在Django中使用给定时区显示时间

Question

I'm developing a Django app for logging dives and each dive has a datetime and a timezone in it. I'm using the django-timezone-field app for the timezone.

class Dive(models.Model):
  ...
  date_time_in = models.DateTimeField(default=timezone.now)
  timezone = TimeZoneField(default=timezone.get_current_timezone_name())

So the user is able to enter a datetime string ("2016-07-11 14:00") and select a timezone ("Asia/Bangkok" - UTC+0700), I then set the timezone of the datetime to the one given in my view like this:

def log_dive(request):
  if request.method == 'POST':
    form = DiveForm(request.POST)
    if form.is_valid():
      dive = form.save(commit=False)
      date = dive.date_time_in
      date = date.replace(tzinfo=None)
      dive.date_time_in = dive.timezone.localize(date)
      dive.save()

The database then stores the datetime as UTC in the database (SELECT statement gives it in my local timezone):

# SELECT date_time_in, timezone FROM divelog_dive ORDER BY number DESC;
      date_time_in      |     timezone     
------------------------+------------------
 2014-07-11 17:00:00+10 | Asia/Bangkok

Now there are two things I'm struggling with:

1) I want to display the dates in the given timezone, however I can't seem to stop it defaulting to the TIME_ZONE setting.

2) If the user edits the record, the time displayed in the edit field should be the one they originally entered (14:00), instead it's showing it in the current timezone (17:00).

Answer 1

在settings.py检查您的时区settings.py

Answer 2

Do you have USE_TZ = true in your settings file? If you created your app using the djangoadmin-startproject command, it is set by default.

Also, I struggled with timezones at my last job but found that using pytz really helped. Have you tried that package yet?

EDIT: Ok man I may be way off, but since noone else has answered and I feel the timezone struggle, here is something I noticed...

You are replacing the date object with tz_info=None, but wouldn't you want to instead replace that with the timezone from the database? So you would get that timezone and do a replace using the valid format (tzinfo=blah...)? Like I said I may be way off but if that helps there you go.

Answer 3

Sorry, I don't think I explained my problem very well. I finally figured this out, so I'll answer my own question.

1) turned out to be easy, Django have a template tag for displaying times in a given zone:

{{ dive.date_time_in|timezone:dive.timezone|date:"Y-m-d H:i e" }}

For 2), I came across [1] which lead me to this solution: In the view, after getting the object from the database, I use astimezone(...) to convert the date value (which the DB stores as UTC) into the given timezone. I then use replace(tzinfo=None) to make it naive and then it displays correctly on my form.

def edit_dive(request, dive_id=None):
  dive = None
  if dive_id != None:
    dive = get_object_or_404(Dive, pk=dive_id)
    local_date = dive.date_time_in.astimezone(timezone(str(dive.timezone)))
    dive.date_time_in = local_date.replace(tzinfo=None)

[1] http://www.saltycrane.com/blog/2009/05/converting-time-zones-datetime-objects-python/