headers.name(-1)
    }
    assertThat(headers.name(0)).isEqualTo("a")
    assertThat(headers.name(1)).isEqualTo("c")
    assertFailsWith<IndexOutOfBoundsException> {
      headers.name(2)
    }
  }

  @Test fun valueIndexesAreStrict() {
    val headers = headersOf("a", "b", "c", "d")
    assertFailsWith<IndexOutOfBoundsException> {
      headers.value(-1)
    }
    assertThat(headers.value(0)).isEqualTo("b")

      Headers
        .Builder()
        .addUnsafeNonAscii("héader1", "value1")
        .build()
    }.also { expected ->
      assertThat(expected.message).isEqualTo("Unexpected char 0xe9 at 1 in header name: héader1")
    }
  }

  @Test fun addUnsafeNonAsciiAcceptsUnicodeValue() {
    val headers =
      Headers
        .Builder()
        .addUnsafeNonAscii("header1", "valué1")
        .build()

            data: Union[str, None] = Header(
                default=None,
                example="header1",
            ),
        ):
            return data

    @app.get("/header_examples/")
    def header_examples(
        data: Union[str, None] = Header(
            default=None,
            examples=[
                "header1",
                "header2",
            ],
        ),
    ):

			header:          true,
			wantColumns:     []string{"header1", "header2", "header3"},
			wantFields:      "ok1,ok2,ok3\n" + `a word,"b"""` + "\n",
			wantErr:         io.EOF,
		},
		{
			// This works since LazyQuotes is true:
			file:            "invalid-badstartline.csv",
			recordDelimiter: "\n",
			fieldDelimiter:  ",",
			sendErr:         nil,
			header:          true,

                                "Header One": {
                                    "summary": "Header One Summary",
                                    "description": "Header One Description",
                                    "value": "header1",
                                },
                                "Header Two": {"value": "header2"},
                            },
                        }

Und da die `Response` häufig zum Setzen von Headern und Cookies verwendet wird, stellt **FastAPI** diese auch unter `fastapi.Response` bereit.

///

## Benutzerdefinierte Header { #custom-headers }

Beachten Sie, dass benutzerdefinierte proprietäre Header <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">mittels des Präfix `X-`</a> hinzugefügt werden können.

# Header-Parameter { #header-parameters }

Sie können Header-Parameter genauso definieren, wie Sie `Query`-, `Path`- und `Cookie`-Parameter definieren.

## `Header` importieren { #import-header }

Importieren Sie zuerst `Header`:

{* ../../docs_src/header_params/tutorial001_an_py310.py hl[3] *}

## `Header`-Parameter deklarieren { #declare-header-parameters }

    fun build(): Headers = commonBuild()
  }

  companion object {
    /** Empty headers. */
    @JvmField
    val EMPTY = Headers(emptyArray())

    /**
     * Returns headers for the alternating header names and values. There must be an even number of
     * arguments, and they must alternate between header names and values.
     */
    @JvmStatic
    @JvmName("of")

Sie können die erforderlichen Header in der Dokumentationsoberfläche unter `/docs` sehen:

<div class="screenshot">
<img src="/img/tutorial/header-param-models/image01.png">
</div>

## Zusätzliche Header verbieten { #forbid-extra-headers }

In einigen speziellen Anwendungsfällen (wahrscheinlich nicht sehr häufig) möchten Sie möglicherweise die **Header einschränken**, die Sie erhalten möchten.

// 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
	}