apiRequestsErrorsTotalMD = NewCounterMD(apiRequestsErrorsTotal,
		"Total number of requests with (4xx and 5xx) errors", "name", "type")
	apiRequests5xxErrorsTotalMD = NewCounterMD(apiRequests5xxErrorsTotal,
		"Total number of requests with 5xx errors", "name", "type")
	apiRequests4xxErrorsTotalMD = NewCounterMD(apiRequests4xxErrorsTotal,
		"Total number of requests with 4xx errors", "name", "type")
	apiRequestsCanceledTotalMD = NewCounterMD(apiRequestsCanceledTotal,

@router.get("/a", responses={501: {"description": "Error 1"}})
async def a():
    return "a"


@router.get(
    "/b",
    responses={
        502: {"description": "Error 2"},
        "4XX": {"description": "Error with range, upper"},
    },
)
async def b():
    return "b"


@router.get(
    "/c",
    responses={
        "400": {"description": "Error with str"},

| `minio_api_requests_5xx_errors_total`          | `counter` | Total number of requests with 5xx errors                | `name,type,pool_index,server`    |
| `minio_api_requests_4xx_errors_total`          | `counter` | Total number of requests with 4xx errors                | `name,type,pool_index,server`    |

某些情况下，需要向客户端返回错误提示。

这里所谓的客户端包括前端浏览器、其他应用程序、物联网设备等。

需要向客户端返回错误提示的场景主要如下：

- 客户端没有执行操作的权限
- 客户端没有访问资源的权限
- 客户端要访问的项目不存在
- 等等 ...

遇到这些情况时，通常要返回 **4XX**（400 至 499）**HTTP 状态码**。

**4XX** 状态码与表示请求成功的 **2XX**（200 至 299） HTTP 状态码类似。

只不过，**4XX** 状态码表示客户端发生的错误。

大家都知道**「404 Not Found」**错误，还有调侃这个错误的笑话吧？

## 使用 `HTTPException`

向客户端返回 HTTP 错误响应，可以使用 `HTTPException`。

### 导入 `HTTPException`

|:----------------------------------------------|:---------------------------------------------------------|
| `minio_s3_requests_4xx_errors_total`          | Total number S3 requests with (4xx) errors.              |
| `minio_s3_requests_5xx_errors_total`          | Total number S3 requests with (5xx) errors.              |

        // If there's a "Expect: 100-continue" header on the request, wait for a "HTTP/1.1 100
        // Continue" response before transmitting the request body. If we don't get that, return
        // what we did get (such as a 4xx response) without ever transmitting the request body.
        if ("100-continue".equals(request.header("Expect"), ignoreCase = true)) {
          exchange.flushRequest()

)

// ResponseRecorder - is a wrapper to trap the http response
// status code and to record the response body
type ResponseRecorder struct {
	http.ResponseWriter
	io.ReaderFrom
	StatusCode int
	// Log body of 4xx or 5xx responses
	LogErrBody bool
	// Log body of all responses
	LogAllBody bool

	TimeToFirstByte time.Duration
	StartTime       time.Time
	// number of bytes written
	bytesWritten int

            "items": {"$ref": REF_PREFIX + "ValidationError"},
        }
    },
}

status_code_ranges: Dict[str, str] = {
    "1XX": "Information",
    "2XX": "Success",
    "3XX": "Redirection",
    "4XX": "Client Error",
    "5XX": "Server Error",
    "DEFAULT": "Default Response",
}


def get_openapi_security_definitions(
    flat_dependant: Dependant,
) -> Tuple[Dict[str, Any], List[Dict[str, Any]]]:

        return True
    # Ref: https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.1.0.md#patterned-fields-1
    if status_code in {
        "default",
        "1XX",
        "2XX",
        "3XX",
        "4XX",
        "5XX",
    }:
        return True
    current_status_code = int(status_code)
    return not (current_status_code < 200 or current_status_code in {204, 205, 304})

		Help:      "Total number of S3 requests with (4xx and 5xx) errors",
		Type:      counterMetric,
	}
}

func getS3Requests4xxErrorsMD() MetricDescription {
	return MetricDescription{
		Namespace: s3MetricNamespace,
		Subsystem: requestsSubsystem,
		Name:      "4xx_" + errorsTotal,
		Help:      "Total number of S3 requests with (4xx) errors",
		Type:      counterMetric,
	}
}