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.

NODEJS_PRELUDE

function chilkatExample() {

    var success = false;

    //  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.

    var ssh = new chilkat.Ssh();

    var port = 22;
    success = ssh.Connect("172.16.16.100",port);
    if (success == false) {
        console.log(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.
    var password = "mySshPassword";

    success = ssh.AuthenticatePw("mySshLogin",password);
    if (success == false) {
        console.log(ssh.LastErrorText);
        return;
    }

    var channelNum = ssh.QuickShell();
    if (channelNum < 0) {
        console.log(ssh.LastErrorText);
        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.ReadTimeoutMs = 15000;

    var caseSensitive = true;

    //  In unprivileged mode the switch prompt ends with ">".
    success = ssh.ChannelReceiveUntilMatch(channelNum,">","utf-8",caseSensitive);
    if (success == false) {
        console.log(ssh.LastErrorText);
        return;
    }

    var received = ssh.GetReceivedText(channelNum,"utf-8");
    if (ssh.LastMethodSuccess == false) {
        console.log(ssh.LastErrorText);
        return;
    }

    console.log(received);

    //  Send "ena" to enter privileged mode.  Cisco devices expect a bare CR to terminate a command.
    success = ssh.ChannelSendString(channelNum,"ena\r","utf-8");
    if (success == false) {
        console.log(ssh.LastErrorText);
        return;
    }

    success = ssh.ChannelReceiveUntilMatch(channelNum,"Password:","utf-8",caseSensitive);
    if (success == false) {
        console.log(ssh.LastErrorText);
        return;
    }

    received = ssh.GetReceivedText(channelNum,"utf-8");
    if (ssh.LastMethodSuccess == false) {
        console.log(ssh.LastErrorText);
        return;
    }

    console.log(received);

    //  The enable password is separate from the login password, and likewise should come from a
    //  secure source rather than being hard-coded.
    var enablePassword = "myEnablePassword";
    success = ssh.ChannelSendString(channelNum,enablePassword,"utf-8");
    if (success == false) {
        console.log(ssh.LastErrorText);
        return;
    }

    success = ssh.ChannelSendString(channelNum,"\r","utf-8");
    if (success == false) {
        console.log(ssh.LastErrorText);
        return;
    }

    //  In privileged mode the prompt ends with "#" instead of ">".
    success = ssh.ChannelReceiveUntilMatch(channelNum,"#","utf-8",caseSensitive);
    if (success == false) {
        console.log(ssh.LastErrorText);
        return;
    }

    received = ssh.GetReceivedText(channelNum,"utf-8");
    if (ssh.LastMethodSuccess == false) {
        console.log(ssh.LastErrorText);
        return;
    }

    console.log(received);

    //  Run a command whose output is delivered a page at a time.
    success = ssh.ChannelSendString(channelNum,"show running-config\r","utf-8");
    if (success == false) {
        console.log(ssh.LastErrorText);
        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.
    var saMatch = new chilkat.StringArray();
    saMatch.Append("MySwitchName#");
    saMatch.Append("--More--");

    var sbReceived = new chilkat.StringBuilder();
    var moreComing = true;

    while (moreComing) {
        success = ssh.ChannelReceiveUntilMatchN(channelNum,saMatch,"utf-8",caseSensitive);
        if (success == false) {
            console.log(ssh.LastErrorText);
            return;
        }

        sbReceived.Clear();
        var pageText = ssh.GetReceivedText(channelNum,"utf-8");
        if (ssh.LastMethodSuccess == false) {
            console.log(ssh.LastErrorText);
            return;
        }

        sbReceived.Append(pageText);
        console.log(pageText);

        //  If this page ended with "--More--", send a SPACE to request the next page.
        moreComing = sbReceived.Contains("--More--",caseSensitive);
        if (moreComing) {
            success = ssh.ChannelSendString(channelNum," ","utf-8");
            if (success == false) {
                console.log(ssh.LastErrorText);
                return;
            }

        }

    }

    ssh.Disconnect();

}

chilkatExample();