Numeric bool: serialized as int <--> used in code like a boolean

numericBool.go

package main

import (
	"encoding/json"
	"fmt"
	"log"
	"strconv"
	"strings"
)

type NumericBool bool

var _ json.Marshaler = (*NumericBool)(nil)
var _ json.Unmarshaler = (*NumericBool)(nil)

func (nb *NumericBool) UnmarshalJSON(blob []byte) error {
	if len(blob) < 1 {
		*nb = false
		return nil
	}

	s := string(blob)
	if strings.ContainsAny(s, "tf") {
		// Try first parsing an integer.
		pBool, err := strconv.ParseBool(s)
		if err == nil {
			*nb = NumericBool(pBool)
			return nil
		}
	}

	pInt, err := strconv.ParseInt(s, 10, 32)
	if err != nil {
		*nb = pInt != 0
		return nil
	}

	return err
}

var (
	oneAsJSON, _  = json.Marshal(1)
	zeroAsJSON, _ = json.Marshal(0)
)

func (nb *NumericBool) MarshalJSON() ([]byte, error) {
	if nb == nil || *nb == false {
		return zeroAsJSON, nil
	}
	return oneAsJSON, nil
}

func main() {
	// Then to test it
	type Request struct {
		Private NumericBool `json:"private"`
	}

	req := &Request{Private: true}
	blob, _ := json.Marshal(req)
	fmt.Printf("Marshaled: %s\n", blob)

	var r1 Request
	if err := json.Unmarshal(blob, &r1); err != nil {
		log.Fatal(err)
	}
	fmt.Printf("Unmarshaled: %#v\n", r1)
}