Files
ds-chat/backend/app/ws/focus_presence.py
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ksmithandClaude Sonnet 5.5 dda85a2b78 Expire presence so users can't get stuck online (#77)
Presence was a per-user refcount in Redis, decremented only when a
connection's cleanup ran. Anything that ended a connection without
cleanup (a crash, an unclean restart, a laptop asleep with the page
frozen) leaked its count forever, so those users never showed offline.
Production had 19 counts for 2 live connections.

Presence is now one expiring entry per connection (90s TTL) for global,
per-room and focus presence, in new presence:v2:* keys. Clients renew
theirs by sending any frame, which the existing 30s ping/pong already
does. The server closes a human connection that sends nothing for 90s
(code 4408), which catches a frozen page whose browser still answers
transport pings. Bot connections can't be expected to answer pings, so
the server renews theirs itself while the handler is alive.

An expiry has no disconnect event to announce it, so a sweeper on each
worker (one per 15s overall, via a Redis lock) prunes expired entries
and broadcasts the offline transition. The old presence:* hashes are
deleted at startup.

Tests cover the expiry store, the sweeper, and the websocket cases.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
2026-10-13 19:21:39 -06:00

47 lines
2.0 KiB
Python

import uuid
from redis.asyncio import Redis
from app.ws.expiring_presence import ExpiringPresenceSet
class FocusPresence:
"""Cross-instance "is this desktop-mode user's window currently
unfocused," used only to widen desktop_notification/push eligibility
beyond plain room-connection state (#59). One expiring entry per
currently-blurred desktop connection (see ExpiringPresenceSet),
parallel to Presence/GlobalPresence.
Absence from the set is the default and means "focused." That default
is also exactly right for every browser-tab connection: only the
desktop client ever sends focus/blur frames at all (see chat.py's
"focus" envelope handling), so a browser user never appears here --
their attention is already fully captured by Presence's room-connection
state, which stays visibility-gated with no separate focus signal.
Same known simplification as before: two desktop windows for one user,
one focused and one blurred, count as "unfocused" (any live blurred
entry) even though the user does have attention somewhere. That errs
toward notifying rather than silently missing one, which is the safer
failure mode for a notification. Entries expire (#77) -- a desktop
window that died while blurred used to leave its user "unfocused"
forever.
"""
KEY = "presence:v2:unfocused"
def __init__(self, redis: Redis, store: ExpiringPresenceSet | None = None) -> None:
self._store = store or ExpiringPresenceSet(redis)
async def mark_blurred(self, user_id: uuid.UUID, conn_id: str) -> None:
await self._store.add(self.KEY, user_id, conn_id)
async def mark_focused(self, user_id: uuid.UUID, conn_id: str) -> None:
await self._store.remove(self.KEY, user_id, conn_id)
async def refresh(self, user_id: uuid.UUID, conn_id: str) -> None:
await self._store.add(self.KEY, user_id, conn_id)
async def is_unfocused(self, user_id: uuid.UUID) -> bool:
return await self._store.is_live(self.KEY, user_id)