Java

SSH Tunnel (Port Forwarding via direct-tcpip channel)

See more SSH Examples

Demonstrates how to create an SSH tunnel to a remote hostname:port via a direct-tcpip channel. 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;

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkSsh ssh = new CkSsh();

    // Connect to an SSH server:
    String hostname;
    int port;

    // Hostname may be an IP address or hostname:
    hostname = "192.168.1.117";
    port = 22;

    success = ssh.Connect(hostname,port);
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Wait a max of 5 seconds when reading responses..
    ssh.put_IdleTimeoutMs(5000);

    // Authenticate using login/password:
    success = ssh.AuthenticatePw("chilkat","myPassword");
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Open a direct-tcpip channel.  We want the SSH server to connect
    // to www.chilkatsoft.com, port 80 (i.e. the web server).
    // Data sent through the SSH tunnel is forwarded to the remote
    // host:port.  (Note: The remote host:port does not need to be 
    // a web server.  It can be anything.  It can be your own
    // customer application server that listens on a port, or any
    // other type of server.)
    // When we read from the SSH channel, we'll be reading data
    // sent from the remote host:port (i.e. the web server in this
    // example).
    int channelNum;
    channelNum = ssh.OpenDirectTcpIpChannel("www.chilkatsoft.com",80);
    if (channelNum < 0) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Build a simple HTTP GET request for http://www.chilkatsoft.com/xyz.html
    String httpReq = "GET /xyz123.html HTTP/1.1\r\nHost: www.chilkatsoft.com\r\n\r\n";

    // Send the HTTP request:
    success = ssh.ChannelSendString(channelNum,httpReq,"ansi");
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Get the HTTP response.
    // First read the HTTP response header which ends with a double CRLF.
    // Calling ChannelReceiveUntilMatch will receive until match string is seen,
    // or until a timeout occurs (IdleTimeoutMs property).  ChannelReceiveUntilMatch
    // may read beyond the match string, but it will stop reading as soon as the match
    // string is seen.
    boolean caseSensitive = false;
    String matchStr = "\r\n\r\n";
    success = ssh.ChannelReceiveUntilMatch(channelNum,matchStr,"ansi",caseSensitive);
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Extract the HTTP header from the receive buffer.
    // (GetReceiveTextS extracts up to and including the match string from the receive buffer)
    String responseHeader;
    responseHeader = ssh.getReceivedTextS(channelNum,matchStr,"ansi");
    System.out.println("---- HTTP Response Header ----");
    System.out.println(responseHeader);

    // Now get the body of the HTTP response (this is the HTML content
    // of http://www.chilkatsoft.com/xyz.html
    // It's possible we've already received the entire HTTP response in the
    // call to ChannelReceiveUntilMatch.  Therefore, we'll poll for any remaining data
    // and wait a max of .2 seconds.
    int numBytesRead;
    int pollTimeoutMs = 200;
    numBytesRead = ssh.ChannelPoll(channelNum,pollTimeoutMs);
    // We're not checking for an error here.
    // A return value of -2 means that no data was available and the poll simply timed out (not an error)
    // A return value of -1 indicates an error.
    // A return value greater than 0 indicates that additional data was received.

    System.out.println("---- HTML BODY ----");

    // Extract the remainder of the accumulated data in the internal receive buffer.
    // This should be our HTML body:
    String htmlBody;
    htmlBody = ssh.getReceivedText(channelNum,"ansi");
    System.out.println(htmlBody);

    // Close the channel:
    success = ssh.ChannelSendClose(channelNum);
    if (success != true) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    // Disconnect
    ssh.Disconnect();
  }
}