{* ../../docs_src/advanced_middleware/tutorial001_py39.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_py39.py hl[2,6:8] *}

The following arguments are supported:

Начнем с примера, а затем разберём его подробнее.

Мы создаём асинхронную функцию `lifespan()` с `yield` примерно так:

{* ../../docs_src/events/tutorial003_py39.py hl[16,19] *}

Beginnen wir mit einem Beispiel und sehen es uns dann im Detail an.

Wir erstellen eine asynchrone Funktion `lifespan()` mit `yield` wie folgt:

{* ../../docs_src/events/tutorial003_py39.py hl[16,19] *}

{* ../../docs_src/advanced_middleware/tutorial001_py39.py hl[2,6] *}

## `TrustedHostMiddleware` { #trustedhostmiddleware }

Erzwingt, dass alle eingehenden Requests einen korrekt gesetzten `Host`-Header haben, um sich vor HTTP-Host-Header-Angriffen zu schützen.

{* ../../docs_src/advanced_middleware/tutorial002_py39.py hl[2,6:8] *}

Die folgenden Argumente werden unterstützt:

Podríamos descargar el JSON de OpenAPI a un archivo `openapi.json` y luego podríamos **remover ese tag prefijado** con un script como este:

{* ../../docs_src/generate_clients/tutorial004_py39.py *}

//// tab | Node.js

```Javascript
{!> ../../docs_src/generate_clients/tutorial004.js!}
```

////

If you don't want **FastAPI** to include an automatic server using the `root_path`, you can use the parameter `root_path_in_servers=False`:

{* ../../docs_src/behind_a_proxy/tutorial004_py39.py hl[9] *}

and then it won't include it in the OpenAPI schema.

## Mounting a sub-application { #mounting-a-sub-application }

import runpy
from unittest.mock import patch

import pytest


@pytest.mark.parametrize(
    "module_name",
    [
        "tutorial001_py39",
        "tutorial002_py39",
    ],
)
def test_run_module(module_name: str):
    with patch("builtins.print") as mock_print:
        runpy.run_module(f"docs_src.python_types.{module_name}", run_name="__main__")

Если вы не хотите, чтобы FastAPI добавлял автоматический сервер, используя `root_path`, укажите параметр `root_path_in_servers=False`:

{* ../../docs_src/behind_a_proxy/tutorial004_py39.py hl[9] *}

и тогда этот сервер не будет добавлен в схему OpenAPI.

## Монтирование вложенного приложения { #mounting-a-sub-application }

Wenn Sie `lifespan` in Ihren Tests ausführen müssen, können Sie den `TestClient` mit einer `with`-Anweisung verwenden:

{* ../../docs_src/app_testing/tutorial004_py39.py hl[9:15,18,27:28,30:32,41:43] *}


Sie können mehr Details unter [„Lifespan in Tests ausführen in der offiziellen Starlette-Dokumentation.“](https://www.starlette.dev/lifespan/#running-lifespan-in-tests) nachlesen.

Quando você precisa que o `lifespan` seja executado em seus testes, você pode utilizar o `TestClient` com a instrução `with`:

{* ../../docs_src/app_testing/tutorial004_py39.py hl[9:15,18,27:28,30:32,41:43] *}

Você pode ler mais detalhes sobre o ["Executando lifespan em testes no site oficial da documentação do Starlette."](https://www.starlette.dev/lifespan/#running-lifespan-in-tests)