{!../../docs_src/middleware/tutorial001.py!}
```

/// tip | "Tipp"

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

          url = "https://url-host.com:${server.port}/".toHttpUrl(),
          headers = headersOf("Host", "header-host"),
        ),
      )
    val response = call.execute()
    assertThat(response.isSuccessful).isTrue()

    val recordedRequest = server.takeRequest()
    assertThat(recordedRequest.requestUrl!!.host).isEqualTo("header-host")
    assertThat(recordedRequest.handshakeServerNames).containsExactly("url-host.com")

        .build(),
    )
    newEventSource("text/plain")
    listener.assertOpen()
    listener.assertEvent(null, null, "hey")
    listener.assertClose()
    assertThat(server.takeRequest().headers["Accept"]).isEqualTo("text/plain")
  }

  @Test
  fun setsMissingAccept() {
    server.enqueue(
      MockResponse.Builder()
        .body(
          """
          |data: hey
          |

        length = 0,
        type = TYPE_SETTINGS,
        flags = FLAG_ACK,
      )
      sink.flush()
    }
  }

  /**
   * HTTP/2 only. Send a push promise header block.
   *
   * A push promise contains all the headers that pertain to a server-initiated request, and a
   * `promisedStreamId` to which response frames will be delivered. Push promise frames are sent as

					case !strict && ver.header.matchesNotStrict(latest.header):
						latestCount++
					default:
						latestCount = 1
					}
					latest = ver
					continue
				}

				// Mismatch, but older.
				if latestCount > 0 && !strict && ver.header.matchesNotStrict(latest.header) {
					latestCount++
					continue
				}
				if latestCount > 0 && ver.header.VersionID == latest.header.VersionID {

	// flag bit is set. However, there are several problems:
	//
	//	* Many ZIP readers still do not support UTF-8.
	//	* If the UTF-8 flag is cleared, several readers simply interpret the
	//	name and comment fields as whatever the local system encoding is.
	//
	// In order to avoid breaking readers without UTF-8 support,
	// we avoid setting the UTF-8 flag if the strings are CP-437 compatible.

* `content` – Ein `str` oder `bytes`.
* `status_code` – Ein `int`-HTTP-Statuscode.
* `headers` – Ein `dict` von Strings.
* `media_type` – Ein `str`, der den Medientyp angibt. Z. B. `"text/html"`.

FastAPI (eigentlich Starlette) fügt automatisch einen Content-Length-Header ein. Außerdem wird es einen Content-Type-Header einfügen, der auf dem media_type basiert, und für Texttypen einen Zeichensatz (charset) anfügen.

}

// 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 {

    internal val reader: Http2Reader,
  ) : Http2Reader.Handler, () -> Unit {
    override fun invoke() {
      var connectionErrorCode = ErrorCode.INTERNAL_ERROR
      var streamErrorCode = ErrorCode.INTERNAL_ERROR
      var errorException: IOException? = null
      try {
        reader.readConnectionPreface(this)
        while (reader.nextFrame(false, this)) {
        }

			withJSON: `{"request":{"uri":"/1","header":{"User-Agent":"test"}}}
{"request":{"uri":"/2","header":{}}}`,
		},
		{
			name:  "is-not-missing-2",
			query: `select * from s3object[*] as s where s.request.header is not missing`,
			wantResult: `{"request":{"uri":"/1","header":{"User-Agent":"test"}}}
{"request":{"uri":"/2","header":{}}}`,
			withJSON: `{"request":{"uri":"/1","header":{"User-Agent":"test"}}}