Lukas
d931e8c6a3
- Cache setup_completed flag in app.state._setup_complete_cached after first successful is_setup_complete() call; all subsequent API requests skip the DB query entirely (one-way transition, cleared on restart). - Add in-memory session token TTL cache (10 s) in require_auth; the second request with the same token within the window skips session_repo.get_session. - Call invalidate_session_cache() on logout so revoked tokens are evicted immediately rather than waiting for TTL expiry. - Add clear_session_cache() for test isolation. - 5 new tests covering the cached fast-path for both optimisations. - 460 tests pass, 83% coverage, zero ruff/mypy warnings.
157 lines
5.1 KiB
Python
157 lines
5.1 KiB
Python
"""FastAPI dependency providers.
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All ``Depends()`` callables that inject shared resources (database
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connection, settings, services, auth guard) are defined here.
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Routers import directly from this module — never from ``app.state``
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directly — to keep coupling explicit and testable.
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"""
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import time
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from typing import Annotated
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import aiosqlite
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import structlog
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from fastapi import Depends, HTTPException, Request, status
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from app.config import Settings
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from app.models.auth import Session
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from app.utils.time_utils import utc_now
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log: structlog.stdlib.BoundLogger = structlog.get_logger()
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_COOKIE_NAME = "bangui_session"
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# ---------------------------------------------------------------------------
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# Session validation cache
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# ---------------------------------------------------------------------------
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#: How long (seconds) a validated session token is served from the in-memory
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#: cache without re-querying SQLite. Eliminates repeated DB lookups for the
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#: same token arriving in near-simultaneous parallel requests.
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_SESSION_CACHE_TTL: float = 10.0
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#: ``token → (Session, cache_expiry_monotonic_time)``
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_session_cache: dict[str, tuple[Session, float]] = {}
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def clear_session_cache() -> None:
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"""Flush the entire in-memory session validation cache.
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Useful in tests to prevent stale state from leaking between test cases.
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"""
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_session_cache.clear()
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def invalidate_session_cache(token: str) -> None:
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"""Evict *token* from the in-memory session cache.
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Must be called during logout so the revoked token is no longer served
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from cache without a DB round-trip.
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Args:
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token: The session token to remove.
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"""
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_session_cache.pop(token, None)
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async def get_db(request: Request) -> aiosqlite.Connection:
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"""Provide the shared :class:`aiosqlite.Connection` from ``app.state``.
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Args:
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request: The current FastAPI request (injected automatically).
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Returns:
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The application-wide aiosqlite connection opened during startup.
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Raises:
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HTTPException: 503 if the database has not been initialised.
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"""
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db: aiosqlite.Connection | None = getattr(request.app.state, "db", None)
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if db is None:
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log.error("database_not_initialised")
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raise HTTPException(
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status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
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detail="Database is not available.",
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)
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return db
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async def get_settings(request: Request) -> Settings:
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"""Provide the :class:`~app.config.Settings` instance from ``app.state``.
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Args:
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request: The current FastAPI request (injected automatically).
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Returns:
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The application settings loaded at startup.
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"""
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return request.app.state.settings # type: ignore[no-any-return]
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async def require_auth(
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request: Request,
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db: Annotated[aiosqlite.Connection, Depends(get_db)],
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) -> Session:
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"""Validate the session token and return the active session.
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The token is read from the ``bangui_session`` cookie or the
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``Authorization: Bearer`` header.
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Validated tokens are cached in memory for :data:`_SESSION_CACHE_TTL`
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seconds so that concurrent requests sharing the same token avoid repeated
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SQLite round-trips. The cache is bypassed on expiry and explicitly
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cleared by :func:`invalidate_session_cache` on logout.
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Args:
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request: The incoming FastAPI request.
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db: Injected aiosqlite connection.
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Returns:
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The active :class:`~app.models.auth.Session`.
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Raises:
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HTTPException: 401 if no valid session token is found.
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"""
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from app.services import auth_service # noqa: PLC0415
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token: str | None = request.cookies.get(_COOKIE_NAME)
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if not token:
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auth_header: str = request.headers.get("Authorization", "")
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if auth_header.startswith("Bearer "):
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token = auth_header[len("Bearer "):]
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if not token:
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raise HTTPException(
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status_code=status.HTTP_401_UNAUTHORIZED,
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detail="Authentication required.",
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headers={"WWW-Authenticate": "Bearer"},
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)
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# Fast path: serve from in-memory cache when the entry is still fresh and
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# the session itself has not yet exceeded its own expiry time.
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cached = _session_cache.get(token)
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if cached is not None:
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session, cache_expires_at = cached
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if time.monotonic() < cache_expires_at and session.expires_at > utc_now().isoformat():
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return session
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# Stale cache entry — evict and fall through to DB.
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_session_cache.pop(token, None)
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try:
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session = await auth_service.validate_session(db, token)
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except ValueError as exc:
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raise HTTPException(
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status_code=status.HTTP_401_UNAUTHORIZED,
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detail=str(exc),
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headers={"WWW-Authenticate": "Bearer"},
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) from exc
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_session_cache[token] = (session, time.monotonic() + _SESSION_CACHE_TTL)
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return session
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# Convenience type aliases for route signatures.
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DbDep = Annotated[aiosqlite.Connection, Depends(get_db)]
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SettingsDep = Annotated[Settings, Depends(get_settings)]
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AuthDep = Annotated[Session, Depends(require_auth)]
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