Swift

Check Whether an SSH Channel is Open

Demonstrates the Chilkat Ssh.ChannelIsOpen method, which reports whether a channel number identifies a channel Chilkat currently considers open for application I/O. The only argument is the channel number. This example checks the channel before and after sending CLOSE.

Background: Because one SSH connection can carry many channels with independent lifetimes, code that manages several needs a way to ask whether a given one is still usable. This returns false for invalid or nonexistent channel numbers, after a local Disconnect, once remote closure is processed, and immediately after ChannelSendClose — which marks the channel locally closed without waiting for the remote side.

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func chilkatTest() {
    var success: Bool = false

    //  Demonstrates the Ssh.ChannelIsOpen method, which reports whether a channel number identifies
    //  a channel Chilkat currently considers open for application I/O.  The only argument is the
    //  channel number.

    let ssh = CkoSsh()!

    var sshPort: Int = 22
    success = ssh.connect(hostname: "ssh.example.com", port: sshPort)
    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
    }

    //  Open a session channel.  A negative return value indicates failure.
    var channelNum: Int = ssh.openSessionChannel().intValue
    if channelNum < 0 {
        print("\(ssh.lastErrorText!)")
        return
    }

    if ssh.channelIsOpen(channelNum: channelNum) {
        print("The channel is open.")
    }
    else {
        print("The channel is not open.")
    }

    //  Send CLOSE, which immediately marks the channel locally closed.
    success = ssh.channelSendClose(channelNum: channelNum)
    if success == false {
        print("\(ssh.lastErrorText!)")
        return
    }

    if ssh.channelIsOpen(channelNum: channelNum) {
        print("Still open.")
    }
    else {
        print("The channel is now closed.")
    }

    ssh.disconnect()

}