```

</div>

/// tip

You can read more about it at <a href="https://12factor.net/config" class="external-link" target="_blank">The Twelve-Factor App: Config</a>.

///

## Types and Validation { #types-and-validation }

    * `Path()`
    * `Query()`
    * `Header()`
    * `Cookie()`

For example, it doesn't receive `datetime` objects, as those are not compatible with JSON.

So, a `datetime` object would have to be converted to a `str` containing the data in <a href="https://en.wikipedia.org/wiki/ISO_8601" class="external-link" target="_blank">ISO format</a>.

The same way, this database wouldn't receive a Pydantic model (an object with attributes), only a `dict`.

You can use `jsonable_encoder` for that.

### `pydantic-settings` installieren { #install-pydantic-settings }

Stellen Sie zunächst sicher, dass Sie Ihre [virtuelle Umgebung](../virtual-environments.md){.internal-link target=_blank} erstellt und aktiviert haben, und installieren Sie dann das Package `pydantic-settings`:

Por causa disso, o próprio **FastAPI** fornece uma documentação alternativa da API (usando ReDoc), que você pode acessar em <a href="http://127.0.0.1:8000/redoc" class="external-link" target="_blank">http://127.0.0.1:8000/redoc</a>:

<img src="/img/tutorial/path-params/image02.png">

`TestClient` 是基于 <a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a> 的。幸运的是，我们可以直接使用它来测试API。

## 示例

举个简单的例子，让我们来看一个[更大的应用](../tutorial/bigger-applications.md){.internal-link target=_blank}和[测试](../tutorial/testing.md){.internal-link target=_blank}中描述的类似文件结构：

```
.
├── app
│   ├── __init__.py
│   ├── main.py
│   └── test_main.py
```

Starlette (y **FastAPI**) están basados en <a href="https://anyio.readthedocs.io/en/stable/" class="external-link" target="_blank">AnyIO</a>, lo que lo hace compatible tanto con el <a href="https://docs.python.org/3/library/asyncio-task.html" class="external-link" target="_blank">asyncio</a> del paquete estándar de Python como con <a href="https://trio.readthedocs.io/en/stable/" class="external-link" target="_blank">Trio</a>.

/// info | Інформація

Щоб використовувати форми, спочатку встановіть <a href="https://github.com/Kludex/python-multipart" class="external-link" target="_blank">`python-multipart`</a>.

Переконайтеся, що Ви створили [віртуальне середовище](../virtual-environments.md){.internal-link target=_blank}, активували його, і потім встановили бібліотеку, наприклад:

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

///

Y el resto será manejado por **FastAPI**.

Si lo ejecutas y vas a <a href="http://localhost:8000/v1/" class="external-link" target="_blank">http://localhost:8000/v1/</a> verás el response de Flask:

```txt
Hello, World from Flask!
```

Y si vas a <a href="http://localhost:8000/v2" class="external-link" target="_blank">http://localhost:8000/v2</a> verás el response de FastAPI:

```JSON
{
    "message": "Hello World"
}

Jede Funktion, die dekoriert werden kann mit:

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

kann auch als gültige **FastAPI**-Abhängigkeit verwendet werden.