String USER_CODE_REQUEST_PARAMETER = "user.code.request.parameter";

    /** The key of the configuration. e.g. 20 */
    String USER_CODE_MIN_LENGTH = "user.code.min.length";

    /** The key of the configuration. e.g. 100 */
    String USER_CODE_MAX_LENGTH = "user.code.max.length";

    /** The key of the configuration. e.g. [a-zA-Z0-9_]+ */
    String USER_CODE_PATTERN = "user.code.pattern";

    }
  }

  /**
   * Returns an optional enum constant for the given type, using {@link Enum#valueOf}. If the
   * constant does not exist, {@link Optional#absent} is returned. A common use case is for parsing
   * user input or falling back to a default enum constant. For example, {@code
   * Enums.getIfPresent(Country.class, countryInput).or(Country.DEFAULT);}
   *
   * @since 12.0
   */

也可以在*响应*生成但是返回之前添加代码.

例如你可以添加自定义请求头 `X-Process-Time` 包含以秒为单位的接收请求和生成响应的时间:

```Python hl_lines="10  12-13"
{!../../docs_src/middleware/tutorial001.py!}
```

## 其他中间件

你可以稍后在 [Advanced User Guide: Advanced Middleware](../advanced/middleware.md){.internal-link target=_blank}阅读更多关于中间件的教程.

// Represents either a MlirTensor or a GraphTensor.
// This base class does not expose any public methods other than to distinguish
// which subclass it actually is. The user is responsible to use the right
// type of AbstractTensor in their context (do not pass an MlirTensor to a
// GraphContext and vice-versa).
class TracingTensorHandle : public AbstractTensorHandle {
 protected:

		shouldLog = false
	}
	l.Unlock()

	if shouldLog {
		logIf(ctx, subsystem, err, errKind...)
	}
}

// Cleanup the map every one hour so that the log message is printed again for the user to notice.
func (l *logOnceType) cleanupRoutine() {
	for {
		time.Sleep(time.Hour)

		l.Lock()
		l.IDMap = make(map[string]onceErr)
		l.Unlock()
	}
}

// Returns logOnceType

// ClusterTrustBundle is a cluster-scoped container for X.509 trust anchors
// (root certificates).
//
// ClusterTrustBundle objects are considered to be readable by any authenticated
// user in the cluster, because they can be mounted by pods using the
// `clusterTrustBundle` projection.  All service accounts have read access to
// ClusterTrustBundles by default.  Users who only have namespace-level access

			// For any config error, we don't need to drop into safe-mode
			// instead its a user error and should be fixed by user.
			if errors.As(err, &cerr) {
				logger.FatalIf(err, "Unable to initialize the server")
			}

			// If context was canceled
			if errors.Is(err, context.Canceled) {
				logger.FatalIf(err, "Server startup canceled upon user request")
			}

			bootLogIf(GlobalContext, err)
		}

@needs_py310
def test_inactive_user(client: TestClient):
    response = client.get("/users/me", headers={"Authorization": "Bearer alice"})
    assert response.status_code == 400, response.text
    assert response.json() == {"detail": "Inactive user"}


@needs_py310
def test_openapi_schema(client: TestClient):
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {

@needs_py310
def test_inactive_user(client: TestClient):
    response = client.get("/users/me", headers={"Authorization": "Bearer alice"})
    assert response.status_code == 400, response.text
    assert response.json() == {"detail": "Inactive user"}


@needs_py310
def test_openapi_schema(client: TestClient):
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {

   * <p>Implementations should be collections of pure functions (i.e. stateless).
   */
  interface Strategy extends java.io.Serializable {

    /**
     * Sets {@code numHashFunctions} bits of the given bit array, by hashing a user element.
     *
     * <p>Returns whether any bits changed as a result of this operation.
     */
    <T extends @Nullable Object> boolean put(
        @ParametricNullness T object,
        Funnel<? super T> funnel,