# Ignition 8.1.17 - after upgrading from 8.1.16, pages message sent doesn't trigger perspective message handler? **URL:** \ **Category:** Module Development\ **Tags:** perspective, ignition81\ **Created:** [May 13, 2022, 1:42pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542 "2022-05-13T13:42:21Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![mazeyrat](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/mazeyrat/32/10955_2.png) [@mazeyrat](https://forum.inductiveautomation.com/u/mazeyrat)\ **Post date:** [May 13, 2022, 1:42pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/1 "2022-05-13T13:42:22Z")
Hi @paul-griffith, I've upgraded an application from Ignition **8.1.16** to Ignition **8.1.17** I have a module that send message to perspective pages. All works fine in 8.1.16, but after upgrading in 8.1.17, the message are not sent or received in the event bus. **Does anything change in the way to send page's message ?** > [@SDK transfert data from gateway to perspective](https://forum.inductiveautomation.com/t/sdk-transfert-data-from-gateway-to-perspective/36349/23): > > Hi @paul-griffith to obtain the sessionId String sessionId = InternalSession.SESSION.get().getSession().getSessionId().toString(); work fine. But if I need to obtain the pageId, I’ve tried: String pageId = InternalSession.SESSION.get().getSession().getPage().getId().toString(); or String pageId = InternalSession.SESSION.get().getPage().getId().toString(); But both of them are triggering a java.lang.NullPointerException: null Did I missed something ? I try to guess in a script function the … The code used by the module to send message: ```auto public void sendCallbackMessage(String strSessionId,String pageId,String sessionName,Dataset data) { try { UUID sessionId = UUID.fromString(strSessionId); perspectiveContext.getSessionMonitor().findSession(sessionId).ifPresent(session -> { Optional pageModel = session.findPage(pageId); if (pageModel.isPresent()){ PyDictionary payloadMap = new PyDictionary(); QualifiedValue value = new BasicQualifiedValue(data); payloadMap.put("data", value); UserScopeMessageEvent message = new UserScopeMessageEvent(sessionName, payloadMap); logger.debug("sendCallbackMessage() send to sessionName={} - sessionId={} - pageId={} - data={}", sessionName, sessionId.toString(), pageId, value); session.queue().submit(() -> pageModel.get().getPageEventBus().post(message)); } else { logger.error("sendCallbackMessage() - sessionId={} - pageId={} not found !", sessionId.toString(), pageId); } }); } catch (Exception e) { logger.error("sendCallbackMessage() - Exception : {}",e); } } ``` According to gateway and browser logs, session id and page id are OK, nevertheless **the message handler that is no more triggered since upgrading in 8.1.17:** ![chrome_PJq8ldbwVB](https://us1.discourse-cdn.com/inductiveautomation/original/3X/d/1/d19c3d96828d9e64459ac79659497bd453106549.png) Perspective page message handler: ![mstsc_uuJG9yOBPQ](https://us1.discourse-cdn.com/inductiveautomation/original/3X/0/a/0a3b6c85bb69719c1f432e8b39ade0dbe6b261d5.png) ---
**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\ **Post date:** [May 13, 2022, 2:43pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/2 "2022-05-13T14:43:52Z")
Instead of subscribing to the page _eventbus_, subscribe to the page’s event manager (you’ll have to bump your SDK version). There was a catastrophic performance cliff in Guava’s eventbus, so we had to migrate away. The API is roughly the same, but the internals are different. ---
**Author:** ![mazeyrat](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/mazeyrat/32/10955_2.png) [@mazeyrat](https://forum.inductiveautomation.com/u/mazeyrat)\ **Post date:** [May 13, 2022, 3:10pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/3 "2022-05-13T15:10:21Z")
Thanks a lot @paul-griffith ! I suppose that it’s the same for **session message** , I have to use event Manager instead of event bus: before 8.1.17: ```auto perspectiveContext.getSessionMonitor().findSession(sessionId).ifPresent(session -> { PyDictionary payloadMap = new PyDictionary(); payloadMap.put("sessionId", sessionId.toString()); payloadMap.put("id", id); payloadMap.put("qv", qv); UserScopeMessageEvent message = new UserScopeMessageEvent(messageHandler, payloadMap); logger.debug("SessionEventBus().post : sessionId={}, id={}, qv={}",sessionId.toString(),id,qv); session.queue().submit(() -> session.getEventBus().post(message)); }); ``` from 8.1.17: ```auto session.queue().submit(() -> session.getEventManager().post(message)); ``` ---
**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\ **Post date:** [May 13, 2022, 4:08pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/4 "2022-05-13T16:08:29Z")
Yeah, pretty much everything in Perspective was refactored to have the two side by side. I think we’re planning to remove the eventbus stuff in Perspective in 8.2.X, but I’m not positive on that. ---
