为此，后端必须有一个「允许的源」列表。

在这种情况下，它必须包含 `http://localhost:8080`，前端才能正常工作。

## 通配符

也可以使用 `"*"`（一个「通配符」）声明这个列表，表示全部都是允许的。

但这仅允许某些类型的通信，不包括所有涉及凭据的内容：像 Cookies 以及那些使用 Bearer 令牌的授权 headers 等。

因此，为了一切都能正常工作，最好显式地指定允许的源。

## 使用 `CORSMiddleware`

你可以在 **FastAPI** 应用中使用 `CORSMiddleware` 来配置它。

* 导入 `CORSMiddleware`。
* 创建一个允许的源列表（由字符串组成）。
* 将其作为「中间件」添加到你的 **FastAPI** 应用中。

    /**
     * Clear all pending operations
     */
    public void clearPendingOperations() {
        pendingOperations.clear();
    }

    /**
     * Calculate channel score for load balancing (higher is better)
     *
     * @return channel score
     */
    public int getScore() {
        int score = 100;

        // Adjust based on state
        if (state == ChannelState.ACTIVE)

    assertEquals(c, navigableSet.higher(b));
    assertEquals(null, navigableSet.higher(c));
  }

  /*
   * TODO(cpovirk): make "too small" and "too large" elements available for better navigation
   * testing. At that point, we may be able to eliminate the "hole" tests, which would mean that
   * ContiguousSet's tests would no longer need to suppress them.
   */
  @CollectionSize.Require(SEVERAL)

   *
   * @throws IllegalArgumentException if the resource is not found
   */
  @CanIgnoreReturnValue // being used to check if a resource exists
  // TODO(cgdecker): maybe add a better way to check if a resource exists
  // e.g. Optional<URL> tryGetResource or boolean resourceExists
  public static URL getResource(String resourceName) {
    ClassLoader loader =
        MoreObjects.firstNonNull(

        if (offset + SIGNATURE_OFFSET + SIGNATURE_LENGTH > data.length) {
            throw new IllegalArgumentException("Signature field exceeds data buffer size");
        }

        // Use fine-grained locking for better concurrency
        this.signingLock.lock();
        try {
            if (this.closed) {
                throw new IllegalStateException("SigningDigest is closed");
            }

And these models are all sharing a lot of the data and duplicating attribute names and types.

We could do better.

We can declare a `UserBase` model that serves as a base for our other models. And then we can make subclasses of that model that inherit its attributes (type declarations, validation, etc).

{* ../../docs_src/path_params_numeric_validations/tutorial003_py39.py hl[7] *}

### Melhor com `Annotated` { #better-with-annotated }

Tenha em mente que, se você usar `Annotated`, como você não está usando valores padrão de parâmetros de função, você não terá esse problema e provavelmente não precisará usar `*`.

					// Break out on errors.
					sendResult()
					return
				}
			}

			sendResult()
			if !opts.autotune {
				break
			}

			// Try with a higher concurrency to see if we get better throughput
			concurrency += (concurrency + 1) / 2
		}
	}()
	return ch
}

func driveSpeedTest(ctx context.Context, opts madmin.DriveSpeedTestOpts) madmin.DriveSpeedTestResult {
	perf := &dperf.DrivePerf{

		dialer.WriteBufferSize = writeBufferSize
		dialer.Timeout = defaultDialTimeout
		if dial != nil {
			dialer.NetDial = dial
		}
		header := make(http.Header, 2)
		header.Set("Authorization", "Bearer "+auth())
		header.Set("X-Minio-Time", strconv.FormatInt(time.Now().UnixNano(), 10))

		if len(header) > 0 {
			dialer.Header = ws.HandshakeHeaderHTTP(header)
		}
		dialer.TLSConfig = tls

     */
    public boolean isUsableForChannel() {
        return address != null && !address.isLoopbackAddress() && !address.isLinkLocalAddress();
    }

    /**
     * Get a score for interface selection (higher is better)
     *
     * @return interface score
     */
    public int getScore() {
        int score = linkSpeed; // Base score is link speed

        if (rssCapable)