细节优化

backend/app/main.py

@@ -18,7 +18,7 @@ from app.api.knowledge_bases import router as kb_router
 from app.public.routes import router as public_router
 from app.core.config import get_settings
 from app.core.db import dispose_engine, get_session_factory
-from app.core.errors import register_exception_handlers
+from app.core.errors import LinkExpiredError, register_exception_handlers
 from app.core.logging import get_logger, setup_logging
 
 logger = get_logger(__name__)
@@ -40,6 +40,43 @@ def _seed_free_plan() -> None:
             logger.debug("Free plan already exists (id=%s)", plan.id)
 
 
+def _cleanup_access_logs() -> int:
+    """清理超过保留期的访问日志。返回删除条数。"""
+    from datetime import datetime, timedelta
+
+    from sqlalchemy import delete
+
+    from app.core.config import get_settings
+    from app.models.access_log import AccessLog
+
+    settings = get_settings()
+    retention = settings.access_log_retention_days
+    if retention <= 0:
+        return 0
+
+    cutoff = (datetime.now() - timedelta(days=retention)).strftime("%Y-%m-%d %H:%M:%S")
+    factory = get_session_factory()
+    with factory() as session:
+        result = session.execute(delete(AccessLog).where(AccessLog.accessed_at < cutoff))
+        session.commit()
+        count = result.rowcount or 0
+        if count:
+            logger.info("已清理 %d 条过期访问日志（保留 %d 天）", count, retention)
+        return count
+
+
+async def _periodic_log_cleanup() -> None:
+    """每 24 小时清理一次过期访问日志（在线程池执行同步 DB 操作）。"""
+    import asyncio
+
+    while True:
+        await asyncio.sleep(24 * 3600)
+        try:
+            await asyncio.to_thread(_cleanup_access_logs)
+        except Exception:  # noqa: BLE001
+            logger.exception("定期清理访问日志失败")
+
+
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     settings = get_settings()
@@ -53,8 +90,18 @@ async def lifespan(app: FastAPI):
     # Seed：确保 free plan 存在
     _seed_free_plan()
 
+    # 启动时清理过期访问日志（不阻塞启动）
+    import asyncio
+
+    cleanup_task = asyncio.create_task(_periodic_log_cleanup())
+    try:
+        await asyncio.wait_for(asyncio.to_thread(_cleanup_access_logs), timeout=15)
+    except Exception:  # noqa: BLE001
+        logger.warning("启动时清理访问日志未完成（首次部署属正常）")
+
     yield
 
+    cleanup_task.cancel()
     dispose_engine()
     logger.info("Backend shutdown complete")
 
@@ -80,6 +127,11 @@ def create_app() -> FastAPI:
 
     register_exception_handlers(app)
 
+    # 链接过期：HTML 返回友好失效页，JSON/MD/TXT 返回对应格式（HTTP 410）
+    from app.public.routes import link_expired_handler
+
+    app.add_exception_handler(LinkExpiredError, link_expired_handler)
+
     # 路由挂载
     app.include_router(health_router, prefix="/api", tags=["health"])
     app.include_router(auth_router, prefix="/api", tags=["auth"])