How to get remote client address in javax.websocket server?

Question

I have a jetty 9.3.6 server that runs a websocket webapp. I would like to get the client IP address for bookeeping purposes, and I can see it is there in the javax.websocket.Session object, but I don't know how to get it as the API doesn't allow for it. Some folks seem to cast it to a TyrusSession object (from org.glassfish.tyrus.core.TyrusSession), but when I tried that, it compiled fine, but raised a ClassCastException in the websocket server at runtime. I have included the following in my build.gradle:

compile 'org.glassfish.tyrus:tyrus-core:1.12'

What's the correct way to get the client IP address in a javax.websocket.Session?

score 2 · Accepted Answer · edited May 23 '17 at 10:27

Consistent with the SO rules, I answer my own question here.

I got my clue when I tried to cast it to TyrusSession and Jetty complained (raised ClassCastException) in the error logs saying it was a JsrSession which cannot be cast into a TyrusSession. However, I had just printed the Session object in my logs, and something like this showed up:

session: WebSocketSession[....]

I then tried to cast it to org.eclipse.jetty.websocket.common.WebSocketSession which then complained about the object actually being a JsrSession which then led to my discovering the following solution:

@ServerEndpoint (value="/mySillyApp", configurator= ..., decoders={...})
public class MySillyWebSocketServer
{
    @OnOpen
    public void open (Session session, EndpointConfig config)
    {
        JsrSession jsrSession = (JsrSession) session; // import org.eclipse.jetty.websocket.jsr356.JsrSession;
        WebSocketSession webSocketSession = jsrSession.getWebSocketSession (); // import org.eclipse.jetty.websocket.common.WebSocketSession;
        String clientIPAddressString = webSocketSession.getRemoteAddress ().getHostString ();
        ....
    }
    ...
}

Obviously, you will have to include the appropriate jars in your classpath. For gradle, you do this in the dependencies {...} section:

  compile 'org.eclipse.jetty.websocket:javax-websocket-client-impl:9.3.6.v20151106'
  compile 'org.eclipse.jetty.websocket:websocket-common:9.1.0.v20131115'

Hope my methodology and details helps someone.

How to get remote client address in javax.websocket server?

1 Answers1