## Duplicate headers

It is possible to receive duplicate headers. That means, the same header with multiple values.

You can define those cases using a list in the type declaration.

You will receive all the values from the duplicate header as a Python `list`.

For example, to declare a header of `X-Token` that can appear more than once, you can write:

// functionality to handle SSE-C copy requests.
var SSECopy = ssecCopy{}

type ssecCopy struct{}

// IsRequested returns true if the HTTP headers contains
// at least one SSE-C copy header. Regular SSE-C headers
// are ignored.
func (ssecCopy) IsRequested(h http.Header) bool {
	if _, ok := h[xhttp.AmzServerSideEncryptionCopyCustomerAlgorithm]; ok {
		return true
	}

def test_read_nonexistent_item():
    response = client.get("/items/baz", headers={"X-Token": "coneofsilence"})
    assert response.status_code == 404
    assert response.json() == {"detail": "Item not found"}


def test_create_item():
    response = client.post(
        "/items/",
        headers={"X-Token": "coneofsilence"},

}

// Apply applies the SSE bucket configuration on the given HTTP headers and
// sets the specified SSE headers.
//
// Apply does not overwrite any existing SSE headers. Further, it will
// set minimal SSE-KMS headers if autoEncrypt is true and the BucketSSEConfig
// is nil.
func (b *BucketSSEConfig) Apply(headers http.Header, opts ApplyOptions) {
	if crypto.Requested(headers) {
		return
	}
	if b == nil {
		if opts.AutoEncrypt {

    get() {
      val result = mutableListOf<Header>()
      for (inputHeader in headers) {
        val (key, value) = inputHeader.entries.iterator().next()
        result.add(Header(key, value))
      }
      return result
    }

  public override fun clone() = Case(seqno, this.wire, headers)

    }

    FLAGS[FLAG_END_HEADERS] = "END_HEADERS" // Same as END_PUSH_PROMISE.
    FLAGS[FLAG_PRIORITY] = "PRIORITY" // Same as FLAG_COMPRESSED.
    FLAGS[FLAG_END_HEADERS or FLAG_PRIORITY] = "END_HEADERS|PRIORITY" // Only valid on HEADERS.
    val frameFlags = intArrayOf(FLAG_END_HEADERS, FLAG_PRIORITY, FLAG_END_HEADERS or FLAG_PRIORITY)

    for (frameFlag in frameFlags) {

  fun parseCacheControlHeaderValueIsRetained() {
    val value = "max-age=12"
    val headers = headersOf("Cache-Control", value)
    val cacheControl = parse(headers)
    assertThat(cacheControl.toString()).isSameAs(value)
  }

  @Test
  fun parseCacheControlHeaderValueInvalidatedByPragma() {
    val headers =
      headersOf(
        "Cache-Control",
        "max-age=12",
        "Pragma",
        "must-revalidate",

def test_security_http_basic_non_basic_credentials():
    payload = b64encode(b"johnsecret").decode("ascii")
    auth_header = f"Basic {payload}"
    response = client.get("/users/me", headers={"Authorization": auth_header})
    assert response.status_code == 401, response.text
    assert response.headers["WWW-Authenticate"] == "Basic"
    assert response.json() == {"detail": "Invalid authentication credentials"}

      result.add(Header(TARGET_PATH, RequestLine.requestPath(request.url)))
      val host = request.header("Host")
      if (host != null) {
        result.add(Header(TARGET_AUTHORITY, host)) // Optional.
      }
      result.add(Header(TARGET_SCHEME, request.url.scheme))

      for (i in 0 until headers.size) {
        // header names must be lowercase.
        val name = headers.name(i).lowercase(Locale.US)

  name: String,
  value: String,
) = apply {
  headers[name] = value
}

fun Response.Builder.commonAddHeader(
  name: String,
  value: String,
) = apply {
  headers.add(name, value)
}

fun Response.Builder.commonRemoveHeader(name: String) =
  apply {
    headers.removeAll(name)
  }

fun Response.Builder.commonHeaders(headers: Headers) =
  apply {
    this.headers = headers.newBuilder()