Converting ASP.Net JSON Date into Python datetime [duplicate]

Question

This is what I came up with, but neither of your example inputs matched up to your example output so I'm not sure whether there's a timezone offset error here or not.

#!/usr/bin/env python

import datetime

def parse_date(datestring):
    timepart = datestring.split('(')[1].split(')')[0]
    milliseconds = int(timepart[:-5])
    hours = int(timepart[-5:]) / 100
    time = milliseconds / 1000

    dt = datetime.datetime.utcfromtimestamp(time + hours * 3600)
    return dt.strftime("%Y-%m-%dT%H:%M:%S") + '%02d:00' % hours

ScheduleDate = "\/Date(1374811200000-0400)\/"
StartTime = "\/Date(-2208931200000-0500)\/"

print(parse_date(ScheduleDate))
print(parse_date(StartTime))

It seems to be the case that Windows doesn't like negative values in datetime.(utc)?fromtimestamp(). It may be possible to ask it to compute a negative time delta from the Unix epoch:

#!/usr/bin/env python

import datetime

EPOCH = datetime.datetime.utcfromtimestamp(0)

def parse_date(datestring):
    timepart = datestring.split('(')[1].split(')')[0]
    milliseconds = int(timepart[:-5])
    hours = int(timepart[-5:]) / 100
    adjustedseconds = milliseconds / 1000 + hours * 3600

    dt = EPOCH + datetime.timedelta(seconds=adjustedseconds)
    return dt.strftime("%Y-%m-%dT%H:%M:%S") + '%02d:00' % hours

ScheduleDate = "\/Date(1374811200000-0400)\/"
StartTime = "\/Date(-2208931200000-0500)\/"

print(parse_date(ScheduleDate))
print(parse_date(StartTime))