fix: 覆写规则条件可使用映射前请求体

新增 rules_original_body 参数贯穿请求构建链路，确保 body_rules/header_rules
条件评估使用模型映射前的原始请求体；附带将 handlers __init__ 改为延迟导入。

Closes #255

Co-authored-by: hemo94931 <[email protected]>

src/api/handlers/__init__.py

@@ -14,11 +14,9 @@ API Handlers - 请求处理器
 注意：Handler 基类和具体 Handler 使用延迟导入以避免循环依赖。
 """
 
-# Adapter 基类（不会引起循环导入，可以直接导入）
+from __future__ import annotations
-from src.api.handlers.base import (
+
-    ChatAdapterBase,
+from typing import Any
-    CliAdapterBase,
-)
 
 __all__ = [
     # Adapter 基类
@@ -49,6 +47,9 @@ __all__ = [
 
 # 延迟导入映射表
 _LAZY_IMPORTS = {
+    # Adapter 基类
+    "ChatAdapterBase": ("src.api.handlers.base.chat_adapter_base", "ChatAdapterBase"),
+    "CliAdapterBase": ("src.api.handlers.base.cli_adapter_base", "CliAdapterBase"),
     # Handler 基类
     "ChatHandlerBase": ("src.api.handlers.base.chat_handler_base", "ChatHandlerBase"),
     "CliMessageHandlerBase": (
@@ -88,7 +89,7 @@ _LAZY_IMPORTS = {
 }
 
 
-def __getattr__(name: str) -> None:
+def __getattr__(name: str) -> Any:
     """延迟导入以避免循环依赖"""
     if name in _LAZY_IMPORTS:
         module_path, attr_name = _LAZY_IMPORTS[name]

src/api/handlers/base/__init__.py

@@ -8,39 +8,9 @@ Handler 基类模块
 会形成循环导入。请直接从具体模块导入 Handler 基类。
 """
 
-# Chat Adapter 基类（不会引起循环导入）
+from __future__ import annotations
-from src.api.handlers.base.chat_adapter_base import (
-    ChatAdapterBase,
-    get_adapter_class,
-    get_adapter_instance,
-    list_registered_formats,
-    register_adapter,
-)
 
-# CLI Adapter 基类
+from typing import Any
-from src.api.handlers.base.cli_adapter_base import (
-    CliAdapterBase,
-    get_cli_adapter_class,
-    get_cli_adapter_instance,
-    list_registered_cli_formats,
-    register_cli_adapter,
-)
-
-# 请求构建器
-from src.api.handlers.base.request_builder import (
-    SENSITIVE_HEADERS,
-    PassthroughRequestBuilder,
-    RequestBuilder,
-    build_passthrough_request,
-)
-
-# 响应解析器
-from src.api.handlers.base.response_parser import (
-    ParsedChunk,
-    ParsedResponse,
-    ResponseParser,
-    StreamStats,
-)
 
 __all__ = [
     # Chat Adapter
@@ -66,3 +36,60 @@ __all__ = [
     "ParsedResponse",
     "StreamStats",
 ]
+
+_LAZY_IMPORTS: dict[str, tuple[str, str]] = {
+    # Chat Adapter
+    "ChatAdapterBase": ("src.api.handlers.base.chat_adapter_base", "ChatAdapterBase"),
+    "register_adapter": ("src.api.handlers.base.chat_adapter_base", "register_adapter"),
+    "get_adapter_class": ("src.api.handlers.base.chat_adapter_base", "get_adapter_class"),
+    "get_adapter_instance": ("src.api.handlers.base.chat_adapter_base", "get_adapter_instance"),
+    "list_registered_formats": (
+        "src.api.handlers.base.chat_adapter_base",
+        "list_registered_formats",
+    ),
+    # CLI Adapter
+    "CliAdapterBase": ("src.api.handlers.base.cli_adapter_base", "CliAdapterBase"),
+    "register_cli_adapter": (
+        "src.api.handlers.base.cli_adapter_base",
+        "register_cli_adapter",
+    ),
+    "get_cli_adapter_class": (
+        "src.api.handlers.base.cli_adapter_base",
+        "get_cli_adapter_class",
+    ),
+    "get_cli_adapter_instance": (
+        "src.api.handlers.base.cli_adapter_base",
+        "get_cli_adapter_instance",
+    ),
+    "list_registered_cli_formats": (
+        "src.api.handlers.base.cli_adapter_base",
+        "list_registered_cli_formats",
+    ),
+    # 请求构建器
+    "RequestBuilder": ("src.api.handlers.base.request_builder", "RequestBuilder"),
+    "PassthroughRequestBuilder": (
+        "src.api.handlers.base.request_builder",
+        "PassthroughRequestBuilder",
+    ),
+    "build_passthrough_request": (
+        "src.api.handlers.base.request_builder",
+        "build_passthrough_request",
+    ),
+    "SENSITIVE_HEADERS": ("src.api.handlers.base.request_builder", "SENSITIVE_HEADERS"),
+    # 响应解析器
+    "ResponseParser": ("src.api.handlers.base.response_parser", "ResponseParser"),
+    "ParsedChunk": ("src.api.handlers.base.response_parser", "ParsedChunk"),
+    "ParsedResponse": ("src.api.handlers.base.response_parser", "ParsedResponse"),
+    "StreamStats": ("src.api.handlers.base.response_parser", "StreamStats"),
+}
+
+
+def __getattr__(name: str) -> Any:
+    """延迟导入以避免不必要的依赖加载。"""
+    if name in _LAZY_IMPORTS:
+        module_path, attr_name = _LAZY_IMPORTS[name]
+        import importlib
+
+        module = importlib.import_module(module_path)
+        return getattr(module, attr_name)
+    raise AttributeError(f"module {__name__!r} has no attribute {name!r}")

