SSH to a Cisco Switch - Processing "More" Responses

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Demonstrates connecting to a Cisco switch, entering privileged mode with the ena command, and running a command whose response is paged. Each page ends with --More-- and requires a SPACE character to request the next page.

Note: QuickShell allocates a PTY, which is what a network device console expects. The device presents an interactive prompt, and each command's output is read up to the next prompt.

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

public class ChilkatExample {

    public static void main(String[] args) {
        // This example requires the Chilkat API to have been previously unlocked.
        // See Global Unlock Sample for sample code.

        // Demonstrates connecting to a Cisco switch, entering privileged mode, and running a command
        // whose response is paged -- each page ends with "--More--" and requires a SPACE character to
        // request the next page.

        Ssh ssh = new Ssh();

        int port = 22;
        try {
            ssh.connect("172.16.16.100", port);
        } 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.quickShell();
        if (channelNum < 0) {
            System.out.println(ssh.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);

        boolean caseSensitive = true;

        // In unprivileged mode the switch prompt ends with ">".
        String received;
        try {
            ssh.channelReceiveUntilMatch(channelNum, ">", "utf-8", caseSensitive);

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

        System.out.println(received);

        // Send "ena" to enter privileged mode.  Cisco devices expect a bare CR to terminate a command.
        try {
            ssh.channelSendString(channelNum, "ena\r", "utf-8");

            ssh.channelReceiveUntilMatch(channelNum, "Password:", "utf-8", caseSensitive);

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

        System.out.println(received);

        // The enable password is separate from the login password, and likewise should come from a
        // secure source rather than being hard-coded.
        String enablePassword = "myEnablePassword";
        try {
            ssh.channelSendString(channelNum, enablePassword, "utf-8");

            ssh.channelSendString(channelNum, "\r", "utf-8");

            // In privileged mode the prompt ends with "#" instead of ">".
            ssh.channelReceiveUntilMatch(channelNum, "#", "utf-8", caseSensitive);

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

        System.out.println(received);

        // Run a command whose output is delivered a page at a time.
        try {
            ssh.channelSendString(channelNum, "show running-config\r", "utf-8");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Each read ends either at the device prompt (output complete) or at "--More--" (another page
        // is waiting).  Match the full prompt rather than a bare "#", because "#" also appears inside
        // configuration text and would match too early.
        StringArray saMatch = new StringArray();
        saMatch.append("MySwitchName#");
        saMatch.append("--More--");

        StringBuilder sbReceived = new StringBuilder();
        boolean moreComing = true;

        while (moreComing) {
            String pageText;
            try {
                ssh.channelReceiveUntilMatchN(channelNum, saMatch, "utf-8", caseSensitive);

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

            sbReceived.append(pageText);
            System.out.println(pageText);

            // If this page ended with "--More--", send a SPACE to request the next page.
            moreComing = sbReceived.contains("--More--", caseSensitive);
            if (moreComing) {
                try {
                    ssh.channelSendString(channelNum, " ", "utf-8");
                } catch (ChilkatException e) {
                    System.out.println(e.getLastErrorText());
                    return;
                }
            }
        }

        ssh.disconnect();
    }
}