# 使用yield的依赖项

FastAPI支持在完成后执行一些<abbr title='有时也被称为"退出"("exit")，"清理"("cleanup")，"拆卸"("teardown")，"关闭"("close")，"上下文管理器"("context managers")。 ...'>额外步骤</abbr>的依赖项.

为此，你需要使用 `yield` 而不是 `return`，然后再编写这些额外的步骤（代码）。

/// tip | 提示

确保在每个依赖中只使用一次 `yield`。

///

/// note | 技术细节

任何一个可以与以下内容一起使用的函数：

    check(trustManagers.size == 1 && trustManagers[0] is X509TrustManager) {
      "Unexpected default trust managers: ${trustManagers.contentToString()}"
    }
    return trustManagers[0] as X509TrustManager
  }

  open fun trustManager(sslSocketFactory: SSLSocketFactory): X509TrustManager? {
    return try {
      // Attempt to get the trust manager from an OpenJDK socket factory. We attempt this on all

원하는 의존성을 원하는 대로 조합할 수 있습니다.

**FastAPI**는 모든 것이 올바른 순서로 실행되도록 보장합니다.

/// note | 기술 세부사항

파이썬의 <a href=“https://docs.python.org/3/library/contextlib.html” class=“external-link” target=“_blank”>Context Managers</a> 덕분에 이 기능이 작동합니다.

**FastAPI**는 이를 내부적으로 컨텍스트 관리자를 사용하여 구현합니다.

///

## `yield`와 `HTTPException`를 사용하는 의존성

`yield`와 `try` 블록이 있는 의존성을 사용하여 예외를 처리할 수 있다는 것을 알게 되었습니다.

        }
        return super.hookBefore(runtime);
    }

    /**
     * Returns the login manager for this action. Search actions do not require
     * a login manager as they handle authentication differently.
     *
     * @return an empty OptionalThing as search actions don't use login managers
     */
    @Override
    protected OptionalThing<LoginManager> myLoginManager() {

    }

    /**
     * Get the channel manager
     *
     * @return channel manager instance
     */
    public ChannelManager getChannelManager() {
        return channelManager;
    }

    /**
     * Get the lease manager for SMB3 lease support
     *
     * @return lease manager instance
     */
    public LeaseManager getLeaseManager() {

    }

    /**
     * Gets the message manager component.
     * @return The message manager.
     */
    public static MessageManager getMessageManager() {
        return getComponent(MESSAGE_MANAGER);
    }

    /**
     * Gets the dictionary manager component.
     * @return The dictionary manager.
     */
    public static DictionaryManager getDictionaryManager() {

            "Unable to extract the trust manager on ${Platform.get()}, " +
              "sslSocketFactory is ${sslSocketFactory.javaClass}",
          )
        this.certificateChainCleaner =
          Platform.get().buildCertificateChainCleaner(x509TrustManagerOrNull!!)
      }

    /**
     * Sets the socket factory and trust manager used to secure HTTPS connections. If unset, the

    had a crash `IllegalArgumentException: Not a Conscrypt trust manager` because we depended on
    initialization order of companion objects.


## Version 4.7.1

_2020-05-18_

 *  Fix: Pass the right arguments in the trust manager created for `addInsecureHost()`. Without the
    fix insecure hosts crash with an `IllegalArgumentException` on Android.

		t.Fatalf("Failed to auto migrate: error: %v", err)
	}
}

func TestAutoMigrateSelfReferential(t *testing.T) {
	type MigratePerson struct {
		ID        uint
		Name      string
		ManagerID *uint
		Manager   *MigratePerson
	}

	DB.Migrator().DropTable(&MigratePerson{})

	if err := DB.AutoMigrate(&MigratePerson{}); err != nil {
		t.Fatalf("Failed to auto migrate, but got error %v", err)
	}

    replace the `OkHttp-Sent-Millis` and `OkHttp-Received-Millis` headers that were
    present in earlier versions of OkHttp.
 *  New: Accept user-provided trust managers in `OkHttpClient.Builder`. This
    allows OkHttp to satisfy its TLS requirements directly. Otherwise OkHttp
    will use reflection to extract the `TrustManager` from the
    `SSLSocketFactory`.