# Custom Response Classes - File, HTML, Redirect, Streaming, etc.

There are several custom response classes you can use to create an instance and return them directly from your *path operations*.

Read more about it in the [FastAPI docs for Custom Response - HTML, Stream, File, others](https://fastapi.tiangolo.com/advanced/custom-response/).

You can import them directly from `fastapi.responses`:

```python
from fastapi.responses import (
    FileResponse,

        .build()
    val response1 = client.newCall(request).execute()
    response1.body.close()
    assertThat(response1.header("X-Response-ID")).isEqualTo("1")
    val response2 = get(url)
    response2.body.close()
    if (expectCached) {
      assertThat(response2.header("X-Response-ID")).isEqualTo("1")
    } else {
      assertThat(response2.header("X-Response-ID")).isEqualTo("2")
    }
  }

# Additional Responses in OpenAPI

!!! warning
    This is a rather advanced topic.

    If you are starting with **FastAPI**, you might not need this.

You can declare additional responses, with additional status codes, media types, descriptions, etc.

Those additional responses will be included in the OpenAPI schema, so they will also appear in the API docs.

          call: Call,
          response: Response,
        ) {
          responses.offer(response.body.string())
        }
      }

    // Make the first request waiting until we get our auth challenge.
    val request = Request(server.url("/"))
    blockingAuthClient.newCall(request).enqueue(callback)
    val response1 = responses.take()
    assertThat(response1).isEqualTo("")

你也可以在直接返回`Response`时添加头部。

按照[直接返回响应](response-directly.md){.internal-link target=_blank}中所述创建响应，并将头部作为附加参数传递：
```Python hl_lines="10-12"
{!../../../docs_src/response_headers/tutorial001.py!}
```


!!! note "技术细节"
    你也可以使用`from starlette.responses import Response`或`from starlette.responses import JSONResponse`。

    **FastAPI**提供了与`fastapi.responses`相同的`starlette.responses`，只是为了方便开发者。但是，大多数可用的响应都直接来自Starlette。

* <a href="https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#responseObject" class="external-link" target="_blank">Objet Response de OpenAPI </a>, vous pouvez inclure n'importe quoi directement dans chaque réponse à l'intérieur de votre paramètre `responses`. Y compris `description`, `headers`, `content` (à l'intérieur de cela, vous...

<img src="/img/tutorial/custom-response/image01.png">

## Available responses

Here are some of the available responses.

Keep in mind that you can use `Response` to return anything else, or even create a custom sub-class.

!!! note "Technical Details"
    You could also use `from starlette.responses import HTMLResponse`.

```

!!! note "Détails techniques"
    Vous pouvez aussi utiliser `from starlette.responses import JSONResponse`.

    **FastAPI** fournit le même objet `starlette.responses` que `fastapi.responses` juste par commodité pour le développeur. Mais la plupart des réponses disponibles proviennent directement de Starlette.

## Renvoyer une `Response` personnalisée

	w.WriteHeader(statusCode)
	if response != nil {
		w.Write(response)
	}
}

// mimeType represents various MIME type used API responses.
type mimeType string

const (
	// Means no response type.
	mimeNone mimeType = ""
	// Means response type is JSON.
	mimeJSON mimeType = "application/json"
	// Means response type is XML.

And tools will also be happy because both `RedirectResponse` and `JSONResponse` are subclasses of `Response`, so the type annotation is correct.

### Annotate a Response Subclass

You can also use a subclass of `Response` in the type annotation:

```Python hl_lines="8-9"
{!> ../../../docs_src/response_model/tutorial003_03.py!}
```