You don’t restrict the UserScopeMessageEvent - you just drill down into the required event bus. From an InternalSession, you can either findPage(<pageid>) or listPages() - then if you want to send a page scoped event, use the page’s event bus: getPageEventBus().
It looks like there’s no complementary function (that’s public) on Page, but sending a ‘View’ scope event would follow a similar model - you need to get to the View you want, then access its event bus.
Thanks a lot for these clarifications 
Hi @PGriffith
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 sessionId and pageId to keep distinct data for multiple sessionId/pageId.
getPage() on a Session object will always return null. A Session may have multiple pages, so you may have to use getPages(), but I’m not sure if there is a way to know which page is open or whatever it is you are looking for.
Yes session have multiple page, but I try to obtain the “context” (sessionId,pageId) in a module script function.
For sessionId,
String sessionId = InternalSession.SESSION.get().getSession().getSessionId().toString();
but to obtain the current pageId from where the script is executed, I don’t see ?
I want to avoid to pass the pageId parameter to each script function…
Try com.inductiveautomation.perspective.gateway.model.PageModel.PAGE.get().
Just a guess… I’m not very familiar with this area.
That’s fine.
