Disconnecting Atmosphere sockets in Grails - ajax

Question

I'm writing a Grails application which uses Atmosphere plugin. The connection works but every time I update the page in a browser I see that my web server adds a new Daemon thread which is never released afterwards.
After the thread count reaches 200 the web server freezes.
There seems to be no documentation explaining what is exactly the right way to handle the resources (disconnect) with the Atmosphere plugin?
My client code does this:
var connectedEndpoint = null;
$(function()
{
function callback(response)
{
if (response.transport != 'polling' && response.state != 'connected' && response.state != 'closed') {
if (response.status == 200) {
eval(response.responseBody);
}
}
}
$.atmosphere.subscribe('${resource(dir: '/atmosphere/channel')}', callback, $.atmosphere.request = {transport: 'streaming'});
connectedEndpoint = $.atmosphere.response;
});
$(window).unload( function ()
{
$.atmosphere.unsubscribe();
connectedEndpoint = null;
});
I use an atmosphere handler on the server side;
package demo
import javax.servlet.http.HttpServletRequest
import javax.servlet.http.HttpServletResponse
import org.atmosphere.cpr.AtmosphereHandler
import org.atmosphere.cpr.AtmosphereResource;
import org.atmosphere.cpr.AtmosphereResourceEvent;
class DemoController implements AtmosphereHandler<HttpServletRequest, HttpServletResponse> {
#Override
public void destroy() {
println "destroy"
}
#Override
public void onRequest( AtmosphereResource<HttpServletRequest, HttpServletResponse> event) throws IOException
{
event.suspend()
}
#Override
public void onStateChange( AtmosphereResourceEvent<HttpServletRequest, HttpServletResponse> event) throws IOException
{
if (event.isSuspended())
{
event.resource.response.writer.with {
def message = event.message
write "set${message.paramName}(\"${message.id}\",\"${message.value}\");"
flush()
}
}
}
}
The destroy function of the handler is never called!
The next picture shows that I have 23 threads running. When I start my application there are about 6 of them and they are added every time I press F5! If I disable atmosphere new threads are not added so this problem is related to the Atmosphere. (I am using SpringSource Tools Suite on Windows7).
If the solution is not trivial I would appreciate detailed step-by step instructions or an example.
UPDATE: After deployment in Tomcat I have the following errors each 20 seconds:
Apr 02, 2012 2:35:15 PM org.apache.catalina.startup.HostConfig deployDescriptor
INFO: Deploying configuration descriptor host-manager.xml
Apr 02, 2012 2:35:16 PM org.apache.catalina.startup.HostConfig deployDescriptor
INFO: Deploying configuration descriptor manager.xml
Apr 02, 2012 2:35:16 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deploying web application directory docs
Apr 02, 2012 2:35:16 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deploying web application directory examples
Apr 02, 2012 2:35:17 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deploying web application directory ROOT
Apr 02, 2012 2:35:17 PM org.apache.coyote.http11.Http11AprProtocol start
INFO: Starting Coyote HTTP/1.1 on http-8080
Apr 02, 2012 2:35:17 PM org.apache.coyote.ajp.AjpAprProtocol start
INFO: Starting Coyote AJP/1.3 on ajp-8009
Apr 02, 2012 2:35:17 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in 11401 ms
2012-04-02 14:41:17,122 [http-8080-39] ERROR cpr.AsynchronousProcessor - failed
to timeout resource AtmosphereResourceImpl{, hasCode-1035775543,
action=org.atmosphere.cpr.AtmosphereServlet$Action#f2718e,
broadcaster=org.atmosphere.cpr.DefaultBroadcaster,
cometSupport=org.atmosphere.container.TomcatCometSupport#107fff7,
serializer=null,
isInScope=true,
useWriter=true,
listeners=[]}
2012-04-02 14:42:15,034 [http-8080-69] ERROR cpr.AsynchronousProcessor - failed
to timeout resource AtmosphereResourceImpl{, hasCode-58082012,
action=org.atmosphere.cpr.AtmosphereServlet$Action#ae4dd4,
broadcaster=org.atmosphere.cpr.DefaultBroadcaster,
cometSupport=org.atmosphere.container.TomcatCometSupport#107fff7,
serializer=null,
isInScope=true,
useWriter=true,
listeners=[]}
2012-04-02 14:44:41,159 [http-8080-13] ERROR cpr.AsynchronousProcessor - failed
to timeout resource AtmosphereResourceImpl{, hasCode648226529,
action=org.atmosphere.cpr.AtmosphereServlet$Action#507e61,
broadcaster=org.atmosphere.cpr.DefaultBroadcaster,
cometSupport=org.atmosphere.container.TomcatCometSupport#107fff7,
serializer=null,
isInScope=true,
useWriter=true,
listeners=[]}
....

Answer 1

Which web server are you using? Sound like the web server isn't detecting when the browser close the connection. You can add, in web.xml, the following timeout detector
org.atmosphere.cpr.CometSupport.maxInactiveActivity=30000 //30 seconds

Answer 2

I believe your issue is in your unload event. "$(window).unload". I know at least in chrome, you can't do much in the unload or beforeunload events. therefore, your browser is probably never firing the unsubscribe().
if u look at Atmospheres jquery pubsub sample, u can see the unsubscribing before connecting,
function connect() {
unsubscribe();
...
you can code a loop to check broadcasters by pushing insignificant data to validate the broadcasters periodically if they arent getting cleaned up. i need to research atmosphere more and hope for a better solution. hopefully you can clean up threads when the new connection is created from a refresh and let old ones expire with the session when the user leaves.