86 lines
2.9 KiB
Python
86 lines
2.9 KiB
Python
from abc import ABC, abstractmethod
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from secrets import token_urlsafe
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from time import monotonic
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from typing import Any, Callable, Optional
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from ._session import Session
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class SessionStore(ABC):
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"""Pluggable backend for session persistence."""
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@abstractmethod
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async def load(self, session_id: str, max_age: Optional[int] = None) -> Optional[Session]:
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"""Load an existing session, or return ``None`` if unknown or expired.
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``max_age`` is the idle timeout in seconds. If provided, the store may
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use it to enforce a server-side expiry and to slide the expiry window
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on each access.
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"""
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pass
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@abstractmethod
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async def save(self, session_id: str, session: Session, max_age: Optional[int] = None) -> None:
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"""Persist the session data under ``session_id``.
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``max_age`` is the idle timeout in seconds. If provided, the store
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should record the expiry time as ``now + max_age``.
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"""
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pass
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@abstractmethod
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async def delete(self, session_id: str) -> None:
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"""Remove the session from the store."""
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pass
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def new_session_id(self) -> str:
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"""Return a new opaque session identifier.
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Subclasses may override this to use a backend-specific ID generator.
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"""
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return token_urlsafe(32)
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class InMemorySessionStore(SessionStore):
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"""Simple in-memory session store.
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Suitable for development and single-process deployments. Session data is
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lost when the process exits and is not shared between processes.
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Sessions can optionally expire server-side after ``max_age`` seconds of
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inactivity. Active sessions slide the expiry window on each access.
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"""
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def __init__(self, clock: Callable[[], float] = monotonic) -> None:
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self._clock = clock
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self._data: dict[str, dict[str, Any]] = {}
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self._expires: dict[str, float] = {}
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async def load(self, session_id: str, max_age: Optional[int] = None) -> Optional[Session]:
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data = self._data.get(session_id)
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if data is None:
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return None
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expires = self._expires.get(session_id)
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now = self._clock()
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if expires is not None and now > expires:
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self._data.pop(session_id, None)
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self._expires.pop(session_id, None)
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return None
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if max_age is not None and expires is not None:
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self._expires[session_id] = now + max_age
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return Session(session_id, data)
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async def save(self, session_id: str, session: Session, max_age: Optional[int] = None) -> None:
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self._data[session_id] = dict(session)
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if max_age is not None:
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self._expires[session_id] = self._clock() + max_age
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else:
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self._expires.pop(session_id, None)
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async def delete(self, session_id: str) -> None:
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self._data.pop(session_id, None)
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self._expires.pop(session_id, None)
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