m1k1o/neko · warning

unknown event type: %s

Error message

unknown event type: %s

What it means

wsToBackend translates legacy websocket events into new backend API calls via a large switch on header.Event. The default branch returns fmt.Errorf("unknown event type: %s", header.Event) for any event string that has no case, meaning the shim has no translation for it and the message is dropped.

Source

Thrown at server/internal/http/legacy/wstobackend.go:384

				"chat.can_send": false,
			},
		}, nil)

	case oldEvent.ADMIN_UNMUTE:
		request := &oldMessage.Admin{}
		err := json.Unmarshal(msg, request)
		if err != nil {
			return err
		}

		return s.apiReq(http.MethodPost, "/api/members/"+request.ID, map[string]any{
			"plugins": map[string]any{
				"chat.can_send": true,
			},
		}, nil)

	default:
		return fmt.Errorf("unknown event type: %s", header.Event)
	}
}

View on GitHub (pinned to b0f01cedea)

Solutions

1. Log header.Event to identify exactly which event string was rejected
2. Check whether the event is handled elsewhere in the new backend and route it there instead of through the legacy shim
3. Add a case for the event in wsToBackend that performs the equivalent backend API call or toBackend forwarding
4. Align the legacy client version with the protocol revision the shim supports

Example fix

// before
conn.send(JSON.stringify({event: "poll_create", ...}))
// after (supported legacy event)
conn.send(JSON.stringify({event: "chat", ...}))

var supportedEvents = map[string]bool{
	oldEvent.CHAT_MESSAGE: true, oldEvent.CHAT_EMOTE: true,
	oldEvent.SCREEN_RESOLUTION: true, oldEvent.ADMIN_LOCK: true,
	// ... full set of shim-supported legacy events
}
if !supportedEvents[header.Event] {
	log.Printf("event %q not supported by legacy shim, dropping", header.Event)
	return
}

func isLegacyEventSupported(event string) bool {
	_, ok := supportedEvents[event]
	return ok
}

if err := s.wsToBackend(msg); err != nil {
	var unknownErr = "unknown event type"
	if strings.Contains(err.Error(), unknownErr) {
		log.Printf("unhandled legacy event %q ignored", header.Event)
		return nil
	}
	return err
}

When it happens

Trigger: A legacy client sends a websocket message whose `event` field does not match any legacy event constant handled by wsToBackend — an unknown/renamed event, a message from a newer old-protocol version, or an event only supported natively by the new backend.

Common situations: Upgraded clients emitting events the legacy shim predates; typos in custom automation scripts sending raw websocket frames; two different clients speaking slightly different revisions of the old protocol against the same server.

Related errors

• unknown resource: %s
• cannot access clipboard
• is not the host
• ErrIsNotAllowedToHost
• ErrIsNotTheHost

AI-assisted analysis of m1k1o/neko@b0f01cedea (2026-09-01). Data as JSON: /api/errors/8382de35e943bfdb. Report an issue: GitHub.