有关事件处理器的详情，请参阅 <a href="https://www.starlette.dev/lifespan/" class="external-link" target="_blank">Starlette 官档 - 事件</a>。

包括如何处理生命周期状态，这可以用于程序的其他部分。

///

## 子应用

`FastAPI` é na verdade uma sub-classe do `Starlette`. Então, se você já conhece ou usa Starlette, a maioria das funcionalidades se comportará da mesma forma.

	// to the nearest second and ignores the AccessTime and ChangeTime fields.
	//
	// To use AccessTime or ChangeTime, specify the Format as PAX or GNU.
	// To use sub-second resolution, specify the Format as PAX.
	ModTime    time.Time // Modification time
	AccessTime time.Time // Access time (requires either PAX or GNU support)

이 문서에는 코드의 다른 영역에서 사용할 수 있는 lifespan 상태를 처리하는 방법도 포함되어 있습니다.

///

## 서브 애플리케이션

	return false
}

// returns true if object was modified after givenTime.
func ifModifiedSince(objTime time.Time, givenTime time.Time) bool {
	// The Date-Modified header truncates sub-second precision, so
	// use mtime < t+1s instead of mtime <= t to check for unmodified.
	return !objTime.Before(givenTime.Add(1 * time.Second))
}

///

### Crear el objeto `Settings` { #create-the-settings-object }

Importa `BaseSettings` de Pydantic y crea una sub-clase, muy similar a un modelo de Pydantic.

De la misma forma que con los modelos de Pydantic, declaras atributos de clase con anotaciones de tipos, y posiblemente, valores por defecto.

	}

	if err := DB.Model(&user).Update("name", DB.Model(&Company{}).Select("name").Where("companies.id = users.company_id")).Error; err != nil {
		t.Errorf("failed to update with sub query, got error %v", err)
	}

	var result User
	DB.First(&result, user.ID)

	if result.Name != user.Company.Name {
		t.Errorf("name should be %v, but got %v", user.Company.Name, result.Name)
	}

<div class="termy">

```console
$ pip install "fastapi[all]"
---> 100%
```

</div>

### Create the `Settings` object { #create-the-settings-object }

Import `BaseSettings` from Pydantic and create a sub-class, very much like with a Pydantic model.

The same way as with Pydantic models, you declare class attributes with type annotations, and possibly default values.

    post_content = content[post_start:]
    new_content = pre_content + message + post_content
    # Remove content between <!-- only-mkdocs --> and <!-- /only-mkdocs -->
    new_content = re.sub(
        r"<!-- only-mkdocs -->.*?<!-- /only-mkdocs -->",
        "",
        new_content,
        flags=re.DOTALL,
    )
    return new_content


@app.command()
def generate_readme() -> None:

如果不想让 **FastAPI** 包含使用 `root_path` 的自动服务器，则要使用参数 `root_path_in_servers=False`：

{* ../../docs_src/behind_a_proxy/tutorial004.py hl[9] *}

这样，就不会在 OpenAPI 概图中包含服务器了。

## 挂载子应用

如需挂载子应用（详见 [子应用 - 挂载](sub-applications.md){.internal-link target=_blank}），也要通过 `root_path` 使用代理，这与正常应用一样，别无二致。