unix timestamp in Golang

timestamp.go

// marshal/unmarshal to/from unix timestamp
// implement the Scanner and Valuer interfaces of gorm (https://gorm.io/docs/data_types.html)

package custom

import (
  "time"
  "fmt"
  "strconv"
  "database/sql/driver"
)

type Timestamp time.Time

func (t *Timestamp) MarshalJSON() ([]byte, error) {
  unixTimestamp := fmt.Sprintf("\"%d\"", time.Time(*t).Unix())
  return []byte(unixTimestamp), nil
}

func (t *Timestamp) UnmarshalJSON(data []byte) error {
  unixTimestamp, err := strconv.ParseInt(string(data), 10, 64)
  if err != nil {
    return err
  }
  *t = Timestamp(time.Unix(unixTimestamp, 0))
  return nil
}

func (t *Timestamp) Scan(value interface{}) error {
  time, ok := value.(time.Time)
  if ok {
    *t = Timestamp(time)
  }
  return nil
}

func (t Timestamp) Value() (driver.Value, error) {
  return time.Time(t), nil
}