Você pode ver os headers necessários na interface gráfica da documentação em `/docs`:

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

## Proibindo Cabeçalhos adicionais { #forbid-extra-headers }

Em alguns casos de uso especiais (provavelmente não muito comuns), você pode querer **restringir** os cabeçalhos que você quer receber.

// NewReaderSize returns a new [Reader] whose buffer has at least the specified
// size. If the argument io.Reader is already a [Reader] with large enough
// size, it returns the underlying [Reader].
func NewReaderSize(rd io.Reader, size int) *Reader {
	// Is it already a Reader?
	b, ok := rd.(*Reader)
	if ok && len(b.buf) >= size {
		return b
	}
	r := new(Reader)
	r.reset(make([]byte, max(size, minReadBufferSize)), rd)

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

## Заборонити додаткові заголовки { #forbid-extra-headers }

У деяких особливих випадках (ймовірно, не дуже поширених) ви можете захотіти **обмежити** заголовки, які хочете отримати.

Ви можете використати конфігурацію моделі Pydantic, щоб `заборонити` будь-які `додаткові` поля:

	return key, err
}

// EncryptSinglePart encrypts an io.Reader which must be the
// body of a single-part PUT request.
func EncryptSinglePart(r io.Reader, key ObjectKey) io.Reader {
	r, err := sio.EncryptReader(r, sio.Config{MinVersion: sio.Version20, Key: key[:]})
	if err != nil {
		logger.CriticalIf(context.Background(), errors.New("Unable to encrypt io.Reader using object key"))
	}
	return r
}

    body.writeTo(bodyContent)

    val reader = MultipartReader(bodyContent, "boundary")

    val quickPart = reader.nextPart()!!
    assertThat(quickPart.headers).isEqualTo(
      headersOf(
        "Content-Type",
        "text/plain; charset=utf-8",
      ),
    )
    assertThat(quickPart.body.readUtf8()).isEqualTo("Quick")

    val brownPart = reader.nextPart()!!
    assertThat(brownPart.headers).isEqualTo(

      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()

        addDocument(indexName, client, num);

        ESSourceReader reader = new ESSourceReader(client, settings, indexName);
        reader.setScrollSize(1);
        reader.setLimitDocNumPercentage("1%");
        int count = 0;
        Set<String> valueSet = Collections.synchronizedSet(new HashSet<>());
        Map<String, Object> source;
        while ((source = reader.read()) != null) {

# 標頭參數模型 { #header-parameter-models }

如果你有一組相關的標頭參數，可以建立一個 Pydantic 模型來宣告它們。

這能讓你在多處重複使用該模型，並一次性為所有參數宣告驗證與中繼資料。😎

/// note | 注意

自 FastAPI 版本 `0.115.0` 起支援。🤓

///

## 以 Pydantic 模型宣告標頭參數 { #header-parameters-with-a-pydantic-model }

在 Pydantic 模型中宣告你需要的標頭參數，然後將參數宣告為 `Header`：

{* ../../docs_src/header_param_models/tutorial001_an_py310.py hl[9:14,18] *}

FastAPI 會從請求的標頭為每個欄位擷取資料，並交給你已定義的 Pydantic 模型實例。

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.

Vous pouvez voir les en-têtes requis dans l'interface de la documentation à `/docs` :

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

## Interdire les en-têtes supplémentaires { #forbid-extra-headers }

Dans certains cas d'utilisation particuliers (probablement pas très courants), vous pourriez vouloir **restreindre** les en-têtes que vous souhaitez recevoir.