operation.operationId = newOperationId
          }
        }
      }
    }

    await fs.promises.writeFile(
      filePath,
      JSON.stringify(openapiContent, null, 2),
    )
    console.log('File successfully modified')
  } catch (err) {
    console.error('Error:', err)
  }
}

const filePath = './openapi.json'

```Python hl_lines="6"
{!../../../docs_src/events/tutorial002.py!}
```

Hier schreibt die `shutdown`-Eventhandler-Funktion eine Textzeile `"Application shutdown"` in eine Datei `log.txt`.

!!! info
    In der Funktion `open()` bedeutet `mode="a"` „append“ („anhängen“), sodass die Zeile nach dem, was sich in dieser Datei befindet, hinzugefügt wird, ohne den vorherigen Inhalt zu überschreiben.

```Python hl_lines="6"
{!../../../docs_src/events/tutorial002.py!}
```

Aqui, a função de manipulação de evento `shutdown` irá escrever uma linha de texto `"Application shutdown"` no arquivo `log.txt`.

!!! info "Informação"
    Na função `open()`, o `mode="a"` significa "acrescentar", então, a linha irá ser adicionada depois de qualquer coisa que esteja naquele arquivo, sem sobrescrever o conteúdo anterior.

    * A "token" is just a string with some content that we can use later to verify this user.
    * Normally, a token is set to expire after some time.
        * So, the user will have to log in again at some point later.
        * And if the token is stolen, the risk is less. It is not like a permanent key that will work forever (in most of the cases).
* The frontend stores that token temporarily somewhere.

只有所有 `startup` 事件处理器运行完毕，**FastAPI** 应用才开始接收请求。

## `shutdown` 事件

使用 `shutdown` 事件声明 `app` 关闭时运行的函数：

```Python hl_lines="6"
{!../../../docs_src/events/tutorial002.py!}
```

此处，`shutdown` 事件处理器函数在 `log.txt` 中写入一行文本 `Application shutdown`。

!!! info "说明"

    `open()` 函数中，`mode="a"` 指的是**追加**。因此这行文本会添加在文件已有内容之后，不会覆盖之前的内容。

!!! tip "提示"

    注意，本例使用 Python `open()` 标准函数与文件交互。

## `shutdown` 이벤트

응용 프로그램이 종료될 때 실행하려는 함수를 추가하려면 `"shutdown"` 이벤트로 선언합니다:

```Python hl_lines="6"
{!../../../docs_src/events/tutorial002.py!}
```

이 예제에서 `shutdown` 이벤트 핸들러 함수는 `"Application shutdown"`이라는 텍스트가 적힌 `log.txt` 파일을 추가할 것입니다.

!!! info "정보"
    `open()` 함수에서 `mode="a"`는 "추가"를 의미합니다. 따라서 이미 존재하는 파일의 내용을 덮어쓰지 않고 새로운 줄을 추가합니다.

!!! tip "팁"
    이 예제에서는 파일과 상호작용 하기 위해 파이썬 표준 함수인 `open()`을 사용하고 있습니다.

    ## Example

    ```python
    from fastapi import BackgroundTasks, FastAPI

    app = FastAPI()


    def write_notification(email: str, message=""):
        with open("log.txt", mode="w") as email_file:
            content = f"notification for {email}: {message}"
            email_file.write(content)


    @app.post("/send-notification/{email}")

**FastAPI** uses it so that, if you use a Pydantic model in `response_model`, and your data has an error, you will see the error in your log.

But the client/user will not see it. Instead, the client will receive an "Internal Server Error" with a HTTP status code `500`.

* 👥 Update FastAPI People. PR [#9181](https://github.com/tiangolo/fastapi/pull/9181) by [@github-actions[bot]](https://github.com/apps/github-actions).
* 🔊 Log GraphQL errors in FastAPI People, because it returns 200, with a payload with an error. PR [#9171](https://github.com/tiangolo/fastapi/pull/9171) by [@tiangolo](https://github.com/tiangolo).

`RequestValidationError` é uma subclasse do <a href="https://docs.pydantic.dev/latest/#error-handling" class="external-link" target="_blank">`ValidationError`</a> existente no Pydantic.

**FastAPI** faz uso dele para que você veja o erro no seu log, caso você utilize um modelo de Pydantic em `response_model`, e seus dados tenham erro.

Contudo, o cliente ou usuário não terão acesso a ele. Ao contrário, o cliente receberá um "Internal Server Error" com o HTTP status code `500`.