And these same full-stack generators were the base of the [**FastAPI** Project Generators](project-generation.md){.internal-link target=_blank}.

!!! info
    Flask-apispec was created by the same Marshmallow developers.

!!! check "Inspired **FastAPI** to"
    Generate the OpenAPI schema automatically, from the same code that defines serialization and validation.

You can add code to be run with the `request`,  before any *path operation* receives it.

And also after the `response` is generated, before returning it.

For example, you could add a custom header `X-Process-Time` containing the time in seconds that it took to process the request and generate a response:

```Python hl_lines="10  12-13"
{!../../../docs_src/middleware/tutorial001.py!}
```

## Other middlewares

It's possible to create a `list` of its items with `list(some_user.items)`.

But the object itself is not a `list`. And it's also not an actual Python <a href="https://docs.python.org/3/glossary.html#term-generator" class="external-link" target="_blank">generator</a>. Because of this, Pydantic doesn't know by default how to convert it to a `list` of Pydantic *models* / schemas.

Sam Courtemanche <******@****.***> 1625235486 +0200

Fabio Serrao <******@****.***> 1602913832 -0300

## Tests

There is a script that you can run locally to test all the code and generate coverage reports in HTML:

<div class="termy">

```console
$ bash scripts/test-cov-html.sh
```

</div>

これらは、より複雑な構成、RabbitMQ や Redis などのメッセージ/ジョブキューマネージャーを必要とする傾向がありますが、複数のプロセス、特に複数のサーバーでバックグラウンドタスクを実行できます。

例を確認するには、[Project Generators](../project-generation.md){.internal-link target=_blank} を参照してください。これらにはすべて、Celery が構築済みです。

ただし、同じ **FastAPI** アプリから変数とオブジェクトにアクセスする必要がある場合、または小さなバックグラウンドタスク (電子メール通知の送信など) を実行する必要がある場合は、単に `BackgroundTasks` を使用できます。

## まとめ

![ReDoc](https://fastapi.tiangolo.com/img/index/index-02-redoc-simple.png)

### OpenAPI

**FastAPI** generates a "schema" with all your API using the **OpenAPI** standard for defining APIs.

#### "Schema"

A "schema" is a definition or description of something. Not the code that implements it, but just an abstract description.

* Add a **JSON Schema** for the response, in the OpenAPI *path operation*.
    * This will be used by the **automatic docs**.
    * It will also be used by automatic client code generation tools.

But most importantly:

* It will **limit and filter** the output data to what is defined in the return type.
    * This is particularly important for **security**, we'll see more of that below.

    Notice that the path parameter is declared to be an integer.

## Standards-based benefits, alternative documentation

And because the generated schema is from the <a href="https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.1.0.md" class="external-link" target="_blank">OpenAPI</a> standard, there are many compatible tools.