src/api/handlers/base/chat_handler_base.py

@@ -932,6 +932,7 @@ class ChatHandlerBase(BaseMessageHandler, ABC):
             endpoint,
             key,
             is_stream=upstream_is_stream,
+            rules_original_body=working_request_body,
             extra_headers=prep.extra_headers if prep.extra_headers else None,
             pre_computed_auth=auth_info.as_tuple() if auth_info else None,
             envelope=envelope,

src/api/handlers/base/chat_sync_executor.py

@@ -452,13 +452,14 @@ class ChatSyncExecutor:
         provider_api_format = str(endpoint.api_format or api_format)
         client_api_format = api_format.value if hasattr(api_format, "value") else str(api_format)
 
+        attempt_body = request_state.build_attempt_body()
         # 构建 Provider 请求（模型映射、格式转换、envelope 包装）
         prep = await handler._prepare_provider_request(
             model=model,
             provider=provider,
             endpoint=endpoint,
             key=key,
-            working_request_body=request_state.build_attempt_body(),
+            working_request_body=attempt_body,
             original_headers=original_headers,
             client_api_format=client_api_format,
             provider_api_format=provider_api_format,
@@ -487,6 +488,7 @@ class ChatSyncExecutor:
             endpoint,
             key,
             is_stream=upstream_is_stream,
+            rules_original_body=attempt_body,
             extra_headers=prep.extra_headers if prep.extra_headers else None,
             pre_computed_auth=auth_info.as_tuple() if auth_info else None,
             envelope=envelope,

src/api/handlers/base/cli_protocol.py

@@ -188,6 +188,7 @@ class CliHandlerProtocol(Protocol):
         endpoint: Any,
         key: Any,
         request_body: dict[str, Any],
+        rules_original_body: dict[str, Any] | None = ...,
         original_headers: dict[str, str],
         query_params: dict[str, str] | None,
         client_api_format: str,

src/api/handlers/base/cli_request_mixin.py

@@ -199,6 +199,7 @@ class CliRequestMixin:
         endpoint: Any,
         key: Any,
         request_body: dict[str, Any],
+        rules_original_body: dict[str, Any] | None = None,
         original_headers: dict[str, str],
         query_params: dict[str, str] | None,
         client_api_format: str,
@@ -319,6 +320,7 @@ class CliRequestMixin:
             endpoint,
             key,
             is_stream=upstream_is_stream,
+            rules_original_body=rules_original_body,
             extra_headers=extra_headers if extra_headers else None,
             pre_computed_auth=auth_info.as_tuple() if auth_info else None,
             envelope=envelope,

src/api/handlers/base/cli_stream_mixin.py

@@ -318,6 +318,7 @@ class CliStreamMixin:
             endpoint=endpoint,
             key=key,
             request_body=request_body,
+            rules_original_body=working_request_body,
             original_headers=original_headers,
             query_params=query_params,
             client_api_format=client_api_format,

src/api/handlers/base/cli_sync_mixin.py

@@ -120,7 +120,8 @@ class CliSyncMixin:
                     provider_id=str(provider.id),
                 )
 
-            request_body = request_state.build_attempt_body()
+            attempt_body = request_state.build_attempt_body()
+            request_body = attempt_body
             if mapped_model:
                 mapped_model_result = mapped_model  # 保存映射后的模型名，用于 Usage 记录
                 request_body = self.apply_mapped_model(request_body, mapped_model)
@@ -135,6 +136,7 @@ class CliSyncMixin:
                 endpoint=endpoint,
                 key=key,
                 request_body=request_body,
+                rules_original_body=attempt_body,
                 original_headers=original_headers,
                 query_params=query_params,
                 client_api_format=client_api_format,

