Dart

Monitor FTP Transfer Progress

Demonstrates the progress properties CurBytesReceived, CurBytesReceivedStr, CurBytesSent, CurBytesSentStr, ProgressMonSize, PercentDoneScale, and AutoGetSizeForProgress.

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: Percentage progress needs a known total, but FTP does not always report a file's size up front — so AutoGetSizeForProgress issues a SIZE command before a download, and ProgressMonSize supplies an expected size when even that is unavailable (a one-shot value consumed by the next transfer). PercentDoneScale sets the resolution of progress callbacks. The current byte counts are exposed both as 32-bit integers and as strings, the string forms avoiding integer-width limits for very large transfers.

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Dart

import 'package:chilkat/chilkat.dart';

void main() {
  final ftp = CkFtp2();

  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';

  try {
    ftp.connect();
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // AutoGetSizeForProgress sends a SIZE command before a download so percentage-based progress can
  // be computed.
  ftp.autoGetSizeForProgress = true;

  // PercentDoneScale sets the value representing one hundred percent in PercentDone callbacks.
  // 1000 gives tenth-of-a-percent resolution.
  ftp.percentDoneScale = 1000;

  // ProgressMonSize is a one-shot expected size for the next download when the size is not
  // otherwise known.  It is consumed by the next download and reset to 0.
  ftp.progressMonSize = 20485760;

  try {
    ftp.getFile('public_html/bigfile.zip', 'qa_output/bigfile.zip');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // After a transfer, the current byte counts are available as 32-bit numbers or as strings (the
  // string forms avoid integer-size limits).
  print('Bytes received: ${ftp.curBytesReceived}');
  print('Bytes received (str): ${ftp.curBytesReceivedStr}');
  print('Bytes sent: ${ftp.curBytesSent}');
  print('Bytes sent (str): ${ftp.curBytesSentStr}');

  try {
    ftp.disconnect();
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }
}