err.Translate(trans) only works if translator passed via param (go-playground/validator)

[fasaya]

I'm trying to translate the validation errors message because I don't like the default error message. When I pass the trans variable via param from controllers to a helper (to handle validation error), err.Translate(trans) worked just like what I want.

Here is the controllers/handler

package handler

import (
	"base-trade-rest/api/request"
	"base-trade-rest/core/helpers"
	"base-trade-rest/core/model"
	"base-trade-rest/core/service"
	"net/http"

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

type ProductHandler struct {
	ProductService service.IProductService
	Validate       *validator.Validate
	Trans          ut.Translator
}

func NewProductHandler(productService service.IProductService) *ProductHandler {

	// NOTE: omitting allot of error checking for brevity
	en := en.New()
	uni := ut.New(en, en)

	// this is usually know or extracted from http 'Accept-Language' header
	// also see uni.FindTranslator(...)
	trans, _ := uni.GetTranslator("en")

	validate := validator.New()
	en_translations.RegisterDefaultTranslations(validate, trans)

	var productHandler = ProductHandler{
		ProductService: productService,
		Validate:       validate,
		Trans:          trans,
	}
	return &productHandler
}

func (h *ProductHandler) Store(ctx *gin.Context) {
	var request request.ProductCreateRequest

	err := ctx.ShouldBind(&request)
	if err != nil {
		helpers.CreateFailedResponse(ctx, http.StatusBadRequest, err.Error())
		return
	}

	err = h.Validate.Struct(request)
	if err != nil {
		helpers.HandleValidationError(ctx, err, h.Trans)
		return
	}


	// Get authenticated user
	userData := helpers.GetAuthUser(ctx)

	product := model.Product{
		Name:     request.Name,
		ImageURL: nil,
		UserID:   userData.ID,
	}

	newUser, err := h.ProductService.CreateProduct(&product)
	if err != nil {
		helpers.CreateFailedResponse(ctx, http.StatusBadRequest, err.Error())
		return
	}

	helpers.CreateSuccessfulResponse(ctx, http.StatusOK, "Product successfully created", newUser)
}

And the helpers

package helpers

import (
	"strings"

	"github.com/gin-gonic/gin"
	ut "github.com/go-playground/universal-translator"
	"github.com/go-playground/validator/v10"
)


func getValidationErrors(err error, trans ut.Translator) map[string]string {
	var errors = make(map[string]string)

	errs := err.(validator.ValidationErrors)
	for _, e := range errs {
		errors[strings.ToLower(e.Field())] = e.Translate(trans)
	}

	return errors
}


func HandleValidationError(ctx *gin.Context, err error, trans ut.Translator) {
	CreateValidationErrorResponse(ctx, getValidationErrors(err, trans))
}

The getValidationErrors() returns just like i expected

{
    "name": "Name is a required field"
}

But because i dont want to repeat the code in every controllers/handlers, i created a helper and init the trans there

package helpers

import (
	"strings"

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

// use single instances, it caches struct info
var trans ut.Translator

func init() {
	en := en.New()
	uni := ut.New(en, en)
	trans, _ = uni.GetTranslator("en")

	validate := validator.New()
	en_translations.RegisterDefaultTranslations(validate, trans)
}

func getValidationErrors(err error) map[string]string {
	var errors = make(map[string]string)

	errs := err.(validator.ValidationErrors)
	for _, e := range errs {
		errors[strings.ToLower(e.Field())] = e.Translate(trans)
	}

	return errors
}

func HandleValidationError(ctx *gin.Context, err error) {
	CreateValidationErrorResponse(ctx, getValidationErrorsTest(err))
}

And call it from controllers like this without passing the h.Trans

err = h.Validate.Struct(request)
if err != nil {
        helpers.HandleValidationError(ctx, err)
return
}

But it returns something like this which i don't want

{
    "name": "Key: 'ProductCreateRequest.Name' Error:Field validation for 'Name' failed on the 'required' tag"
}

Is there something i missed or is this a wrong way?