Pydantic, which is what powers all the data validation and serialization in FastAPI, has a special behavior when you use `Optional` or `Union[Something, None]` without a default value, you can read more about it in the Pydantic docs about <a href="https://docs.pydantic.dev/2.3/usage/models/#required-optional-fields" class="external-link" target="_blank">Required fields</a>.

///

/// tip

///

## Check the automatic API docs

Now, run your app:

<div class="termy">

```console
$ fastapi dev app/main.py

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

</div>

And open the docs at <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>.

    * В запросах и ответах будет представлен в виде общего количества секунд типа `float`.
    * Pydantic также позволяет представить его как "Кодировку разницы во времени ISO 8601", <a href="https://docs.pydantic.dev/latest/concepts/serialization/#json_encoders" class="external-link" target="_blank">см. документацию для получения дополнительной информации</a>.
* `frozenset`:
    * В запросах и ответах обрабатывается так же, как и `set`:

-e .[all]
-r requirements-tests.txt
-r requirements-docs.txt
pre-commit >=2.17.0,<5.0.0
# For generating screenshots

```

////

Notice that the *path operations* define the models they use for request payload and response payload, using the models `Item` and `ResponseMessage`.

### API Docs

If you go to the API docs, you will see that it has the **schemas** for the data to be sent in requests and received in responses:

<img src="/img/tutorial/generate-clients/image01.png">

* 使用 `spooled` 文件：
    * 存储在内存的文件超出最大上限时，FastAPI 会把文件存入磁盘；
* 这种方式更适于处理图像、视频、二进制文件等大型文件，好处是不会占用所有内存；
* 可获取上传文件的元数据；
* 自带 <a href="https://docs.python.org/zh-cn/3/glossary.html#term-file-like-object" class="external-link" target="_blank">file-like</a> `async` 接口；
* 暴露的 Python <a href="https://docs.python.org/zh-cn/3/library/tempfile.html#tempfile.SpooledTemporaryFile" class="external-link" target="_blank">`SpooledTemporaryFile`</a> 对象，可直接传递给其他预期「file-like」对象的库。

Aber FastAPI unterstützt auf die gleiche Weise auch die Verwendung von <a href="https://docs.python.org/3/library/dataclasses.html" class="external-link" target="_blank">`dataclasses`</a>:

```Python hl_lines="1  7-12  19-20"
{!../../docs_src/dataclasses/tutorial001.py!}
```

## Explore Further

- [MinIO | Golang Client API Reference](https://min.io/docs/minio/linux/developers/go/API.html#setbucketlifecycle-ctx-context-context-bucketname-config-lifecycle-configuration-error)

<div class="screenshot">
<img src="/img/tutorial/cookie-param-models/image01.png">
</div>

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here. Ref: https://github.com/minio/minio/tree/master/docs/tls/kubernetes#2-create-kubernetes-secret certSecret: "" publicCrt: public.crt privateKey: private.key ## Trusted Certificates Settings for MinIO. Ref: https://docs.minio.io/docs/how-to-secure-access-to-minio-server-with-tls#install-certificates-from-third-party-cas ## Bundle multiple trusted certificates into one secret and pass that here. Ref: https://github.com/minio/minio/tree/master/docs/tls/kubernetes#2-create-kubernetes-secret ## When...