**Author:** ![Ahmed\_mohamed](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/ahmed_mohamed/32/53025_2.png) [@Ahmed\_mohamed](https://forum.inductiveautomation.com/u/Ahmed_mohamed)\ **Post date:** [November 16, 2022, 9:46pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/5 "2022-11-16T21:46:44Z")
is that required to depend on the Perspective module !? ---
**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\ **Post date:** [November 16, 2022, 10:11pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/6 "2022-11-16T22:11:39Z")
If you plan to use Perspective APIs in your code, you **must** do two things: 1. At compile time of your module, provide the appropriate Perspective SDK dependencies via your build system of choice. 2. Declare a dependency on the Perspective module in your `module.xml`, so that Ignition knows to load your code (on the Gateway, at least) within an appropriate classloader. If you want to handle Perspective being _optional_, things get somewhat more complicated and can require reflection to handle cleanly. ---
**Author:** ![Ahmed\_mohamed](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/ahmed_mohamed/32/53025_2.png) [@Ahmed\_mohamed](https://forum.inductiveautomation.com/u/Ahmed_mohamed)\ **Post date:** [November 16, 2022, 10:48pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/7 "2022-11-16T22:48:42Z")
Sorry for bothering you, there is an Archetype for Perspective Module To import an empty Template To write My code there. Thanks in Advanced ---
**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\ **Post date:** [November 16, 2022, 10:58pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/8 "2022-11-16T22:58:03Z")
No, there are no Maven archetypes for a Perspective component. We use Gradle internally, and no one (to my knowledge) has yet figured out how to build a Perspective component with Maven. There are two public examples of a Perspective component built using Gradle: > **[ignition-sdk-examples/perspective-component at master ·...](https://github.com/inductiveautomation/ignition-sdk-examples/tree/master/perspective-component)** > > master/perspective-component > > > This adds another perspective module component example, in the most simplified f…orm possible. There is no front-end tooling, and only the minimal required APIs for registering a component are demonstrated. > > This example is not 'production grade', as it is intended to be useful as a learning tool rather than the basis of a new module. > > Fixes #81 ---
**Author:** ![Ahmed\_mohamed](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/ahmed_mohamed/32/53025_2.png) [@Ahmed\_mohamed](https://forum.inductiveautomation.com/u/Ahmed_mohamed)\ **Post date:** [November 16, 2022, 11:00pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/9 "2022-11-16T23:00:15Z")
Thanks [PGriffith](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/8) ❤ ---
**Author:** ![Thomas\_Mulcahy](https://avatars.discourse-cdn.com/v4/letter/t/f1d935/32.png) [@Thomas\_Mulcahy](https://forum.inductiveautomation.com/u/Thomas_Mulcahy)\ **Post date:** [February 2, 2023, 3:04pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/10 "2023-02-02T15:04:17Z")
Hi, In relation to the above, I have got this mechanism working with Message Handlers on views (root). But I can't seem to get this to work with the Perspective Session Events mechanism. Am I supposed to be doing something different? ---
**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\ **Post date:** [February 2, 2023, 4:20pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/11 "2023-02-02T16:20:42Z")
It's not clear at all to me what issue you're having or how it relates to the above. Are you also developing a module? What have you done/what are you currently doing/what's going wrong? ---
**Author:** ![Thomas\_Mulcahy](https://avatars.discourse-cdn.com/v4/letter/t/f1d935/32.png) [@Thomas\_Mulcahy](https://forum.inductiveautomation.com/u/Thomas_Mulcahy)\ **Post date:** [February 2, 2023, 4:26pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/12 "2023-02-02T16:26:24Z")
Sorry, should have added some context. I am trying to send a message from a Module running on the gateway to a connected client. So I have my module configured as it is laid out in this thread. Although, when I send the message using: ```auto session.queue().submit(() -> session.getEventManager().post(message)); ``` I can only register that message on the client, if I put my message handler on one of the pages in my project (I used the root for this test). What I actually want to do, is have the message handler in the Perspective Session Events. I tested it with the Session Events and it seems that I cannot handle the message being sent from my module. ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/d/e/dee1c91ea587b207a2fb0174239c65a586afaa95.png) I do not get the message printed to the log from this message handler. ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/f/3/f3bc1297502e745f14bffe0d282f91028412b65f.png) But I do from this message handler. So I assume I need to send the messages in a different context, if it is possible at all? ---
