zwave-js-ui, nginx, HA websocket issue

[kantlivelong]

This is a bit lengthy but here it goes...

I've got a seemingly weird issue with zwave-js-ui and nginx. For whatever reason the websocket connection only works if I CTRL+F5(no-cache reload). If I do a simple F5 refresh afterwards the websocket connection fails.

Digging into this further I've found that on a regular page load/refresh zwave-js-ui or socket.io is returning what seems to be bogus sid and it's always the same sid. If I no-cache refresh a valid sid is returned and the websocket session connects without issue.

I've checked the issue trackers for zwave-js-ui and socket.io as well as done some general web searching to see what I can find. From what I can tell my nginx config should be fine as it does work via CLI via wscat and does work on a no-cache reload.

My setup is pretty simple but is as follows

• zwave-js-ui is running inside a container on a raspberry pi with the dongle. Sitting along side it is another container running zigbee2mqtt with it's respective dongle.
• nginx is on the same subnet but running in another machine(VM)
• HA is also running in this environment but is on it's own VM.

Config: https://pastebin.com/YkytXi15

Checking the Firefox dev console on a regular load/reload I see the first request to socket.io via https://homeassistant.FQDN:8124/_/zwavejs2mqtt/socket.io/?EIO=4&transport=polling&t=OGVHQXK and it receives the response 0{"sid":"QHEjB7LIw5v_fO0rAAEl","upgrades":["websocket"],"pingInterval":25000,"pingTimeout":20000,"maxPayload":1000000}. The sid in this response is always the same.

When I no-cache reload I see the same initial connection but with a valid sid. I can verify the same behavior with curl

Mid ticket update:

So I've found that zwave-js-ui will work fine until I sign into HA. Once I sign into HA the problematic behavior occurs.

HA URL: https://homeassistant.FQDN:8124/
zwave-js-ui URL: https://homeassistant.FQDN:8124/_/zwavejs2mqtt/

I found that simply adding an extra port (8125) to the nginx config then connecting to zwave-js-ui works perfectly at the URL above until I sign into HA at the URL above.

Is there some sort of cookie or session storage collision going on here?

[robertsLando]

Never seen such kind of problems, just to be clear, are you speaking about the zwave-js UI websocket or the home hassistant websocket? Is your problem on the z-ui UI side or home assistant side?

[kantlivelong]

The UI Websocket. I have the HA websocket disabled.

[robertsLando]

At first sight it seems to me a cache problem in nginx configuration, I'm not an nginx expert but I know hass addon works without any problem (and it's using nginx) and I also have a working example using nginx

[AaronSeibert]

Your location / matches all requests, and you have websocket headers in there. If you don't need the websocket on / and only on the zigbee/hass/zwavejs parts can probably take it out of there.

FWIW, it may be easier to use a separate host header for each. Would make the configs easier to troubleshoot vs having child paths.

[kantlivelong]

So I've finally had some time to look into this a bit more. What I'm seeing is that the websocket connection is being routed to the appropriate backend(zwavejsui). I confirmed this by opening the UI and follow nginx logs. During the storm of HTTP 400 Session ID unknown errors I stopped zwavejsui and starting receiving HTTP 502s.

This brings me right back to the initial ticket where zwavejsui for whatever reason is providing an invalid sid.

[kantlivelong]

Okay wow this is REALLY weird....

I ran a packet capture on the host running zwavejsui and on the client desktop machine.

capture from host running zwavejsui:

zwavejsui returns sid -aj3FwnPgnv_OOZHAAj7

capture from desktop running firefox:

Also seeing sid -aj3FwnPgnv_OOZHAAj7

Now here's where it all falls on it's face.

Somehow the browser is reporting a different response!? What the...

[kantlivelong]

I've pinpointed the issue and opened a ticket with Home Assistant - Frontend. In short it's service-worker is caching any http responses with a status of 200. Since socket.io provides the session id in a response with status 200 the data is cached and the correct sid is never recieved by zwavejsui unless the browser is refreshed with the cache being cleared (Shift+F5)

home-assistant/frontend#14836

[robertsLando]

@kantlivelong Great finding! Let me know if there could be something to do on my side, keep me updated on this