return deeply nested json objects with response_model fastAPI and Pydantic

Question

This is my schema file

from pydantic import BaseModel
from typing import Optional


class HolidaySchema(BaseModel):
    year: int
    month: int
    country: str
    language: str


class HolidayDateSchema(BaseModel):
    name: str
    date: str
    holidays: HolidaySchema | None = None

    class Config:
        orm_mode = True

and this is the router that I have

@router.get("/holidays/",response_model = List[HolidayDateSchema])

The response I want to get is

[
    {
        "date": "2021-08-14",
        "name": "Independence Day",
        "holidays": { "year": 2022, "month":5, "country":"pk", "language":"en"},
        "id": 13
    },
]

Right now it doesn't support the pydantic schema with response model, I don't know why and it gives error pydantic.error_wrappers.ValidationError: 2 validation errors for HolidayDateSchema and value is not a valid dict

It would be great if anyone can specify the best to get deeply nested JSON objects with response_model.

Answer 1

HolidaySchema isn't configured with orm_mode = True .

You need this for all the models that you want to automagically convert from SQLAlchemy model objects.

class HolidaySchema(BaseModel):
    year: int
    month: int
    country: str
    language: str

    class Config:
        orm_mode = True

You can configure that setting on a common BaseModel and inherit from that instead if you want the setting for all your models.