Você irá aprender mais sobre adicionar informações extras posteriormente nessa documentação, quando estiver aprendendo a declarar exemplos.

## Recapitulando

Você pode usar `Field` do Pydantic para declarar validações extras e metadados para atributos do modelo.

would be valid to use as a **FastAPI** dependency.

In fact, FastAPI uses those two decorators internally.

///

## A database dependency with `yield` { #a-database-dependency-with-yield }

For example, you could use this to create a database session and close it after finishing.

Only the code prior to and including the `yield` statement is executed before creating a response:

time="2020-07-12T20:45:50Z" level=info msg="config issuer: http://127.0.0.1:5556/dex"
time="2020-07-12T20:45:50Z" level=info msg="config storage: sqlite3"
time="2020-07-12T20:45:50Z" level=info msg="config static client: Example App"
time="2020-07-12T20:45:50Z" level=info msg="config connector: mock"
time="2020-07-12T20:45:50Z" level=info msg="config connector: local passwords enabled"

       *
       * Example:
       * ```
       * --> POST /greeting http/1.1 (3-byte body)
       *
       * <-- 200 OK (22ms, 6-byte body)
       * ```
       */
      BASIC,

      /**
       * Logs request and response lines and their respective headers.
       *
       * Example:
       * ```
       * --> POST /greeting http/1.1
       * Host: example.com
       * Content-Type: plain/text

Asegúrate de crear un [entorno virtual](../virtual-environments.md){.internal-link target=_blank}, actívalo y luego instálalo, por ejemplo:

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

///

## Importar `File` y `Form`

{* ../../docs_src/request_forms_and_files/tutorial001_an_py39.py hl[3] *}

## Definir parámetros `File` y `Form`

For example "**Python 3.6+**" means it's compatible with Python 3.6 or above (including 3.7, 3.8, 3.9, 3.10, etc). And "**Python 3.9+**" means it's compatible with Python 3.9 or above (including 3.10, etc).

If you can use the **latest versions of Python**, use the examples for the latest version, those will have the **best and simplest syntax**, for example, "**Python 3.10+**".

#### List { #list }

As all these methods are `async` methods, you need to "await" them.

For example, inside of an `async` *path operation function* you can get the contents with:

```Python
contents = await myfile.read()
```

If you are inside of a normal `def` *path operation function*, you can access the `UploadFile.file` directly, for example:

```Python
contents = myfile.file.read()
```

/// note | `async` Technical Details

{* ../../docs_src/path_params/tutorial001.py hl[6:7] *}

La valeur du paramètre `item_id` sera transmise à la fonction dans l'argument `item_id`.

Donc, si vous exécutez cet exemple et allez sur <a href="http://127.0.0.1:8000/items/foo" class="external-link" target="_blank">http://127.0.0.1:8000/items/foo</a>,
vous verrez comme réponse :

```JSON
{"item_id":"foo"}
```

**FastAPI** will keep the additional information from `responses`, and combine it with the JSON Schema from your model.

For example, you can declare a response with a status code `404` that uses a Pydantic model and has a custom `description`.

And a response with a status code `200` that uses your `response_model`, but includes a custom `example`:

{* ../../docs_src/additional_responses/tutorial003.py hl[20:31] *}

For example, in the URL:

```
http://127.0.0.1:8000/items/?skip=0&limit=10
```

...the query parameters are:

* `skip`: with a value of `0`
* `limit`: with a value of `10`

As they are part of the URL, they are "naturally" strings.

But when you declare them with Python types (in the example above, as `int`), they are converted to that type and validated against it.