fix: 添加受限的 __import__ 函数支持白名单模块导入

解决脚本执行时 KeyError: '__import__' 错误

backend/app/services/script_executor.py

@@ -156,9 +156,30 @@ class ScriptExecutor:
         import random
         import hashlib
         import base64
+        import time
+        import collections
         from datetime import datetime, date, timedelta
         from urllib.parse import urlencode, quote, unquote
         
+        # 允许导入的模块白名单
+        ALLOWED_MODULES = {
+            'json': json,
+            're': re,
+            'math': math,
+            'random': random,
+            'hashlib': hashlib,
+            'base64': base64,
+            'time': time,
+            'datetime': __import__('datetime'),
+            'collections': collections,
+        }
+        
+        def safe_import(name, globals=None, locals=None, fromlist=(), level=0):
+            """受限的 import 函数"""
+            if name in ALLOWED_MODULES:
+                return ALLOWED_MODULES[name]
+            raise ImportError(f"不允许导入模块: {name}。已内置可用: {', '.join(ALLOWED_MODULES.keys())}")
+        
         # 安全的内置函数
         safe_builtins = {name: getattr(__builtins__, name, None) 
                         for name in ALLOWED_BUILTINS 
@@ -170,12 +191,16 @@ class ScriptExecutor:
                            for name in ALLOWED_BUILTINS 
                            if name in __builtins__}
         
+        # 添加受限的 __import__
+        safe_builtins['__import__'] = safe_import
+        
         # 添加常用异常
         safe_builtins['Exception'] = Exception
         safe_builtins['ValueError'] = ValueError
         safe_builtins['TypeError'] = TypeError
         safe_builtins['KeyError'] = KeyError
         safe_builtins['IndexError'] = IndexError
+        safe_builtins['ImportError'] = ImportError
         
         return {
             '__builtins__': safe_builtins,
@@ -215,6 +240,7 @@ class ScriptExecutor:
             'datetime': datetime,
             'date': date,
             'timedelta': timedelta,
+            'time': time,
             'urlencode': urlencode,
             'quote': quote,
             'unquote': unquote,