Go Gin：Validator参数验证

「本文正在参加金石计划」

1. 下载

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

2. 为结构体添加validate标签

   type User struct {
   	Name    string  `validate:"require,len=12"`
   	Age     uint8   `validate:"gte=0,lte=130"`
   	Gender  uint8   `validate:"oneof=0 1"`
   	Email   string  `validate:"required,email"`
   	Address Address `validate:"required,dive,required"`
   }
   
   type Address struct {
   	Country  string `validate:"required"`
   	Province string `validate:"required"`
   	City     string `validate:"required"`
   	Street   string `validate:"required"`
   }
   

   常用的标签

   Comparisons:

   Tag	Description	Usage
   eq	=	`validate:"eq=1"`
   gt	>	`validate:"gt=0"`
   gte	>=	`validate:"gte=0"`
   lt	<	`validate:"lt=130"`
   lte	<=	`validate:"lte=130"`
   ne	!=	`validate:"ne=38"`

   Other:

   Tag	Description	Usage
   required	是否必须	`validate:"required"`
   len	设置长度	`validate:"len=9"`
   max	最大值	`validate:"max=100"`
   min	最小值	`validate:"min=1"`
   oneof	值只能是多少（区间内）	`validate:"oneof=0 1"` // 0或1

3. 生成

   addr1 := Address{
     Country:  "China",
     Province: "GuangDong",
     City:     "GuangZhou",
     Street:   "DongFang Street",
   }
   u1 := User{
     Name:    "Catlinie",
     Age:     135,
     Gender:  1,
     Email:   "1388888888@qq.com",
     Address: &addr1,
   }
   err := validate.Struct(&user)
   if err != nil{
   	validationErrors, ok := err.(validator.ValidationErrors)
        if !ok{
           panic("validationError")
        }
     ...
   }
   

4. 与Gin配合

   此时不需要单独重新封装validator，因为Gin的参数校验使用的就是它。在我们每次使用ShouldBind()的时候，Gin底层都会使用validate.Struct()。在Gin中，用户不使用validate Tag而是binding Tag。

   type TestAPI struct {
   	ID     uint   `form:"id"`
   	Name   string `form:"name" binding:"required"`
   	Age    uint   `form:"age" binding:"required,min=0,max=120"`
   	Gender uint8  `form:"gender,default=1" binding:"oneof=0 1"`
   	Desc   string `form:"desc"`
   }
   
   func main(){
   	r := gin.Default()
     
   	r.GET("/ping", func(context *gin.Context) {
   		t := TestAPI{}
   		err := context.ShouldBind(&t)
   		if err != nil {
   			errs, ok := err.(validator.ValidationErrors)
   			if !ok {
   				// ...
   				return
   			}
   			// 输出错误
         // validator允许用户添加翻译器
   			return
   		}
   		// 后续操作
   	})
   
   	r.Run(":8000")
   }
   

5. 错误翻译本地化

   1. 获取翻译器组

      import(
        zh "github.com/go-playground/locales/zh"
        en "github.com/go-playground/locales/en"
        ut "github.com/go-playground/universal-translatior"
      )
      
      uni := ut.New(zh.New(), en.New())
      

   2. 获取指定翻译器

      trans, _ := uni.GetTranslator("zh")

   3. 将翻译器注册进validator里

      import zh_translations "github.com/go-playground/validator/v10/translations/zh"
      
      zh_translations.RegisterDefaultTransltions(validate, trans)
      

   4. 翻译

      err := validate.Struct(user)
      if err != nil{
        errs, ok := err.(validator.ValidationErrors)
        if !ok{
          return
        }
        fmt.Println(errs.Translate(trans))
      }