Python string to Django timezone (aware datetime)

Question

TL;DR;

How to convert 2016-01-01 to Django timezone?

Full version:

I receive a query string parameter from a form and I wanna get that string and use it as a datetime filter in Django. The problem is that when I convert the string to a datetime, it's not making an aware datetime and so I lose a few hours due to timezone different. Maybe I'm losing myself in the formatting, but I'm not being able to do it.

I have pytz, I have USE_TZ = True in my settings as well.

example:

from datetime import date
# Example from what I receive as GET querystring parameter
start_date, end_date = '15-01-2016', '16-01-2016'
DATE_FORMAT = '%Y-%m-%d'
start_date = start_date.split('-')
start_date = date(int(start_date[2]), int(start_date[1]), int(start_date[0]))
sd_filter = start_date.strftime(DATE_FORMAT)

end_date = end_date.split('-')
end_date = date(int(end_date[2]), int(end_date[1]), int(end_date[0]))
ed_filter = end_date.strftime(DATE_FORMAT)

#query
my_list = MyModel.objects.filter(created_at__range=(sd_filter, ed_filter))

the problem lies in the filter. I'm losing a few hours due to timezone from Django settings.

UPDATE: I don't need to convert a datetime.now() to my time. I need to convert a string to datetime.

Solution 1

I know this is old but maybe will be helpful since I got into this situation as well:

What about using make_aware() ?

from datetime import datetime
from django.utils.timezone import make_aware

date = '22-05-2018'
aware = make_aware(datetime.strptime(date, '%d-%m-%Y'))

This will use the currently active timezone (activated by timezone.activate). If no timezone is activated explicitly, it would use the default timezone -- TIME_ZONE specified in settings.py.

Solution 2

You are comparing time-zone unaware Python Date objects with the time-zone aware DateTimeField fields in your database. It is probably more intuitive to use DateTime objects - and these can be made time-zone aware easily as follows:

import datetime
import pytz

start_date = '15-01-2016' 
end_date = '16-01-2016'
date_format = '%d-%m-%Y'

unaware_start_date = datetime.datetime.strptime(start_date, date_format)
aware_start_date = pytz.utc.localize(unaware_start_date)

unaware_end_date = datetime.datetime.strptime(end_date, date_format)
aware_end_date = pytz.utc.localize(unaware_end_date)

my_list = MyModel.objects.filter(created_at__range=(aware_start_date, aware_end_date))

This creates unaware_start_date and unaware_end_date DateTime objects using strptime(). It then uses pytz.utc.localize to make the objects time-zone aware (you will need to replace utc with your relevant time-zone).

You can then have time-zone aware DateTime objects - aware_start_date and aware_end_date. Feeding these into your filter should yield the desired results.

Solution 3

from django.utils import timezone
timestamp_raw = timezone.now() #current time, or use whatever time you have
date_format = '%Y-%m-%d %H:%M:%S' #time format day-month-year hour:minutes:seconds
timestamp = timezone.datetime.strftime(timestamp_raw, date_format)

Or Using the new f-string formatter

f"{timezone:%Y-%m-%d %H:%M:%S %p}"

Comments

[gtlambert]

What field type are you using in your model? A DateField()? If so, you can just pass the two date objects (start_date and end_date) to your created_at__range=() filter.

[Lajos Arpad]

Possible duplicate of Python Timezone conversion

[jarussi]

@lambo477 It's a DateTimeField and I tryed doing that .. but it's still missing a few hours from utc.

[jarussi]

@LajosArpad I tried using what was said in the answers but it didn't work for me :(

[gtlambert]

If you don't have the pytz module installed, run pip install pytz from your command line

[Gustavo Oliveira]

Does this apply to a date ISO string?

[salafi]

Yes, It does . I have also edited the answer to include example using the new f-string formatter.