# Form Models { #form-models }

You can use **Pydantic models** to declare **form fields** in FastAPI.

/// info

To use forms, first install <a href="https://github.com/Kludex/python-multipart" class="external-link" target="_blank">`python-multipart`</a>.

Make sure you create a [virtual environment](../virtual-environments.md){.internal-link target=_blank}, activate it, and then install it, for example:

```console
$ pip install python-multipart
```

import org.gradle.api.tasks.TaskAction
import org.gradle.util.GradleVersion
import org.gradle.work.DisableCachingByDefault
import java.io.File


@DisableCachingByDefault(because = "Not worth caching")
abstract class UpdateReleasedVersions : DefaultTask() {

    @get:Internal
    abstract val releasedVersionsFile: RegularFileProperty

    @get:Internal
    abstract val currentReleasedVersion: Property<ReleasedVersion>

 */
package gradlebuild.docs.dsl.source.model;

import org.gradle.api.Action;

import java.io.Serializable;

/**
 * Static meta-data about a property extracted from the source for the class.
 */
public class PropertyMetaData extends AbstractLanguageElement implements Serializable, TypeContainer {
    private TypeMetaData type;
    private final String name;
    private final ClassMetaData ownerClass;

import org.gradle.api.tasks.testing.Test
import org.gradle.build.event.BuildEventsListenerRegistry
import org.gradle.kotlin.dsl.*
import org.gradle.kotlin.dsl.support.serviceOf
import java.io.File


class TestFilesCleanupRootPlugin : Plugin<Project> {
    override fun apply(project: Project) {
        require(project.rootProject == project) { "This plugin should be applied to root project!" }

package org.gradle.test;

public class JavaClassWithFullyQualifiedNames extends org.gradle.test.sub.SubClass implements org.gradle.test.sub.SubJavaInterface, java.lang.Runnable {
    org.gradle.test.sub.SubJavaInterface getProp() {
        return this;
    }

    public void run() {
    }

### Modelo de Entrada en la Documentación { #input-model-in-docs }

Puedes confirmar eso en la documentación, el campo `description` no tiene un **asterisco rojo**, no está marcado como requerido:

<div class="screenshot">
<img src="/img/tutorial/separate-openapi-schemas/image01.png">
</div>

### Modelo para Salida { #model-for-output }

Pero si usas el mismo modelo como salida, como aquí:

### Modelo de Entrada na Documentação { #input-model-in-docs }

Você pode confirmar que na documentação, o campo `description` não tem um **asterisco vermelho**, não é marcado como obrigatório:

<div class="screenshot">
<img src="/img/tutorial/separate-openapi-schemas/image01.png">
</div>

### Modelo para Saída { #model-for-output }

Mas se você usar o mesmo modelo como saída, como aqui:

/**
 *<strong>Warning:</strong> This is an internal utility class that is only public for technical reasons, it is not part
 * of the public API. In particular, this class can be changed or deleted without prior notice. Use
 * {@link org.apache.maven.project.MavenProjectHelper#attachArtifact} instead.
 */
@Deprecated
public class AttachedArtifact extends DefaultArtifact {

    private final Artifact parent;

Все блоки кода можно копировать и использовать напрямую (это действительно протестированные файлы Python).

Чтобы запустить любой из примеров, скопируйте код в файл `main.py` и запустите `fastapi dev` с:

<div class="termy">

```console
$ <font color="#4E9A06">fastapi</font> dev <u style="text-decoration-style:solid">main.py</u>

///

/// note | 技术细节

任何一个可以与以下内容一起使用的函数：

* <a href="https://docs.python.org/3/library/contextlib.html#contextlib.contextmanager" class="external-link" target="_blank">`@contextlib.contextmanager`</a> 或者
* <a href="https://docs.python.org/3/library/contextlib.html#contextlib.asynccontextmanager" class="external-link" target="_blank">`@contextlib.asynccontextmanager`</a>

都可以作为 **FastAPI** 的依赖项。

实际上，FastAPI内部就使用了这两个装饰器。

///