我们在web开发中，你的应用可能会在不同国家使用，所以需要将相关的错误提示根据本地语言进行相应的提示，也即是所谓的国际化。本文简单的介绍一下，在Gin中如何实现多语言的验证。我们借助validator.v10以及相应的语言包。

集成关键点

1. 导入需要转换语言包
   • 公共包： "github.com/go-playground/validator/v10"
   • 需要转换的包，比如英文和中文

    en2 "github.com/go-playground/locales/en"
    zh2 "github.com/go-playground/locales/zh"
    ut "github.com/go-playground/universal-translator"
    en_translations "github.com/go-playground/validator/v10/translations/en"
    zh_translations "github.com/go-playground/validator/v10/translations/zh"

2. 结构体定义不在是 binding,而是validate

type Person struct {
    Age     int    `form:"age" validate:"required,gt=10"`
    Name    string `form:"name" validate:"required"`
    Address string `form:"address" validate:"required"`
}

3. 构建语言转换器以及注册

tans, _ := uni.GetTranslator(local)
tans, _ := uni.GetTranslator(local)
    switch local {
    case "en":
        en_translations.RegisterDefaultTranslations(validate, tans)
    case "zh":
        zh_translations.RegisterDefaultTranslations(validate, tans)
    default:
        en_translations.RegisterDefaultTranslations(validate, tans)
    }

4. 校验以及获取错误信息

   校验，调用err := validate.Struct(xx)；如果对返回的错误信息进行处理，validator返回的绑定错误信息格式：key = namespace & value = translated error；我们可以一次性获取所有的转换信息或者每次一次，具体如下：

err := validate.Struct(person)
if err != nil {
    errs := err.(validator.ValidationErrors)
    // 一次性转换所有与的错误信息方式
    fmt.Println(errs.Translate(trans))
    // 每次转换一次
    for _, e := range errs {
            fmt.Println(e.Translate(trans))
    }
}

具体示例

package main
import (
    "github.com/gin-gonic/gin"
    en2 "github.com/go-playground/locales/en"
    zh2 "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"
    "log"
    "net/http"
)

type Person struct {
    Age     int    `form:"age" validate:"required,gt=10"`
    Name    string `form:"name" validate:"required"`
    Address string `form:"address" validate:"required"`
}

// use a single instance , it caches struct info
var (
    uni      *ut.UniversalTranslator
    validate *validator.Validate
)

func multiLangBindingHandler(c *gin.Context) {
    local := c.DefaultQuery("local", "en")
    log.Println("local:", local)
    tans, _ := uni.GetTranslator(local)
    switch local {
    case "en":
        en_translations.RegisterDefaultTranslations(validate, tans)
    case "zh":
        zh_translations.RegisterDefaultTranslations(validate, tans)
    default:
        en_translations.RegisterDefaultTranslations(validate, tans)
    }
    var person Person

    if err := c.ShouldBind(&person); err != nil {
        c.JSON(http.StatusBadRequest, gin.H{
            "message": err.Error(),
        })
        return
    }
    if err := validate.Struct(person); err != nil {

        errs := err.(validator.ValidationErrors)
        sliceErrs := []string{}
        for _, e := range errs {
            // can translate each error one at a time.
            sliceErrs = append(sliceErrs, e.Translate(tans))
        }
        c.JSON(http.StatusBadRequest, gin.H{
            // translate all error at once
            // returns a map with key = namespace & value = translated error
            // NOTICE: 2 errors are returned and you'll see something surprising
            // translations are i18n aware!!!!
            // eg. '10 characters' vs '1 character'
            "message":   errs.Translate(tans),
            "sliceErrs": sliceErrs,
        })
        return
    }
    c.JSON(http.StatusOK, gin.H{
        "personInfo": person,
    })
}

func main() {
    zh := zh2.New()
    en := en2.New()
    uni = ut.New(en, zh)

    validate = validator.New()
    router := gin.Default()
    router.GET("/testMultiLangBinding", multiLangBindingHandler)
    router.Run(":9999")
}

测试

参考资料

validator.v10
Translations & Custom Errors