Java Requires Chilkat v11.0.0+

WebSocket through SSH Tunnel

See more WebSocket Examples

This example shows how to establish a WebSocket connection through an SSH tunnel. The WebSocket protocol communications will be encapsulated within an SSH tunnel. Chilkat2 Java

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Rest;
import com.chilkatsoft.chilkat2.Socket;
import com.chilkatsoft.chilkat2.WebSocket;

public class ChilkatExample {

    public static void main(String[] args) {
        // This example requires the Chilkat API to have been previously unlocked.
        // See Global Unlock Sample for sample code.

        // --------------------------------------------------
        // This example borrows the code from the REST through SSH Tunnel example.
        // We first use the Chilkat Socket object to establish a connection to the WebSocket server through an SSH Tunnel.
        // Next, the Rest object uses the Socket object for its connection.
        // Finally, the WebSocket object uses the Rest object for its connection.
        //
        // Hopefully the flexibility of this architecture is easy to see.  All of the HTTP functionality of the Rest object,
        // such as HTTP authentication, custom headers, etc. is available to the WebSocket.  Likewise, all of the advanced functionality
        // of the Socket object is in turn available to the Rest object.

        // The high-level steps for accomplishing the task of running the WebSocket protocol through an SSH accomplished as follows:
        // 1) Create the SSH tunnel using Chilkat Socket.
        // 2) Open a port-forwarding channel (to the WebSocket server) within the tunnel.
        // 2) Tell Rest to use the Socket object.
        // 3) Tell WebSocket to use the Rest object.

        Socket tunnel = new Socket();

        String sshHostname = "sftp.example.com";
        int sshPort = 22;

        // Connect to an SSH server and establish the SSH tunnel:
        try {
            tunnel.sshOpenTunnel(sshHostname, sshPort);

            // Authenticate with the SSH server via a login/password
            // or with a public key.
            // This example demonstrates SSH password authentication.
            tunnel.sshAuthenticatePw("mySshLogin", "mySshPassword");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        //  OK, the SSH tunnel is setup.  Now open a channel within the tunnel.

        boolean bTls = true;
        int port = 443;
        int maxWaitMs = 5000;

        // This returns a socket object that is a single channel within the SSH tunnel.
        // The SSH channel is our logical port-forwarded connection through the SSH tunnel.
        // Note: This example establishes a TLS connection to the target WebSocket server.
        // (The TLS protocol will run on the logical channel within the SSH tunnel.)
        // Your application can just as easily make a non-TLS connection by changing the arguments
        // passed to SshNewChannel.
        Socket channel = new Socket();
        try {
            tunnel.sshNewChannel("some-websocket-server.com", port, bTls, maxWaitMs, channel);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Create a REST object and tell it to use the SSH channel.
        // This connection is a TLS running on an SSH channel through an SSH tunnel.
        // In other words, TLS is wrapped within the SSH tunnel.
        Rest rest = new Rest();
        try {
            rest.useConnection(channel, false);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Finally, tell our WebSocket object to use the Rest object..
        WebSocket ws = new WebSocket();

        // Tell the WebSocket to use this connection.
        String responseBody;
        try {
            ws.useConnection(rest);

            // Add the standard WebSocket open handshake headers that will be needed.
            // (This adds the required HTTP request headers to the rest object.)
            ws.addClientHeaders();

            // Add any additional headers that might be desired.
            // Two common WebSocketSpecific headers are "Sec-WebSocket-Protocol" and "Origin".
            rest.addHeader("Sec-WebSocket-Protocol", "x-some-websocket-subprotocol");
            rest.addHeader("Origin", "http://some-websocket-server.com");

            // Do the open handshake.
            responseBody = rest.fullRequestNoBody("GET", "/something");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // If successful, the HTTP response status code should be 101,
        // and the response body will be empty. (If it failed, we'll have a look
        // at the response body..)
        int statusCode = rest.getResponseStatusCode();
        System.out.println("Response status code: " + statusCode);

        if (statusCode != 101) {
            System.out.println(responseBody);
            System.out.println("-- Failed because of unexpected response status code.");
            return;
        }

        // We have the expected 101 response, so let's now validate the
        // contents of the response, such as the value sent by the server in the
        // Sec-WebSocket-Accept header.
        try {
            ws.validateServerHandshake();
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("WebSocket connection successful.");

        // The application may now begin sending and receiving frames on the WebSocket connection.
        // (At this point, we're done with the rest object...)
    }
}