Dart

Request SSH X11 Forwarding

Demonstrates the Chilkat Ssh.SendReqX11Forwarding method, which sends an X11-forwarding request on a session channel. The arguments are the channel number, whether forwarding is limited to a single connection, and the X11 authentication protocol, cookie, and screen number.

Background: X11 forwarding lets a graphical program running on the remote host display its window on your local machine, tunneled over SSH. This is a low-level method that only sends the protocol request — your application is still responsible for the local X server side of the arrangement. The authentication cookie guards the forwarded display, so it should be a freshly generated value rather than a fixed constant.

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Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the Ssh.SendReqX11Forwarding method, which sends an SSH X11-forwarding request
  // on a session channel.  The 1st argument is the channel number, the 2nd limits forwarding to a
  // single connection, and the 3rd through 5th supply the X11 authentication protocol, cookie,
  // and screen number.

  final ssh = CkSsh();

  final sshPort = 22;
  try {
    ssh.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 {
    ssh.authenticatePw('mySshLogin', password);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Open a session channel.  A negative return value indicates failure.
  final channelNum = ssh.openSessionChannel();
  if (channelNum < 0) {
    print(ssh.lastErrorText);
    return;
  }

  // Request X11 forwarding.  Named variables make each argument's meaning clear.
  final singleConnection = false;
  final authProt = 'MIT-MAGIC-COOKIE-1';
  final authCookie = 'd92f5e1a7c8b4306af17c2e5b9d43081';
  final screenNum = 0;
  try {
    ssh.sendReqX11Forwarding(channelNum, singleConnection, authProt, authCookie, screenNum);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('X11 forwarding requested.');

  ssh.disconnect();
}