**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\ **Post date:** [February 2, 2023, 5:00pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/13 "2023-02-02T17:00:14Z")
Ah, yeah. The former are messages sent via (typically) `system.util.sendMessage`, on an overall platform-level bus. The latter are messages sent via `system.perspective.sendMessage`, on a Perspective-specific bus. To use the overall system bus, you want the [`MessageDispatchManager`](https://files.inductiveautomation.com/sdk/javadoc/ignition81/8.1.24/com/inductiveautomation/ignition/common/script/message/MessageDispatchManager.html) you get from `GatewayContext`. You build up a `Properties` instance with the static string constant keys in MessageDispatchManager. ---
**Author:** ![Thomas\_Mulcahy](https://avatars.discourse-cdn.com/v4/letter/t/f1d935/32.png) [@Thomas\_Mulcahy](https://forum.inductiveautomation.com/u/Thomas_Mulcahy)\ **Post date:** [February 3, 2023, 8:49am UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/14 "2023-02-03T08:49:47Z")
So this is what I have tried at the moment. ```auto PyDictionary payload = new PyDictionary(); payload.put("param", number); Properties filterParams = new Properties(); filterParams.setProperty(MessageDispatchManager.KEY_SCOPE, MessageDispatchManager.SCOPE_CLIENT_ONLY); dispatchManager.dispatch("ProjectName", "test", payload, filterParams); ``` The ProjectName is the actual name of my project. Looking through the KEYs in MessageDispatchManager I can't see any other I need (I could be wrong) The message is still not handled by the client. ---
**Author:** ![victordcq](https://avatars.discourse-cdn.com/v4/letter/v/f6c823/32.png) [@victordcq](https://forum.inductiveautomation.com/u/victordcq)\ **Post date:** [February 3, 2023, 12:55pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/15 "2023-02-03T12:55:48Z")
> [@Thomas\_Mulcahy](#): > > `SCOPE_CLIENT_ONLY` I think this is vision client, for perspective its probabbly SCOPE\_SESSION > [@Thomas\_Mulcahy](#): > > The ProjectName is the actual name of my project you should probably not hardcode a project name in a module ---
**Author:** ![Thomas\_Mulcahy](https://avatars.discourse-cdn.com/v4/letter/t/f1d935/32.png) [@Thomas\_Mulcahy](https://forum.inductiveautomation.com/u/Thomas_Mulcahy)\ **Post date:** [February 3, 2023, 1:06pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/16 "2023-02-03T13:06:44Z")
Ah! That worked. Thank you. Yes, the ProjectName will come from the configuration eventually. It is easier to ignore that for now. One last question, is there a way that I can display a Popup from the Perspective Session Events handler. ```auto com.inductiveautomation.ignition.common.script.JythonExecException: Traceback (most recent call last): File "", line 2, in handleMessage at com.inductiveautomation.perspective.gateway.script.AbstractScriptingFunctions.lambda$operateOnPage$0(AbstractScriptingFunctions.java:64) at com.inductiveautomation.perspective.gateway.script.AbstractScriptingFunctions.operateOnSession(AbstractScriptingFunctions.java:120) at com.inductiveautomation.perspective.gateway.script.AbstractScriptingFunctions.operateOnPage(AbstractScriptingFunctions.java:47) at com.inductiveautomation.perspective.gateway.script.PerspectiveScriptingFunctions.popupAction(PerspectiveScriptingFunctions.java:758) at com.inductiveautomation.perspective.gateway.script.PerspectiveScriptingFunctions.openPopup(PerspectiveScriptingFunctions.java:240) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.base/java.lang.reflect.Method.invoke(Unknown Source) java.lang.IllegalArgumentException: java.lang.IllegalArgumentException: No perspective page attached to this thread. at org.python.core.Py.JavaError(Py.java:547) at org.python.core.Py.JavaError(Py.java:538) at org.python.core.PyReflectedFunction. __call__ (PyReflectedFunction.java:192) at com.inductiveautomation.ignition.common.script.ScriptManager$ReflectedInstanceFunction. __call__ (ScriptManager.java:552) at org.python.core.PyObject. __call__ (PyObject.java:477) at org.python.core.PyObject. __call__ (PyObject.java:481) at org.python.pycode._pyx351.handleMessage$1(:2) at org.python.pycode._pyx351.call_function() at