from fastapi import FastAPI
from fastapi.responses import Response
from langserve import add_routes
from langgraph.graph import StateGraph, END
from typing import TypedDict, List


# 定义状态结构
class AgentState(TypedDict):
    input: str
    output: List[str]


# 创建节点
def node1(state: AgentState):
    return {"output": [f"处理: {state['input']}"]}


def node2(state: AgentState):
    return {"output": state["output"] + ["追加处理"]}

# 构建工作流
graph = StateGraph(AgentState)
graph.add_node("node1", node1)
graph.add_node("node2", node2)
graph.set_entry_point("node1")
graph.add_edge("node1", "node2")
graph.add_edge("node2", END)

graph = graph.compile()  # 编译为可运行对象


app = FastAPI(
    title="My LangServer",
    version="0.1.0",
    description="暴露 LangGraph workflow 为 REST API",
)


add_routes(
    app,
    graph,
    path="/workflow",
    input_type=AgentState,
    playground_type="default"
)


@app.get("/hello")
async def hello():
    return Response("hello, world")


if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=8000)

运行以上服务并在浏览器里请求:http://localhost:8000/workflow/playground/ 进行测试