```

これで、ブラウザがパスワードを使ってユーザーを作成する際に、APIがレスポンスで同じパスワードを返すようになりました。

この場合、ユーザー自身がパスワードを送信しているので問題ないかもしれません。

しかし、同じモデルを別の*path operation*に使用すると、すべてのクライアントにユーザーのパスワードを送信してしまうことになります。

!!! danger "危険"
    ユーザーの平文のパスワードを保存したり、レスポンスで送信したりすることは絶対にしないでください。

## 出力モデルの追加

代わりに、平文のパスワードを持つ入力モデルと、パスワードを持たない出力モデルを作成することができます:

```Python hl_lines="9 11 16"
{!../../../docs_src/response_model/tutorial003.py!}
```

They tend to require more complex configurations, a message/job queue manager, like RabbitMQ or Redis, but they allow you to run background tasks in multiple processes, and especially, in multiple servers.

# 🔗 ⏮️ 🌾

FastAPI 🐕‍🦺 🔗 👈 <abbr title='sometimes also called "exit", "cleanup", "teardown", "close", "context managers", ...'>➕ 🔁 ⏮️ 🏁</abbr>.

👉, ⚙️ `yield` ↩️ `return`, &amp; ✍ ➕ 🔁 ⏮️.

!!! tip
    ⚒ 💭 ⚙️ `yield` 1️⃣ 👁 🕰.

!!! note "📡 ℹ"
    🙆 🔢 👈 ☑ ⚙️ ⏮️:

    * <a href="https://docs.python.org/3/library/contextlib.html#contextlib.contextmanager" class="external-link" target="_blank">`@contextlib.contextmanager`</a> ⚖️

In particular, this may be a good alternative to logic in a middleware.

For example, if you want to read or manipulate the request body before it is processed by your application.

!!! danger
    This is an "advanced" feature.

    If you are just starting with **FastAPI** you might want to skip this section.

## Use cases

Some use cases include:

# 🛃 📨 & APIRoute 🎓

💼, 👆 5️⃣📆 💚 🔐 ⚛ ⚙️ `Request` & `APIRoute` 🎓.

🎯, 👉 5️⃣📆 👍 🎛 ⚛ 🛠️.

🖼, 🚥 👆 💚 ✍ ⚖️ 🔬 📨 💪 ⏭ ⚫️ 🛠️ 👆 🈸.

!!! danger
    👉 "🏧" ⚒.

    🚥 👆 ▶️ ⏮️ **FastAPI** 👆 💪 💚 🚶 👉 📄.

## ⚙️ 💼

⚙️ 💼 🔌:

* 🏭 🚫-🎻 📨 💪 🎻 (✅ <a href="https://msgpack.org/index.html" class="external-link" target="_blank">`msgpack`</a>).
* 🗜 🗜-🗜 📨 💪.
* 🔁 🚨 🌐 📨 💪.

from fastapi import FastAPI

tags_metadata = [
    {
        "name": "users",
        "description": "Operations with users. The **login** logic is also here.",
    },
    {
        "name": "items",
        "description": "Manage items. So _fancy_ they have their own docs.",
        "externalDocs": {
            "description": "Items external docs",
            "url": "https://fastapi.tiangolo.com/",
        },
    },
]

                "name": "users",
                "description": "Operations with users. The **login** logic is also here.",
            },
            {
                "name": "items",
                "description": "Manage items. So _fancy_ they have their own docs.",
                "externalDocs": {
                    "description": "Items external docs",
                    "url": "https://fastapi.tiangolo.com/",
                },

# FastAPI CLI

**FastAPI CLI** is a command line program `fastapi` that you can use to serve your FastAPI app, manage your FastAPI project, and more.

When you install FastAPI (e.g. with `pip install fastapi`), it includes a package called `fastapi-cli`, this package provides the `fastapi` command in the terminal.

To run your FastAPI app for development, you can use the `fastapi dev` command:

<div class="termy">

```console

Das kann insbesondere eine gute Alternative zur Logik in einer Middleware sein.

Wenn Sie beispielsweise den Requestbody lesen oder manipulieren möchten, bevor er von Ihrer Anwendung verarbeitet wird.

!!! danger "Gefahr"
    Dies ist eine „fortgeschrittene“ Funktion.

    Wenn Sie gerade erst mit **FastAPI** beginnen, möchten Sie diesen Abschnitt vielleicht überspringen.

## Anwendungsfälle

Einige Anwendungsfälle sind:

* The **input model** needs to be able to have a password.
* The **output model** should not have a password.
* The **database model** would probably need to have a hashed password.

!!! danger
    Never store user's plaintext passwords. Always store a "secure hash" that you can then verify.