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.

func chilkatTest() {
    var success: Bool = 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.

    let ssh = CkoSsh()!

    var port: Int = 22
    success = ssh.connect(hostname: "172.16.16.100", port: port)
    if success == false {
        print("\(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: String? = "mySshPassword"

    success = ssh.authenticatePw(login: "mySshLogin", password: password)
    if success == false {
        print("\(ssh.lastErrorText!)")
        return
    }

    var channelNum: Int = ssh.quickShell().intValue
    if channelNum < 0 {
        print("\(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: Bool = true

    //  In unprivileged mode the switch prompt ends with ">".
    success = ssh.channelReceive(untilMatch: channelNum, matchPattern: ">", charset: "utf-8", caseSensitive: caseSensitive)
    if success == false {
        print("\(ssh.lastErrorText!)")
        return
    }

    var received: String? = ssh.getReceivedText(channelNum: channelNum, charset: "utf-8")
    if ssh.lastMethodSuccess == false {
        print("\(ssh.lastErrorText!)")
        return
    }

    print("\(received!)")

    //  Send "ena" to enter privileged mode.  Cisco devices expect a bare CR to terminate a command.
    success = ssh.channelSendString(channelNum: channelNum, strData: "ena\r", charset: "utf-8")
    if success == false {
        print("\(ssh.lastErrorText!)")
        return
    }

    success = ssh.channelReceive(untilMatch: channelNum, matchPattern: "Password:", charset: "utf-8", caseSensitive: caseSensitive)
    if success == false {
        print("\(ssh.lastErrorText!)")
        return
    }

    received = ssh.getReceivedText(channelNum: channelNum, charset: "utf-8")
    if ssh.lastMethodSuccess == false {
        print("\(ssh.lastErrorText!)")
        return
    }

    print("\(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: String? = "myEnablePassword"
    success = ssh.channelSendString(channelNum: channelNum, strData: enablePassword, charset: "utf-8")
    if success == false {
        print("\(ssh.lastErrorText!)")
        return
    }

    success = ssh.channelSendString(channelNum: channelNum, strData: "\r", charset: "utf-8")
    if success == false {
        print("\(ssh.lastErrorText!)")
        return
    }

    //  In privileged mode the prompt ends with "#" instead of ">".
    success = ssh.channelReceive(untilMatch: channelNum, matchPattern: "#", charset: "utf-8", caseSensitive: caseSensitive)
    if success == false {
        print("\(ssh.lastErrorText!)")
        return
    }

    received = ssh.getReceivedText(channelNum: channelNum, charset: "utf-8")
    if ssh.lastMethodSuccess == false {
        print("\(ssh.lastErrorText!)")
        return
    }

    print("\(received!)")

    //  Run a command whose output is delivered a page at a time.
    success = ssh.channelSendString(channelNum: channelNum, strData: "show running-config\r", charset: "utf-8")
    if success == false {
        print("\(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.
    let saMatch = CkoStringArray()!
    saMatch.append(str: "MySwitchName#")
    saMatch.append(str: "--More--")

    let sbReceived = CkoStringBuilder()!
    var moreComing: Bool = true

    while moreComing {
        success = ssh.channelReceive(untilMatchN: channelNum, matchPatterns: saMatch, charset: "utf-8", caseSensitive: caseSensitive)
        if success == false {
            print("\(ssh.lastErrorText!)")
            return
        }

        sbReceived.clear()
        var pageText: String? = ssh.getReceivedText(channelNum: channelNum, charset: "utf-8")
        if ssh.lastMethodSuccess == false {
            print("\(ssh.lastErrorText!)")
            return
        }

        sbReceived.append(value: pageText)
        print("\(pageText!)")

        //  If this page ended with "--More--", send a SPACE to request the next page.
        moreComing = sbReceived.contains(str: "--More--", caseSensitive: caseSensitive)
        if moreComing {
            success = ssh.channelSendString(channelNum: channelNum, strData: " ", charset: "utf-8")
            if success == false {
                print("\(ssh.lastErrorText!)")
                return
            }

        }

    }

    ssh.disconnect()

}