* Etre notifié quand je fais des annonces ou que je lance de nouveaux outils (bien que j'utilise plus souvent Twitter 🤷‍♂).
* Lire ce que j’écris (ou me suivre) sur <a href="https://dev.to/tiangolo" class="external-link" target="_blank">**Dev.to**</a> ou <a href="https://medium.com/@tiangolo" class="external-link" target="_blank">**Medium**</a>.
    * Lire d'autres idées, articles, et sur les outils que j'ai créés.

    * A Python `datetime.timedelta`.
    * In requests and responses will be represented as a `float` of total seconds.
    * Pydantic also allows representing it as a "ISO 8601 time diff encoding", <a href="https://docs.pydantic.dev/latest/concepts/serialization/#json_encoders" class="external-link" target="_blank">see the docs for more info</a>.
* `frozenset`:
    * In requests and responses, treated the same as a `set`:

=== "Linux, macOS"

    <div class="termy">

    ```console
    $ curl -fsSL https://get.deta.dev/cli.sh | sh
    ```

    </div>

=== "Windows PowerShell"

    <div class="termy">

    ```console
    $ iwr https://get.deta.dev/cli.ps1 -useb | iex
    ```

    </div>

安装完 CLI 后，打开新的 Terminal，就能检测到刚安装的 CLI。

在新的 Terminal 里，用以下命令确认 CLI 是否正确安装：

## 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

Installieren Sie zunächst das Package `pydantic-settings`:

```

You can receive and send binary, text, and JSON data.

## Try it

If your file is named `main.py`, run your application with:

<div class="termy">

```console
$ fastapi dev main.py

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

{!../../../docs_src/query_params_str_validations/tutorial006c.py!}
```

!!! tip
    Pydantic 是 FastAPI 中所有数据验证和序列化的核心，当你在没有设默认值的情况下使用 `Optional` 或 `Union[Something, None]` 时，它具有特殊行为，你可以在 Pydantic 文档中阅读有关<a href="https://docs.pydantic.dev/latest/concepts/models/#required-optional-fields" class="external-link" target="_blank">必需可选字段</a>的更多信息。

### 使用Pydantic中的`Required`代替省略号(`...`)

如果你觉得使用 `...` 不舒服，你也可以从 Pydantic 导入并使用 `Required`：

    <img src="https://github.com/tiangolo/fastapi/workflows/Test/badge.svg?event=push&branch=master" alt="Test">
</a>
<a href="https://coverage-badge.samuelcolvin.workers.dev/redirect/tiangolo/fastapi" target="_blank">
    <img src="https://coverage-badge.samuelcolvin.workers.dev/tiangolo/fastapi.svg" alt="Əhatə">
</a>
<a href="https://pypi.org/project/fastapi" target="_blank">

    <img src="https://github.com/tiangolo/fastapi/workflows/Test/badge.svg?event=push&branch=master" alt="Test">
</a>
<a href="https://coverage-badge.samuelcolvin.workers.dev/redirect/tiangolo/fastapi" target="_blank">
    <img src="https://coverage-badge.samuelcolvin.workers.dev/tiangolo/fastapi.svg" alt="Coverage">
</a>
<a href="https://pypi.org/project/fastapi" target="_blank">

    <img src="https://github.com/tiangolo/fastapi/workflows/Test/badge.svg?event=push&branch=master" alt="Test">
</a>
<a href="https://coverage-badge.samuelcolvin.workers.dev/redirect/tiangolo/fastapi" target="_blank">
    <img src="https://coverage-badge.samuelcolvin.workers.dev/tiangolo/fastapi.svg" alt="Coverage">
</a>
<a href="https://pypi.org/project/fastapi" target="_blank">

    <img src="https://github.com/tiangolo/fastapi/workflows/Test/badge.svg?event=push&branch=master" alt="Test">
</a>
<a href="https://coverage-badge.samuelcolvin.workers.dev/redirect/tiangolo/fastapi" target="_blank">
    <img src="https://coverage-badge.samuelcolvin.workers.dev/tiangolo/fastapi.svg" alt="Coverage">
</a>
<a href="https://pypi.org/project/fastapi" target="_blank">