org.python.core.PyTableCode.call(PyTableCode.java:173) at org.python.core.PyBaseCode.call(PyBaseCode.java:306) at org.python.core.PyFunction.function ___call__ (PyFunction.java:474) at org.python.core.PyFunction. __call__ (PyFunction.java:469) at org.python.core.PyFunction. __call__ (PyFunction.java:464) at com.inductiveautomation.ignition.common.script.ScriptManager.runFunction(ScriptManager.java:846) at com.inductiveautomation.ignition.common.script.ScriptManager.runFunction(ScriptManager.java:828) at com.inductiveautomation.ignition.gateway.project.ProjectScriptLifecycle$TrackingProjectScriptManager.runFunction(ProjectScriptLifecycle.java:832) at com.inductiveautomation.ignition.common.script.ScriptManager$ScriptFunctionImpl.invoke(ScriptManager.java:1009) at com.inductiveautomation.ignition.gateway.project.ProjectScriptLifecycle$AutoRecompilingScriptFunction.invoke(ProjectScriptLifecycle.java:897) at com.inductiveautomation.perspective.gateway.script.ScriptFunctionHelper.invoke(ScriptFunctionHelper.java:147) at com.inductiveautomation.perspective.gateway.script.ScriptRunner.run(ScriptRunner.java:23) at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) at java.base/java.util.concurrent.FutureTask.run(Unknown Source) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at com.inductiveautomation.perspective.gateway.threading.BlockingWork$BlockingWorkRunnable.run(BlockingWork.java:58) at java.base/java.lang.Thread.run(Unknown Source) Caused by: org.python.core.PyException: java.lang.IllegalArgumentException: java.lang.IllegalArgumentException: No perspective page attached to this thread. ... 26 common frames omitted Caused by: java.lang.IllegalArgumentException: No perspective page attached to this thread. at com.inductiveautomation.perspective.gateway.script.AbstractScriptingFunctions.lambda$operateOnPage$0(AbstractScriptingFunctions.java:64) at com.inductiveautomation.perspective.gateway.script.AbstractScriptingFunctions.operateOnSession(AbstractScriptingFunctions.java:120) at com.inductiveautomation.perspective.gateway.script.AbstractScriptingFunctions.operateOnPage(AbstractScriptingFunctions.java:47) at com.inductiveautomation.perspective.gateway.script.PerspectiveScriptingFunctions.popupAction(PerspectiveScriptingFunctions.java:758) at com.inductiveautomation.perspective.gateway.script.PerspectiveScriptingFunctions.openPopup(PerspectiveScriptingFunctions.java:240) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.base/java.lang.reflect.Method.invoke(Unknown Source) at org.python.core.PyReflectedFunction. __call__ (PyReflectedFunction.java:190) ``` Because I get this error, so I am assuming I can't use system.perspective.openPopup without calling from within a Perspective View? ---
**Author:** ![victordcq](https://avatars.discourse-cdn.com/v4/letter/v/f6c823/32.png) [@victordcq](https://forum.inductiveautomation.com/u/victordcq)\ **Post date:** [February 3, 2023, 1:10pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/17 "2023-02-03T13:10:40Z")
you can put you will need to fill in a pageId, as the session has many pages ---
**Author:** ![Thomas\_Mulcahy](https://avatars.discourse-cdn.com/v4/letter/t/f1d935/32.png) [@Thomas\_Mulcahy](https://forum.inductiveautomation.com/u/Thomas_Mulcahy)\ **Post date:** [February 3, 2023, 1:11pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/18 "2023-02-03T13:11:16Z")
Ok great, I will take a look at that. Thank you. ---
**Author:** ![victordcq](https://avatars.discourse-cdn.com/v4/letter/v/f6c823/32.png) [@victordcq](https://forum.inductiveautomation.com/u/victordcq)\ **Post date:** [February 3, 2023, 1:12pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/19 "2023-02-03T13:12:40Z")
> [@Open popup from session event](https://forum.inductiveautomation.com/t/open-popup-from-session-event/53148/5): > > Session Events have no context of “page”. Consider the following code: def runAction(self, event): """ This event is fired when the 'action' of the component occurs. Arguments: self: A reference to the component that is invoking this function. event: An empty event object. """ system.perspective.openPopup(“0”,‘Popups/PopupLoginAck’) Note that you are NOT supplying a pageId. This sort of usage allows the thread in use to fallback to the page which is in use, because this is from a… ---
**Author:** ![Thomas\_Mulcahy](https://avatars.discourse-cdn.com/v4/letter/t/f1d935/32.png) [@Thomas\_Mulcahy](https://forum.inductiveautomation.com/u/Thomas_Mulcahy)\ **Post date:** [February 3, 2023, 1:15pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-17-after-upgrading-from-8-1-16-pages-message-sent-doesnt-trigger-perspective-message-handler/59542/20 "2023-02-03T13:15:20Z")
Great! That got it working. Many thanks.