How to access client hostname, http headers etc fr

问题:

I've followed many tutorials and sample sample code but I am yet to see a way to access client's HTTP header, hostname etc like the way we can in Servlet's request object.

How do I go about it?

Let's say I've onOpen defined as-

@OnOpen
    public void onOpen(Session session) {

} 

In above method, is there a way I can access underlying HTTP connection details using session field? I am okay even if I can get to underlying Servlet (if there is any)

回答1:

see chapter 4.1.1.5 at Tyrus user guide. It requires some amount of work to get the info from ServerEnpointConfig.Configurator to endpoint instance, but it can be done. (see ModifyRequestResponseHeadersTest.java)

回答2:

Based on link1 and link2

I finally figured out that we can get the client IP with the following two classes, actually you can do more with the exposed httpservletRequest...

ServletAwareConfigurator .java

package examples;
import java.lang.reflect.Field;

import javax.servlet.http.HttpServletRequest;

import javax.websocket.HandshakeResponse;
import javax.websocket.server.HandshakeRequest;
import javax.websocket.server.ServerEndpointConfig;
import javax.websocket.server.ServerEndpointConfig.Configurator;

public class ServletAwareConfigurator extends ServerEndpointConfig.Configurator {

    @Override
    public void modifyHandshake(ServerEndpointConfig config, HandshakeRequest request, HandshakeResponse response) {
        HttpServletRequest httpservletRequest = getField(request, HttpServletRequest.class);
        String sClientIP = httpservletRequest.getRemoteAddr();
        config.getUserProperties().put("clientip", sClientIP);
        // ...
    }

    //hacking reflector to expose fields...
    private static < I, F > F getField(I instance, Class < F > fieldType) {
        try {
            for (Class < ? > type = instance.getClass(); type != Object.class; type = type.getSuperclass()) {
                for (Field field: type.getDeclaredFields()) {
                    if (fieldType.isAssignableFrom(field.getType())) {
                        field.setAccessible(true);
                        return (F) field.get(instance);
                    }
                }
            }
        } catch (Exception e) {
            // Handle?
        }
        return null;
    }
}

GetHttpSessionSocket.java

package examples;
import java.io.IOException;
import javax.servlet.http.HttpSession;
import javax.websocket.EndpointConfig;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;

@ServerEndpoint(value = "/example",
    configurator = ServletAwareConfigurator.class)
public class GetHttpSessionSocket {
    private Session wsSession;
    private String sClientIP;

    @OnOpen
    public void open(Session session, EndpointConfig config) {
        this.wsSession = session;
        this.sClientIP = (String) config.getUserProperties()
            .get("clientip");
    }
    @OnMessage
    public void echo(String msg) throws IOException {
        wsSession.getBasicRemote().sendText(msg);
    }
}