ion.Timestamp to json time

Question

I saw that if I store QLDB ion.Timestamp, it cannot be converted directly to json time string (YYYY-MM-DDThh:mm:ss.sssZ).

for example:

// result of querying data object from histories(table, from, to)
var val map[string]interface{} 
err := ion.Unmarshal(tables.GetCurrentData(), &val) // from multiple table
val == map[string]interface {}{
        "createdAt": &ion.Timestamp{
            dateTime: time.Time{
                wall: 0x41cdb40,
                ext:  63746482222,
                loc:  (*time.Location)(nil),
            },
            precision:            0x6,
            kind:                 0x1,
            numFractionalSeconds: 0x3,
        },
        // some other nested column
    }
// val when marshalled to json will show:
{"createdAt":{}}

How to force ion.Timestamp into json string or int64 unix/epoch when marshalled? or I have to check the map recursively whether it's ion.Timestamp or not, then overwrite the map to json string?

current workaround (not yet recursive)

for k, v := range data {
  switch t := v.(type) {
    case ion.Timestamp:
      data[k] = t.String()
    case *ion.Timestamp:
      if t != nil {
        data[k] = t.String()
      }
  }
}

Answer 1

To convert a Timestamp to JSON in a particular way, you can implement the Marshaler interface for Timestamp.

For example, to convert it as a Unix timestamp, use this function (try it in the Go Playground).

func (t Timestamp) MarshalJSON() ([]byte, error) {
    return json.Marshal(t.GetDateTime().Unix())
}

To convert it as a date string, use this function (try it in the Go Playground).

func (t Timestamp) MarshalJSON() ([]byte, error) {
    return json.Marshal(t.GetDateTime())
}

For further reading, see the documentation for the encoding/json package, or check out this Gopher Academy blog post on advanced encoding and decoding.