Dart

Start SSH Tunnel Keyboard-Interactive Authentication

Demonstrates the Chilkat SshTunnel.StartKeyboardAuth method, which begins keyboard-interactive authentication. The only argument is the login name. It returns XML describing the server's prompts, which are answered with ContinueKeyboardAuth.

Background: Keyboard-interactive is the prompt-driven authentication method: the server sends one or more questions — a password, a one-time code, a security question — and the client answers each. This is how a tunnel supports two-factor and other challenge-response schemes. The returned XML says exactly what to ask and whether to mask the input.

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Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the SshTunnel.StartKeyboardAuth method, which begins keyboard-interactive
  // authentication.  The only argument is the login name.  It returns XML describing the server's
  // prompts, which are answered with ContinueKeyboardAuth.

  final tunnel = CkSshTunnel();

  // The tunnel forwards accepted local connections to this destination through the SSH server.
  tunnel.destHostname = 'db.internal.example.com';
  tunnel.destPort = 5432;

  // Connect to the SSH server.  This performs the TCP/proxy connection and SSH handshake, but
  // does not authenticate yet.
  final sshPort = 22;
  try {
    tunnel.connect('ssh.example.com', sshPort);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Begin keyboard-interactive authentication.  The returned XML describes the server's prompts.
  final String infoRequestXml;
  try {
    infoRequestXml = tunnel.startKeyboardAuth('mySshLogin');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print(infoRequestXml);

  // Answer the prompt(s) with ContinueKeyboardAuth, then call BeginAccepting.

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