gin框架配合go-playground/validator完成json的验证以及json验证错误翻译成中文

安装 go-playground/validator
go get github.com/go-playground/validator/v10

代码如下

package main

import (
	"fmt"
	"net/http"
	"reflect"
	"strings"

	"github.com/gin-gonic/gin"
	"github.com/gin-gonic/gin/binding"
	"github.com/go-playground/locales/en"
	"github.com/go-playground/locales/zh"
	ut "github.com/go-playground/universal-translator"
	"github.com/go-playground/validator/v10"
	en_translations "github.com/go-playground/validator/v10/translations/en"
	zh_translations "github.com/go-playground/validator/v10/translations/zh"
)

type LoginForm struct {
	User     string `json:"user" binding:"required,min=3,max=10"`
	Password string `json:"password" binding:"required"`
}

type SignupForm struct {
	Age        uint8  `json:"age" binding:"gte=18,lte=130"`
	Name       string `json:"name" binding:"required,min=3"`
	Email      string `json:"email" binding:"required,email"`
	Password   string `json:"password" binding:"required,min=6"`
	RePassword string `json:"re_password" binding:"required,eqfield=Password"` // 跨字段验证
}

var trans ut.Translator

func removeTopStruct(fields map[string]string) map[string]string {
	// "LoginForm.user": "user长度不能超过10个字符"
	// 提取user,去掉LoginForm -- "user": "user长度不能超过10个字符"
	rsp := make(map[string]string)
	for field, err := range fields {
		rsp[field[strings.Index(field, ".")+1:]] = err
	}
	return rsp
}

func InitTrans(locale string) (err error) {
	// 修改gin框架中的validator引擎属性，实现定制
	if v, ok := binding.Validator.Engine().(*validator.Validate); ok {
		// 注册一个获取json的tag的自定义方法
		// "LoginForm.User": "User长度不能超过10个字符"
		// 将大写的User替换为json中定义的tag标签 -- "LoginForm.user": "user长度不能超过10个字符"
		v.RegisterTagNameFunc(func(field reflect.StructField) string {
			name := strings.SplitN(field.Tag.Get("json"), ",", 2)[0]
			if name == "-"{
				return ""
			}
			return name
		})

		zhT := zh.New() // 中文翻译器
		enT := en.New() // 英文翻译器
		// 第一个参数是备用的语言环境，后面的参数是应该支持的语言环境
		uni := ut.New(enT, zhT, enT)
		trans, ok = uni.GetTranslator(locale)
		fmt.Println(ok)
		if !ok {
			return fmt.Errorf("uni.GetTranslator(%s)", locale)
		}
		switch locale {
		case "en":
			en_translations.RegisterDefaultTranslations(v, trans)
		case "zh":
			zh_translations.RegisterDefaultTranslations(v, trans)
		default:
			en_translations.RegisterDefaultTranslations(v, trans)
		}
		return
	}
	return
}

func main() {
	if err := InitTrans("zh"); err != nil {
		fmt.Println("初始化翻译器错误")
		return
	}
	r := gin.Default()

	r.POST("/login", loginView)
	r.POST("/signup", signupView)

	r.Run()
}

func signupView(context *gin.Context) {
	var signupForm SignupForm
	if err := context.ShouldBind(&signupForm); err != nil {
		context.String(http.StatusBadRequest, err.Error())
		return
	}
	context.JSON(http.StatusOK, gin.H{"message": "注册成功"})
}

func loginView(context *gin.Context) {
	var loginForm LoginForm
	if err := context.ShouldBind(&loginForm); err != nil {
		errs, ok := err.(validator.ValidationErrors)
		if !ok{
			context.String(400, err.Error())
		}
		context.JSON(400, removeTopStruct(errs.Translate(trans)))
		return
	}
	context.JSON(http.StatusOK, gin.H{"message": "登录成功"})
}

go-playground/validator源码
go-playground/validator官方文档
json验证错误翻译成中文参考源码