I'm calling a older api, and its returning objects in the form of.
{ value: 1, time: "/Date(1412321990000)/" }
Using a struct defined with
type Values struct{
Value int
Time time.Time
}
Gives me a &time.ParseError. I'm a beginner at Go, is there a way for me to define how this should be serialized/deserialized?. Ultimately I do want it as a time.Time object.
This date format seems to be an older .NET format too. Can't really get the output changed either.
You need to implement the json Unmarshaler interface on your Values struct.
// UnmarshalJSON implements json's Unmarshaler interface
func (v *Values) UnmarshalJSON(data []byte) error {
// create tmp struct to unmarshal into
var tmp struct {
Value int `json:"value"`
Time string `json:"time"`
}
if err := json.Unmarshal(data, &tmp); err != nil {
return err
}
v.Value = tmp.Value
// trim out the timestamp
s := strings.TrimSuffix(strings.TrimPrefix(tmp.Time, "/Date("), ")/")
i, err := strconv.ParseInt(s, 10, 64)
if err != nil {
return err
}
// create and assign time using the timestamp
v.Time = time.Unix(i/1000, 0)
return nil
}
Check out this working example.
A different approach is to define a custom type for the time instead of manually creating a temp struct.
Also embedding time.Time makes it easier to access all the functions defined on it, like .String().
type WeirdTime struct{ time.Time }
type Value struct {
Value int
Time WeirdTime
}
func (wt *WeirdTime) UnmarshalJSON(data []byte) error {
if len(data) < 9 || data[6] != '(' || data[len(data)-3] != ')' {
return fmt.Errorf("unexpected input %q", data)
}
t, err := strconv.ParseInt(string(data[7:len(data)-3]), 10, 64)
if err != nil {
return err
}
wt.Time = time.Unix(t/1000, 0)
return nil
}
time.Time.Time.