Delphi ActiveX

Upload a Large File in Chunks (FTP)

Demonstrates the Chilkat Ftp2.LargeFileUpload method, which uploads a local file as a sequence of transfers, each up to a given chunk size. The arguments are the local path, the remote path, and the chunk size in bytes.

Note: The local paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: Some servers, proxies, or firewalls impose a limit on the size or duration of a single data transfer, which a very large file can exceed. This method sidesteps that by sending the file in pieces — the first with STOR to create or replace the file, each subsequent one appended — so no single transfer is oversized. Choose a chunk size comfortably under whatever limit you are working around.

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var
success: Integer;
ftp: TChilkatFtp2;
chunkSize: Integer;

begin
success := 0;

//  Demonstrates the Ftp2.LargeFileUpload method, which uploads a local file as a sequence of
//  transfers, each up to a given chunk size.  The 1st argument is the local path, the 2nd is the
//  remote path, and the 3rd is the chunk size in bytes.

ftp := TChilkatFtp2.Create(Self);

ftp.Hostname := 'ftp.example.com';
ftp.Username := 'myFtpLogin';

//  Normally you would not hard-code the password in source.  You should instead obtain it
//  from an interactive prompt, environment variable, or a secrets vault.
ftp.Password := 'myPassword';

success := ftp.Connect();
if (success = 0) then
  begin
    Memo1.Lines.Add(ftp.LastErrorText);
    Exit;
  end;

//  The first chunk is sent with STOR (creating/replacing the remote file); each later chunk is
//  appended.  Uploading in chunks can work around server or network limits on a single transfer.
chunkSize := 10485760;
success := ftp.LargeFileUpload('qa_data/bigfile.zip','uploads/bigfile.zip',chunkSize);
if (success = 0) then
  begin
    Memo1.Lines.Add(ftp.LastErrorText);
    Exit;
  end;
Memo1.Lines.Add('Large file uploaded.');

success := ftp.Disconnect();
if (success = 0) then
  begin
    Memo1.Lines.Add(ftp.LastErrorText);
    Exit;
  end;