denis-anisimov
commented
5 years ago Some investigation notes:
Seems those dependencies have websocket impl for jetty:
<dependency>
<groupId>org.eclipse.jetty.websocket</groupId>
<artifactId>javax-websocket-server-impl</artifactId>
<version>9.4.12.v20180830</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.eclipse.jetty.websocket</groupId>
<artifactId>javax-websocket-client-impl</artifactId>
<version>9.4.12.v20180830</version>
<scope>provided</scope>
</dependency>BUT I have no idea whether they are those deps which we need to enable proper websocket support in Felix Jetty.
The functionality in those bundles heavily relies on ServletContainerInitializer (which doesn't work in Felix Jetty).
E.g. there is class WebSocketServerContainerInitializer which sets javax.websocket.server.ServerContainer attribute value.
I've made a very very ugly hack in the test-root-context module: I've added the javax-websocket-server-impl dep to it and changed the Activator code to:
@VaadinServletConfiguration(productionMode = false)
private static class FixedViewServlet extends ViewTestServlet {
@Override
public void init(ServletConfig servletConfig) throws ServletException {
ServletContext servletContext = servletConfig.getServletContext();
ServletContext originalContext = servletContext.getContext("/");
try {
WebSocketServerContainerInitializer initializer = new WebSocketServerContainerInitializer();
initializer.onStartup(Collections.emptySet(), originalContext);
} catch (Exception e) {
}
String attr = javax.websocket.server.ServerContainer.class
.getName();
servletContext.setAttribute(attr,
originalContext.getAttribute(attr));
System.out.println(
"wwwwwwwwwww " + servletContext.getAttribute(attr));
JSR356WebsocketInitializer jsr356Initializer = new JSR356WebsocketInitializer();
jsr356Initializer.contextInitialized(
new ServletContextEvent(servletConfig.getServletContext()));
super.init(servletConfig);
getService().setClassLoader(getClass().getClassLoader());
}
}This code shows how things are complicated : the servletContext is not the real instance which Jetty classes expects. Inside OSGi this is a proxy for a real servlet context.
The real servlet context is originalContext. I pass it to WebSocketServerContainerInitializer and
then it sets the requires attribute value.
Then I need to transfer it to the servletContext and I have to call servletContext.getAttribute otherwise nothing will work (proxy implementation detail).
Then I initialize servlet context via JSR356WebsocketInitializer directly.
Also I had to register a servlet in this way:
Dictionary<String, String> params = new Hashtable<>();
params.put(
"org.atmosphere.container.JSR356AsyncSupport.mappingPath",
"/view/*");
httpService.registerServlet("/view/*",
new FixedViewServlet(), params, null);Otherwise there will be an exception again related to the fact that in OSGi the servlet registered in the servlet context is a proxy for Jetty servlet (and there is some code which tries to find a servlet by its name which differs).
With this config I'm able at least get JSR356AsyncSupport somehow working.
At least there is ServerContainer attribute value.
But Push with websockets still doesn't work.
So there are so many questions and the very basic questions are about proper project setup so that websocket works with web server in OSGi.
pleku
Sandared
cosbadescu
Maurice-Betzel
mpetzold
This ticket follows up https://github.com/vaadin/flow/issues/5081.
It's quite complicated even just describe the ticket.
The simplest description is:
Use base-starter-flow-osgi and add @Push annotation to MainView.java. Push won't work.
By default the transport is Websockets. And that's the reason why it doesn't work. It's possible to use Long polling as a transport.
Note that it's not clear whether this issue is a project configuration issue or it's an issue in our websocket support with OSGi.
First of all you should add websocket api dependency to the project :
But this is not enough. Push with websockets won't work. The reason why it doesn't work is:
ServerContainer is nullin theorg.atmosphere.container.JSR356AsyncSupporthere:And that's the most complicated thing: it's totally unknown which bundle should set the attribute in the
ServletContext. Apparently there should be some websocket implementation bundle for jetty which should set the attribute at the servlet initialization phase.This is normally done either by a
ServletContainerInitializerorServletContextListener. The problem is : neither one nor another doesn't work in OSGi out of the box (at least they doesn't work in Felix jetty).So the questions are:
It's not even clear whether it's possible to configure Felix Jetty at all to work properly with Atmosphere so that
JSR356AsyncSupportdoesn't fail. May be it's just not possible at all and we should use another OSGi container/ web container ?If it's possible then what bundles should be deployed in addition to
javax.websocket-apito enable websocket support (not a generic web sockets support but makeJSR356AsyncSupportworks as it should)?If we find those bundles and deploy then then what's required from Flow to make websocket Push works ?
We have
JSR356WebsocketInitializerwhich is aggregated byServletContextListeners(which is@WebListener) and it's not activated in OSGi out of the box. So this is one thing in addition to all other which we should take care.Read also comments in another ticket starting from this one : https://github.com/vaadin/flow/issues/5081#issuecomment-467372123.