this:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i uses
ftpsend; function ReadFtpToImage(const IP, Port, FileName, User, Pass:
string; Image1: TImage): boolean;begin  Result := False;  with
TFTPSend.Create do    try      if User <> '' then      begin       
Username := User;        Password := Pass;      end;      TargetHost
:= IP;      TargetPort := Port;      if not Login then Exit;     
DirectFileName := 'dummyfilename';      DirectFile := False;     //
<------ Important !!      Result := RetrieveFile(FileName, False);   
  if Result then        Image1.Picture.LoadFromStream(DataStream);   
  Logout;    finally      Free;    end;end;

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xinyiman · 2016-06-07 06:39

Ok rvk, it works great , and if I wanted to do it reverse ? That is,
send to FTP the contents of a TImage component ?

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rvk · 2016-06-07 08:12

I've taken the source of FtpGetFile() to create the ReadFtpToImage.
So for the reverse you could have taken the FtpPutFile() and done the
same.

Here is a (non-tested) example:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i uses
ftpsend; // source taken from FtpPutFile()function
WriteImageToFtp(const IP, Port, FileName, User, Pass: string; Image1:
TImage): boolean;begin  Result := False;  with TFTPSend.Create do   
try      if User <> '' then      begin        Username := User;      
Password := Pass;      end;      TargetHost := IP;      TargetPort :=
Port;      if not Login then Exit;      DirectFileName :=
'dummyfilename';      DirectFile := False;        // <------ Important
!!       Image1.Picture.SaveToStream(DataStream); // <-- this saves
the image to ftp-stream       Result := StoreFile(FileName, False); //
and transfers it to Filename on ftp server      Logout;    finally   
 Free;    end;end;

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xinyiman · 2016-06-07 09:20

But with the ' last example I refer to the file What ftp server
resides on HD , I want to pass the content of image , then RAM to FTP

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rvk · 2016-06-07 09:23

Yes, that's what the WriteImageToFtp() I showed you does. It does the
reverse from the previous ReadFtpToImage().

You supply WriteImageToFtp with a filename to store on the FTP side
and the TImage with content. It will take the content of that TImage
and store it on the FTP-side in Filename.

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xinyiman · 2016-06-07 11:04

You're right , it works well . thank you so much