{* ../../docs_src/metadata/tutorial004_py310.py hl[21,26] *}

/// info | Info

Lesen Sie mehr zu Tags unter [Pfadoperation-Konfiguration](path-operation-configuration.md#tags).

///

### Die Dokumentation testen { #check-the-docs }

Wenn Sie nun die Dokumentation ansehen, werden dort alle zusätzlichen Metadaten angezeigt:

<img src="/img/tutorial/metadata/image02.png">

### Reihenfolge der Tags { #order-of-tags }

/// info | Información

Lee más sobre etiquetas en [Configuración de Path Operation](path-operation-configuration.md#tags).

///

### Revisa la documentación { #check-the-docs }

Ahora, si revisas la documentación, mostrará toda la metadata adicional:

<img src="/img/tutorial/metadata/image02.png">

### Orden de las etiquetas { #order-of-tags }

You can use [`bump-pydantic`](https://github.com/pydantic/bump-pydantic) from the same Pydantic team.

This tool will help you to automatically change most of the code that needs to be changed.

After this, you can run the tests and check if everything works. If it does, you are done. 😎

## Pydantic v1 in v2 { #pydantic-v1-in-v2 }

## 선택적 매개변수 { #optional-parameters }

같은 방법으로 기본값을 `None`으로 설정하여 선택적 매개변수를 선언할 수 있습니다:

{* ../../docs_src/query_params/tutorial002_py310.py hl[7] *}

이 경우 함수 매개변수 `q`는 선택적이며 기본값으로 `None` 값이 됩니다.

/// check

또한 **FastAPI**는 `item_id`가 경로 매개변수이고 `q`는 경로 매개변수가 아니라서 쿼리 매개변수라는 것을 알 정도로 충분히 똑똑하다는 점도 확인하세요.

///

## 쿼리 매개변수 형변환 { #query-parameter-type-conversion }

`bool` 형으로 선언할 수도 있고, 아래처럼 변환됩니다:

		debug.PrintStack()
		return metacache{}
	}

	// Grab a write lock, since we create one if we cannot find one.
	b.mu.Lock()
	defer b.mu.Unlock()

	// Check if exists already.
	if c, ok := b.caches[o.ID]; ok {
		c.lastHandout = time.Now()
		b.caches[o.ID] = c
		b.debugf("returning existing %v", o.ID)
		return c
	}

	if !o.Create {
		return metacache{

	"hash/crc64"
	"math/bits"
)

// AddPart will merge a part checksum into the current,
// as if the content of each was appended.
// The size of the content that produced the second checksum must be provided.
// Not all checksum types can be merged, use the CanMerge method to check.
// Checksum types must match.
func (c *Checksum) AddPart(other Checksum, size int64) error {
	if !other.Type.CanMerge() {

### Argument Validation

Use `AssertionUtil` at method entry:
- `AssertionUtil.assertArgumentNotNull("argName", value)`
- `AssertionUtil.assertArgumentNotEmpty("argName", value)`

### Exception Handling

- Wrap checked exceptions in runtime exceptions from `org.codelibs.core.exception`
- Use error codes (e.g., "ECL0008" = null argument)

### Test Structure

- JUnit 4 + Hamcrest matchers
- Test class: `{ClassName}Test.java`

{* ../../docs_src/query_params/tutorial002_py310.py hl[7] *}

En este caso, el parámetro de función `q` será opcional y será `None` por defecto.

/// check | Revisa

Además, nota que **FastAPI** es lo suficientemente inteligente para notar que el parámetro de path `item_id` es un parámetro de path y `q` no lo es, por lo tanto, es un parámetro de query.

///

/// tip | Consejo

Tal vez recuerdes que los request bodies también se declaran con modelos de Pydantic.

Aquí **FastAPI** no se confundirá porque estás usando `Depends`.

///

/// check | Revisa

El modo en que este sistema de dependencias está diseñado nos permite tener diferentes dependencias (diferentes "dependables") que todas devuelven un modelo `User`.

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

**FastAPI** はリクエストの**ヘッダー**から**各フィールド**の値を**抽出**し、定義した Pydantic モデルとして渡します。

## ドキュメントの確認 { #check-the-docs }

`/docs` のドキュメント UI で必要なヘッダーを確認できます:

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

## 余分なヘッダーを禁止 { #forbid-extra-headers }