Keep notification counts and stopwatches in sync when tabs open or
reconnect, closing the gap behind [this
flake](https://github.com/go-gitea/gitea/actions/runs/31312525323/job/93242429394).
1. Send current notification counts and stopwatch state on each
WebSocket connection, replacing the separate state fetches tabs made on
every connect.
2. Tabs joining an already open connection fetch current state once,
since its snapshot went out before they attached.
3. Send events queued during the handshake before the snapshot, so older
events can't roll it back.
4. Wait for the Redis SUBSCRIBE acknowledgement, so the snapshot read
after subscribing can't miss an event.
* Closes#36942
* Fixes#19265
Replaces the SSE-based push channel (`/user/events`) with a WebSocket
endpoint (`/-/ws`).
### What changes
- **New `/-/ws` endpoint** (authenticated). One WebSocket per origin,
shared across tabs via a single `SharedWorker`.
- **Pubsub broker** (`services/pubsub`) for fan-out by topic, behind a
`Broker` interface. `MemoryBroker` is the default (single process); a
Redis backend is available for multi-process setups, configured via
`[websocket].PUBSUB_TYPE` / `PUBSUB_CONN_STR`. The internal Gitea queue
was not usable here because it has FIFO/single-consumer semantics.
- **Push-only event production.** Events are emitted by write-triggered
notifiers — `NotificationCountChange`, `PublishStopwatchesForUser`, and
the logout publisher — wired into the existing `notify.Notifier`
interface. No server-side pollers.
- **Typed pub/sub on the client.** `web_src/js/modules/worker.ts` is a
singleton transport; features subscribe per event type via
`onUserEvent('notification-count', cb)` instead of branching on
`event.data.type`.
- **Wire contract** (`UserEventType` union) is shared between the worker
and consumers via `web_src/js/types.ts`, kept in sync with
`services/websocket/events.go`.
- **Client-side periodic polling fallback** kicks in only when the
WebSocket cannot be established (e.g. proxy blocks WS, browser lacks
module-SharedWorker support).
### What's removed
- `modules/eventsource` (SSE manager, run loop, messenger).
- `/user/events` route and `tests/integration/eventsource_test.go`.
- All server-side polling for stopwatches and notification counts.
### Stopwatch multi-tab fix
The navbar stopwatch icon was previously rendered conditionally on `{{if
$activeStopwatch}}`, so tabs loaded before the timer started had no DOM
element to update. The icon and popup are now always rendered (toggled
with `tw-hidden`), and the start/stop/cancel handlers POST silently so
all open tabs reflect the change in real time.
### Deployment note
WebSocket needs the upgrade headers to pass through a reverse proxy,
e.g. for nginx:
```nginx
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
```
Without them the WebSocket cannot be established, and after 3
consecutive failed opens the shared worker signals `push-unavailable`:
the notification count and stopwatch fall back to periodic polling on
the existing `[ui.notification]` timeouts. Real-time push is lost, the
features keep working. The reverse-proxy docs need the same note (see
the `docs-update-needed` label).
---------
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Epid <rexmrj@gmail.com>
Part of #27065
This PR touches functions used in templates. As templates are not static
typed, errors are harder to find, but I hope I catch it all. I think
some tests from other persons do not hurt.
silverwind