Java

Upgrade an FTP Control Channel to TLS (ConvertToTls)

Demonstrates the Chilkat Ftp2.ConvertToTls method, which upgrades an already-connected clear FTP control channel to explicit TLS. It takes no arguments and is used with a manually staged connection created by ConnectOnly while Ssl is disabled.

Background: This exposes the explicit-FTPS AUTH TLS upgrade as a discrete step for the rare case where you need to do something on the clear connection first — inspect the greeting, apply a workaround — before securing it. In the normal case you simply set AuthTls and let Connect perform the upgrade automatically; this manual path exists for staged control.

Chilkat Java Downloads

Download Chilkat for Java

Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean success = false;

    //  Demonstrates the Ftp2.ConvertToTls method, which upgrades an already-connected clear FTP control
    //  channel to explicit TLS.  It takes no arguments.  It is used with a manually staged connection
    //  created by ConnectOnly while Ssl is disabled.

    CkFtp2 ftp = new CkFtp2();

    ftp.put_Hostname("ftp.example.com");
    ftp.put_Port(21);

    //  Connect in clear text first (Ssl is false).
    success = ftp.ConnectOnly();
    if (success == false) {
        System.out.println(ftp.lastErrorText());
        return;
        }

    //  Upgrade the control channel to explicit TLS (AUTH TLS).
    success = ftp.ConvertToTls();
    if (success == false) {
        System.out.println(ftp.lastErrorText());
        return;
        }

    //  Now authenticate over the encrypted control channel.
    ftp.put_Username("myFtpLogin");
    ftp.put_Password("myPassword");
    success = ftp.LoginAfterConnectOnly();
    if (success == false) {
        System.out.println(ftp.lastErrorText());
        return;
        }

    System.out.println("Control channel upgraded to TLS and logged in.");

    success = ftp.Disconnect();
    if (success == false) {
        System.out.println(ftp.lastErrorText());
        return;
        }
  }
}