**FastAPI** provides the same `starlette.responses` as `fastapi.responses` just as a convenience for you, the developer. But most of the available responses come directly from Starlette.

    And as the `Response` can be used frequently to set headers and cookies, **FastAPI** also provides it at `fastapi.Response`.

    This defines the name of the query parameter that should be provided in the request
    with the API key and integrates that into the OpenAPI documentation. It extracts
    the key value sent in the query parameter automatically and provides it as the
    dependency result. But it doesn't define how to send that API key to the client.

    ## Usage

    Create an instance object and use that object as the dependency in `Depends()`.

To **deploy** an application means to perform the necessary steps to make it **available to the users**.

For a **web API**, it normally involves putting it in a **remote machine**, with a **server program** that provides good performance, stability, etc, so that your **users** can **access** the application efficiently and without interruptions or problems.

```

!!! note "Technical Details"
    You could also use `from starlette.requests import Request` and `from starlette.responses import JSONResponse`.

    **FastAPI** provides the same `starlette.responses` as `fastapi.responses` just as a convenience for you, the developer. But most of the available responses come directly from Starlette. The same with `Request`.

## Override the default exception handlers

!!! note "Technical Details"
    You could also use `from starlette.templating import Jinja2Templates`.

    **FastAPI** provides the same `starlette.templating` as `fastapi.templating` just as a convenience for you, the developer. But most of the available responses come directly from Starlette. The same with `Request` and `StaticFiles`.

## Writing templates

## 安装依赖项

安装 `jinja2`：

<div class="termy">

```console
$ pip install jinja2

---> 100%
```

</div>

如需使用静态文件，还要安装 `aiofiles`：

<div class="termy">

```console
$ pip install aiofiles

---> 100%
```

</div>

## 使用 `Jinja2Templates`

* 导入 `Jinja2Templates`
* 创建可复用的 `templates` 对象
* 在返回模板的*路径操作*中声明 `Request` 参数

=== "Python 3.8+"

    ```Python hl_lines="10"
    {!> ../../../docs_src/header_params/tutorial002.py!}
    ```

!!! warning "Aviso"
    Antes de definir `convert_underscores` como `False`, lembre-se de que alguns proxies e servidores HTTP não permitem o uso de cabeçalhos com sublinhados.

## Cabeçalhos duplicados

É possível receber cabeçalhos duplicados. Isso significa, o mesmo cabeçalho com vários valores.

    ```Python hl_lines="10"
    {!> ../../../docs_src/header_params/tutorial002.py!}
    ```

!!! warning
    Before setting `convert_underscores` to `False`, bear in mind that some HTTP proxies and servers disallow the usage of headers with underscores.

## Duplicate headers

It is possible to receive duplicate headers. That means, the same header with multiple values.

The API docs use **Swagger UI** and **ReDoc**, and each of those need some JavaScript and CSS files.

By default, those files are served from a <abbr title="Content Delivery Network: A service, normally composed of several servers, that provides static files, like JavaScript and CSS. It's commonly used to serve those files from the server closer to the client, improving performance.">CDN</abbr>.

استفاده شده توسط Starlette:

* <a href="https://www.python-httpx.org" target="_blank"><code>HTTPX</code></a> - در صورتی که می‌خواهید از `TestClient` استفاده کنید.
* <a href="https://github.com/Tinche/aiofiles" target="_blank"><code>aiofiles</code></a> - در صورتی که می‌خواهید از `FileResponse` و `StaticFiles` استفاده کنید.