CometD + Java + jQuery: Too much publishes with one call

Question

Hello im having the next issue using cometd + jquery + java doing some testing in broadcasting a message.

This is my web.xml, im using the Annotations implementation of cometd:

<!-- Cometd Servlet -->
<servlet>
    <servlet-name>cometd</servlet-name>
    <servlet-class>org.cometd.java.annotation.AnnotationCometdServlet</servlet-class>
    <init-param>
        <param-name>timeout</param-name>
        <param-value>60000</param-value>
    </init-param>
    <init-param>
        <param-name>logLevel</param-name>
        <param-value>3</param-value>
    </init-param>
    <init-param>
        <param-name>services</param-name>
        <param-value>com.api.services.UserStatusService</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
    <async-supported>true</async-supported>
</servlet>
<servlet-mapping>
    <servlet-name>cometd</servlet-name>
    <url-pattern>/do/cometd/*</url-pattern>
</servlet-mapping>

This is the service i registered:

package com.api.services;

import java.util.HashMap;

import javax.inject.Inject;

import org.cometd.bayeux.Message;
import org.cometd.bayeux.client.ClientSession;
import org.cometd.bayeux.client.ClientSessionChannel;
import org.cometd.bayeux.server.BayeuxServer;
import org.cometd.java.annotation.Service;
import org.cometd.java.annotation.Session;
import org.cometd.java.annotation.Subscription;

@Service
public class UserStatusService
{
    @Inject
    private BayeuxServer bayeux;
    @Session
    private ClientSession bayeuxClient;

    @Subscription("/userStatus")
    public void userStatus (Message message)
    {
        HashMap<String, String> mapa = new HashMap<String,String>();
        String channel = message.getChannel();
        System.out.println("*** The Channel is "+channel+" ***");
        ClientSessionChannel chann = bayeuxClient.getChannel(channel);
        mapa.put("canal", channel);
        mapa.put("mensaje", "Hola Wi!!");
        mapa.put("ServChan", bayeux.getChannels().get(0).toString());
        chann.publish(mapa);
    }
}

And this is the JS jQuery code im using to subscribe and publish (is part of a larger object so im just pasting the main thing related to this):

     /** On document ready i call this one **/
     initBroad:function(){
    $.cometd.unregisterTransport('websocket');
    $.cometd.init('http://localhost/MyApp/do/cometd');
    console.log("Set cometd initialization");
    main.broadListener();
},
count:0,
subscription:null,
refresh:function(){
    this.appUnsubscribe();
    this.appSubscribe();
},
appUnsubscribe:function(){
    if (this.subscription) 
        $.cometd.unsubscribe(this.subscription);
    this.subscription = null;
},
appSubscribe:function(){
    func = function(msg){
                    /** I had to do this in order to avoid ALL the 500 times it does it :S **/
        if(main.count < 1){
            console.log(main.count + ": " +  msg.data.mensaje);
        }
        main.count++;
    };
    this.subscription = $.cometd.subscribe("/userStatus",func);
},
broadListener:function(){
    console.log("Set the broadListener");
    main.refresh();
},
publishBroad:function(){
    main.refresh();
    $.cometd.publish('/userStatus', {mensaje:"Hola"});
},

Well, after trying to run the method publishBroad over the console, it actually runs, but 450-500 times IN THE SERVER with just one click/request (yes it is just one request from browser to the java server, the 450-500 times get repeated only on the server side and reaches the browser in the response that many times)!!

What have i done wrong? Im using the latests cometd.js and jquery.cometd.js from cometd official site.

Also, when i check this in the console (im using JBoss AS7), i left some output log lines to see if my call entered the method ( the Sys out println that says The Channel is:. and it also shows that log line 450-500 times in JBoss console!

Can anyone please help me to fix this up??

Thanks!!

Answer 1

Your problem is that you're using a ClientSession in your service.

If, in your service, you just want to reply to the sender, then do this:

@Service
public class UserStatusService
{
    @Session
    private LocalSession session;

    @Subscribe("/userStatus")
    public void userStatus(ServerSession remoteClient, ServerMessage message)
    {
        Map<String, String> map = new HashMap<String,String>();
        map.put("mensaje", "Hola Wi!!");
        remoteClient.deliver(session, message.getChannel(), map, null);
    }
}

Please refer to the CometD concepts to understand the difference between a ClientSession, a ServerSession and a LocalSession, and to the annotated services reference.

The reason for the loop you noticed (1 request caused the service to be executed 500+ times) is because you're re-broadcasting to the same channel in the last line if your service.