164 lines
6.9 KiB
Python
164 lines
6.9 KiB
Python
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import uuid
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import json
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from fastapi import APIRouter
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from fastapi.responses import StreamingResponse
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from src.schemas.chat import ChatRequest, HistoryResponse, HistoryItem
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from src.server.agent.graph import app # 导入已经 compile 好的 graph
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from langchain_core.messages import HumanMessage
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router = APIRouter(prefix="/chat", tags=["Furniture Design Chat"])
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@router.post("/stream")
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async def chat_stream(request: ChatRequest):
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"""
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### 家具设计流式对话接口 (SSE)
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通过此接口与 AI 家具设计专家团队进行实时沟通。支持 **记忆持久化** 和 **历史回溯分叉**。
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#### 1. 核心功能
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* **实时反馈**: 采用 Server-Sent Events (SSE) 技术，实时推送主管、设计师、视觉专家等节点的思考过程。
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* **上下文记忆**: 传入 `thread_id` 即可恢复之前的对话进度。
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* **版本分溯**: 传入 `checkpoint_id` 可准确定位到历史中的某一轮，并从该点开启新的设计分支。
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#### 2. 请求参数
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* `message`: 用户的设计意图（如：'我想设计一个极简风格的橡木办公桌'）。
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* `thread_id`: (可选) 现有项目的唯一标识。若不传，系统将自动分配并返回。
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* `checkpoint_id`: (可选) 历史快照 ID。
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#### 3. 响应流说明 (Data Format)
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响应以 `data: ` 开头的 JSON 字符串流形式发送：
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- **Session Start**: `{"thread_id": "...", "status": "start"}`
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- **Node Message**: `{"node": "Designer", "content": "...", "checkpoint_id": "..."}`
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- **Session End**: `{"status": "end"}`
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#### 4. 请求示例
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```
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{
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"message": "设计一款北欧风格的躺椅."
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}
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{
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"message": "就以上信息直接生成sketch.",
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"thread_id": "187e58af"
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}
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{
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"message": "不要躺椅,要桌子",
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"thread_id": "187e58af",
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"checkpoint_id": "1f101aa2-8f24-6e2a-8001-2952c3a7447a"
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}
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```
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"""
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source_thread_id = request.thread_id
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checkpoint_id = request.checkpoint_id
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# 1. 确定目标 thread_id
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# 如果是回溯操作，我们生成一个新的 ID，或者由前端传入一个新的 target_thread_id
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is_branching = source_thread_id and checkpoint_id
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target_thread_id = str(uuid.uuid4())[:8] if is_branching else (source_thread_id or str(uuid.uuid4())[:8])
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# 2. 如果是分叉请求，我们需要先“搬家”状态
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if is_branching:
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# 获取旧状态
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source_config = {"configurable": {"thread_id": source_thread_id, "checkpoint_id": checkpoint_id}}
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older_state = await app.aget_state(source_config)
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# 将旧状态的消息，作为新 thread 的初始值注入
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# 注意：这里我们手动把旧消息塞给新 thread
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new_config = {"configurable": {"thread_id": target_thread_id}}
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await app.aupdate_state(new_config, older_state.values)
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# 现在的 config 指向新 Thread
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current_config = new_config
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else:
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current_config = {"configurable": {"thread_id": target_thread_id}}
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async def event_generator():
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# 告诉前端：现在是在哪个 Thread 上工作（如果是分叉，前端需要更新本地存储的 ID）
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yield f"data: {json.dumps({'thread_id': target_thread_id, 'is_branch': is_branching}, ensure_ascii=False)}\n\n"
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async for event in app.astream(
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{"messages": [HumanMessage(content=request.message)]},
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current_config,
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stream_mode="updates"
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):
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# ... 发送流式内容的逻辑保持不变 ...
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for node_name, output in event.items():
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if "messages" in output:
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msg = output["messages"][-1]
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state = await app.aget_state(current_config)
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yield f"data: {json.dumps({'node': node_name, 'content': msg.content, 'checkpoint_id': state.config['configurable']['checkpoint_id']}, ensure_ascii=False)}\n\n"
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return StreamingResponse(event_generator(), media_type="text/event-stream")
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@router.get("/history/{thread_id}", response_model=HistoryResponse)
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async def get_chat_history(thread_id: str):
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"""
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### 获取项目设计历史记录
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此接口用于拉取指定 `thread_id` 下的所有历史状态快照。它是实现 **“版本回溯”** 和 **“方案对比”** 的核心数据来源。
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#### 1. 功能说明
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* **快照列表**: 返回该项目从启动至今的所有关键节点（Checkpoints）。
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* **版本定位**: 每个历史点都包含一个唯一的 `checkpoint_id`。
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* **数据回溯**: 客户端获取此列表后，可以引导用户选择任意一个版本，并将其 `checkpoint_id` 传回 `/chat/stream` 接口以开启新的设计分支。
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#### 2. 路径参数
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* `thread_id`: 设计项目的唯一标识符（由 `/chat/stream` 首次调用时生成或指定）。
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#### 3. 返回字段定义
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* `thread_id`: 当前查询的项目ID。
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* `history`: 历史记录数组，包含：
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- `checkpoint_id`: 必填，回溯时使用的关键凭证。
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- `last_message`: 该阶段的最后一条消息摘要（方便前端预览）。
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- `node`: 产生该快照的节点名称（如 Designer, Visualizer）。
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- `timestamp`: 逻辑步骤序号。
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#### 4. 响应示例
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```json
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{
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"thread_id": "proj_001",
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"history": [
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{
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"checkpoint_id": "d82f3a12",
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"last_message": "我想设计一款北欧风书架",
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"node": "Supervisor",
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"timestamp": 1
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},
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{
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"checkpoint_id": "f4k92m1a",
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"last_message": "建议使用浅色橡木材质，增加简约感...",
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"node": "Designer",
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"timestamp": 2
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}
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]
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}
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```
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"""
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config = {"configurable": {"thread_id": thread_id}}
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history_data = []
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async for state in app.aget_state_history(config):
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msg_content = "Initial"
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if state.values and "messages" in state.values:
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msgs = state.values["messages"]
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if msgs and len(msgs) > 0:
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last_msg = msgs[-1]
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# 获取内容并做摘要截断
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content = getattr(last_msg, "content", str(last_msg))
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msg_content = content[:50] + ("..." if len(content) > 50 else "")
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history_data.append(HistoryItem(
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checkpoint_id=state.config["configurable"]["checkpoint_id"],
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last_message=msg_content[:50],
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node=state.metadata.get("source"),
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timestamp=state.metadata.get("step")
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))
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return HistoryResponse(thread_id=thread_id, history=history_data)
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# try:
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# except Exception as e:
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# raise HTTPException(status_code=404, detail=f"History not found: {str(e)}")
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