Datetime localization with python/django

Question

I am trying to parse an RSS feed. Entries in the feed have date elements like:

<dc:date>2016-09-21T16:00:00+02:00</dc:date>

Using feedparser, I try to do:

published_time = datetime.fromtimestamp(mktime(entry.published_parsed))

But the problem is that I seem to be getting the wrong time stored in the database. In this particular case, the datetime is stored as:

2016-09-21 13:00:00

... when I would expect 14:00 - the correct UTC time.

I assume the problem is in our django settings, where we have:

TIME_ZONE = 'Europe/Berlin'

Because when I switch to:

TIME_ZONE = 'UTC'

... the datatime is stored as correct UTC time:

2016-09-21 14:00:00

Is there any way to keep the django settings as they are, but to parse and store this datetime correctly, without the django timezone setting affecting it?

EDIT: Maybe it's more clear like this...

print entry.published_parsed
published_time = datetime.fromtimestamp(mktime(entry.published_parsed))
print published_time
localized_time = pytz.timezone(settings.TIME_ZONE).localize(published_time, is_dst=None)
print localized_time

time.struct_time(tm_year=2016, tm_mon=9, tm_mday=21, tm_hour=14, tm_min=0, tm_sec=0, tm_wday=2, tm_yday=265, tm_isdst=0)
2016-09-21 15:00:00
2016-09-21 15:00:00+02:00

Answer 1

feedparser's entry.published_parsed is always a utc time tuple whatever the input time string is. To get timezone-aware datetime object:

from datetime import datetime

utc_time = datetime(*entry.published_parsed[:6], tzinfo=utc)

where utc is a tzinfo object such as datetime.timezone.utc, pytz.utc, or just your custom tzinfo (for older python versions).

You shouldn't pass utc time to mktime() that expects a local time. Same error: Have a correct datetime with correct timezone.

Make sure USE_TZ=True so that django uses aware datetime objects everywhere. Given a timezone-aware datetime object, django should save it to db correctly whatever your TIME_ZONE or timezone.get_current_timezone() are.

Answer 2

Have you tried using datetime.utcfromtimestamp() instead of datetime.fromtimestamp()?

As a secondary solution, you can get the unparsed data (I believe it's available as entry.published?) and just use python-dateutil to parse the string, then convert it to pytz.utc timezone like this.

>>> import pytz
>>> from dateutil import parser
>>> dt = parser.parse('2016-09-21T16:00:00+02:00')
>>> dt
datetime.datetime(2016, 9, 21, 16, 0, tzinfo=tzoffset(None, 7200))
>>> dt.astimezone(pytz.utc)
datetime.datetime(2016, 9, 21, 14, 0, tzinfo=<UTC>)