refactor: proxy api

center/router/router_proxy.go

 package router
 
 import (
+	"bytes"
 	"context"
 	"crypto/tls"
+	"fmt"
+	"io"
 	"net"
 	"net/http"
 	"net/http/httputil"
@@ -164,10 +167,39 @@ func (rt *Router) dsProxy(c *gin.Context) {
 		transportPut(dsId, ds.UpdatedAt, transport)
 	}
 
+	modifyResponse := func(r *http.Response) error {
+		// 当后端服务返回401时，改变响应状态码和内容
+		if r.StatusCode == http.StatusUnauthorized {
+			body, err := io.ReadAll(r.Body)
+			if err != nil {
+				return err
+			}
+			r.Body.Close()
+
+			// 重新填充响应体
+			r.Body = io.NopCloser(bytes.NewBuffer(body))
+
+			// 创建自定义错误，并返回
+			customErr := fmt.Errorf("unauthorized access: %v", string(body))
+
+			// 调整返回的HTTP状态码和内容
+			r.StatusCode = http.StatusOK
+			r.Status = "200 OK"
+
+			c.JSON(http.StatusOK, gin.H{
+				"err": customErr.Error(),
+			})
+
+			return customErr
+		}
+		return nil
+	}
+
 	proxy := &httputil.ReverseProxy{
-		Director:     director,
-		Transport:    transport,
-		ErrorHandler: errFunc,
+		Director:       director,
+		Transport:      transport,
+		ErrorHandler:   errFunc,
+		ModifyResponse: modifyResponse,
 	}
 
 	proxy.ServeHTTP(c.Writer, c.Request)