I'm using Vaadin 7.1.2 on a OpenShift instance (RedHat).
OpenShift offers a node.js proxy which should be compatible with WebSocket, but the WebSocket connections get closed immediately after they have been open with no error message (Vaadin just display "connection closed", "wasclean:true", "reason:").
Because there is no error then Vaadin/Atmosphere doesn't fall back to the streaming mode and instead continues to open Websocket once every two seconds.
I'm looking for a way to disable websocket in Vaadin/atmosphere altogether and enable streaming instead.
You can disable websockets and enforce streaming by using the following annotation in your UI class:
@Push(transport = Transport.STREAMING)
public class PushUI extends UI {
...
}