# Header Parameter Models { #header-parameter-models }

If you have a group of related **header parameters**, you can create a **Pydantic model** to declare them.

This would allow you to **re-use the model** in **multiple places** and also to declare validations and metadata for all the parameters at once. 😎

/// note

This is supported since FastAPI version `0.115.0`. 🤓

///

pkg archive/tar, const TypeGNUSparse = 83
pkg archive/tar, const TypeGNUSparse ideal-char
pkg archive/tar, type Header struct, Xattrs map[string]string
pkg compress/gzip, method (*Reader) Reset(io.Reader) error
pkg crypto/tls, const CurveP256 = 23
pkg crypto/tls, const CurveP256 CurveID
pkg crypto/tls, const CurveP384 = 24
pkg crypto/tls, const CurveP384 CurveID
pkg crypto/tls, const CurveP521 = 25
pkg crypto/tls, const CurveP521 CurveID

# Header-параметры

Вы можете определить параметры заголовка таким же образом, как вы определяете параметры `Query`, `Path` и `Cookie`.

## Импорт `Header`

Сперва импортируйте `Header`:

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

## Объявление параметров `Header`

Затем объявите параметры заголовка, используя ту же структуру, что и с `Path`, `Query` и `Cookie`.

 * limitations under the License.
 */
package okhttp3.internal.http2

import okio.ByteString
import okio.ByteString.Companion.encodeUtf8

/** HTTP header: the name is an ASCII string, but the value can be UTF-8. */
data class Header(
  /** Name in case-insensitive ASCII encoding. */
  @JvmField val name: ByteString,
  /** Value in UTF-8 encoding. */
  @JvmField val value: ByteString,
) {

<%@page pageEncoding="UTF-8" contentType="text/html; charset=UTF-8"%>
<nav class="main-header navbar navbar-expand navbar-dark navbar-secondary">
	<ul class="navbar-nav">
		<li class="nav-item">
			<a class="nav-link" data-widget="pushmenu" href="#">
				<em class="fas fa-bars">
				<span class="sr-only"><la:message
						key="labels.admin_toggle_navi" /></span>
			</a>
		</li>
	</ul>
	<ul class="navbar-nav ml-auto">
		<c:if test="${eoled}">

    /**
     * Add a header with the specified name and formatted date. Does validation of header names and
     * value.
     */
    fun add(
      name: String,
      value: Date,
    ) = add(name, value.toHttpDateString())

    /**
     * Add a header with the specified name and formatted instant. Does validation of header names
     * and value.
     */

pkg html/template, func ParseFS(fs.FS, ...string) (*Template, error)
pkg html/template, method (*Template) ParseFS(fs.FS, ...string) (*Template, error)
pkg io, func NopCloser(Reader) ReadCloser
pkg io, func ReadAll(Reader) ([]uint8, error)
pkg io, type ReadSeekCloser interface { Close, Read, Seek }
pkg io, type ReadSeekCloser interface, Close() error
pkg io, type ReadSeekCloser interface, Read([]uint8) (int, error)

	req, _ := http.NewRequest(http.MethodOptions, s.endPoint, nil)
	req.Header.Set("Origin", "http://foobar.com")
	res, err := s.client.Do(req)
	if err != nil {
		c.Fatal(err)
	}

	for k := range expectedMap {
		if v, ok := res.Header[k]; !ok {
			c.Errorf("Expected key %s missing from %v", k, res.Header)
		} else {
			expectedSet := set.CreateStringSet(expectedMap[k]...)

👆 💪 🔬 🎚 🔢 🎏 🌌 👆 🔬 `Query`, `Path` & `Cookie` 🔢.

## 🗄 `Header`

🥇 🗄 `Header`:

{* ../../docs_src/header_params/tutorial001.py hl[3] *}

## 📣 `Header` 🔢

⤴️ 📣 🎚 🔢 ⚙️ 🎏 📊 ⏮️ `Path`, `Query` & `Cookie`.

🥇 💲 🔢 💲, 👆 💪 🚶‍♀️ 🌐 ➕ 🔬 ⚖️ ✍ 🔢:

{* ../../docs_src/header_params/tutorial001.py hl[9] *}

/// note | 📡 ℹ

`Header` "👭" 🎓 `Path`, `Query` & `Cookie`. ⚫️ 😖 ⚪️➡️ 🎏 ⚠ `Param` 🎓.

/// note | Detalhes Técnicos

`Header` é uma classe "irmã" de `Path`, `Query` e `Cookie`. Ela também herda da mesma classe em comum `Param`.

Mas lembre-se que quando você importa `Query`, `Path`, `Header`, e outras de `fastapi`, elas são na verdade funções que retornam classes especiais.

///

/// info