langserve--1--fastapi接口示例

本地使用ollama部署的deepseek-r1:1.5b模型

from fastapi import FastAPI
from fastapi.responses import Response
from langserve import add_routes
from langchain.prompts import ChatPromptTemplate
from langchain_community.chat_models import ChatOllama
from pydantic import BaseModel


app = FastAPI(
    title="My LangServer",
    version="0.1.0",
    description="暴露 LangChain 链为 REST API",
    debug=True
)


class JokeInput(BaseModel):
    topic: str


chat_model = ChatOllama(
    model="deepseek-r1:1.5b",
    base_url="http://localhost:11434",
    temperature=0
)
prompt = ChatPromptTemplate.from_template("讲一个关于{topic}的笑话")
joke_chain = prompt | chat_model


add_routes(
    app,
    joke_chain,
    path="/joke",
    input_type=JokeInput
)


@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)