Dart

FTP over Implicit TLS (Ssl, AuthSsl, AutoFix)

Demonstrates the SSL/TLS connection-mode properties Ssl, AuthSsl, and AutoFix. Setting Ssl true selects implicit FTPS, in which TLS begins immediately after the TCP connection on port 990.

Background: FTP has two ways to add TLS: implicit (this example) starts encrypted from the first byte on a dedicated port, 990; explicit (via AuthTls) connects in the clear on port 21 and issues AUTH TLS to upgrade. Explicit is the modern standard; implicit persists mainly for legacy servers. AuthSsl is an obsolete AUTH SSL variant to avoid. AutoFix, on by default, infers the mode from the port — disable it when you set these properties explicitly so it does not override your choice.

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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';

  // Ssl = true selects IMPLICIT FTPS: TLS begins immediately after the TCP connection, before
  // the greeting.  Port 990 is conventional for implicit FTPS.  Ssl takes priority over AuthTls
  // and AuthSsl.
  ftp.ssl = true;
  ftp.port = 990;

  // AuthSsl selects the legacy AUTH SSL command and is very uncommon -- use AuthTls (explicit
  // FTPS) for modern servers instead.  Left false here.
  ftp.authSsl = false;

  // AutoFix (default true) automatically adjusts Ssl/AuthTls/AuthSsl based solely on the Port
  // (21 or 990).  Disable it when setting these properties explicitly, as here.
  ftp.autoFix = false;

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

  print('Connected using implicit FTPS.');

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