from fastapi import FastAPI, Request, status from fastapi.encoders import jsonable_encoder from fastapi.exceptions import RequestValidationError from fastapi.responses import JSONResponse from pydantic import BaseModel app = FastAPI() @app.exception_handler(RequestValidationError) async def validation_exception_handler(request: Request, exc: RequestValidationError): return JSONResponse( status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, content=jsonable_encoder({"detail": exc.errors(), "body": exc.body}), ) class Item(BaseModel): title: str size: int @app.post("/items/") async def create_item(item: Item): return item