Using Pydantic field aliases to bridge inconsistent naming

pydantic_field_aliases_example.py

import pytest
from pydantic import BaseModel, Field, ValidationError


class Item(BaseModel):
    item_id: str
    is_available: bool = Field(alias='isAvailable')  # 1


def test_field_aliasing_bridges_inconsistant_conventions():
    item1 = Item(item_id='test-item-id', isAvailable=True)  # 2
    assert item1.is_available is True  # 3
    # Note that referring to is_available raises a ValidationErrror
    # https://github.com/samuelcolvin/pydantic/issues/565#issuecomment-497467975-permalink:~:text=aliases%20as%20I%20think%20of%20them,the%20names%20used%20in%20your%20application
    with pytest.raises(ValidationError):  # 4
        Item(item_id='test-item-id', is_available=True)  # 4


class ItemWithVisibleId(BaseModel):
    item_id: str = Field(alias='_id')  # 1
    is_available: bool


def test_field_aliasing_solves_field_hiding():
    item = ItemWithVisibleId(_id='test-item-id', is_available=True)  # 2
    assert item.item_id == 'test-item-id'  # 3
    assert item.dict(by_alias=True).get('_id') == 'test-item-id'  # 5