How to keep JSF Conversations from expiring

Question

I have a requirement to keep the JSF 2.2 CDI conversation from expiring. I tried implementing a heartbeat mechanism where I click a 'hidden' button using Ajax which in turn calls a servlet. But the Conversation still expires. I set the timeout to 10s for testing purposes and my code is as shown below.

// The begin conversation method in my managed bean
public void beginConversation() {
      if (conversation.isTransient())
      {
          conversation.setTimeout(10000);
          conversation.begin();
      }
}

// JQuery document ready function
$(document).ready(function() {
setInterval(function(){$.get("/HeartbeatServlet");}, 5000);

});

// Heartbeat servlet
@WebServlet("/HeartbeatServlet")
public class HeartbeatServlet extends HttpServlet{

private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response)
{
    System.out.println("Heartbeat Received");
    request.getSession();
}
}

It prints the "Heartbeat Recieved" text every 5 seconds. But the conversation still expires.

score 1 · Answer 1 · answered Dec 16 '14 at 01:22

1

The conversation timeout is how long the conversation will stay alive. It is not a permanent tracker of a conversation. It is not meant to be a keep alive on requests.

There is no extend conversation concept, however you can use begin(id) to recreate a conversation. Any bean state in that conversation will be lost.

answered Dec 16 '14 at 01:22

John Ament

11,595
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For Ajax call this doesn't work for me. I still get error: WELD-000321 No conversation found to restore for id 1 even if I use begin(). If I use begin(1) I get "conversation ID 1 is already in use". – zdenekca Mar 12 '15 at 01:43
Conversation timeout is not "how long the conversation will stay alive", JBoss Weld documentation clearly states "The timeout is the period of inactivity before the conversation is destroyed **(as opposed to the amount of time the conversation is active)**", please see http://docs.jboss.org/weld/reference/latest/en-US/html_single/#_conversation_timeout – jpangamarca Dec 05 '17 at 05:02

score 1 · Answer 2 · answered Mar 03 '15 at 17:18

We had the same problem. Adding "cid" to the request for the servlet did not help. In our experience, the heartbeat Servlet does not know about the Conversation. It will keep the current session going, but won't help with the Conversation.

Our solution for this was to add a viewscoped managedbean in which we inject the Conversation. On the UI we used PrimeFaces p:poll to periodically call a method on the managebean.

The method is just printing log statements.

@ManagedBean
@ViewScoped
public class ConversationListener implements Serializable {

...

/**
 * Inject Conversation instance if it is available.
 */
@Inject
private Conversation conversation;
@Inject
FacesBroker facesBroker;

...

/**
 * Method to refresh current conversation
 */
public void renewConversation() {

    if (conversation == null) {
        System.out.println("no conversation");
    } else {
        HttpServletRequest request = (HttpServletRequest) facesBroker.getContext().getExternalContext().getRequest();
        log.info("***     ConversationListener called for conversation ID: {}", new Object[] { conversation.getId() });
        log.info("***     ConversationListener called for session ID: {}", new Object[] { request.getSession().getId() });
    }
}
}

I'm not sure if your solution keeps conversation beans from expiring and avoids BusyConversationException but you're absolutely right about "the heartbeat Servlet does not know about the Conversation. It will keep the current session going, but won't help with the Conversation". — Rita, Nov 25 '15 at 10:28
Wouldn't it suffice to call a method on the conversation scoped bean with p:poll? — jpangamarca, Dec 06 '17 at 03:30

jpangamarca · Answer 3 · 2017-12-13T23:40:05.223

1

I've found that keeping a conversation from expiring can be achieved by calling a method on the conversation scoped bean periodically with Primefaces' p:poll, configured to use a reasonable interval (5 min interval has worked for me), no fancy magic required.

edited Dec 13 '17 at 23:40

answered Dec 13 '17 at 17:37

jpangamarca

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score 0 · Answer 4 · answered Dec 17 '14 at 20:32

this could be implementation specififc but if you start a conversation with begin() as you do, the framework should append a conversation id as a requestparameter. this is how the conversation is mapped to a request.

with weld as cdi implementation this should be "cid". i dont know how other implementations handle the conversation.

try to append the parameter to your heartbeat request and it should map the conversation and maybe refresh the timeout.

hope that helps

tell me if it works, im interested if the conversation expires anyway as John Ament mentioned... — Tobi, Dec 17 '14 at 20:41

How to keep JSF Conversations from expiring

4 Answers4