Dart

Send an FTP NOOP (Keep-Alive)

Demonstrates the Chilkat Ftp2.Noop method, which sends the FTP NOOP command. It takes no arguments and succeeds only when the server returns a positive reply.

Background: NOOP asks the server to do nothing and simply reply, which makes it the standard keep-alive: sending one periodically resets the server's idle timer so a long-running job does not lose its control connection between transfers. Because it exercises a real request/reply round trip, a successful NOOP is also firmer evidence the connection is alive than CheckConnection.

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Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the Ftp2.Noop method, which sends the FTP NOOP command.  It takes no arguments.
  // The server must return a positive reply for the method to succeed.

  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';

  // Connect and log in (Connect performs both).
  try {
    ftp.connect();
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // NOOP does nothing on the server, but a successful reply confirms the control connection is
  // still responsive -- useful as a keep-alive during an otherwise idle session.
  try {
    ftp.noop();
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('NOOP acknowledged by the server.');

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