Pascal (Lazarus/Delphi)

Async SFTP Progress Info

See more SFTP Examples

Demonstrates checking for progress info updates when running a task asynchronously. This example demonstrates an SFTP download. Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.SFtp,
  Chilkat.Task;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  sftp: TSFtp;
  localFilePath: string;
  remoteFilePath: string;
  task: TTask;
  curPctDone: Integer;
  name: string;
  value: string;

begin
  success := False;

  //  This example assumes the Chilkat API to have been previously unlocked.
  //  See Global Unlock Sample for sample code.

  sftp := TSFtp.Create;

  //  Set some timeouts, in milliseconds:
  sftp.ConnectTimeoutMs := 15000;
  sftp.IdleTimeoutMs := 15000;

  //  Connect to the SFTP server.  
  success := sftp.Connect('sftp.example.com',22);
  if (success <> True) then
    begin
      WriteLn(sftp.LastErrorText);
      Exit;
    end;

  //  Authenticate with the SSH server.  Chilkat SFTP supports
  //  both password-based authenication as well as public-key
  //  authentication.  This example uses password authenication.
  success := sftp.AuthenticatePw('myLogin','myPassword');
  if (success <> True) then
    begin
      WriteLn(sftp.LastErrorText);
      Exit;
    end;

  //  After authenticating, the SFTP subsystem must be initialized:
  success := sftp.InitializeSftp();
  if (success <> True) then
    begin
      WriteLn(sftp.LastErrorText);
      Exit;
    end;

  //  --------------------
  //  Download a file
  //  --------------------
  localFilePath := 'c:/temp/hamlet.xml';
  remoteFilePath := 'subdir1/subdir2/hamlet.xml';

  //  Call the async version of the DownloadFileByName method to return a task object.
  //  The task object is loaded, but is in the Inert state -- meaning it is
  //  not yet scheduled to run on Chilkat's background thread pool.
  task := sftp.DownloadFileByNameAsync(remoteFilePath,localFilePath);
  if (sftp.LastMethodSuccess = False) then
    begin
      WriteLn(sftp.LastErrorText);
      Exit;
    end;

  //  Before starting the task, tell it to keep an in-memory log of what would've been
  //  ProgressInfo callbacks.
  task.KeepProgressLog := True;

  //  Schedule the task for running on the thread pool.  This changes the task's state
  //  from Inert to Live.
  success := task.Run();
  if (success <> True) then
    begin
      WriteLn(task.LastErrorText);
      task.Free;
      Exit;
    end;

  //  The application is now free to do anything else
  //  while the file is being downloaded.

  //  For this example, we'll simply sleep and periodically
  //  check to see if the download is finished, and report the progress
  //  along the way.
  curPctDone := 0;

  while task.Finished <> True do
    begin

      if (task.PercentDone <> curPctDone) then
        begin
          curPctDone := task.PercentDone;
          WriteLn(curPctDone + ' percent done');
        end;

      //  Check the progress info log.
      //  Emit any log entries..
      while (task.ProgressLogSize > 0) do
        begin
          //  Get the 1st entry, emit it, and then remove it..
          name := task.ProgressInfoName(0);
          value := task.ProgressInfoValue(0);

          //  Entries reporting the received byte count will have the name "RcvByteCount"
          //  Entries reporting the current bytes-per-second will have the name "RcvBytesPerSec"

          WriteLn(name + ': ' + value);
          task.RemoveProgressInfo(0);
        end;

      //  Sleep 100 ms.
      task.SleepMs(100);

    end;

  //  Just in case there are any remaining entries...
  while (task.ProgressLogSize > 0) do
    begin
      //  Get the 1st entry, emit it, and then remove it..
      name := task.ProgressInfoName(0);
      value := task.ProgressInfoValue(0);
      WriteLn(name + ': ' + value);
      task.RemoveProgressInfo(0);
    end;

  //  A finished task could be one that was canceled, aborted, or truly finished.  

  //  If the task was "canceled", it was canceled prior to actually starting.  This could
  //  happen if the task was canceled while waiting in a thread pool queue to be scheduled by Chilkat's
  //  background thread pool scheduler.  

  //  If the task was "aborted", it indicates that it was canceled while running in a background thread.  
  //  The ResultErrorText will likely indicate that the task was aborted.

  //  If the task "completed", then it ran to completion, but the actual success/failure of the method
  //  is determined by the result obtained via a GetResult* method.  (A "completed" task will
  //  have a StatusInt equal to 7.   If the task finished, but was not completed, then it must've
  //  been aborted or canceled:
  if (task.StatusInt <> 7) then
    begin
      WriteLn('Task did not complete.');
      WriteLn('task status: ' + task.Status);
      task.Free;
      Exit;
    end;

  //  The DownloadFileByName method returns a boolean.  Therefore, after the task is finished,
  //  we can get the boolean result by calling GetResultBool.  This is the return value had
  //  we called DownloadFileByName synchronously.
  success := task.GetResultBool();
  if (success <> True) then
    begin
      //  The task's ResultErrorText contains what would have been in the LastErrorText property had
      //  the DownloadFileByName method been called synchronously.
      WriteLn(task.ResultErrorText);
    end
  else
    begin
      WriteLn('File downloaded asynchronously.');
    end;

  task.Free;


  sftp.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.