Files
Sith/counter/middleware.py
T

67 lines
2.3 KiB
Python

from typing import TYPE_CHECKING, Callable
from django.http import HttpRequest, HttpResponse
from django.utils.functional import SimpleLazyObject
from core.models import User
from counter.models import Permanency
if TYPE_CHECKING:
from django.contrib.sessions.backends.base import SessionBase
SESSION_PERMANENCES_KEY = "permanence_ids"
def get_cached_barmen(request: HttpRequest) -> set[User]:
if not hasattr(request, "_cached_barmen"):
session: SessionBase = request.session
if session_ids := session.get(SESSION_PERMANENCES_KEY, None):
# Get ongoing permanences which id is in session.
# Note : we store permanence ids rather than user id to be sure
# not to wrongfully mark someone as logged here,
# even if it logged out then logged in elsewhere.
permanences = (
Permanency.objects.filter(end=None, id__in=session_ids)
.order_by("id")
.select_related("user")
)
# if the list of permanences occurring on this device has changed
# since the last page load, change the ids stored in session
real_ids = [p.id for p in permanences]
if real_ids != session_ids:
session[SESSION_PERMANENCES_KEY] = real_ids
request._cached_barmen = {p.user for p in permanences}
else:
request._cached_barmen = set()
return request._cached_barmen
class BarmenMiddleware:
"""Inject barmen logged in the current session.
In a similar fashion as `request.user`, `request.barmen` contains
users that are barmen in the current session, and ONLY them ;
if a user is logged as a barman on another session,
it will not be in `request.barmen`.
Notes:
In case of ended permanence, users will be automatically
removed from `request.barmen`.
However, in case of newly started permanence, this middleware
cannot add new barmen in the session data, so that operation
must be explicitly done in the barman login view.
"""
def __init__(self, get_response: Callable[[HttpRequest], HttpResponse]):
self.get_response = get_response
def __call__(self, request: HttpRequest):
request.barmen = SimpleLazyObject(lambda: get_cached_barmen(request))
return self.get_response(request)