from fastapi.exception_handlers import request_validation_exception_handler
from fastapi.exceptions import RequestValidationError

app = FastAPI()

@app.exception_handler(RequestValidationError)
async def handle(request: Request, exc: Exception):
    if isinstance(exc.__context__, JSONDecodeError):
        return Response(str(exc),status_code=400)
    return await request_validation_exception_handler(request, exc)