支持 MySQL 迁移与性能优化

web/backend/database.py

@@ -2,13 +2,48 @@
 
 import os
 from pathlib import Path
+from urllib.parse import quote_plus
+
 from sqlalchemy import create_engine, event
 from sqlalchemy.orm import sessionmaker, declarative_base
 
 PROJECT_ROOT = Path(__file__).resolve().parents[2]
 DB_PATH = PROJECT_ROOT / "data" / "web.db"
 DB_PATH.parent.mkdir(parents=True, exist_ok=True)
-DATABASE_URL = os.getenv("DATABASE_URL", f"sqlite:///{DB_PATH}")
+
+
+def _env_int(name: str, default: int) -> int:
+    """读取正整数环境变量，非法值回退到默认值。"""
+    try:
+        value = int(os.getenv(name, str(default)))
+    except ValueError:
+        return default
+    return value if value > 0 else default
+
+
+def _get_database_url() -> str:
+    """优先使用完整连接串，否则按 DB_* 环境变量构造 MySQL 连接。"""
+    database_url = os.getenv("DATABASE_URL", "").strip()
+    if database_url:
+        return database_url
+
+    db_host = os.getenv("DB_HOST", "").strip()
+    if db_host:
+        db_port = _env_int("DB_PORT", 3306)
+        db_name = os.getenv("DB_NAME", "douyu_login").strip()
+        db_user = os.getenv("DB_USER", "douyu_login").strip()
+        db_password = os.getenv("DB_PASSWORD", "")
+        if not db_name or not db_user or not db_password:
+            raise RuntimeError("使用 DB_HOST 时必须同时设置 DB_NAME、DB_USER 和 DB_PASSWORD")
+        return (
+            f"mysql+pymysql://{quote_plus(db_user)}:{quote_plus(db_password)}"
+            f"@{db_host}:{db_port}/{db_name}?charset=utf8mb4"
+        )
+
+    return f"sqlite:///{DB_PATH}"
+
+
+DATABASE_URL = _get_database_url()
 
 connect_args = (
     {"check_same_thread": False, "timeout": 30}
@@ -16,11 +51,20 @@ connect_args = (
     else {}
 )
 
-engine = create_engine(
-    DATABASE_URL,
-    connect_args=connect_args,
-    echo=False,
-)
+engine_options = {
+    "connect_args": connect_args,
+    "echo": False,
+}
+if not DATABASE_URL.startswith("sqlite"):
+    engine_options.update(
+        pool_pre_ping=True,
+        pool_size=_env_int("DB_POOL_SIZE", 20),
+        max_overflow=_env_int("DB_MAX_OVERFLOW", 20),
+        pool_timeout=_env_int("DB_POOL_TIMEOUT", 30),
+        pool_recycle=_env_int("DB_POOL_RECYCLE", 1800),
+    )
+
+engine = create_engine(DATABASE_URL, **engine_options)
 
 
 if DATABASE_URL.startswith("sqlite"):