Receive from an SSH Channel Until a Pattern Matches

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Demonstrates the Chilkat Ssh.ChannelReceiveUntilMatch method, which receives text until the accumulated text matches a pattern. The arguments are the channel number, the pattern, the charset, and whether matching is case-sensitive. Existing buffered text is checked before waiting for more network data.

Important: Set the ReadTimeoutMs property before calling this method. It defaults to 0, meaning no limit, so without it the call waits forever if the received data never contains a match.

func chilkatTest() {
    var success: Bool = false

    //  Demonstrates the Ssh.ChannelReceiveUntilMatch method, which receives text until the
    //  accumulated text matches a pattern.  The 1st argument is the channel number, the 2nd is the
    //  pattern, the 3rd is the charset, and the 4th selects case-sensitive matching.  The pattern
    //  supports literal characters plus "*", which matches zero or more characters.

    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
    }

    var channelNum: Int = ssh.openSessionChannel().intValue
    if channelNum < 0 {
        print("\(ssh.lastErrorText!)")
        return
    }

    //  Start a shell WITHOUT requesting a PTY.  Without a PTY the shell sees it is connected to a
    //  raw data pipe and enters non-interactive mode: it suppresses the command prompt, does not
    //  echo typed commands back, and skips interactive login scripts.  The output is therefore
    //  clean and easily parseable -- but because no prompt is ever sent, code must not wait for
    //  one.  Instead, have each command print a predictable marker, or wait for EOF / channel close.
    success = ssh.sendReqShell(channelNum: channelNum)
    if success == false {
        print("\(ssh.lastErrorText!)")
        return
    }

    //  There is no prompt to wait for, so make the command itself announce when it has finished
    //  by echoing a marker after it.
    success = ssh.channelSendString(channelNum: channelNum, strData: "ls -l /tmp; echo DONE_MARKER\n", charset: "utf-8")
    if success == false {
        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

    //  Receive until the marker appears in the output.
    var caseSensitive: Bool = false
    success = ssh.channelReceive(untilMatch: channelNum, matchPattern: "DONE_MARKER", charset: "utf-8", caseSensitive: caseSensitive)
    if success == false {
        print("\(ssh.lastErrorText!)")
        return
    }

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

    print("\(output!)")

    ssh.disconnect()

}