48 lines
1.4 KiB
Python
48 lines
1.4 KiB
Python
"""
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LangGraph Hello World - 最简单的图
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"""
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from langgraph.graph import StateGraph, START, END
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from typing import TypedDict, Annotated
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import operator
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# 1️⃣ 定义状态 - 这是节点之间传递的数据结构
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class GraphState(TypedDict):
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"""图的状态 - 节点之间共享的数据"""
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message: str # 一条消息
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# 2️⃣ 定义节点 - 每个节点是一个函数，接收状态并返回更新
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def greet_node(state: GraphState):
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"""问候节点"""
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print(f"[问候节点] 收到: {state['message']}")
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return {"message": "你好！我是 LangGraph 智能体 👋"}
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def process_node(state: GraphState):
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"""处理节点"""
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print(f"[处理节点] 收到: {state['message']}")
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return {"message": state['message'] + " 很高兴见到你！"}
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# 3️⃣ 构建图
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graph = StateGraph(GraphState)
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# 添加节点
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graph.add_node("greet", greet_node)
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graph.add_node("process", process_node)
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# 添加边 - 定义流程走向
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# START -> greet -> process -> END
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graph.add_edge(START, "greet") # 开始 -> 问候节点
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graph.add_edge("greet", "process") # 问候 -> 处理节点
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graph.add_edge("process", END) # 处理 -> 结束
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# 编译图
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app = graph.compile()
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# 4️⃣ 运行！
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print("=" * 40)
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print("🚀 运行 LangGraph Hello World")
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print("=" * 40)
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result = app.invoke({"message": "Hi!"})
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print()
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print("最终结果:", result['message']) |