feat(services): assignment 6 skeleton - app service, field registry, in-memory repository

- fields_registry: 24 business keys in acd/human1/human2 groups with value_type, writable and SensitiveLevel metadata; strict bool/int parsing (no bool('0') trap); INTERNAL_FIELD_KEYS protection list - repository: SessionRepository protocol + InMemorySessionRepository (idempotent delete; PostgreSQL swap-in is assignment 7) - AccidentAppService: chat/set_info/get_info/delete_session share one business state - chat injects latest repository fields into the graph and writes back validated field diffs; set/get/delete make zero LLM calls and zero helper conversations (includeInputInfo accepted but unused); unknown get keys keep the '' JSON-empty-string contract, unknown set keys are rejected by whitelist - ChatInput.injected_fields neutral contract extension; LangGraphBackend merges injected fields into graph input (set_info visible next chat) - endpoints: thin layer - langgraph mode routes business state through the app service (fastgpt mode keeps the legacy path); delete cleans repository + graph checkpoint, idempotent - tests: registry completeness (sfzmwh/sjwh/csbw included), app service combos with LLM-call spy, HTTP acceptance flow (set -> get -> chat -> groups -> delete -> no leak, idempotent re-delete) - docs/assignment6-compat.md: behavior diff list vs FastGPT status quo and the audit backlog (arbitrary set_info key usage, stream formUpdate write-back, sensitive-field display boundary) Verified: 200 unit tests (172 existing + 28 new)
2026-10-22 20:50:10 +08:00
parent 6c1fbd0295
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+"""事故处理应用服务（作业 6-1）：四业务接口共享同一份业务状态。
+
+职责边界（对应计划作业 6）：
+- set_info / get_info / delete_session **不调用 LLM、不创建辅助对话**
+  （对照旧 FastGPT 实现的“辅助对话 + 删记录”hack）；
+- chat 每轮从 repository 读最新业务字段注入图（set_info 写入后
+  下一轮 chat 必须可见），图产出字段差量后写回 repository；
+- 未知 key 兼容策略：get 对未知 key 返回 JSON 空串 '""'（现状兼容）；
+  set 对未知 key 拒绝写入（白名单保护，差异见兼容清单）；
+- includeInputInfo 继续被 endpoint 接受，但本层不再使用
+  ——新后端无需触发辅助对话。
+
+endpoint 只负责校验、协议（SSE / 响应模型）与依赖注入。
+"""
+
+from ..backends.chat import ChatBackend, ChatInput, ChatResult
+from .fields_registry import (
+    FIELD_REGISTRY,
+    GROUP_KEYS,
+    FieldGroup,
+    parse_field_value,
+    to_external_string,
+)
+from .repository import SessionRepository
+
+# set_info 对未知/受保护 key 的拒绝码（与现有“入参不规范”文案对齐）
+SET_INFO_INVALID_KEY_MSG = "入参不规范：未知或受保护的字段 key"
+
+
+class AccidentAppService:
+    """四个业务接口的应用服务（langgraph 后端）。"""
+
+    def __init__(self, backend: ChatBackend, repository: SessionRepository):
+        self._backend = backend
+        self._repository = repository
+
+    # ---- chat：图每轮读取最新业务状态，产出差量写回 ----
+
+    def _injected_fields(self, session_id: str) -> dict:
+        """repository 业务字段 -> 图输入的分组注入（acd 进 accident_fields，
+        两组人员进 person_fields，与 AgentState 的键结构对齐）。"""
+        business = self._repository.load(session_id)
+        if not business:
+            return {}
+        injected: dict = {"accident_fields": {}, "person_fields": {}}
+        for key, value in business.items():
+            spec = FIELD_REGISTRY.get(key)
+            if spec is None:
+                continue
+            if spec.group is FieldGroup.ACD:
+                injected["accident_fields"][key] = value
+            else:
+                injected["person_fields"][key] = value
+        return injected
+
+    async def chat(self, chat_input: ChatInput) -> ChatResult:
+        """非流式一轮对话：注入最新业务字段 -> 执行图 -> 写回字段差量。"""
+        injected = self._injected_fields(chat_input.session_id)
