Dart

Open a Custom SSH Channel Type

Demonstrates the Chilkat Ssh.OpenCustomChannel method, which requests a channel whose application-defined type is supplied as the only argument. It returns the channel number, or -1 if the server rejects the channel. The server must implement that channel type.

Background: The SSH protocol allows vendor- and application-specific channel types beyond the standard session and direct-tcpip kinds; by convention these carry an @domain suffix to avoid name collisions. This method is the escape hatch for talking to a server that implements such a type. On rejection, inspect ChannelOpenFailCode to learn why.

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Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the Ssh.OpenCustomChannel method, which requests a custom SSH channel whose
  // application-defined type is supplied as the only argument.  It returns the channel number,
  // or -1 if the server rejects the channel.  The server must implement that channel type.

  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;
  }

  // Request an application-defined channel type.  The server must support it.
  final channelType = 'my-custom-channel@example.com';
  final channelNum = ssh.openCustomChannel(channelType);
  if (channelNum < 0) {
    print(ssh.lastErrorText);
    return;
  }

  print('Opened custom channel: $channelNum');

  // The channel is used with the normal channel send, receive, EOF, CLOSE, and release methods.

  ssh.disconnect();
}