每次你「使用」Facebook、Google、GitHub、Microsoft、X（Twitter）「登入」時，那個應用就是在使用帶有 scopes 的 OAuth2。

在本節中，你將看到如何在你的 FastAPI 應用中，用同樣的帶有 scopes 的 OAuth2 管理驗證與授權。

/// warning

這一節算是進階內容。如果你剛開始，可以先跳過。

你不一定需要 OAuth2 scopes，你可以用任何你想要的方式處理驗證與授權。

但帶有 scopes 的 OAuth2 可以很漂亮地整合進你的 API（透過 OpenAPI）與 API 文件。

無論如何，你仍然會在程式碼中，依你的需求，強制檢查那些 scopes，或其他任何安全性／授權需求。

.input-hint {
    font-size: 0.6875rem;
    color: #8993a4;
}

.char-counter {
    font-size: 0.6875rem;
    color: #8993a4;
    font-variant-numeric: tabular-nums;
}

.char-counter.warning {
    color: #ff991f;
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    color: #de350b;
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/* ============================================
   Responsive adjustments
   ============================================ */

  /**
   * Returns a new target iterator each time it's called. This is the iterator you are trying to
   * test. This must return an Iterator that returns the expected elements passed to the constructor
   * in the given order. Warning: it is not enough to simply pull multiple iterators from the same
   * source Iterable, unless that Iterator is unmodifiable.
   */
  protected abstract I newTargetIterator();

  /**

 *       {@link #verifyNotNull(Object)} and {@link Preconditions#checkNotNull(Object)} perform the
 *       same function with more clarity.
 * </ul>
 *
 * <h3>Warning about performance</h3>
 *
 * <p>Remember that parameter values for message construction must all be computed eagerly, and
 * autoboxing and varargs array creation may happen as well, even when the verification succeeds and

 * read operations will work correctly. To allow concurrent update operations, wrap your multimap
 * with a call to {@link Multimaps#synchronizedSetMultimap}.
 *
 * <p><b>Warning:</b> Do not modify either a key <i>or a value</i> of a {@code LinkedHashMultimap}
 * in a way that affects its {@link Object#equals} behavior. Undefined behavior and bugs will
 * result.
 *

      return constructor.newInstance();
    } catch (InstantiationException | IllegalAccessException impossible) {
      throw new AssertionError(impossible);
    } catch (InvocationTargetException e) {
      logger.log(Level.WARNING, "Exception while invoking default constructor.", e.getCause());
      return arbitraryConstantInstanceOrNull(type);
    }
  }

  private static <T> @Nullable T arbitraryConstantInstanceOrNull(Class<T> type) {

 * read operations will work correctly. To allow concurrent update operations, wrap your multimap
 * with a call to {@link Multimaps#synchronizedSetMultimap}.
 *
 * <p><b>Warning:</b> Do not modify either a key <i>or a value</i> of a {@code LinkedHashMultimap}
 * in a way that affects its {@link Object#equals} behavior. Undefined behavior and bugs will
 * result.
 *

當 `with` 區塊結束時，它會確保關閉檔案，即使發生了例外也一樣。

當你建立一個含 `yield` 的相依時，**FastAPI** 會在內部為它建立一個情境管理器，並與其他相關工具結合。

### 在含 `yield` 的相依中使用情境管理器 { #using-context-managers-in-dependencies-with-yield }

/// warning

這大致算是一個「進階」概念。

如果你剛開始學習 **FastAPI**，此處可以先跳過。

///

在 Python 中，你可以透過[建立一個擁有 `__enter__()` 與 `__exit__()` 兩個方法的類別](https://docs.python.org/3/reference/datamodel.html#context-managers)來建立情境管理器。

### Utilizando gerenciadores de contexto em dependências com `yield` { #using-context-managers-in-dependencies-with-yield }

/// warning | Atenção

Isso é uma ideia mais ou menos "avançada".

Se você está apenas iniciando com o **FastAPI** você pode querer pular isso por enquanto.

///

Nesta seção, você verá como gerenciar a autenticação e autorização com os mesmos escopos do OAuth2 em sua aplicação **FastAPI**.

/// warning | Atenção

Isso é uma seção mais ou menos avançada. Se você está apenas começando, você pode pular.