internal constructor(
    requestLine: String,
    headers: Headers,
    chunkSizes: List<Int>,
    bodySize: Long,
    body: Buffer,
    sequenceNumber: Int,
    failure: IOException?,
    method: String?,
    path: String?,
    handshake: Handshake?,
    requestUrl: HttpUrl?,
  ) {
    this.requestLine = requestLine
    this.headers = headers
    this.chunkSizes = chunkSizes
    this.bodySize = bodySize

/// warning | Advertencia

Antes de establecer `convert_underscores` a `False`, ten en cuenta que algunos proxies y servidores HTTP no permiten el uso de headers con guiones bajos.

///

## Headers duplicados { #duplicate-headers }

Es posible recibir headers duplicados. Eso significa, el mismo header con múltiples valores.

Puedes definir esos casos usando una lista en la declaración del tipo.

**FastAPI** will **extract** the data for **each field** from the **headers** in the request and give you the Pydantic model you defined.

## Check the Docs { #check-the-docs }

You can see the required headers in the docs UI at `/docs`:

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

## Forbid Extra Headers { #forbid-extra-headers }

// getCanonicalHeaders generate a list of request headers with their values
func getCanonicalHeaders(signedHeaders http.Header) string {
	var headers []string
	vals := make(http.Header, len(signedHeaders))
	for k, vv := range signedHeaders {
		k = strings.ToLower(k)
		headers = append(headers, k)
		vals[k] = vv
	}
	sort.Strings(headers)

	var buf bytes.Buffer
	for _, k := range headers {
		buf.WriteString(k)
		buf.WriteByte(':')

  @Test fun basicChallenge() {
    val headers =
      Headers
        .Builder()
        .add("WWW-Authenticate: Basic realm=\"protected area\"")
        .build()
    assertThat(headers.parseChallenges("WWW-Authenticate"))
      .isEqualTo(listOf(Challenge("Basic", mapOf("realm" to "protected area"))))
  }

  @Test fun basicChallengeWithCharset() {
    val headers =
      Headers
        .Builder()

    }
  }
  return null
}

internal fun Headers.Builder.commonAdd(
  name: String,
  value: String,
) = apply {
  headersCheckName(name)
  headersCheckValue(value, name)
  commonAddLenient(name, value)
}

internal fun Headers.Builder.commonAddAll(headers: Headers) =
  apply {
    for (i in 0 until headers.size) {
      commonAddLenient(headers.name(i), headers.value(i))
    }
  }

      .build()
  }

  companion object {
    /** Combines cached headers with a network headers as defined by RFC 7234, 4.3.4. */
    private fun combine(
      cachedHeaders: Headers,
      networkHeaders: Headers,
    ): Headers {
      val result = Headers.Builder()

      for (index in 0 until cachedHeaders.size) {
        val fieldName = cachedHeaders.name(index)

	public final fun getThrottleBytesPerPeriod ()J
	public final fun getThrottlePeriodNanos ()J
	public final fun getTrailers ()Lokhttp3/Headers;
	public final fun getTrailersDelayNanos ()J
	public final fun getWebSocketListener ()Lokhttp3/WebSocketListener;
	public final fun headers (Lokhttp3/Headers;)Lmockwebserver3/MockResponse$Builder;
	public final fun headersDelay (JLjava/util/concurrent/TimeUnit;)Lmockwebserver3/MockResponse$Builder;

    assert response.status_code == 401, response.text
    assert response.headers["WWW-Authenticate"] == 'Basic realm="simple"'


def test_security_http_basic_invalid_credentials():
    response = client.get(
        "/users/me", headers={"Authorization": "Basic notabase64token"}
    )
    assert response.status_code == 401, response.text
    assert response.headers["WWW-Authenticate"] == 'Basic realm="simple"'

          ),
        ).build()
    server.enqueue(MockResponse())
    get(server.url("/"))
    val request = server.takeRequest()
    assertThat(request.headers["Cookie"]).isEqualTo("Bar=bar; Baz=baz")
    assertThat(request.headers["Cookie2"]).isNull()
    assertThat(request.headers["Quux"]).isNull()
  }

  @Test
  fun acceptOriginalServerMatchesSubdomain() {