# 全局依赖项

有时，我们要为整个应用添加依赖项。

通过与定义[*路径装饰器依赖项*](dependencies-in-path-operation-decorators.md){.internal-link target=_blank} 类似的方式，可以把依赖项添加至整个 `FastAPI` 应用。

这样一来，就可以为所有*路径操作*应用该依赖项：

{* ../../docs_src/dependencies/tutorial012.py hl[15] *}

[*路径装饰器依赖项*](dependencies-in-path-operation-decorators.md){.internal-link target=_blank} 一章的思路均适用于全局依赖项， 在本例中，这些依赖项可以用于应用中的所有*路径操作*。

## 为一组路径操作定义依赖项

### Preferred translations / glossary

Use the following preferred translations when they apply in documentation prose:

- request (HTTP): 请求
- response (HTTP): 响应
- path operation: 路径操作
- path operation function: 路径操作函数

### `///` admonitions

1) Keep the admonition keyword in English (do not translate `note`, `tip`, etc.).
2) If a title is present, prefer these canonical titles:

- `/// tip | 提示`

   */
  @Deprecated
  @Override
  @DoNotCall("Always throws UnsupportedOperationException")
  public final void remove(Range<K> range) {
    throw new UnsupportedOperationException();
  }

  /**
   * Guaranteed to throw an exception and leave the {@code RangeMap} unmodified.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Unsupported operation.
   * @since 28.1
   */

Entonces podemos usar la dependencia con:

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[23] *}

/// info | Información

Fíjate que solo estamos declarando una dependencia en la *path operation function*, `query_or_cookie_extractor`.

Pero **FastAPI** sabrá que tiene que resolver `query_extractor` primero, para pasar los resultados de eso a `query_or_cookie_extractor` al llamarlo.

///

```mermaid
graph TB

// If the most recent read or write operation on the buffer was
// not a successful [Buffer.ReadRune], UnreadRune returns an error.  (In this regard
// it is stricter than [Buffer.UnreadByte], which will unread the last byte
// from any read operation.)
func (b *Buffer) UnreadRune() error {
	if b.lastRead <= opInvalid {
		return errors.New("bytes.Buffer: UnreadRune: previous operation was not a successful ReadRune")
	}

///

### Funciones de *path operation* { #path-operation-functions }

Cuando declaras una *path operation function* con `def` normal en lugar de `async def`, se ejecuta en un threadpool externo que luego es esperado, en lugar de ser llamado directamente (ya que bloquearía el servidor).

[*경로 작동 데코레이터*에 `dependencies` 추가하기](dependencies-in-path-operation-decorators.md){.internal-link target=_blank}와 유사한 방법으로 `FastAPI` 애플리케이션에 그것들을 추가할 수 있습니다.

그런 경우에, 애플리케이션의 모든 *경로 작동*에 적용될 것입니다:

{* ../../docs_src/dependencies/tutorial012_an_py39.py hl[16] *}

그리고 [*경로 작동 데코레이터*에 `dependencies` 추가하기](dependencies-in-path-operation-decorators.md){.internal-link target=_blank}에 대한 아이디어는 여전히 적용되지만 여기에서는 앱에 있는 모든 *경로 작동*에 적용됩니다.

    offerAll(elements.iterator());
  }

  /**
   * Adds each member of {@code elements} as a candidate for the top {@code k} elements. This
   * operation takes amortized linear time in the length of {@code elements}. The iterator is
   * consumed after this operation completes.
   *
   * <p>If all input data to this {@code TopKSelector} is in a single {@code Iterator}, prefer

```JSON
{
    "name": "Foo",
    "price": 45.2
}
```

## Déclarez-le comme paramètre

Pour l'ajouter à votre *opération de chemin*, déclarez-le comme vous déclareriez des paramètres de chemin ou de requête :

{* ../../docs_src/body/tutorial001.py hl[18] *}

...et déclarez que son type est le modèle que vous avez créé : `Item`.

  /** Puts all the associations from {@code rangeMap} into this range map (optional operation). */
  void putAll(RangeMap<K, ? extends V> rangeMap);

  /** Removes all associations from this range map (optional operation). */
  void clear();

  /**
   * Removes all associations from this range map in the specified range (optional operation).
   *