You can declare a parameter of type `Response` in your *path operation function* (as you can do for cookies).

And then you can set headers in that *temporal* response object.

{* ../../docs_src/response_headers/tutorial002_py310.py hl[1, 7:8] *}

And then you can return any object you need, as you normally would (a `dict`, a database model, etc).

---> 100%
```

</div>

## Utiliser `Jinja2Templates` { #using-jinja2templates }

- Importez `Jinja2Templates`.
- Créez un objet `templates` que vous pourrez réutiliser par la suite.
- Déclarez un paramètre `Request` dans le *chemin d'accès* qui renverra un template.

///

## Pydantic Models for Forms { #pydantic-models-for-forms }

You just need to declare a **Pydantic model** with the fields you want to receive as **form fields**, and then declare the parameter as `Form`:

{* ../../docs_src/request_form_models/tutorial001_an_py310.py hl[9:11,15] *}

**FastAPI** will **extract** the data for **each field** from the **form data** in the request and give you the Pydantic model you defined.

   * Throwable}. But we <i>can</i> write {@code sneakyThrow(t);}.
   *
   * <p>We sometimes also use {@code sneakyThrow} for testing how our code responds to
   * sneaky checked exception.
   *
   * @return never; this method declares a return type of {@link Error} only so that callers can
   *     write {@code throw sneakyThrow(t);} to convince the compiler that the statement will always
   *     throw.
   */
  @CanIgnoreReturnValue

Dans ce cas, la liste devrait inclure `http://localhost:8080` pour que le frontend `:8080` fonctionne correctement.

## Caractères génériques { #wildcards }

Il est également possible de déclarer la liste comme « * » (un « wildcard ») pour indiquer que toutes sont autorisées.

* A documentação alternativa também irá refletir o novo parâmetro query e o corpo:

![ReDoc](https://fastapi.tiangolo.com/img/index/index-06-redoc-02.png)

### Recapitulando { #recap }

Resumindo, você declara **uma vez** os tipos dos parâmetros, corpo etc. como parâmetros de função.

Você faz isso com os tipos padrão do Python moderno.

Although any other parameter declared normally (for example, the body with a Pydantic model) would still be validated, converted, annotated, etc.

But there are specific cases where it's useful to get the `Request` object.

 * declared to be copied.
 * <br>
 * <i>For example:</i>
 * <pre>
 * restResources {
 *   restApi {
 *     includeXpack 'enrich'
 *   }
 * }
 * </pre>
 * Will copy the entire core Rest API specifications (assuming the project has tests) and any of the the X-pack specs starting with enrich*.

Si chaque élément JSON que vous voulez renvoyer est de type `Item` (un modèle Pydantic) et que c'est une fonction async, vous pouvez déclarer le type de retour comme `AsyncIterable[Item]` :

{* ../../docs_src/stream_json_lines/tutorial001_py310.py ln[1:24] hl[9:11,22] *}

Si vous déclarez le type de retour, FastAPI l'utilisera pour **valider** les données, les **documenter** dans OpenAPI, les **filtrer**, et les **sérialiser** avec Pydantic.

Estas funciones pueden ser declaradas con `async def` o `def` normal.

### Evento `startup` { #startup-event }

Para añadir una función que debería ejecutarse antes de que la aplicación inicie, declárala con el evento `"startup"`:

{* ../../docs_src/events/tutorial001_py310.py hl[8] *}

En este caso, la función manejadora del evento `startup` inicializará los ítems de la "base de datos" (solo un `dict`) con algunos valores.