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.

bool 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.

Chilkat.Ssh ssh = new Chilkat.Ssh();

int port = 22;
success = ssh.Connect("172.16.16.100",port);
if (success == false) {
    Debug.WriteLine(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) {
    Debug.WriteLine(ssh.LastErrorText);
    return;
}

int channelNum = ssh.QuickShell();
if (channelNum < 0) {
    Debug.WriteLine(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;

bool caseSensitive = true;

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

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

Debug.WriteLine(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) {
    Debug.WriteLine(ssh.LastErrorText);
    return;
}

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

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

Debug.WriteLine(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";
success = ssh.ChannelSendString(channelNum,enablePassword,"utf-8");
if (success == false) {
    Debug.WriteLine(ssh.LastErrorText);
    return;
}

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

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

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

Debug.WriteLine(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) {
    Debug.WriteLine(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.
Chilkat.StringArray saMatch = new Chilkat.StringArray();
saMatch.Append("MySwitchName#");
saMatch.Append("--More--");

Chilkat.StringBuilder sbReceived = new Chilkat.StringBuilder();
bool moreComing = true;

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

    sbReceived.Clear();
    string pageText = ssh.GetReceivedText(channelNum,"utf-8");
    if (ssh.LastMethodSuccess == false) {
        Debug.WriteLine(ssh.LastErrorText);
        return;
    }

    sbReceived.Append(pageText);
    Debug.WriteLine(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) {
            Debug.WriteLine(ssh.LastErrorText);
            return;
        }

    }

}

ssh.Disconnect();