/// note | Détails techniques

`FastAPI` est une classe héritant directement de `Starlette`.

Vous pouvez donc aussi utiliser toutes les fonctionnalités de <a href="https://www.starlette.dev/" class="external-link" target="_blank">Starlette</a> depuis `FastAPI`.

///

### Étape 2 : créer une "instance" `FastAPI`

{* ../../docs_src/first_steps/tutorial001.py hl[3] *}

## Instale manipuladores de exceções customizados { #install-custom-exception-handlers }

Você pode adicionar manipuladores de exceção customizados com <a href="https://www.starlette.dev/exceptions/" class="external-link" target="_blank">a mesma seção de utilidade de exceções presentes no Starlette</a>.

$ pip install python-multipart
```

Isso ocorre porque o **OAuth2** usa "form data" para enviar o `username` e o `password`.

///

Execute o exemplo com:

<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>

## Verifique-o { #check-it }

The same way, there are many compatible tools. Including code generation tools for many languages.

## Pydantic { #pydantic }

All the data validation is performed under the hood by <a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic</a>, so you get all the benefits from it. And you know you are in good hands.

You can use the same type declarations with `str`, `float`, `bool` and many other complex data types.

That extra info will be added as-is to the output **JSON Schema** for that model, and it will be used in the API docs.

You can use the attribute `model_config` that takes a `dict` as described in <a href="https://docs.pydantic.dev/latest/api/config/" class="external-link" target="_blank">Pydantic's docs: Configuration</a>.

## Instalar manejadores de excepciones personalizados { #install-custom-exception-handlers }

Puedes agregar manejadores de excepciones personalizados con <a href="https://www.starlette.dev/exceptions/" class="external-link" target="_blank">las mismas utilidades de excepciones de Starlette</a>.

Supongamos que tienes una excepción personalizada `UnicornException` que tú (o un paquete que usas) podrías lanzar.

## Pydantic { #pydantic }

Toda la validación de datos se realiza internamente con <a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic</a>, así que obtienes todos los beneficios de esta. Y sabes que estás en buenas manos.

$ pip install python-multipart
```

Esto se debe a que **OAuth2** utiliza "form data" para enviar el `username` y `password`.

///

Ejecuta el ejemplo con:

<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>

## Revisa { #check-it }

apiVersion: v1 appVersion: RELEASE.2022-04-09T15-09-52Z description: Multi-Cloud Object Storage home: https://min.io icon: https://min.io/resources/img/logo/MINIO_wordmark.png keywords: - minio - storage - object-storage - s3 - cluster maintainers: - email: dev@minio.io name: MinIO, Inc name: minio sources: - https://github.com/minio/minio version: 3.6.4 minio/values.yaml ## Provide a name in place of minio for `app:` labels ## nameOverride: "" ## Provide a name to substitute for the full names of resources...

apiVersion: v1 appVersion: RELEASE.2021-12-20T22-07-16Z description: Multi-Cloud Object Storage home: https://min.io icon: https://min.io/resources/img/logo/MINIO_wordmark.png keywords: - minio - storage - object-storage - s3 - cluster maintainers: - email: dev@minio.io name: MinIO, Inc name: minio sources: - https://github.com/minio/minio version: 3.4.3 minio/values.yaml ## Provide a name in place of minio for `app:` labels ## nameOverride: "" ## Provide a name to substitute for the full names of resources...