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,  #这个变量huggingfacehub_api_token名称似乎没有问题！
                     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")

print(f"定义处理多余的Context文本的函数")
def remove_context(text):
    # 检查 'Context:' 是否存在
    if 'Context:' in text:
        # 找到第一个 '\n\n' 的位置
        end_of_context = text.find('\n\n')
        # 删除 'Context:' 到第一个 '\n\n' 之间的部分
        return text[end_of_context + 2:]  # '+2' 是为了跳过两个换行符
    else:
        # 如果 'Context:' 不存在，返回原始文本
        return text
print(f"处理多余的Context文本函数定义结束")    

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(chat_request: ChatRequest):  
#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(result)
        print()
        
        result=str(result)   #找到之前总是POST Error的原因：chain.run(docs)的结果，格式不是str，导致{...}的json故障所致
        cleaned_initial_ai_response = remove_context(result)
        print(cleaned_initial_ai_response)
        print()
        
        final_ai_response = cleaned_initial_ai_response.split('<|end|>')[0].strip().replace('\n\n', '\n').replace('<|end|>', '').replace('<|user|>', '').replace('<|system|>', '').replace('<|assistant|>', '')
        new_final_ai_response = final_ai_response.split('Unhelpful Answer:')[0].strip()
        final_result = new_final_ai_response.split('Note:')[0].strip()        
        
        #result="Hi FastAPI"   #用这个调试OK
        print("AI Summarization: " + final_result)
        #return {'response': result}  #FastAPI方式下，这个返回形式，有问题？ - NO！不是的！可以工作！
        return JSONResponse({'response': final_result})   #这个形式也是OK的 - 只要result是字符形式即可？
        
        #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)