Dart

SSH Tunnel Uncommon Options

Demonstrates the UncommonOptions property, which enables optional behavior for uncommon requirements. The default is an empty string; provide a comma-separated list of keywords to enable more than one option. Available keywords are listed in the reference documentation.

Background: This is a catch-all for narrow workarounds that do not warrant their own properties — forcing a specific signature algorithm, disabling the periodic keep-alive, removing weak MACs, bypassing a VPN on Android, and so on. Most applications never set it. When you do, it is usually to satisfy a particular server's quirk or a specific security requirement, and the exact keyword matters, so consult the documented list rather than guessing.

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Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the SshTunnel.UncommonOptions property, which enables optional behavior for
  // uncommon requirements.  The default is an empty string, appropriate for most applications.
  // Provide a comma-separated list of keywords to enable more than one option.

  final tunnel = CkSshTunnel();

  // For example, disable the periodic keep-alive ignore message and remove weak MAC algorithms
  // from those offered.  Available keywords are listed in the reference documentation.
  tunnel.uncommonOptions = 'NoKeepAliveIgnoreMsg,no-weak-mac-algs';

  tunnel.destHostname = 'db.internal.example.com';
  tunnel.destPort = 5432;

  final sshPort = 22;
  try {
    tunnel.connect('ssh.example.com', sshPort);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // 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.
  final password = 'mySshPassword';

  try {
    tunnel.authenticatePw('mySshLogin', password);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  final listenPort = 1080;
  try {
    tunnel.beginAccepting(listenPort);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Tunnel established.');

  final waitForThreadExit = true;
  try {
    tunnel.closeTunnel(waitForThreadExit);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }
}