Android™

Check Whether an SSH Channel is Open

Demonstrates the Chilkat Ssh.ChannelIsOpen method, which reports whether a channel number identifies a channel Chilkat currently considers open for application I/O. The only argument is the channel number. This example checks the channel before and after sending CLOSE.

Background: Because one SSH connection can carry many channels with independent lifetimes, code that manages several needs a way to ask whether a given one is still usable. This returns false for invalid or nonexistent channel numbers, after a local Disconnect, once remote closure is processed, and immediately after ChannelSendClose — which marks the channel locally closed without waiting for the remote side.

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// Important: Don't forget to include the call to System.loadLibrary
// as shown at the bottom of this code sample.
package com.test;

import android.app.Activity;
import com.chilkatsoft.*;

import android.widget.TextView;
import android.os.Bundle;

public class SimpleActivity extends Activity {

  private static final String TAG = "Chilkat";

  // Called when the activity is first created.
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    boolean success = false;

    //  Demonstrates the Ssh.ChannelIsOpen method, which reports whether a channel number identifies
    //  a channel Chilkat currently considers open for application I/O.  The only argument is the
    //  channel number.

    CkSsh ssh = new CkSsh();

    int sshPort = 22;
    success = ssh.Connect("ssh.example.com",sshPort);
    if (success == false) {
        Log.i(TAG, ssh.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.
    String password = "mySshPassword";

    success = ssh.AuthenticatePw("mySshLogin",password);
    if (success == false) {
        Log.i(TAG, ssh.lastErrorText());
        return;
        }

    //  Open a session channel.  A negative return value indicates failure.
    int channelNum = ssh.OpenSessionChannel();
    if (channelNum < 0) {
        Log.i(TAG, ssh.lastErrorText());
        return;
        }

    if (ssh.ChannelIsOpen(channelNum)) {
        Log.i(TAG, "The channel is open.");
        }
    else {
        Log.i(TAG, "The channel is not open.");
        }

    //  Send CLOSE, which immediately marks the channel locally closed.
    success = ssh.ChannelSendClose(channelNum);
    if (success == false) {
        Log.i(TAG, ssh.lastErrorText());
        return;
        }

    if (ssh.ChannelIsOpen(channelNum)) {
        Log.i(TAG, "Still open.");
        }
    else {
        Log.i(TAG, "The channel is now closed.");
        }

    ssh.Disconnect();

  }

  static {
      System.loadLibrary("chilkat");

      // Note: If the incorrect library name is passed to System.loadLibrary,
      // then you will see the following error message at application startup:
      //"The application <your-application-name> has stopped unexpectedly. Please try again."
  }
}