代码提交

app/core/database.py

@@ -0,0 +1,66 @@
+"""数据库引擎 / 会话 / 依赖注入 / 自动建库。"""
+
+from __future__ import annotations
+
+import logging
+from collections.abc import Generator
+
+from sqlalchemy import create_engine, text
+from sqlalchemy.engine import Engine
+from sqlalchemy.orm import Session, sessionmaker
+
+from app.core.config import settings
+
+logger = logging.getLogger(__name__)
+
+
+def _build_engine() -> Engine:
+    if settings.DB_DRIVER.startswith("sqlite"):
+        return create_engine(
+            settings.database_url,
+            echo=settings.DB_ECHO,
+            connect_args={"check_same_thread": False},
+        )
+    return create_engine(
+        settings.database_url,
+        echo=settings.DB_ECHO,
+        pool_size=settings.DB_POOL_SIZE,
+        pool_recycle=settings.DB_POOL_RECYCLE,
+        pool_pre_ping=True,
+        future=True,
+    )
+
+
+engine: Engine = _build_engine()
+SessionLocal = sessionmaker(bind=engine, autocommit=False, autoflush=False, class_=Session)
+
+
+def ensure_database_exists() -> None:
+    """MySQL 下若目标库不存在则自动创建，省去手工建库。"""
+    if settings.DB_DRIVER.startswith("sqlite"):
+        return
+    root_engine = create_engine(settings.server_url_without_db, future=True)
+    try:
+        with root_engine.connect() as conn:
+            conn.execute(
+                text(
+                    f"CREATE DATABASE IF NOT EXISTS `{settings.DB_NAME}` "
+                    f"DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci"
+                )
+            )
+            conn.commit()
+    finally:
+        root_engine.dispose()
+
+
+def get_db() -> Generator[Session, None, None]:
+    """FastAPI 依赖：每个请求一个会话，结束即关闭。"""
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()
+
+
+def dialect_name() -> str:
+    return engine.dialect.name