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package main
import (
"database/sql"
"database/sql/driver"
"fmt"
"reflect"
"github.com/go-playground/validator/v10"
)
// DbBackedUser User struct
type DbBackedUser struct {
Name sql.NullString `validate:"required"`
Age sql.NullInt64 `validate:"required"`
}
// use a single instance of Validate, it caches struct info
var validate *validator.Validate
func main() {
validate = validator.New()
// register all sql.Null* types to use the ValidateValuer CustomTypeFunc
validate.RegisterCustomTypeFunc(ValidateValuer, sql.NullString{}, sql.NullInt64{}, sql.NullBool{}, sql.NullFloat64{})
// build object for validation
x := DbBackedUser{Name: sql.NullString{String: "", Valid: true}, Age: sql.NullInt64{Int64: 0, Valid: false}}
err := validate.Struct(x)
if err != nil {
fmt.Printf("Err(s):\n%+v\n", err)
}
}
// ValidateValuer implements validator.CustomTypeFunc
func ValidateValuer(field reflect.Value) interface{} {
if valuer, ok := field.Interface().(driver.Valuer); ok {
val, err := valuer.Value()
if err == nil {
return val
}
// handle the error how you want
}
return nil
}
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