Server stops pushing changes

[mperktold]

Description of the bug

Some of our users report cases where push stops working correctly. In these cases, changes to the UI are never pushed. Instead, only when the user triggers another event, the server sends the previous changes along the response to the new event.

In the browser console, there is no indication of any error regarding push:
console.log

We did logs like these on the server side:

Connection unexpectedly closed for resource c1ad1a97-61f2-4a6c-90cd-1298a83f80cb with transport WEBSOCKET

This happens mostly with notebook clients connected via WIFI, and more often when the client is busy also with other applications running and having opened multiple tabs of our application.

Expected behavior

When the push connection is lost, both client and server should notice and reconnect.

Minimal reproducible example

I don't have a reproducer, since the problem seems to depend very much on the environment and is hard to reproduce even in the environment we observe it the most.

Versions

• Vaadin / Flow version: 24.4.20
• Java version: Eclipse Temurin 21.0.5+11
• OS version: Windows 11
• Browser version (if applicable): Edge 131.0.2903