RudimentaryPTY.java

package com.github.signed.tryanderror.sftp;

import net.schmizz.sshj.SSHClient;
import net.schmizz.sshj.common.StreamCopier;
import net.schmizz.sshj.connection.channel.direct.Session;
import net.schmizz.sshj.connection.channel.direct.Session.Shell;
import net.schmizz.sshj.transport.verification.ConsoleKnownHostsVerifier;
import net.schmizz.sshj.transport.verification.OpenSSHKnownHosts;

import java.io.File;
import java.io.IOException;

/**
 * A very rudimentary psuedo-terminal based on console I/O.
 */
class RudimentaryPTY {

    public static void main(String... args) throws IOException {

        final SSHClient ssh = new SSHClient();

        final File knownHostsFile = new File(OpenSSHKnownHosts.detectSSHDir(), "known_hosts");
        ssh.addHostKeyVerifier(new ConsoleKnownHostsVerifier(knownHostsFile, System.console()));

        ssh.connect("localhost");
        try {

            ssh.authPublickey(System.getProperty("user.name"));

            final Session session = ssh.startSession();
            try {

                session.allocateDefaultPTY();

                final Shell shell = session.startShell();

                new StreamCopier(shell.getInputStream(), System.out)
                        .bufSize(shell.getLocalMaxPacketSize())
                        .spawn("stdout");

                new StreamCopier(shell.getErrorStream(), System.err)
                        .bufSize(shell.getLocalMaxPacketSize())
                        .spawn("stderr");

                // Now make System.in act as stdin. To exit, hit Ctrl+D (since that results in an EOF on System.in)
                // This is kinda messy because java only allows console input after you hit return
                // But this is just an example... a GUI app could implement a proper PTY
                new StreamCopier(System.in, shell.getOutputStream())
                        .bufSize(shell.getRemoteMaxPacketSize())
                        .copy();

            } finally {
                session.close();
            }

        } finally {
            ssh.disconnect();
        }
    }

}