println("onResponseStarted ${info.headers.asMap} ${info.negotiatedProtocol}")
            request.read(ByteBuffer.allocateDirect(4096 * 8))
          }

          override fun onReadCompleted(
            request: UrlRequest,
            info: UrlResponseInfo,
            byteBuffer: ByteBuffer,
          ) {
            println("onReadCompleted ${info.headers.asMap}")
            byteBuffer.flip()

{
    "dynamic_templates": [
      {
        "headers": {
          "path_match": "headers.*",
          "mapping": {
            "type": "keyword"
          }
        }
      },
      {
        "search_fields": {
          "path_match": "searchField.*",
          "mapping": {
            "type": "keyword"
          }
        }
      },
      {
        "documents": {
          "path_match": "documents.*",

**FastAPI** will use that *temporal* response to extract the cookies (also headers and status code), and will put them in the final response that contains the value you returned, filtered by any `response_model`.

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

## Return a `Response` directly

@app.get("/items/{item_id}")
async def read_item(item_id: str):
    if item_id not in items:
        raise HTTPException(
            status_code=404,
            detail="Item not found",
            headers={"X-Error": "Some custom header"},
        )
    return {"item": items[item_id]}


@app.get("/http-no-body-statuscode-exception")
async def no_body_status_code_exception():
    raise HTTPException(status_code=204)

def test_get_invalid_one_header(client: TestClient):
    response = client.get("/items/", headers={"X-Token": "invalid"})
    assert response.status_code == 400, response.text
    assert response.json() == {"detail": "X-Token header invalid"}


@needs_py39
def test_get_invalid_second_header(client: TestClient):
    response = client.get(
        "/items/", headers={"X-Token": "fake-super-secret-token", "X-Key": "invalid"}
    )

client = TestClient(app)


def test_security_oauth2():
    response = client.get("/users/me", headers={"Authorization": "Bearer footokenbar"})
    assert response.status_code == 200, response.text
    assert response.json() == {"username": "Bearer footokenbar"}


def test_security_oauth2_password_other_header():
    response = client.get("/users/me", headers={"Authorization": "Other footokenbar"})
    assert response.status_code == 200, response.text

    host: str
    save_data: bool
    if_modified_since: str | None = None
    traceparent: str | None = None
    x_tag: list[str] = []


@app.get("/items/")
async def read_items(headers: CommonHeaders = Header()):

    save_data: bool
    if_modified_since: Union[str, None] = None
    traceparent: Union[str, None] = None
    x_tag: List[str] = []


@app.get("/items/")
async def read_items(headers: Annotated[CommonHeaders, Header()]):

                    detail="Not authenticated",
                    headers=unauthorized_headers,
                )
            else:
                return None
        invalid_user_credentials_exc = HTTPException(
            status_code=HTTP_401_UNAUTHORIZED,
            detail="Invalid authentication credentials",
            headers=unauthorized_headers,
        )
        try:

     */
    @JvmField
    val FORCE_CACHE = commonForceCache()

    /**
     * Returns the cache directives of [headers]. This honors both Cache-Control and Pragma headers
     * if they are present.
     */
    @JvmStatic
    fun parse(headers: Headers): CacheControl = commonParse(headers)
  }