return *CommonError instead of errorString (#568)

util/error.go

@@ -8,10 +8,15 @@ import (
 
 // CommonError 微信返回的通用错误json
 type CommonError struct {
+	apiName string
 	ErrCode int64  `json:"errcode"`
 	ErrMsg  string `json:"errmsg"`
 }
 
+func (c *CommonError) Error() string {
+	return fmt.Sprintf("%s Error , errcode=%d , errmsg=%s", c.apiName, c.ErrCode, c.ErrMsg)
+}
+
 // DecodeWithCommonError 将返回值按照CommonError解析
 func DecodeWithCommonError(response []byte, apiName string) (err error) {
 	var commError CommonError
@@ -19,8 +24,9 @@ func DecodeWithCommonError(response []byte, apiName string) (err error) {
 	if err != nil {
 		return
 	}
+	commError.apiName = apiName
 	if commError.ErrCode != 0 {
-		return fmt.Errorf("%s Error , errcode=%d , errmsg=%s", apiName, commError.ErrCode, commError.ErrMsg)
+		return &commError
 	}
 	return nil
 }
@@ -45,7 +51,11 @@ func DecodeWithError(response []byte, obj interface{}, apiName string) error {
 		return fmt.Errorf("errcode or errmsg is invalid")
 	}
 	if errCode.Int() != 0 {
-		return fmt.Errorf("%s Error , errcode=%d , errmsg=%s", apiName, errCode.Int(), errMsg.String())
+		return &CommonError{
+			apiName: apiName,
+			ErrCode: errCode.Int(),
+			ErrMsg:  errMsg.String(),
+		}
 	}
 	return nil
 }