gin: 校验参数时返回自定义错误信息

一，代码

1,global/validator.go

package global

import "github.com/go-playground/validator/v10"

//存放GetMessages()方法
type Validator interface {
	GetMessages() ValidatorMessages
}

//校验信息
type ValidatorMessages map[string]string

// GetErrorMsg方法， 获取错误信息
func GetErrorMsg(request interface{}, err error) string {
	if _, isValidatorErrors := err.(validator.ValidationErrors); isValidatorErrors {
		_, isValidator := request.(Validator)

		for _, v := range err.(validator.ValidationErrors) {
			// 若 request 结构体实现 Validator 接口即可实现自定义错误信息
			if isValidator {
				if message, exist := request.(Validator).GetMessages()[v.Field() + "." + v.Tag()]; exist {
					return message
				}
			}
			return v.Error()
		}
	}

	return "Parameter error"
}

2,request/Image.og

package request

import (
	"imagebank/global"
)

//ImageList请求参数struct
type ImageListRequest struct {
	Cid        int  `form:"cid" json:"cid" binding:"required,gte=1,lte=100"`
	Category       string `form:"category" json:"category" binding:"required,min=2,max=10"`
}

//保存自定义错误信息
func (request ImageListRequest) GetMessages() global.ValidatorMessages {
	return global.ValidatorMessages{
		"Cid.required": "cid不能为空",
		"Cid.gte": "cid不能小于1",
		"Cid.lte": "cid不能大于100",
		"Category.required": "类型不能为空",
		"Category.min": "类型最少2个字符",
		"Category.max": "类型最多10个字符",
	}
}

3,controller/ImageController.go

//得到列表
func (ic *ImageController) List(c *gin.Context) {

	var req request.ImageListRequest
	if err := c.ShouldBindQuery(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"err": global.GetErrorMsg(req, err),})
		return
	}

	fmt.Println("cid:",req.Cid)
	fmt.Println("category:",req.Category)

	c.JSON(http.StatusOK, gin.H{
		"message": "image list",
	})
}