I have this JSON API that returns the delivery date as a UNIX timestamp. I would prefer using Time in the rest of the application. The following works but doesn't feel very Go like.
type Delivery struct {
Time string `json:"time"`
}
func timestampToTime(s string) time.Time {
i, _ := strconv.ParseInt(s, 10, 64)
returns time.Unix(i, 0)
}
fmt.Println(timestampToTime(Delivery.Time))
// 2019-02-17 11:55:00 +0100 CET
Is there a way to cast an incoming value in a struct?
You can do something very similar to the custom JSON Unmarshal method described here:
http://choly.ca/post/go-json-marshalling/
Assuming that the JSON contains a string in your case this would look like this:
package main
import (
"encoding/json"
"fmt"
"os"
"strconv"
"time"
)
const input = `{"time": "946684799"}`
type Delivery struct {
Time time.Time `json:"time"`
}
func (d *Delivery) UnmarshalJSON(data []byte) error {
type Alias Delivery
aux := &struct {
Time string `json:"time"`
*Alias
}{
Alias: (*Alias)(d),
}
if err := json.Unmarshal(data, &aux); err != nil {
return err
}
i, err := strconv.ParseInt(aux.Time, 10, 64)
if err != nil {
return err
}
d.Time = time.Unix(i, 0)
return nil
}
func main() {
var delivery Delivery
err := json.Unmarshal([]byte(input), &delivery)
if err != nil {
fmt.Println(err.Error())
os.Exit(1)
}
fmt.Println(delivery.Time)
}