Use Literal types for config field validation

Replaced manual string validation with Python's Literal type for 'client_type' in APIProvider and 'search_strategy' in WebSearchConfig. This simplifies validation and improves type safety by restricting allowed values at the type level.

src/config/api_ada_configs.py

@@ -1,4 +1,4 @@
-from typing import List, Dict, Any
+from typing import List, Dict, Any, Literal
 from pydantic import Field, field_validator
 
 from src.config.config_base import ValidatedConfigBase
@@ -10,7 +10,7 @@ class APIProvider(ValidatedConfigBase):
     name: str = Field(..., min_length=1, description="API提供商名称")
     base_url: str = Field(..., description="API基础URL")
     api_key: str = Field(..., min_length=1, description="API密钥")
-    client_type: str = Field(default="openai", description="客户端类型（如openai/google等，默认为openai）")
+    client_type: Literal["openai", "gemini", "aiohttp_gemini"] = Field(default="openai", description="客户端类型（如openai/google等，默认为openai）")
     max_retry: int = Field(default=2, ge=0, description="最大重试次数（单个模型API调用失败，最多重试的次数）")
     timeout: int = Field(default=10, ge=1, description="API调用的超时时长（超过这个时长，本次请求将被视为'请求超时'，单位：秒）")
     retry_interval: int = Field(default=10, ge=0, description="重试间隔（如果API调用失败，重试的间隔时间，单位：秒）")
@@ -33,15 +33,6 @@ class APIProvider(ValidatedConfigBase):
             raise ValueError("API密钥不能为空")
         return v
 
-    @field_validator('client_type')
-    @classmethod
-    def validate_client_type(cls, v):
-        """验证客户端类型"""
-        allowed_types = ["openai", "gemini","aiohttp_gemini"]
-        if v not in allowed_types:
-            raise ValueError(f"客户端类型必须是以下之一: {allowed_types}")
-        return v
-
     def get_api_key(self) -> str:
         return self.api_key
 

src/config/official_configs.py

@@ -618,7 +618,7 @@ class WebSearchConfig(ValidatedConfigBase):
     enable_web_search_tool: bool = Field(default=True, description="启用网络搜索工具")
     enable_url_tool: bool = Field(default=True, description="启用URL工具")
     enabled_engines: list[str] = Field(default_factory=lambda: ["ddg"], description="启用的搜索引擎")
-    search_strategy: str = Field(default="single", description="搜索策略")
+    search_strategy: Literal["fallback","single","parallel"] = Field(default="single", description="搜索策略")
 
 
 class AntiPromptInjectionConfig(ValidatedConfigBase):