etesync-server/etebase_fastapi/routers/websocket.py

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import asyncio
import typing as t
import aioredis
from asgiref.sync import sync_to_async
from django.db.models import QuerySet
from fastapi import APIRouter, Depends, WebSocket, WebSocketDisconnect, status
import nacl.encoding
import nacl.utils
from django_etebase import models
from django_etebase.utils import CallbackContext, get_user_queryset
from myauth.models import UserType, get_typed_user_model
from ..dependencies import get_collection_queryset, get_item_queryset
from ..exceptions import NotSupported
from ..msgpack import MsgpackRoute, msgpack_decode, msgpack_encode
from ..redis import redisw
from ..utils import BaseModel, permission_responses
User = get_typed_user_model()
websocket_router = APIRouter(route_class=MsgpackRoute, responses=permission_responses)
CollectionQuerySet = QuerySet[models.Collection]
TICKET_VALIDITY_SECONDS = 10
class TicketRequest(BaseModel):
collection: str
class TicketOut(BaseModel):
ticket: str
class TicketInner(BaseModel):
user: int
req: TicketRequest
async def get_ticket(
ticket_request: TicketRequest,
user: UserType,
):
"""Get an authentication ticket that can be used with the websocket endpoint for authentication"""
if not redisw.is_active:
raise NotSupported(detail="This end-point requires Redis to be configured")
uid = nacl.encoding.URLSafeBase64Encoder.encode(nacl.utils.random(32))
ticket_model = TicketInner(user=user.id, req=ticket_request)
ticket_raw = msgpack_encode(ticket_model.dict())
await redisw.redis.set(uid, ticket_raw, expire=TICKET_VALIDITY_SECONDS * 1000)
return TicketOut(ticket=uid)
async def load_websocket_ticket(websocket: WebSocket, ticket: str) -> t.Optional[TicketInner]:
content = await redisw.redis.get(ticket)
if content is None:
await websocket.close(code=status.WS_1008_POLICY_VIOLATION)
return None
await redisw.redis.delete(ticket)
return TicketInner(**msgpack_decode(content))
def get_websocket_user(websocket: WebSocket, ticket_model: t.Optional[TicketInner] = Depends(load_websocket_ticket)):
if ticket_model is None:
return None
user_queryset = get_user_queryset(User.objects.all(), CallbackContext(websocket.path_params))
return user_queryset.get(id=ticket_model.user)
@websocket_router.websocket("/{ticket}/")
async def websocket_endpoint(
websocket: WebSocket,
stoken: t.Optional[str] = None,
user: t.Optional[UserType] = Depends(get_websocket_user),
ticket_model: TicketInner = Depends(load_websocket_ticket),
):
if user is None:
return
await websocket.accept()
await redis_connector(websocket, ticket_model, user, stoken)
async def send_item_updates(
websocket: WebSocket,
collection: models.Collection,
user: UserType,
stoken: t.Optional[str],
):
from .collection import item_list_common
done = False
while not done:
queryset = await sync_to_async(get_item_queryset)(collection)
response = await sync_to_async(item_list_common)(queryset, user, stoken, limit=50, prefetch="auto")
done = response.done
if len(response.data) > 0:
await websocket.send_bytes(msgpack_encode(response.dict()))
async def redis_connector(websocket: WebSocket, ticket_model: TicketInner, user: UserType, stoken: t.Optional[str]):
async def producer_handler(r: aioredis.Redis, ws: WebSocket):
channel_name = f"col.{ticket_model.req.collection}"
(channel,) = await r.psubscribe(channel_name)
assert isinstance(channel, aioredis.Channel)
# Send missing items if we are not up to date
queryset: QuerySet[models.Collection] = get_collection_queryset(user)
collection: t.Optional[models.Collection] = await sync_to_async(
queryset.filter(uid=ticket_model.req.collection).first
)()
if collection is None:
await websocket.close(code=status.WS_1008_POLICY_VIOLATION)
return
await send_item_updates(websocket, collection, user, stoken)
try:
while True:
# We wait on the websocket so we fail if web sockets fail or get data
receive = asyncio.create_task(websocket.receive())
done, pending = await asyncio.wait(
{receive, channel.wait_message()}, return_when=asyncio.FIRST_COMPLETED
)
for task in pending:
task.cancel()
if receive in done:
# Web socket should never receieve any data
await websocket.close(code=status.WS_1008_POLICY_VIOLATION)
return
message_raw = t.cast(t.Optional[t.Tuple[str, bytes]], await channel.get())
if message_raw:
_, message = message_raw
await ws.send_bytes(message)
except aioredis.errors.ConnectionClosedError:
await websocket.close(code=status.WS_1012_SERVICE_RESTART)
except WebSocketDisconnect:
pass
redis = redisw.redis
await producer_handler(redis, websocket)