Golang/mgo : How can I store Date (not ISODate) in mongodb? - mongodb

Question

If I store current time like this:
type Test struct {
Id string `bson:"id" json:"id,omitempty"`
TestTime time.Time `bson:"testTime" json:"testTime,omitempty"`
}
...
t := Test {
Id : "TEST0001",
TestTime : time.Now(),
}
...
c.Insert(t)
Then I use mongochef to search it :
{
"_id" : ObjectId("576bc7a48114a14b47920d60"),
"id" : "TEST0001",
"testTime" : ISODate("2016-06-23T11:27:30.447+0000")
}
So, mgo store ISODate by default, how can I store Date not ISODate ?

Answer 1

mgo automagically converts time.Time into a Mongo internal date data type (source, actually it's just a timestamp with no timezone info and it's always corrected to UTC). Any other functionaly has to be manually implemented by you.
You can force mgo to correctly (de)serialize your types by implementing the Getter and Setter interfaces from package mgo/bson thought it's pretty low-level so be careful.

Answer 2

You should define a custom struct that saves the timezone like this.
The you can define a custom Unmarshal that changes the location of the date on loading.
func (t *TimeWithTimezone) Unmarshal(in []byte, out interface{}) (err error) {
type decode TimeWithTimezone
var d decode
if err := bson.NewDecoder(in).Decode(&d); err != nil {
return err
}
loc, err := FixedZone(d.Timezone, d.Timezone)
if err != nil {
return fmt.Errorf("Invalid Timezone: %s", d.Timezone)
}
t.Time = d.Time.In(loc)
t.Timezone = d.Timezone
return nil
}
Something like this should do the trick, it's not tested, just to give you an idea!