from typing import Union

from pydantic.v1 import BaseModel


class Item(BaseModel):
    name: str
    description: Union[str, None] = None

from fastapi import FastAPI
from fastapi.responses import RedirectResponse

app = FastAPI()


@app.get("/pydantic", response_class=RedirectResponse, status_code=302)
async def redirect_pydantic():

## Les modèles Pydantic

<a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic</a> est une bibliothèque Python pour effectuer de la validation de données.

Vous déclarez la forme de la donnée avec des classes et des attributs.

Chaque attribut possède un type.

from fastapi import FastAPI, Form
from pydantic import BaseModel

app = FastAPI()


class FormData(BaseModel):
    username: str
    password: str


@app.post("/login/")
async def login(data: FormData = Form()):

Если вы хотите обезопасить свой API, есть несколько более эффективных вещей, которые можно сделать, например:

* Убедитесь, что у вас чётко определены Pydantic-модели для тел запросов и ответов.
* Настройте необходимые разрешения и роли с помощью зависимостей.
* Никогда не храните пароли в открытом виде, только хэши паролей.

from fastapi import FastAPI
from pydantic.v1 import BaseModel


class Item(BaseModel):
    name: str
    description: str | None = None
    size: float


app = FastAPI()


@app.post("/items/")
async def create_item(item: Item) -> Item:

from typing import Annotated

from fastapi import FastAPI, Form
from pydantic import BaseModel

app = FastAPI()


class FormData(BaseModel):
    username: str
    password: str


@app.post("/login/")
async def login(data: Annotated[FormData, Form()]):

from fastapi import FastAPI
from pydantic import BaseModel as BaseModelV2
from pydantic.v1 import BaseModel


class Item(BaseModel):
    name: str
    description: str | None = None
    size: float


class ItemV2(BaseModelV2):
    name: str
    description: str | None = None
    size: float


app = FastAPI()


@app.post("/items/", response_model=ItemV2)
async def create_item(item: Item):

from pydantic.v1 import BaseModel


class Item(BaseModel):
    name: str
    description: str | None = None

The same way, there are many compatible tools. Including code generation tools for many languages.

## Pydantic { #pydantic }

All the data validation is performed under the hood by <a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic</a>, so you get all the benefits from it. And you know you are in good hands.