return True
    origin = get_origin(annotation)
    if origin is Union or origin is UnionType:
        for arg in get_args(annotation):
            if lenient_issubclass(arg, UploadFile):
                return True
    return False


def is_bytes_sequence_annotation(annotation: Any) -> bool:
    origin = get_origin(annotation)
    if origin is Union or origin is UnionType:
        at_least_one = False

    headers = {
        "Origin": "https://localhost.tiangolo.com",
        "Access-Control-Request-Method": "GET",
        "Access-Control-Request-Headers": "X-Example",
    }
    response = client.options("/", headers=headers)
    assert response.status_code == 200, response.text
    assert response.text == "OK"
    assert (
        response.headers["access-control-allow-origin"]
        == "https://localhost.tiangolo.com"

hinzugefügt werden können.

Wenn Sie jedoch benutzerdefinierte Header haben, die ein Client in einem Browser sehen können soll, müssen Sie diese zu Ihren CORS-Konfigurationen hinzufügen (weitere Informationen finden Sie unter [CORS (Cross-Origin Resource Sharing)](../tutorial/cors.md){.internal-link target=_blank}), unter Verwendung des Parameters `expose_headers`, dokumentiert in <a href="https://www.starlette.io/middleware/#corsmiddleware" class="external-link" target="_blank">Starlettes...

class="external-link" target="_blank">usando el prefijo 'X-'</a>.

Si tienes headers personalizados y deseas que un cliente pueda verlos en el navegador, es necesario que los añadas a tus configuraciones de CORS (puedes leer más en [CORS (Cross-Origin Resource Sharing)](../tutorial/cors.md){.internal-link target=_blank}), usando el parámetro `expose_headers` documentado en <a href="https://www.starlette.io/middleware/#corsmiddleware" class="external-link" target="_blank">Starlette's CORS docs</a>....

* 🌐 Add Korean translation for Tutorial - First Steps. PR [#2323](https://github.com/tiangolo/fastapi/pull/2323) by [@hard-coders](https://github.com/hard-coders).
* 🌐 Add Chinese translation for Tutorial - CORS (Cross-Origin Resource Sharing). PR [#2540](https://github.com/tiangolo/fastapi/pull/2540) by [@blt232018](https://github.com/blt232018).

    assert response.headers["content-type"] == "text/html; charset=utf-8"
    assert "swagger-ui-dist" in response.text
    print(client.base_url)
    assert (
        f"oauth2RedirectUrl: window.location.origin + '{swagger_ui_oauth2_redirect_url}'"
        in response.text
    )


def test_swagger_ui_oauth2_redirect():
    response = client.get(swagger_ui_oauth2_redirect_url)

from fastapi.routing import APIRoute


class ValidationErrorLoggingRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            try:
                return await original_route_handler(request)
            except RequestValidationError as exc:
                body = await request.body()

This time, it will overwrite the method `APIRoute.get_route_handler()`.

This method returns a function. And that function is what will receive a request and return a response.

Here we use it to create a `GzipRequest` from the original request.

```Python hl_lines="18-26"
{!../../../docs_src/custom_request_and_route/tutorial001.py!}
```

!!! note "Technical Details"

In unserem obigen Codebeispiel verwenden wir ihn nicht direkt, sondern übergeben ihn an FastAPI, damit es ihn verwenden kann.

We can declare all that without having to modify the original `APIRouter` by passing those parameters to `app.include_router()`:

```Python hl_lines="14-17" title="app/main.py"
{!../../../docs_src/bigger_applications/app/main.py!}
```