src/api/handlers/base/request_builder.py

@@ -1140,6 +1140,7 @@ class RequestBuilder(ABC):
         envelope: ProviderEnvelope | None = None,
         body: dict[str, Any] | None = None,
         original_body: dict[str, Any] | None = None,
+        rules_original_body: dict[str, Any] | None = None,
     ) -> dict[str, str]:
         """构建请求头"""
         pass
@@ -1151,6 +1152,7 @@ class RequestBuilder(ABC):
         endpoint: Any,
         key: Any,
         *,
+        rules_original_body: dict[str, Any] | None = None,
         mapped_model: str | None = None,
         is_stream: bool = False,
         extra_headers: dict[str, str] | None = None,
@@ -1166,6 +1168,7 @@ class RequestBuilder(ABC):
             original_headers: 原始请求头
             endpoint: 端点配置
             key: Provider API Key
+            rules_original_body: 规则条件评估用的“原始请求体”（如模型映射前的请求体）；不传则使用 original_body
             mapped_model: 映射后的模型名
             is_stream: 是否为流式请求
             extra_headers: 额外请求头
@@ -1175,6 +1178,9 @@ class RequestBuilder(ABC):
         Returns:
             Tuple[payload, headers]
         """
+        effective_rules_original_body = (
+            rules_original_body if rules_original_body is not None else original_body
+        )
         payload = self.build_payload(
             original_body,
             mapped_model=mapped_model,
@@ -1187,7 +1193,7 @@ class RequestBuilder(ABC):
             payload = apply_body_rules(
                 payload,
                 body_rules,
-                original_body=original_body,
+                original_body=effective_rules_original_body,
             )
 
         effective_provider_api_format = provider_api_format or getattr(endpoint, "api_format", None)
@@ -1209,6 +1215,7 @@ class RequestBuilder(ABC):
             envelope=envelope,
             body=payload,
             original_body=original_body,
+            rules_original_body=effective_rules_original_body,
         )
         return payload, headers
 
@@ -1314,6 +1321,7 @@ class PassthroughRequestBuilder(RequestBuilder):
         envelope: ProviderEnvelope | None = None,
         body: dict[str, Any] | None = None,
         original_body: dict[str, Any] | None = None,
+        rules_original_body: dict[str, Any] | None = None,
     ) -> dict[str, str]:
         """
         透传请求头 - 清理敏感头部（黑名单），透传其他所有头部
@@ -1325,6 +1333,8 @@ class PassthroughRequestBuilder(RequestBuilder):
             extra_headers: 额外请求头
             pre_computed_auth: 预先计算的认证信息 (auth_header, auth_value)，
                                用于 Service Account 等异步获取 token 的场景
+            original_body: 原始请求体（对应 build() 的 original_body）
+            rules_original_body: 规则条件评估用的“原始请求体”（如模型映射前的请求体）；不传则使用 original_body
         """
         raw_family = getattr(endpoint, "api_family", None)
         raw_kind = getattr(endpoint, "endpoint_kind", None)
@@ -1366,7 +1376,9 @@ class PassthroughRequestBuilder(RequestBuilder):
                 header_rules,
                 protected_keys,
                 body=body,
-                original_body=original_body,
+                original_body=rules_original_body
+                if rules_original_body is not None
+                else original_body,
                 condition_evaluator=evaluate_condition,
             )
 

tests/unit/test_request_builder_rules_original_body.py

@@ -0,0 +1,60 @@
+from types import SimpleNamespace
+
+from src.api.handlers.base.request_builder import PassthroughRequestBuilder
+
+
+def test_passthrough_request_builder_rules_original_body_drives_conditions() -> None:
+    """
+    When model mapping mutates the outbound body, body/header rules should still be
+    able to evaluate conditions against the pre-mapping payload via `source=original`.
+    """
+    builder = PassthroughRequestBuilder()
+
+    endpoint = SimpleNamespace(
+        api_family="openai",
+        endpoint_kind="chat",
+        body_rules=[
+            {
+                "action": "set",
+                "path": "route",
+                "value": "by-original-model",
+                "condition": {
+                    "source": "original",
+                    "path": "model",
+                    "op": "eq",
+                    "value": "client-model",
+                },
+            }
+        ],
+        header_rules=[
+            {
+                "action": "set",
+                "key": "X-Model-Source",
+                "value": "client",
+                "condition": {
+                    "source": "original",
+                    "path": "model",
+                    "op": "eq",
+                    "value": "client-model",
+                },
+            }
+        ],
+    )
+    key = SimpleNamespace(api_key="unused")
+
+    mapped_body = {"model": "provider-model", "messages": []}
+    original_body = {"model": "client-model", "messages": []}
+
+    payload, headers = builder.build(
+        mapped_body,
+        {},
+        endpoint,
+        key,
+        rules_original_body=original_body,
+        pre_computed_auth=("Authorization", "Bearer upstream-token"),
+    )
+
+    assert payload["model"] == "provider-model"
+    assert payload["route"] == "by-original-model"
+    assert headers["X-Model-Source"] == "client"
+    assert headers["Authorization"] == "Bearer upstream-token"