Java

Send an FTP NOOP (Keep-Alive)

Demonstrates the Chilkat Ftp2.Noop method, which sends the FTP NOOP command. It takes no arguments and succeeds only when the server returns a positive reply.

Background: NOOP asks the server to do nothing and simply reply, which makes it the standard keep-alive: sending one periodically resets the server's idle timer so a long-running job does not lose its control connection between transfers. Because it exercises a real request/reply round trip, a successful NOOP is also firmer evidence the connection is alive than CheckConnection.

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import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Ftp2;

public class ChilkatExample {

    public static void main(String[] args) {
        // Demonstrates the Ftp2.Noop method, which sends the FTP NOOP command.  It takes no arguments.
        // The server must return a positive reply for the method to succeed.

        Ftp2 ftp = new Ftp2();

        ftp.setHostname("ftp.example.com");
        ftp.setUsername("myFtpLogin");

        // 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.
        ftp.setPassword("myPassword");

        // Connect and log in (Connect performs both).
        try {
            ftp.connect();

            // NOOP does nothing on the server, but a successful reply confirms the control connection is
            // still responsive -- useful as a keep-alive during an otherwise idle session.
            ftp.noop();
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("NOOP acknowledged by the server.");

        try {
            ftp.disconnect();
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }
    }
}