myYouTube/backend/app/core/auth_dependency.py

from fastapi import HTTPException, Request

from app.services.sync_trigger import maybe_trigger_videos_sync


def require_session(request: Request) -> None:
    if not request.session.get("authenticated"):
        raise HTTPException(status_code=401, detail="Not authenticated")
    # Every authenticated request may trigger a background videos sync when it
    # is due (cheap check: lock + one app_settings row read).
    maybe_trigger_videos_sync()