from dataclasses import field  # (1)
from typing import List, Union

from fastapi import FastAPI
from pydantic.dataclasses import dataclass  # (2)


@dataclass
class Item:
    name: str
    description: Union[str, None] = None


@dataclass
class Author:
    name: str
    items: List[Item] = field(default_factory=list)  # (3)


app = FastAPI()

### Pydantic v1 `regex` statt `pattern`

Vor Pydantic Version 2 und vor FastAPI Version 0.100.0, war der Name des Parameters `regex` statt `pattern`, aber das ist jetzt <abbr title="deprecated – obsolet, veraltet: Es soll nicht mehr verwendet werden">deprecated</abbr>.

Sie könnten immer noch Code sehen, der den alten Namen verwendet:

//// tab | Python 3.10+ Pydantic v1

```Python hl_lines="11"

## Prérequis

FastAPI repose sur les épaules de géants :

* <a href="https://www.starlette.io/" class="external-link" target="_blank">Starlette</a> pour les parties web.
* <a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic</a> pour les parties données.

## Installation

<div class="termy">

```console
$ pip install fastapi

---> 100%
```

</div>

Cela a en fait inspiré la mise à jour de certaines parties de Pydantic, afin de supporter le même style de déclaration de validation (toute cette fonctionnalité est maintenant déjà disponible dans Pydantic).

///

### <a href="https://github.com/hugapi/hug" class="external-link" target="_blank">Hug</a>

                                    "title": "Q",
                                }
                            )
                            | IsDict(
                                # TODO: remove when deprecating Pydantic v1
                                {"title": "Q", "type": "string"}
                            ),
                            "name": "q",
                            "in": "query",
                        },

                    "msg": "Field required",
                    "input": None,
                },
            ]
        }
    ) | IsDict(
        # TODO: remove when deprecating Pydantic v1
        {
            "detail": [
                {
                    "loc": ["header", "x-token"],
                    "msg": "field required",
                    "type": "value_error.missing",

/// warning | "注意"

これらは今のあなたにとって重要でない場合は省略しても良い技術的な詳細です。

///

`RequestValidationError`はPydanticの<a href="https://docs.pydantic.dev/latest/concepts/models/#error-handling" class="external-link" target="_blank">`ValidationError`</a>のサブクラスです。

**FastAPI** は`response_model`でPydanticモデルを使用していて、データにエラーがあった場合、ログにエラーが表示されるようにこれを使用しています。

E depois nós validamos esse dado com o modelo Pydantic (capturando a exceção `ValidationError`), e se nós obtemos um erro ao ler o token JWT ou validando os dados com o Pydantic, nós levantamos a exceção `HTTPException` que criamos anteriormente.

Para isso, nós atualizamos o modelo Pydantic `TokenData` com a nova propriedade `scopes`.

from fastapi import FastAPI, Header, HTTPException
from pydantic import BaseModel

fake_secret_token = "coneofsilence"

fake_db = {
    "foo": {"id": "foo", "title": "Foo", "description": "There goes my hero"},
    "bar": {"id": "bar", "title": "Bar", "description": "The bartenders"},
}

app = FastAPI()


class Item(BaseModel):
    id: str
    title: str
    description: str | None = None

                        }
                    },
                },
            }
        },
    }


# TODO: remove when deprecating Pydantic v1
@needs_py39
@needs_pydanticv1
def test_openapi_schema_pv1(client: TestClient):
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {