"input": "plumbus"
        }
    ]
}
```

## Summary { #summary }

You can use **Pydantic models** to declare **query parameters** in **FastAPI**. 😎

/// tip

Spoiler alert: you can also use Pydantic models to declare cookies and headers, but you will read about that later in the tutorial. 🤫

And then, right after the `yield`, we unload the model. This code will be executed **after** the application **finishes handling requests**, right before the *shutdown*. This could, for example, release resources like memory or a GPU.

/// tip

The `shutdown` would happen when you are **stopping** the application.

Maybe you need to start a new version, or you just got tired of running it. 🤷

///

### Lifespan function { #lifespan-function }

    ],
    "paths": {
            // ほかの項目
    }
}
```

/// tip | 豆知識

`root_path` から取得した `url` 値 `/api/v1` を持つ server が自動生成されている点に注目してください。

///

ドキュメント UI（[http://127.0.0.1:9999/api/v1/docs](http://127.0.0.1:9999/api/v1/docs)）では次のように表示されます:

<img src="/img/tutorial/behind-a-proxy/image03.png">

/// tip | 豆知識

ドキュメント UI は、選択した server と対話します。

///

/// note | 技術詳細

addAttachmentClass(attachment) {\n    $(this.getTipElement()).addClass(`${CLASS_PREFIX}-${attachment}`)\n  }\n\n  getTipElement() {\n    this.tip = this.tip || $(this.config.template)[0]\n    return this.tip\n  }\n\n  setContent() {\n    const tip = this.getTipElement()\n    this.setElementContent($(tip.querySelectorAll(SELECTOR_TOOLTIP_INNER)), this.getTitle())\n    $(tip).removeClass(`${CLASS_NAME_FADE} ${CLASS_NAME_SHOW}`)\n  }\n\n  setElementContent($element, content) {\n    if (typeof content === 'object'...

      <span style="background-color:#007166"><font color="#D3D7CF"> tip </font></span>  Running in development mode, for production use:
             <b>fastapi run</b>

             Logs:

To do that, you can create a response as described in [Return a Response Directly](response-directly.md).

Then set Cookies in it, and then return it:

{* ../../docs_src/response_cookies/tutorial001_py310.py hl[10:12] *}

/// tip

Keep in mind that if you return a response directly instead of using the `Response` parameter, FastAPI will return it directly.

你还可以在直接响应`Response`时直接创建cookies。

为此，你可以按照[直接返回 Response](response-directly.md)中的说明创建一个响应。

然后设置Cookies，并返回：

{* ../../docs_src/response_cookies/tutorial001_py310.py hl[10:12] *}

/// tip | 提示

需要注意，如果你直接反馈一个response对象，而不是使用`Response`入参，FastAPI则会直接反馈你封装的response对象。

所以你需要确保你响应数据类型的正确性，如：你可以使用`JSONResponse`来兼容JSON的场景。

同时，你也应当仅反馈通过`response_model`过滤过的数据。

///

### 更多信息 { #more-info }

/// note

路徑參數一定是必填，因為它必須是路徑的一部分。即使你將其宣告為 `None` 或設定預設值，也不會有任何影響，它仍然是必填。

///

## 依需求調整參數順序 { #order-the-parameters-as-you-need }

/// tip

如果你使用 `Annotated`，這點大概沒那麼重要或必要。

///

假設你想把查詢參數 `q` 宣告為必要的 `str`。

而你不需要為該參數宣告其他內容，所以其實不需要用 `Query`。

但你仍需要為路徑參數 `item_id` 使用 `Path`，而且基於某些理由你不想用 `Annotated`。

<div class="screenshot">
<img src="/img/tutorial/json-base64-bytes/image01.png">
</div>

You could send a request like:

```json
{
    "description": "Some data",
    "data": "aGVsbG8="
}
```

/// tip

`aGVsbG8=` is the base64 encoding of `hello`.

///

And then Pydantic will decode the base64 string and give you the original bytes in the `data` field of the model.

You will receive a response like:

But in those cases with really bad errors that crash the running **process**, you would want an external component that is in charge of **restarting** the process, at least a couple of times...

/// tip

...Although if the whole application is just **crashing immediately** it probably doesn't make sense to keep restarting it forever. But in those cases, you will probably notice it during development, or at least right after deployment.