cross-fields validation

go-playground/validator.v9を使って、CustomバリデーションはMininのStructの場合、メモしました。

package main

import (
	"fmt"

	"gopkg.in/go-playground/validator.v9"
)

type A struct {
	String string `validate:"required"`
}
type B struct {
	Int int64 `validate:"custom=A.String"`
}
type C struct {
	A
	B
}

func main() {
	v := validator.New()
	v.RegisterValidation("custom", customFunc)
	c := &C{}
	// Key: 'C.B.Int' Error:Field validation for 'Int' failed on the 'custom' tag
	c.String = "hoge"
	c.Int = 3
	err := v.Struct(c)
	fmt.Println(err)
	// nil
	c.String = "foo"
	c.Int = 3
	err = v.Struct(c)
	fmt.Println(err)
}

func customFunc(fl validator.FieldLevel) bool {
	param := fl.Param()
	field, _, _, found := fl.GetStructFieldOKAdvanced2(fl.Top(), param)
	return found && int(fl.Field().Int()) == len(field.String())
}