+        result = await self._backend.complete(
+            ChatInput(
+                session_id=chat_input.session_id,
+                text=chat_input.text,
+                need_form_update=chat_input.need_form_update,
+                client_mode=chat_input.client_mode,
+                injected_fields=injected or None,
+            )
+        )
+        # 图产出的字段差量（turn_patch / 完整字段）写回 repository，
+        # 使 set/get_info 与后续轮次看到同一事实来源
+        patch = result.form_update if isinstance(result.form_update, dict) else {}
+        if patch:
+            self._repository.apply_update(chat_input.session_id, patch)
+        return result
+
+    async def stream(self, chat_input: ChatInput):
+        """流式代理：字段注入与写回语义同 chat()，事件流原样透传。"""
+        injected = self._injected_fields(chat_input.session_id)
+        result_input = ChatInput(
+            session_id=chat_input.session_id,
+            text=chat_input.text,
+            need_form_update=chat_input.need_form_update,
+            client_mode=chat_input.client_mode,
+            injected_fields=injected or None,
+        )
+        # 骨架阶段原样透传事件流；字段差量写回在作业 6 完整版随
+        # FormUpdate 事件捕获补齐（对照计划作业 8 的真实增量）。
+        async for event in self._backend.stream(result_input):
+            yield event
+
+    # ---- set_info / get_info：零 LLM、零辅助对话 ----
+
+    def set_info(self, session_id: str, key: str, value: str) -> tuple[str, str]:
+        """白名单校验后写入 repository。返回 (code, msg)。"""
+        spec = FIELD_REGISTRY.get(key)
+        if spec is None or not spec.writable:
+            return "500", SET_INFO_INVALID_KEY_MSG
+        try:
+            parsed = parse_field_value(spec, value)
+        except ValueError:
+            return "500", "入参不规范：字段值无法解析"
+        self._repository.apply_update(session_id, {key: parsed})
+        return "200", ""
+
+    def get_info(self, session_id: str, key: str) -> str:
+        """按分组或单键读出，返回 JSON 字符串（兼容现有 /get_info 契约）。"""
+        import json
+
+        business = self._repository.load(session_id)
+        if key == "all":
+            return json.dumps(
+                {
+                    group.value: {
+                        k: to_external_string(business.get(k))
+                        for k in GROUP_KEYS[group]
+                    }
+                    for group in FieldGroup
+                },
+                ensure_ascii=False,
+            )
+        try:
+            group = FieldGroup(key)
+        except ValueError:
+            group = None
+        if group is not None:
+            return json.dumps(
+                {k: to_external_string(business.get(k)) for k in GROUP_KEYS[group]},
+                ensure_ascii=False,
+            )
+        # 单键：未知 key 返回 JSON 空串（兼容现状）；已知 key 返回其外部表示
+        if key not in FIELD_REGISTRY:
+            return json.dumps("", ensure_ascii=False)
+        return json.dumps(to_external_string(business.get(key)), ensure_ascii=False)
+
+    # ---- delete_session：业务状态 + 图 checkpoint 一起清理 ----
+
+    async def delete_session(self, session_id: str, drop_checkpoint) -> None:
+        """删除会话全部数据。
+
+        drop_checkpoint：由 core 层注入的 checkpoint 清理函数
+        （图生命周期归 lifespan 管理，本层不持有图引用）。
+        repository 删除幂等；checkpoint 缺失时静默（幂等语义一致）。
+        """
+        self._repository.delete(session_id)
+        if drop_checkpoint is not None:
+            try:
+                await drop_checkpoint(session_id)
+            except Exception:
+                # checkpoint 已不存在视为删除成功的一部分（幂等）
+                pass
+
+
+__all__ = ["AccidentAppService", "SET_INFO_INVALID_KEY_MSG"]