zulip/zerver/lib/safe_session_cached_db.py

27 lines
1006 B
Python

from django.contrib.sessions.backends.cached_db import SessionStore as CachedDbSessionStore
from django.db.transaction import get_connection
from typing_extensions import override
class SessionStore(CachedDbSessionStore):
"""Caching session object which does not leak into the cache.
django.contrib.sessions.backends.cached_db does write-through to
the cache and the backing database. If the database is in a
transaction, this may leak not-yet-committed changes to the cache,
which can lead to inconsistent state. This class wraps changes to
the session in assertions which enforce that the database cannot
be in a transaction before writing.
"""
@override
def save(self, must_create: bool = False) -> None:
assert not get_connection().in_atomic_block
super().save(must_create)
@override
def delete(self, session_key: str | None = None) -> None:
assert not get_connection().in_atomic_block
super().delete(session_key)