main.py

from fastapi import FastAPI, Request, HTTPException
from fastapi.responses import JSONResponse
from pydantic import BaseModel

from langchain.document_loaders import WebBaseLoader
from langchain.chains.summarize import load_summarize_chain
#https://python.langchain.com/docs/use_cases/summarization
from langchain import HuggingFaceHub
from huggingface_hub import InferenceClient
from bs4 import BeautifulSoup
import requests
import sys
import os
from dotenv import load_dotenv
load_dotenv()

hf_token = os.environ.get('HUGGINGFACEHUB_API_TOKEN')
repo_id=os.environ.get('repo_id')
#port = os.getenv('port')

llm = HuggingFaceHub(repo_id=repo_id,  # for StarChat
                     huggingfacehub_api_token=hf_token,
                     model_kwargs={"min_length": 512,  # for StarChat
                                   "max_new_tokens": 1024, "do_sample": True,  # for StarChat
                                   "temperature": 0.01,
                                   "top_k": 50,
                                   "top_p": 0.95, "eos_token_id": 49155})
#chain = load_summarize_chain(llm, chain_type="stuff")
chain = load_summarize_chain(llm, chain_type="refine")

app = FastAPI()
class ChatRequest(BaseModel):
    target_url: str
#似乎必须要有这个class定义？？？

#@app.post('/')
#async def home_api(request: Request):
#    data = await request.json()
#    target_url = data['target_url']
#    print(target_url)
#    return {"Message": "FastAPI Home API Deploy Success on HF"}

@app.post('/api/chat')
async def chat(request: Request, chat_request: ChatRequest):
    target_url = chat_request.target_url

#@app.post('/api/chat')
#async def chat(request: Request):
#    data = await request.json()
#    target_url = data['target_url']
#以上四行代码，可能有问题？出在data = await request.json()？？？理论上似乎也没有问题，因为后面的print(target_url)，能够成功打印
    
    print(target_url)
    try:
        loader = WebBaseLoader(target_url)
        print(target_url)
        docs = loader.load()
        result = chain.run(docs)
        print("AI Summarization: " + result)
        return {'response': result}  #FastAPI方式下，这个返回形式，有问题？
        #return JSONResponse({'response': result})
        
        #对比FlaskAPI的：return jsonify({'response': result})，JSONResponse vs jsonify（都需要相应的from ... import ...）
    except Exception as e:
        err_msg = "Wrong URL or URL not parsable."
        print(err_msg)
        raise HTTPException(status_code=400, detail=err_msg)