, ⏮️ 📟 🔛 👈 🚫 ⚙️ Pydantic 🎯, FastAPI ⚙️ Pydantic 🗜 📚 🐩 🎻 Pydantic 👍 🍛 🎻.

& ↗️, ⚫️ 🐕‍🦺 🎏:

* 💽 🔬
* 💽 🛠️
* 💽 🧾, ♒️.

👉 👷 🎏 🌌 ⏮️ Pydantic 🏷. & ⚫️ 🤙 🏆 🎏 🌌 🔘, ⚙️ Pydantic.

!!! info
    ✔️ 🤯 👈 🎻 💪 🚫 🌐 Pydantic 🏷 💪.

    , 👆 5️⃣📆 💪 ⚙️ Pydantic 🏷.

    ✋️ 🚥 👆 ✔️ 📚 🎻 🤥 🤭, 👉 👌 🎱 ⚙️ 👫 🏋️ 🕸 🛠️ ⚙️ FastAPI. 👶

因此，即便上述代码没有显式使用 Pydantic，FastAPI 仍会使用 Pydantic 把标准数据类转换为 Pydantic 数据类（`dataclasses`）。

并且，它仍然支持以下功能：

* 数据验证
* 数据序列化
* 数据存档等

数据类的和运作方式与 Pydantic 模型相同。实际上，它的底层使用的也是 Pydantic。

!!! info "说明"

    注意，数据类不支持 Pydantic 模型的所有功能。

    因此，开发时仍需要使用 Pydantic 模型。

    但如果数据类很多，这一技巧能给 FastAPI 开发 Web API 增添不少助力。🤓

## `response_model` 使用数据类

在 `response_model` 参数中使用 `dataclasses`：

## Pydantic `Settings`

Fortunately, Pydantic provides a great utility to handle these settings coming from environment variables with <a href="https://docs.pydantic.dev/latest/usage/pydantic_settings/" class="external-link" target="_blank">Pydantic: Settings management</a>.

### Install `pydantic-settings`

First, install the `pydantic-settings` package:

<div class="termy">

## Pydantic `Settings`

Glücklicherweise bietet Pydantic ein großartiges Werkzeug zur Verarbeitung dieser Einstellungen, die von Umgebungsvariablen stammen, mit <a href="https://docs.pydantic.dev/latest/concepts/pydantic_settings/" class="external-link" target="_blank">Pydantic: Settings Management</a>.

### `pydantic-settings` installieren

        # TODO: remove when deprecating Pydantic v1
        "Param(Ellipsis)",
    )


def test_param_repr_number():
    assert repr(Param(1)) == "Param(1)"


def test_param_repr_list():
    assert repr(Param([])) == "Param([])"


def test_path_repr():
    assert repr(Path()) == IsOneOf(
        "Path(PydanticUndefined)",
        # TODO: remove when deprecating Pydantic v1
        "Path(Ellipsis)",
    )

=== "Pydantic v2"

    ```Python hl_lines="17-22  24"
    {!> ../../../docs_src/path_operation_advanced_configuration/tutorial007.py!}
    ```

=== "Pydantic v1"

    ```Python hl_lines="17-22  24"

=== "Pydantic v2"

    ```Python hl_lines="26-33"
    {!> ../../../docs_src/path_operation_advanced_configuration/tutorial007.py!}
    ```

=== "Pydantic v1"

    ```Python hl_lines="26-33"
    {!> ../../../docs_src/path_operation_advanced_configuration/tutorial007_pv1.py!}
    ```

!!! info

      - name: Install Dependencies
        if: steps.cache.outputs.cache-hit != 'true'
        run: pip install -r requirements-tests.txt
      - name: Install Pydantic v1
        if: matrix.pydantic-version == 'pydantic-v1'
        run: pip install "pydantic>=1.10.0,<2.0.0"

from docs_src.custom_response.tutorial006c import app

client = TestClient(app)


def test_redirect_status_code():
    response = client.get("/pydantic", follow_redirects=False)
    assert response.status_code == 302
    assert response.headers["location"] == "https://docs.pydantic.dev/"


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text

if PYDANTIC_V2:
    from pydantic import PydanticSchemaGenerationError as PydanticSchemaGenerationError
    from pydantic import TypeAdapter
    from pydantic import ValidationError as ValidationError
    from pydantic._internal._schema_generation_shared import (  # type: ignore[attr-defined]
        GetJsonSchemaHandler as GetJsonSchemaHandler,
    )
    from pydantic._internal._typing_extra import eval_type_lenient