///

如果你的旧 FastAPI 应用在用 Pydantic v1，这里将向你展示如何迁移到 Pydantic v2，以及 FastAPI 0.119.0 中可帮助你渐进式迁移的功能。

## 官方指南 { #official-guide }

Pydantic 有一份从 v1 迁移到 v2 的官方[迁移指南](https://docs.pydantic.dev/latest/migration/)。

其中包含变更内容、校验如何更准确更严格、可能的注意事项等。

你可以阅读以更好地了解变更。

## 测试 { #tests }

请确保你的应用有[测试](../tutorial/testing.md)，并在持续集成（CI）中运行它们。

这样你就可以升级并确保一切仍按预期工作。

## `bump-pydantic` { #bump-pydantic }

Sie können dies mit [Pydantics `AfterValidator`](https://docs.pydantic.dev/latest/concepts/validators/#field-after-validator) innerhalb von `Annotated` erreichen.

/// tip | Tipp

Pydantic unterstützt auch [`BeforeValidator`](https://docs.pydantic.dev/latest/concepts/validators/#field-before-validator) und andere. 🤓

///

Você pode fazer isso usando o [`AfterValidator` do Pydantic](https://docs.pydantic.dev/latest/concepts/validators/#field-after-validator) dentro de `Annotated`.

/// tip | Dica

O Pydantic também tem [`BeforeValidator`](https://docs.pydantic.dev/latest/concepts/validators/#field-before-validator) e outros. 🤓

///

	requestMaxBodySize = globalMaxObjectSize + requestFormDataSize

	// Maximum size for http headers - See: https://docs.aws.amazon.com/AmazonS3/latest/dev/UsingMetadata.html
	maxHeaderSize = 8 * 1024

	// Maximum size for user-defined metadata - See: https://docs.aws.amazon.com/AmazonS3/latest/dev/UsingMetadata.html
	maxUserDataSize = 2 * 1024

	// maxBuckets upto 500000 for any MinIO deployment.
	maxBuckets = 500 * 1000
)

### 其他可选依赖 { #additional-optional-dependencies }

还有一些你可能想安装的可选依赖。

额外的 Pydantic 可选依赖：

* [`pydantic-settings`](https://docs.pydantic.dev/latest/usage/pydantic_settings/) - 用于配置管理。
* [`pydantic-extra-types`](https://docs.pydantic.dev/latest/usage/types/extra_types/extra_types/) - 用于在 Pydantic 中使用的额外类型。

额外的 FastAPI 可选依赖：

* [`orjson`](https://github.com/ijl/orjson) - 使用 `ORJSONResponse` 时需要。

kubeadm has been updated to drop an unnecessary redirection from ci/latest.txt to ci-cross/latest.txt. Users should know exactly where the builds are stored on Google Cloud storage buckets from now on. For example for 1.9 and 1.10, users can specify ci/latest-1.9 and ci/latest-1.10 as the CI build jobs what build images correctly updates those. The CI jobs for master update the ci-cross/latest location, so if you are looking for latest master builds, then the correct parameter to use would be ci-cross/latest....

Vous pouvez y parvenir en utilisant [`AfterValidator` de Pydantic](https://docs.pydantic.dev/latest/concepts/validators/#field-after-validator) à l’intérieur de `Annotated`.

/// tip | Astuce

Pydantic a aussi [`BeforeValidator`](https://docs.pydantic.dev/latest/concepts/validators/#field-before-validator) et d’autres. 🤓

///

Есть дополнительные зависимости, которые вы можете установить.

Дополнительные опциональные зависимости Pydantic:

* [`pydantic-settings`](https://docs.pydantic.dev/latest/usage/pydantic_settings/) — для управления настройками.
* [`pydantic-extra-types`](https://docs.pydantic.dev/latest/usage/types/extra_types/extra_types/) — дополнительные типы для использования с Pydantic.

Дополнительные опциональные зависимости FastAPI:

/// info | Информация

Если вы уже прошли всё руководство и вернулись, чтобы узнать больше о типах, хорошим ресурсом будет [«шпаргалка» от `mypy`](https://mypy.readthedocs.io/en/latest/cheat_sheet_py3.html).

Apart from normal singular types like `str`, `int`, `float`, etc. you can use more complex singular types that inherit from `str`.

To see all the options you have, checkout [Pydantic's Type Overview](https://docs.pydantic.dev/latest/concepts/types/). You will see some examples in the next chapter.

For example, as in the `Image` model we have a `url` field, we can declare it to be an instance of Pydantic's `HttpUrl` instead of a `str`: