Python JSON encoder to support datetime?

Question

is there any elegant way to make Python JSON encoder support datetime? some 3rd party module or easy hack?

I am using tornado\'s database wrapper to fetch some rows

Answer 1

The docs suggest subclassing JSONEncoder and implementing your own default method. Seems like you're basically there, and it's not a "dirty hack".

The reason dates aren't handled by the default encoder is there is no standard representation of a date in JSON. Some people are using the format /Date(1198908717056)/, but I prefer ISO format personally.

import json
import datetime


class DateTimeEncoder(json.JSONEncoder):

    def default(self, obj):
        if isinstance(obj, (datetime.datetime, datetime.date, datetime.time)):
            return obj.isoformat()
        elif isinstance(obj, datetime.timedelta):
            return (datetime.datetime.min + obj).time().isoformat()

        return super(DateTimeEncoder, self).default(obj)

now = datetime.datetime.now()
encoder = DateTimeEncoder()
encoder.encode({"datetime": now, "date": now.date(), "time": now.time()})
> {"datetime": "2019-07-02T16:17:09.990126", "date": "2019-07-02", "time": "16:17:09.990126"}