def timezone_today():
"""
Return the current date in the current time zone.
"""
if settings.USE_TZ:
return timezone.localtime(timezone.now()).date()
else:
return datetime.date.today()
def do_timezone(value, arg):
"""
Converts a datetime to local time in a given time zone.
The argument must be an instance of a tzinfo subclass or a time zone name.
If it is a time zone name, pytz is required.
Naive datetimes are assumed to be in local time in the default time zone.
"""
if not isinstance(value, datetime):
return ''
# Obtain a timezone-aware datetime
try:
if timezone.is_naive(value):
default_timezone = timezone.get_default_timezone()
value = timezone.make_aware(value, default_timezone)
# Filters must never raise exceptions, and pytz' exceptions inherit
# Exception directly, not a specific subclass. So catch everything.
except Exception:
return ''
# Obtain a tzinfo instance
if isinstance(arg, tzinfo):
tz = arg
elif isinstance(arg, six.string_types) and pytz is not None:
try:
tz = pytz.timezone(arg)
except pytz.UnknownTimeZoneError:
return ''
else:
return ''
result = timezone.localtime(value, tz)
# HACK: the convert_to_local_time flag will prevent
# automatic conversion of the value to local time.
result = datetimeobject(result.year, result.month, result.day,
result.hour, result.minute, result.second,
result.microsecond, result.tzinfo)
result.convert_to_local_time = False
return result
def _get_next_prev(generic_view, date, is_previous, period):
"""
Helper: Get the next or the previous valid date. The idea is to allow
links on month/day views to never be 404s by never providing a date
that'll be invalid for the given view.
This is a bit complicated since it handles different intervals of time,
hence the coupling to generic_view.
However in essence the logic comes down to:
* If allow_empty and allow_future are both true, this is easy: just
return the naive result (just the next/previous day/week/month,
reguardless of object existence.)
* If allow_empty is true, allow_future is false, and the naive result
isn't in the future, then return it; otherwise return None.
* If allow_empty is false and allow_future is true, return the next
date *that contains a valid object*, even if it's in the future. If
there are no next objects, return None.
* If allow_empty is false and allow_future is false, return the next
date that contains a valid object. If that date is in the future, or
if there are no next objects, return None.
"""
date_field = generic_view.get_date_field()
allow_empty = generic_view.get_allow_empty()
allow_future = generic_view.get_allow_future()
get_current = getattr(generic_view, '_get_current_%s' % period)
get_next = getattr(generic_view, '_get_next_%s' % period)
# Bounds of the current interval
start, end = get_current(date), get_next(date)
# If allow_empty is True, the naive result will be valid
if allow_empty:
if is_previous:
result = get_current(start - datetime.timedelta(days=1))
else:
result = end
if allow_future or result <= timezone_today():
return result
else:
return None
# Otherwise, we'll need to go to the database to look for an object
# whose date_field is at least (greater than/less than) the given
# naive result
else:
# Construct a lookup and an ordering depending on whether we're doing
# a previous date or a next date lookup.
if is_previous:
lookup = {'%s__lt' % date_field: generic_view._make_date_lookup_arg(start)}
ordering = '-%s' % date_field
else:
lookup = {'%s__gte' % date_field: generic_view._make_date_lookup_arg(end)}
ordering = date_field
# Filter out objects in the future if appropriate.
if not allow_future:
# Fortunately, to match the implementation of allow_future,
# we need __lte, which doesn't conflict with __lt above.
if generic_view.uses_datetime_field:
now = timezone.now()
else:
now = timezone_today()
lookup['%s__lte' % date_field] = now
qs = generic_view.get_queryset().filter(**lookup).order_by(ordering)
# Snag the first object from the queryset; if it doesn't exist that
# means there's no next/previous link available.
try:
result = getattr(qs[0], date_field)
except IndexError:
return None
# Convert datetimes to dates in the current time zone.
if generic_view.uses_datetime_field:
if settings.USE_TZ:
result = timezone.localtime(result)
result = result.date()
# Return the first day of the period.
return get_current(result)
def test_localtime(self):
now = datetime.datetime.utcnow().replace(tzinfo=timezone.utc)
local_tz = timezone.LocalTimezone()
local_now = timezone.localtime(now, local_tz)
self.assertEqual(local_now.tzinfo, local_tz)
