Java

Connect to an FTP Server Without Logging In

Demonstrates the Chilkat Ftp2.ConnectOnly method, which establishes the connection (including any proxy and TLS setup) and receives the greeting, but does not send USER or PASS. It takes no arguments; authentication is completed with LoginAfterConnectOnly.

Background: Splitting connect from login gives you a window between the two — to read the greeting, decide which account to use, or set up TLS options that depend on the server — that the all-in-one Connect does not. After ConnectOnly the control connection is open and CheckConnection returns true even though the session is not yet authenticated.

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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.ConnectOnly method, which establishes the connection (including any proxy
    //  and TLS setup) and receives the greeting, but does NOT send USER or PASS.  It takes no
    //  arguments.  Authentication is completed separately with LoginAfterConnectOnly.

    CkFtp2 ftp = new CkFtp2();

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

    //  Connect without logging in.
    success = ftp.ConnectOnly();
    if (success == false) {
        System.out.println(ftp.lastErrorText());
        return;
        }

    System.out.println("Connected (not yet logged in).");

    //  The greeting is now available; credentials can be set based on it, then authenticate.
    ftp.put_Username("myFtpLogin");
    ftp.put_Password("myPassword");

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

    System.out.println("Logged in.");

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