Java

WebSocket Connect through HTTP Proxy

See more WebSocket Examples

This example shows how to establish a WebSocket connection through an HTTP proxy server. 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 requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // --------------------------------------------------
    // This example borrows the code from the REST using HTTP Proxy example.
    // We first use the Chilkat Socket object to establish a connection to the WebSocket server through an HTTP proxy.
    // Next, the Rest object uses the Socket object for its connection.
    // Finally, the WebSocket object uses the Rest object for its connection.  
    // 

    CkRest rest = new CkRest();
    CkSocket socket = new CkSocket();

    // Set the HTTP proxy domain or IP address, and port.
    socket.put_HttpProxyHostname("192.168.1.79");
    socket.put_HttpProxyPort(808);

    // Provide authentication to the HTTP proxy, if needed.
    socket.put_HttpProxyUsername("HTTP_PROXY_LOGIN");
    socket.put_HttpProxyPassword("HTTP_PROXY_PASSWORD");
    socket.put_HttpProxyAuthMethod("Basic");

    // Indicate that HTTP requests (i.e. the WebSocket opening handshake) will be sent over the socket.
    // This is important for how the HTTP proxy connection is established.
    socket.put_HttpProxyForHttp(true);

    // Connect to the websocket server through the HTTP proxy.
    boolean bTls = false;
    int port = 80;
    int maxWaitMs = 5000;
    success = socket.Connect("some-websocket-server.com",port,bTls,maxWaitMs);
    if (success != true) {
        System.out.println("Connect Failure Error Code: " + socket.get_ConnectFailReason());
        System.out.println(socket.lastErrorText());
        return;
        }

    // Tell the Rest object to use the connected socket.
    success = rest.UseConnection(socket,true);
    if (success != true) {
        System.out.println(rest.lastErrorText());
        return;
        }

    CkWebSocket ws = new CkWebSocket();

    // Tell the WebSocket to use this connection.
    success = ws.UseConnection(rest);
    if (success != true) {
        System.out.println(ws.lastErrorText());
        return;
        }

    // 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.
    String responseBody = rest.fullRequestNoBody("GET","/something");
    if (rest.get_LastMethodSuccess() != true) {
        System.out.println(rest.lastErrorText());
        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.get_ResponseStatusCode();
    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. 
    success = ws.ValidateServerHandshake();
    if (success != true) {
        System.out.println(ws.lastErrorText());
        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 and socket objects...)

    System.out.println("Success.");
  }
}