CODEWITHSUNDEEP
djangotimezoneutc
user3792705
user3792705

Reputation: 617

How to make Django DateTimeField to store Pacific time with UTC format

After reading many doc, I am confused by UTC, UTC timezone and how it's used in Django.

Is UTC format and UTC timezone same thing? Can UTC format store Pacific timezone date+time?

I have a django project with database and UI.

class FunModel(models.Model):
   fun_time = models.DateTimeField()

What I am expecting:

1) Page 1. click a button in a browser in Pacific timezone. Server to create/store (on server side, not client to create time) 'fun_time' as Pacific time zone date + time (not UTC zone, but format is UTC format)

2) Page 2. When page 2 is loaded. it retrieves time as Pacific date + time (Not UTC zone)

3) In database, I expect to see time stored is Pacific date+time.

4) As far as my understanding, FunModel class will store time as Pacific time with UTC format. The timezone is configured in settings.

----Settings.py

# Tried 'US/Pacific' as well. No difference. Date+time stored in db is the same. Really confused!
TIME_ZONE = 'UTC'  

# Only for retrieving date from db to be Pacific by calling active(USER_TIME_ZONE)? 
USER_TIME_ZONE = 'US/Pacific'  

# With above 2 settings, date stored/retrieved will be Pacific zone automatically. Not really!

USE_I18N = True
USE_L10N = True
USE_TZ = True

My expectation is database will store time as US/Pacific timezone, and the time format is UTC (always UTC format right?)

----Page1_Save.py
from django.utils import timezone

timezone.activate(settings.USER_TIME_ZONE)
time_param = timezone.localtime(timezone.now())

fun_time_obj = FunModel(fun_time=time_param)
fun_time_obj.save()

# time_param = 2019-04-16 01:00:00
# database: 2019-04-16 01:00:00 + 7 hours = 2019-04-16 08:00:00  (Not correct!)

I am expecting database: 2019-04-16 01:00:00.

I also tried,

time_param = timezone.now()

Same result:

# time_param = 2019-04-16 01:00:00
# database: 2019-04-16 01:00:00 + 7 hours = 2019-04-16 08:00:00  (Not correct!)

Where I did wrong?

---Page2_Load.py  (Use Q to compare date stored in db)

# Browser in Pacific timezone without timezone passed to server. Just time picked from Javascript.
ui_date = '2019-04-16 01:00:00'

I want to use Q function to compare:

Q(fun_time__exact=ui_date)

A) If database time is Pacific time, comparison is valid.

B) If database time is UTC time, the comparison is not valid. Now, I can't compare the date stored in db!!! How to fix it?

C) I don't want date+time in database to be UTC timezone!!!

Upvotes: 0

Views: 411

Answers (1)

user3792705
user3792705

Reputation: 617

I got it to work, but I am more confused by Django time zone settings.

Server computer system clock is UTC timezone.

---settings.py

# Totally useless
#TIME_ZONE = 'UTC'  # comment out, and server runs well.

# I suspect this is useless as well. 
USER_TIME_ZONE = 'US/Pacific'  

USE_I18N = True
USE_L10N = True
USE_TZ = False   # Make server timezone not aware.

---page1_save.py

  from datetime import datetime
  import  pytz
  utc = pytz.utc.localize(datetime.utcnow())  # Generate time from server, which is UTC timezone
  instance_time_zone = pytz.timezone('US/Pacific')  
  time_param = utc.astimezone(instance_time_zone)
  time_param = time_param.replace(tzinfo=None)  # USE_TZ = False. Make it without timezone.

  fun_time_obj = FunModel(fun_time=time_param)
  fun_time_obj.save()

Now, time in db is Pacific time, which is what I expect.

TIME_ZONE, USER_TIME_ZONE are useless in this case, when USE_TZ = False. Also, with USE_TZ = True, TIME_ZONE = 'What ever' seems also useless, as I tried TIME_ZONE = 'US/Pacific', USER_TIME_ZONE = 'US/Pacific', and can't get db to store pacific time.

Upvotes: 0

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