You can also declare the `Response` parameter in dependencies, and set headers (and cookies) in them.

## Return a `Response` directly

You can also add headers when you return a `Response` directly.

Create a response as described in [Return a Response Directly](response-directly.md){.internal-link target=_blank} and pass the headers as an additional parameter:

```Python hl_lines="10-12"

application/x-bcpio            bcpio            #
application/x-cpio             cpio             #
application/x-csh              csh              # C-Shell Program
application/x-director         dcr              # Director File
application/x-dvi              dvi              # TeX dvi Format
application/x-gtar             gtar             # Gzip and Tar file
application/x-gzip             gz tgz           # Gzip and Tar file

            val dir = File("..", it.path)
            assertEquals(it.unitTests, File(dir, "src/test").isDirectory, "${it.name}'s unitTests is wrong!")
            assertEquals(it.functionalTests, File(dir, "src/integTest").isDirectory, "${it.name}'s functionalTests is wrong!")
            assertEquals(it.crossVersionTests, File(dir, "src/crossVersionTest").isDirectory, "${it.name}'s crossVersionTests is wrong!")
        }
    }

    @Test

  If it is not possible or desirable to put the notice in a particular
  file, then You may include the notice in a location (such as a LICENSE
  file in a relevant directory) where a recipient would be likely to
  look for such a notice.

  You may add additional accurate notices of copyright ownership.

================================================================

name: Privileged
description: You are @tiangolo or he asked you directly to create an issue here. If not, check the other options. 👇
body:
  - type: markdown
    attributes:
      value: |
        Thanks for your interest in FastAPI! 🚀

        If you are not @tiangolo or he didn't ask you directly to create an issue here, please start the conversation in a [Question in GitHub Discussions](https://github.com/fastapi/fastapi/discussions/categories/questions) instead.

func (f *Forwarder) ServeHTTP(w http.ResponseWriter, inReq *http.Request) {
	outReq := new(http.Request)
	*outReq = *inReq // includes shallow copies of maps, but we handle this in Director

	revproxy := httputil.ReverseProxy{
		Director: func(req *http.Request) {
			f.modifyRequest(req, inReq.URL)
		},
		BufferPool:    newBufPool(128 << 10),
		Transport:     f.RoundTripper,
		FlushInterval: defaultFlushInterval,

To achieve that, import `JSONResponse`, and return your content there directly, setting the `status_code` that you want:

{* ../../docs_src/additional_status_codes/tutorial001_an_py310.py hl[4,25] *}

/// warning

When you return a `Response` directly, like in the example above, it will be returned directly.

It won't be serialized with a model, etc.

You can also declare the `Response` parameter in dependencies, and set cookies (and headers) in them.

## Return a `Response` directly

You can also create cookies when returning a `Response` directly in your code.

To do that, you can create a response as described in [Return a Response Directly](response-directly.md){.internal-link target=_blank}.

Then set Cookies in it, and then return it:

```Python hl_lines="10-12"

```Python
contents = myfile.file.read()
```

/// note | "`async` Technical Details"

When you use the `async` methods, **FastAPI** runs the file methods in a threadpool and awaits for them.

///

/// note | "Starlette Technical Details"

You can use the `TestClient` class to test FastAPI applications without creating an actual HTTP and socket connection, just communicating directly with the FastAPI code.

Read more about it in the [FastAPI docs for Testing](https://fastapi.tiangolo.com/tutorial/testing/).

You can import it directly from `fastapi.testclient`:

```python
from fastapi.testclient import TestClient
```