# 使用数据类

FastAPI 基于 **Pydantic** 构建，前文已经介绍过如何使用 Pydantic 模型声明请求与响应。

但 FastAPI 还可以使用数据类（<a href="https://docs.python.org/3/library/dataclasses.html" class="external-link" target="_blank">`dataclasses`</a>）：

{* ../../docs_src/dataclasses_/tutorial001.py hl[1,7:12,19:20] *}

这还是借助于 **Pydantic** 及其<a href="https://pydantic-docs.helpmanual.io/usage/dataclasses/#use-of-stdlib-dataclasses-with-basemodel" class="external-link" target="_blank">内置的 `dataclasses`</a>。

{* ../../docs_src/schema_extra_example/tutorial003_an_py310.py hl[22:29] *}

### Beispiel in der Dokumentations-Benutzeroberfläche { #example-in-the-docs-ui }

Mit jeder der oben genannten Methoden würde es in `/docs` so aussehen:

<img src="/img/tutorial/body-fields/image01.png">

### `Body` mit mehreren `examples` { #body-with-multiple-examples }

      when (val protocol = sslSocket.applicationProtocol) {
        null, "" -> null
        else -> protocol
      }
    } catch (e: UnsupportedOperationException) {
      // https://docs.oracle.com/javase/9/docs/api/javax/net/ssl/SSLSocket.html#getApplicationProtocol--
      null
    }

  @SuppressLint("NewApi")
  override fun configureTlsExtensions(
    sslSocket: SSLSocket,
    hostname: String?,

[Extending the Kubernetes API with the aggregation layer](https://kubernetes.io/docs/concepts/api-extension/apiserver-aggregation/), [Configure the aggregation layer](https://kubernetes.io/docs/tasks/access-kubernetes-api/configure-aggregation-layer/), and [Setup an extension API server](https://kubernetes.io/docs/tasks/access-kubernetes-api/setup-extension-api-server/).

* [alpha] Adding admissionregistration API group which enables dynamic registration of initializers and external admission...

    # Load the client after setting the env var
    client = get_client()
    response = client.get("/openapi.json")
    assert response.status_code == 404, response.text
    response = client.get("/docs")
    assert response.status_code == 404, response.text
    response = client.get("/redoc")
    assert response.status_code == 404, response.text


def test_root():
    client = get_client()

{* ../../docs_src/schema_extra_example/tutorial003_an_py310.py hl[22:29] *}

### Пример в UI документации { #example-in-the-docs-ui }

С любым из перечисленных выше методов это будет выглядеть так в `/docs`:

<img src="/img/tutorial/body-fields/image01.png">

### `Body` с несколькими `examples` { #body-with-multiple-examples }

Конечно, вы можете передать и несколько `examples`:

updateStrategy: RollingUpdate ## Pod priority settings ## ref: https://kubernetes.io/docs/concepts/configuration/pod-priority-preemption/ ## priorityClassName: "" ## Pod runtime class name ## ref https://kubernetes.io/docs/concepts/containers/runtime-class/ ## runtimeClassName: "" ## Set default rootUser, rootPassword ## AccessKey and secretKey is generated when not set ## Distributed MinIO ref: https://docs.minio.io/docs/distributed-minio-quickstart-guide ## rootUser: "" rootPassword: "" ## Use existing...

updateStrategy: RollingUpdate ## Pod priority settings ## ref: https://kubernetes.io/docs/concepts/configuration/pod-priority-preemption/ ## priorityClassName: "" ## Pod runtime class name ## ref https://kubernetes.io/docs/concepts/containers/runtime-class/ ## runtimeClassName: "" ## Set default rootUser, rootPassword ## AccessKey and secretKey is generated when not set ## Distributed MinIO ref: https://docs.minio.io/docs/distributed-minio-quickstart-guide ## rootUser: "" rootPassword: "" ## Use existing...

**FastAPI** **извлечёт** данные для **каждого поля** из **данных формы** в запросе и выдаст вам объявленную Pydantic-модель.

## Проверьте документацию { #check-the-docs }

Вы можете проверить это в интерфейсе документации по адресу `/docs`:

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

## Запрет дополнительных полей формы { #forbid-extra-form-fields }

**FastAPI** **extraerá** los datos para **cada campo** de los **parámetros query** en el request y te proporcionará el modelo de Pydantic que definiste.

## Revisa la Documentación { #check-the-docs }

Puedes ver los parámetros query en la UI de documentación en `/docs`:

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

## Prohibir Parámetros Query Extras { #forbid-extra-query-parameters }