```Python hl_lines="1  3"
{!> ../../docs_src/query_params_str_validations/tutorial002_an_py310.py!}
```

////

//// tab | Python 3.8+

In Versionen unter Python 3.9 importieren Sie `Annotated` von `typing_extensions`.

Es wird bereits mit FastAPI installiert sein.

```Python hl_lines="3-4"
{!> ../../docs_src/query_params_str_validations/tutorial002_an.py!}
```

////

/// info

### `OAuth2PasswordRequestForm`

Importieren Sie zunächst `OAuth2PasswordRequestForm` und verwenden Sie es als Abhängigkeit mit `Depends` in der *Pfadoperation* für `/token`:

{* ../../docs_src/security/tutorial003_an_py310.py hl[4,78] *}

`OAuth2PasswordRequestForm` ist eine Klassenabhängigkeit, die einen Formularbody deklariert mit:

* Dem `username`.
* Dem `password`.

### `OAuth2PasswordRequestForm`

Primero, importa `OAuth2PasswordRequestForm`, y úsalo como una dependencia con `Depends` en la *path operation* para `/token`:

{* ../../docs_src/security/tutorial003_an_py310.py hl[4,78] *}

`OAuth2PasswordRequestForm` es una dependencia de clase que declara un body de formulario con:

* El `username`.
* El `password`.

```Python hl_lines="1  3"
{!> ../../docs_src/query_params_str_validations/tutorial002_an_py310.py!}
```

////

//// tab | Python 3.8+

В версиях Python ниже Python 3.9 `Annotation` импортируется из `typing_extensions`.

Эта библиотека будет установлена вместе с FastAPI.

```Python hl_lines="3-4"
{!> ../../docs_src/query_params_str_validations/tutorial002_an.py!}
```

////

## `Annotated` как тип для query-параметра `q`

{* ../../docs_src/path_operation_configuration/tutorial002b.py hl[1,8:10,13,18] *}

## 📄 & 📛

👆 💪 🚮 `summary` & `description`:

{* ../../docs_src/path_operation_configuration/tutorial003.py hl[20:21] *}

## 📛 ⚪️➡️ #️⃣

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

 `main.py`는 아래와 같아야 합니다:

{* ../../docs_src/async_tests/main.py *}

`test_main.py` 파일은 `main.py`에 대한 테스트가 있을 텐데, 다음과 같을 수 있습니다:

{* ../../docs_src/async_tests/test_main.py *}

## 실행하기

아래의 명령어로 테스트 코드를 실행합니다:

<div class="termy">

```console
$ pytest

**FastAPI** will take care of solving them.

## First dependency "dependable" { #first-dependency-dependable }

You could create a first dependency ("dependable") like:

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[8:9] *}

It declares an optional query parameter `q` as a `str`, and then it just returns it.

This is quite simple (not very useful), but will help us focus on how the sub-dependencies work.

Prenons un exemple simple :

{*../../docs_src/python_types/tutorial001.py*}

Exécuter ce programe affiche :

```
John Doe
```

La fonction :

* Prend un `first_name` et un `last_name`.
* Convertit la première lettre de chaque paramètre en majuscules grâce à `title()`.
* Concatène les résultats avec un espace entre les deux.

{*../../docs_src/python_types/tutorial001.py hl[2] *}

### Limitations

{* ../../docs_src/advanced_middleware/tutorial001.py hl[2,6] *}

## `TrustedHostMiddleware` { #trustedhostmiddleware }

Enforces that all incoming requests have a correctly set `Host` header, in order to guard against HTTP Host Header attacks.

{* ../../docs_src/advanced_middleware/tutorial002.py hl[2,6:8] *}

The following arguments are supported:

## `Header` 임포트

먼저 `Header`를 임포트합니다:

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

## `Header` 매개변수 선언

`Path`, `Query` 그리고 `Cookie`를 사용한 동일한 구조를 이용하여 헤더 매개변수를 선언합니다.

첫 번째 값은 기본값이며, 추가 검증이나 어노테이션 매개변수 모두 전달할 수 있습니다:

{* ../../docs_src/header_params/tutorial001.py hl[9] *}

/// note | 기술 세부사항

`Header`는 `Path`, `Query` 및 `Cookie`의 "자매"클래스입니다. 이 역시 동일한 공통 `Param` 클래스를 상속합니다.