Sebastián Ramírez <******@****.***> 1558958893 +0400

ここで、タスク関数はファイル書き込みを実行します (メール送信のシミュレーション)。

また、書き込み操作では `async` と `await` を使用しないため、通常の `def` で関数を定義します。

```Python hl_lines="6-9"
{!../../../docs_src/background_tasks/tutorial001.py!}
```

## バックグラウンドタスクの追加

*path operations 関数* 内で、`.add_task()` メソッドを使用してタスク関数を *background tasks* オブジェクトに渡します。

```Python hl_lines="14"
{!../../../docs_src/background_tasks/tutorial001.py!}
```

`.add_task()` は以下の引数を受け取ります:

```

...that's because the client generator uses the OpenAPI internal **operation ID** for each *path operation*.

OpenAPI requires that each operation ID is unique across all the *path operations*, so FastAPI uses the **function name**, the **path**, and the **HTTP method/operation** to generate that operation ID, because that way it can make sure that the operation IDs are unique.

But I'll show you how to improve that next. 🤓

    ```

And all the ideas in the section about [adding `dependencies` to the *path operation decorators*](dependencies-in-path-operation-decorators.md){.internal-link target=_blank} still apply, but in this case, to all of the *path operations* in the app.

## Dependencies for groups of *path operations*

But here's the key point.

The security and dependency injection stuff is written once.

And you can make it as complex as you want. And still, have it written only once, in a single place. With all the flexibility.

But you can have thousands of endpoints (*path operations*) using the same security system.

And we can add a list of `dependencies` that will be added to all the *path operations* in the router and will be executed/solved for each request made to them.

!!! tip

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

Let's say that now the file `main.py` with your **FastAPI** app has some other **path operations**.

It has a `GET` operation that could return an error.

It has a `POST` operation that could return several errors.

Both *path operations* require an `X-Token` header.

=== "Python 3.10+"

    ```Python
    {!> ../../../docs_src/app_testing/app_b_an_py310/main.py!}

### Top-level application

First, create the main, top-level, **FastAPI** application, and its *path operations*:

```Python hl_lines="3  6-8"
{!../../../docs_src/sub_applications/tutorial001.py!}
```

### Sub-application

Then, create your sub-application, and its *path operations*.

    It is the "**path operation decorator**".

You can also use the other operations:

* `@app.post()`
* `@app.put()`
* `@app.delete()`

And the more exotic ones:

* `@app.options()`
* `@app.head()`
* `@app.patch()`
* `@app.trace()`

!!! tip
    You are free to use each operation (HTTP method) as you wish.

To add tags to your *path operations*, and group them in the docs UI, read the docs for [Tutorial - Path Operation Configurations - Tags](../tutorial/path-operation-configuration.md#tags){.internal-link target=_blank}.

## Documentation Summary and Description - OpenAPI