# 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,

  }

  @Throws(IOException::class)
  fun openResponseBody(response: Response): ResponseBody {
    try {
      val contentType = response.header("Content-Type")
      val contentLength = codec.reportedContentLength(response)
      val rawSource = codec.openResponseBodySource(response)
      val source = ResponseBodySource(rawSource, contentLength)
      return RealResponseBody(contentType, contentLength, source.buffer())

    response = client.get(path)
    assert response.status_code == expected_status
    assert response.json() == expected_response


@needs_py310
def test_openapi_schema(client: TestClient):
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",

    monkeypatch.setenv("ADMIN_EMAIL", "******@****.***")
    from docs_src.settings.tutorial001_pv1 import app

    client = TestClient(app)
    response = client.get("/info")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "app_name": "Awesome API",
        "admin_email": "******@****.***",
        "items_per_user": 50,

    response = client.get("/query_examples/")
    assert response.status_code == 200, response.text
    response = client.get("/query_example_examples/")
    assert response.status_code == 200, response.text
    response = client.get("/header_example/")
    assert response.status_code == 200, response.text
    response = client.get("/header_examples/")
    assert response.status_code == 200, response.text

import okio.ForwardingSource
import okio.buffer

/** Rewrites the response body returned from the server to be all uppercase.  */
class UppercaseResponseInterceptor : Interceptor {
  @Throws(IOException::class)
  override fun intercept(chain: Chain): Response {
    return uppercaseResponse(chain.proceed(chain.request()))
  }

  private fun uppercaseResponse(response: Response): Response {
    val uppercaseBody: ResponseBody =

    ],
)
def test(path, headers, expected_status, expected_response):
    response = client.get(path, headers=headers)
    assert response.status_code == expected_status
    assert response.json() == expected_response


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200
    assert response.json() == {
        "openapi": "3.1.0",

@needs_pydanticv2
def test_post_body_form(client: TestClient):
    response = client.post("/login/", data={"username": "Foo", "password": "secret"})
    assert response.status_code == 200
    assert response.json() == {"username": "Foo", "password": "secret"}


@needs_pydanticv2
def test_post_body_extra_form(client: TestClient):
    response = client.post(

    return {"segment": segment, "id": id}


app.include_router(router, prefix="/{segment}")


client = TestClient(app)


def test_get():
    response = client.get("/seg/users/foo")
    assert response.status_code == 200, response.text

    response = client.get("/")
    assert response.status_code == 200, response.text
    assert b"<form" in response.content


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {