[undertow-dev] WebSocketContainer configuration

[Stuart Douglas]

Ryan Hermanson wrote:
> I have had good luck with use of Undertow recently but now I’ve come up
> against a problem.  When the deployment is strictly a server (I.e.
> handling inbound requests over web sockets), all is happy.  Recently,
> there is a need to support outbound “client” sessions.  And, all is not
> well.  I’ll be as detailed as possible to keep the speculation of
> specifics to a minimum.  Thanks for your patience.
>
> My problem is two fold.  The client session needs to have associated
> sslContext (presumably thru EndpointConfig instance), as well as a way
> to control/configure the underlying HTTP timeouts (presumably thru
> socketOptions).  When I do something as simple as
>
> ContainerProvider.getWebSocketContainer().connectToServer(annotatedClientEndpoint.class,
> path)
>
> , the client connection is established with far-end as hoped, but the
> sslContext defined for our undertow instance is not employed.  To add to
> the headache, if the remote server is unresponsive, the connection
> attempt blocks for roughly 5 minutes.  Neither of these scenarios is
> ideal, obviously.


The ssl context can be set in three ways.

1) Use the version of connect that takes a ClientEndpointConfig and set 
the io.undertow.websocket.SSL_CONTEXT property to the SSL context you 
want to use (unfortunatly this won't work with annotated endpoints).

2) Call 
io.undertow.websockets.jsr.DefaultWebSocketClientSslProvider#setSslContext() 
which sets the thread local SSL context.

3) Implement io.undertow.websockets.jsr.WebsocketClientSslProvider and 
add a META-INF/services entry pointing to your implementation.

(The web socket API is sadly lacking when it comes to configuring SSL).

>
> ServerWebSocketContainer serverContainer = (ServerWebSocketContainer)
> deployment.getDeployment()
>
> .getServletContext().getAttribute(ServerContainer.class.getName());
> serverContainer.connectToServer(annotatedClientEndpoint.class, path);
>
> The above attempt to leverage the deployed ServerWebSocketContainer
> (simpleAnnotatedServerEndpoint), successfully establishes the remote
> connection, but any attempt at handling a message via @OnMessage (public
> void onMessage(String msg)), yields NPE (BufferPool is null) with stack
> trace of:

Make sure you set the buffer pool on the WebSocketDeploymentInfo 
(io.undertow.websockets.jsr.WebSocketDeploymentInfo#setBuffers).

Stuart

>
> 2014-08-21 16:03:30,978;20667;DEBUG;core.request;(XNIO-1 I/O-1);Invoking
> receive listener
> 2014-08-21 16:03:30,978;20667;ERROR;xnio.listener;(XNIO-1
> I/O-1);XNIO001007: A channel event listener threw an exception
> java.lang.NullPointerException
>      at
> io.undertow.server.protocol.framed.AbstractFramedChannel.receive(AbstractFramedChannel.java:234)
>      at
> io.undertow.websockets.core.AbstractReceiveListener.handleEvent(AbstractReceiveListener.java:20)
>      at
> io.undertow.websockets.core.AbstractReceiveListener.handleEvent(AbstractReceiveListener.java:15)
>      at
> org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92)
>      at
> io.undertow.server.protocol.framed.AbstractFramedChannel$FrameReadListener.handleEvent(AbstractFramedChannel.java:632)
>      at
> io.undertow.server.protocol.framed.AbstractFramedChannel$FrameReadListener.handleEvent(AbstractFramedChannel.java:618)
>      at
> org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92)
>      at
> org.xnio.conduits.ReadReadyHandler$ChannelListenerHandler.readReady(ReadReadyHandler.java:66)
>      at org.xnio.nio.NioSocketConduit.handleReady(NioSocketConduit.java:87)
>      at org.xnio.nio.WorkerThread.run(WorkerThread.java:539)
>
> Based on description above and the relevant code snippets below, how
> should I proceed in order to successfully establish outbound “client”
> connection with functional xnioWorker instance, including SSL_CONTEXT
> and working channels?  Thank you for any suggestions.
>
> Undertow version: 1.0.15 Final
> Xnio version: 3.2.2 Final
>
> My undertow instance:
>
>        undertow = Undertow.builder()
>              .addHttpListener(wsDefaultPort, WS_HOST)
>              .addHttpsListener(wssDefaultPort, WS_HOST,
> MySSLSocketFactory.getSslContext())
>              .setHandler(rootPath)
>              .build();
>        undertow.start();
>
> ….
>        final WebSocketDeploymentInfo deployment = new
> WebSocketDeploymentInfo();
>
>        try
>        {
>           final Xnio xnio = Xnio.getInstance("nio",
> Undertow.class.getClassLoader());
>           final XnioWorker xnioWorker =
> xnio.createWorker(OptionMap.builder().getMap());
>
>           deployment.setWorker(xnioWorker);
>           deployment.addEndpoint(simpleAnnotatedServerEndpoint.class);
> ….
>           final DeploymentManager deploymentManager =
> defaultContainer().addDeployment(deployment()
>              .setClassLoader(classLoader)
>              .setContextPath(prefixPath)
>              .setDeploymentName(prefixPath)
>              .addServletContextAttribute(ATTRIBUTE_NAME, deployment));
>           deploymentManager.deploy();
> .…
>           rootPath.addPrefixPath(prefixPath, deploymentManager.start());
>           deployments.put(prefixPath, deploymentManager);
>
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