Setting Timestamp in Python w/ timezonedb.com

Question

I have an app that uses timezonedb to grab local timezone information when creating a new post, but I am not sure of the math in order to get the new posts to reflect the timezone where I am. For example, I am currently in South Africa, posted an update to my server (which is using UTC time), and the date/time on the post gives PST. I would love some help with the code here, as it may just be me being bad at math.

At this time UTC: Wed Jan 26 05:33:09 UTC 2022 I made a post with timestampdb info:

timestamp: 1643182360
dst: 0
offset: 7200 

The post showed up on my app as 09:33pm yesterday (it was 7:33 am here). I am normally based in California, so I'm not sure if there is something I can do to fix this.

In my Django settings app, I am using "TIME_ZONE = US/Pacific" and "USE_TZ = True"

In my views:

def post(self, request, *args, **kwargs):
    if data['timestamp'] != '':
        offset = data['tz_offset']
        timestamp = data['timestamp']
        if timestamp != '' and offset != '':
            if int(offset) < 0:
                timestamp = int(data['timestamp']) + abs(int(offset))
            else:
                timestamp = int(data['timestamp']) - abs(int(offset))
        naive_time = datetime.datetime.fromtimestamp(int(timestamp))
        localtz = pytz.timezone(data['tz_location'])
        aware_est = localtz.localize(naive_time)
        utc = aware_est.astimezone(pytz.utc)
        data['timestamp'] = pytz.timezone(data['tz_location']).localize(
            naive_time, is_dst=data['tz_dst'])
    else:
        data['timestamp'] = datetime.datetime.now()

Is this an issue that I could fix with my settings.py or is it an issue with my views?

Answer 1

A few things:

• 1643182360 == 2022-01-26T07:32:40Z. Z means UTC, and Unix Timestamps are always in terms of UTC. Thus, your input timestamp is shifted prematurely. Don't try to adjust the timestamp for time zone when you save it - just save the UTC time.

• You are doing too much math in your view. In general, any time you find yourself adding or subtracting an offset from a timestamp, you're likely picking a different point in time - not adjusting the time zone. None of that math should be there.

• It's a bit unclear what data you are posting at which step and how/why you are using timezonedb.com. You show a tz_location in your code, but not in your data.

• If indeed you have a time zone identifier, you don't need either the offset or the DST flag at all. Just convert from UTC directly to that time zone. Let pytz (or dateutil, arrow, or the built-in zoneinfo in Python 3.9+) do the work for you.