Update main.py

main.py

@@ -1,4 +1,7 @@
 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
@@ -28,6 +31,7 @@ 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):