Golang parse json with invalid "string-int" types

main.go

package main

import (
	"encoding/json"
	"fmt"
	"reflect"
	"strconv"
)

type invalidStrNums []int

type User struct {
	Id uint `json:"id"`
	//RoleIds  []uint   `json:"role_ids"`
	OtherIds invalidStrNums `json:"other_ids"`
}

func main() {
	in := `{"id":96,"other_ids": ["33",55,"66"] }`
	var u User

	if err := json.Unmarshal([]byte(in), &u); err != nil {
		panic("failed")
	}
	fmt.Printf("%#v", u)
	fmt.Println("")

	b, _ := json.Marshal(u)
	fmt.Println("internal presentation:", string(b))
	fmt.Println("")

	otherUser := &User{
		Id:       69,
		OtherIds: []int{5,99},
	}
	b, _ = json.Marshal(otherUser)
	fmt.Println("external presentation: ", string(b))
}

func (c *invalidStrNums) MarshalJSON() ([]byte, error) {
	var r []string
	for _, item := range *c {
		r = append(r, fmt.Sprintf("%v", item))
	}
	return json.Marshal(r)
}

func (c *invalidStrNums) UnmarshalJSON(b []byte) error {
	var n invalidStrNums

	fmt.Printf("%v\n", string(b))
	fmt.Printf("type: %v , %v\n", reflect.TypeOf(*c), *c)

	var nums []interface{}

	err := json.Unmarshal(b, &nums)
	if err != nil {
		return err
	}
	//fmt.Printf("%v\n", nums)

	for _, item := range nums {
		switch value := item.(type) {
		case int:
			n = append(n, item.(int))
		case float64:
			n = append(n, int(value))
		case string:
			num, err := strconv.Atoi(value)
			if err != nil {
				return err
			}
			n = append(n, num)
		}
	}

	*c = n
	return nil
}

/*
["33",55,"66"]
type: main.invalidStrNums , []
main.User{Id:0x60, OtherIds:main.invalidStrNums{33, 55, 66}}
internal presentation: {"id":96,"other_ids":[33,55,66]}

external presentation:  {"id":69,"other_ids":["5","99"]}
 */