cometd: published message to a channel does not show up in subscribed listener

I am trying to publish a test data into the cometd-demo server channel members/hello/. handshake done, can get a subscribed message on callback and can get published message on publish() callback. But i can't get that published message on subscribe() listener.

Groovy Script:

import org.cometd.bayeux.Message;
import org.cometd.bayeux.Message.Mutable
import org.cometd.bayeux.client.ClientSessionChannel;
import org.cometd.bayeux.client.ClientSessionChannel.MessageListener;
import org.cometd.client.BayeuxClient
import org.cometd.client.transport.ClientTransport
import org.cometd.client.transport.LongPollingTransport
import org.eclipse.jetty.client.HttpClient as MyHttpClient

ClientSessionChannel.MessageListener mylistener = new Mylistener();

def myurl = "http://localhost:8080/cometd/"

MyHttpClient httpClient = new MyHttpClient();

httpClient.start()

Map<String, Object> options = new HashMap<String, Object>();

ClientTransport transport = new LongPollingTransport(options, httpClient);

BayeuxClient client = new BayeuxClient(myurl, transport)

client.handshake(30000)

def channel = client.getChannel("/members/hello/")

channel.subscribe(mylistener,mylistener)  

while (true)

{

    sleep(5000)

    channel.publish( 'hai' )

}

class Mylistener implements ClientSessionChannel.MessageListener {

        public void onMessage(ClientSessionChannel channel, Message message) {

            println message

        }

    }

While running this script I can't get the published data on listener even JVM not killed with the while loop. What am I missing?

Solution

You have specified incorrect channel path in:

def channel = client.getChannel("/members/hello/")

Channel path cannot end with / - it should be /members/hello.

Also double check if you use correct URL. I've used very simple CometD server application (https://github.com/wololock/dojo-jetty9-primer) that uses /dojo-jetty9-primer/ context path, so in my case URL to CometD server was:

def url = "http://localhost:8080/dojo-jetty9-primer/cometd/"

You can also simplify your script to something like that:

import org.cometd.bayeux.Message
import org.cometd.bayeux.client.ClientSessionChannel
import org.cometd.client.BayeuxClient
import org.cometd.client.transport.LongPollingTransport
import org.eclipse.jetty.client.HttpClient

final String url = "http://localhost:8080/dojo-jetty9-primer/cometd/"

final HttpClient httpClient = new HttpClient()
httpClient.start()

final BayeuxClient client = new BayeuxClient(url, new LongPollingTransport([:], httpClient))
client.handshake()
client.waitFor(1000, BayeuxClient.State.CONNECTED)

final ClientSessionChannel channel = client.getChannel("/members/hello")
channel.subscribe(new MyListener())

while (true) {
    sleep(1000)
    channel.publish("test")
}

class MyListener implements ClientSessionChannel.MessageListener {
    @Override
    void onMessage(ClientSessionChannel channel, Message message) {
        println "[${new Date()}] Received message from channel (${channel.id}): ${message}"
    }
}

Especially a part client.handshake(30000) can be simplified in your script - you don't have to wait 30 seconds here.

When you run it you will see a new message showing up in the console every 1 second:

[Mon Feb 19 10:15:02 CET 2018] Received message from channel (/members/hello): [data:test, channel:/members/hello]
[Mon Feb 19 10:15:03 CET 2018] Received message from channel (/members/hello): [data:test, channel:/members/hello]
[Mon Feb 19 10:15:04 CET 2018] Received message from channel (/members/hello): [data:test, channel:/members/hello]
[Mon Feb 19 10:15:05 CET 2018] Received message from channel (/members/hello): [data:test, channel:/members/hello]
[Mon Feb 19 10:15:06 CET 2018] Received message from channel (/members/hello): [data:test, channel:/members/hello]

Hope it helps.