# `Response` class

You can declare a parameter in a *path operation function* or dependency to be of type `Response` and then you can set data for the response like headers or cookies.

You can also use it directly to create an instance of it and return it from your *path operations*.

Read more about it in the [FastAPI docs about returning a custom Response](https://fastapi.tiangolo.com/advanced/response-directly/#returning-a-custom-response)

        // When remoteAddr is not a trusted proxy, headers should be ignored
        final MockletHttpServletRequest request = getMockRequest();
        request.setRemoteAddr("192.168.1.100");
        request.addHeader("X-Forwarded-For", "203.0.113.50");
        request.addHeader("X-Real-IP", "203.0.113.75");
        // Should return remoteAddr, not the spoofed headers

		if !httpWriter.HasWritten() {
			// write error response only if no data or headers has been written to client yet
			writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
			return
		}
		return
	}

	if err = httpWriter.Close(); err != nil {
		if !httpWriter.HasWritten() { // write error response only if no data or headers has been written to client yet
			writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)

from fastapi.routing import APIRoute


class GzipRequest(Request):
    async def body(self) -> bytes:
        if not hasattr(self, "_body"):
            body = await super().body()
            if "gzip" in self.headers.getlist("Content-Encoding"):
                body = gzip.decompress(body)
            self._body = body
        return self._body


class GzipRoute(APIRoute):
    def get_route_handler(self) -> Callable:

from fastapi.routing import APIRoute


class GzipRequest(Request):
    async def body(self) -> bytes:
        if not hasattr(self, "_body"):
            body = await super().body()
            if "gzip" in self.headers.getlist("Content-Encoding"):
                body = gzip.decompress(body)
            self._body = body
        return self._body


class GzipRoute(APIRoute):
    def get_route_handler(self) -> Callable:

### CORS 预检请求 { #cors-preflight-requests }

这是些带有 `Origin` 和 `Access-Control-Request-Method` 请求头的 `OPTIONS` 请求。

在这种情况下，中间件将拦截传入的请求并进行响应，出于提供信息的目的返回一个使用了适当的 CORS headers 的 `200` 或 `400` 响应。

### 简单请求 { #simple-requests }

任何带有 `Origin` 请求头的请求。在这种情况下，中间件将像平常一样传递请求，但是在响应中包含适当的 CORS headers。

## 更多信息 { #more-info }

Заголовки проксі:

* [X-Forwarded-For](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/X-Forwarded-For)
* [X-Forwarded-Proto](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/X-Forwarded-Proto)
* [X-Forwarded-Host](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/X-Forwarded-Host)

///

También puede ayudar a evitar confusiones para nuevos desarrolladores que vean un parámetro no usado en tu código y puedan pensar que es innecesario.

///

/// info | Información

En este ejemplo usamos headers personalizados inventados `X-Key` y `X-Token`.

Pero en casos reales, al implementar seguridad, obtendrías más beneficios usando las [Utilidades de Seguridad integradas (el próximo capítulo)](../security/index.md).

///

 *    * connection held ([connectionAcquired], [connectionReleased])
 *      * request ([requestFailed])
 *        * headers ([requestHeadersStart], [requestHeadersEnd])
 *        * body ([requestBodyStart], [requestBodyEnd])
 *      * response ([responseFailed])
 *        * headers ([responseHeadersStart], [responseHeadersEnd])
 *        * body ([responseBodyStart], [responseBodyEnd])
 *

  // Optional: confirm that your app made the HTTP requests you were expecting.
  val request1 = server.takeRequest()
  assertEquals("/v1/chat/messages/", request1.url.encodedPath)
  assertNotNull(request1.headers["Authorization"])

  val request2 = server.takeRequest()
  assertEquals("/v1/chat/messages/2", request2.url.encodedPath)

  val request3 = server.takeRequest()