## Bodies of arbitrary `dict`s

You can also declare a body as a `dict` with keys of some type and values of some other type.

This way, you don't have to know beforehand what the valid field/attribute names are (as would be the case with Pydantic models).

    'full_name': None,
}
```

#### Unwrapping a `dict`

If we take a `dict` like `user_dict` and pass it to a function (or class) with `**user_dict`, Python will "unwrap" it. It will pass the keys and values of the `user_dict` directly as key-value arguments.

So, continuing with the `user_dict` from above, writing:

```Python
UserInDB(**user_dict)
```

would result in something equivalent to:

```Python
UserInDB(

    "name": "Mary",
    "joined": "2018-11-30",
}

my_second_user: User = User(**second_user_data)
```

!!! info
    `**second_user_data` means:

    Pass the keys and values of the `second_user_data` dict directly as key-value arguments, equivalent to: `User(id=4, name="Mary", joined="2018-11-30")`

### Editor support

    ```

🚥 👆 🔗 ⏮️ 👈 *➡ 🛠️* 📨 2️⃣ 🇺🇸🔍 🎚 💖:

```
X-Token: foo
X-Token: bar
```

📨 🔜 💖:

```JSON
{
    "X-Token values": [
        "bar",
        "foo"
    ]
}
```

## 🌃

📣 🎚 ⏮️ `Header`, ⚙️ 🎏 ⚠ ⚓ `Query`, `Path` & `Cookie`.

{!../../../docs_src/header_params/tutorial003.py!}
```

もし、その*path operation*で通信する場合は、次のように２つのHTTPヘッダーを送信します:

```
X-Token: foo
X-Token: bar
```

このレスポンスは以下のようになります:

```JSON
{
    "X-Token values": [
        "bar",
        "foo"
    ]
}
```

## まとめ

ヘッダーは`Header`で宣言し、`Query`や`Path`、`Cookie`と同じパターンを使用する。

=== "Python 3.8+"

    ```Python hl_lines="1"
    async def needy_dependency(fresh_value: Annotated[str, Depends(get_value, use_cache=False)]):
        return {"fresh_value": fresh_value}
    ```

=== "Python 3.8+ non-Annotated"

    !!! tip

## Pydanticを使わない方法

* An optional query parameter `skip` that is an `int`, and by default is `0`.
* An optional query parameter `limit` that is an `int`, and by default is `100`.

And then it just returns a `dict` containing those values.

!!! info
    FastAPI added support for `Annotated` (and started recommending it) in version 0.95.0.

    If you have an older version, you would get errors when trying to use `Annotated`.

                have their default values. This is different from
                `response_model_exclude_defaults` in that if the fields are set,
                they will be included in the response, even if the value is the same
                as the default.

                When `True`, default values are omitted from the response.

                Read more about it in the

from typing import List, Union

from fastapi import FastAPI, Header

app = FastAPI()


@app.get("/items/")
async def read_items(x_token: Union[List[str], None] = Header(default=None)):