Receive from an SSH Channel Until a Pattern Matches

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Demonstrates the Chilkat Ssh.ChannelReceiveUntilMatch method, which receives text until the accumulated text matches a pattern. The arguments are the channel number, the pattern, the charset, and whether matching is case-sensitive. Existing buffered text is checked before waiting for more network data.

Important: Set the ReadTimeoutMs property before calling this method. It defaults to 0, meaning no limit, so without it the call waits forever if the received data never contains a match.

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Ssh;

public class ChilkatExample {

    public static void main(String[] args) {
        // Demonstrates the Ssh.ChannelReceiveUntilMatch method, which receives text until the
        // accumulated text matches a pattern.  The 1st argument is the channel number, the 2nd is the
        // pattern, the 3rd is the charset, and the 4th selects case-sensitive matching.  The pattern
        // supports literal characters plus "*", which matches zero or more characters.

        Ssh ssh = new Ssh();

        int sshPort = 22;
        try {
            ssh.connect("ssh.example.com", sshPort);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            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";

        try {
            ssh.authenticatePw("mySshLogin", password);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        int channelNum = ssh.openSessionChannel();
        if (channelNum < 0) {
            System.out.println(ssh.getLastErrorText());
            return;
        }

        // Start a shell WITHOUT requesting a PTY.  Without a PTY the shell sees it is connected to a
        // raw data pipe and enters non-interactive mode: it suppresses the command prompt, does not
        // echo typed commands back, and skips interactive login scripts.  The output is therefore
        // clean and easily parseable -- but because no prompt is ever sent, code must not wait for
        // one.  Instead, have each command print a predictable marker, or wait for EOF / channel close.
        try {
            ssh.sendReqShell(channelNum);

            // There is no prompt to wait for, so make the command itself announce when it has finished
            // by echoing a marker after it.
            ssh.channelSendString(channelNum, "ls -l /tmp; echo DONE_MARKER\n", "utf-8");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // IMPORTANT: Set a read timeout before receiving until a match.  ReadTimeoutMs defaults to 0,
        // which means no limit -- without it, this call waits forever if the received data never
        // contains a match.
        ssh.setReadTimeoutMs(15000);

        // Receive until the marker appears in the output.
        boolean caseSensitive = false;
        String output;
        try {
            ssh.channelReceiveUntilMatch(channelNum, "DONE_MARKER", "utf-8", caseSensitive);

            output = ssh.getReceivedText(channelNum, "utf-8");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println(output);

        ssh.disconnect();
    }
}