Fixed #18323 -- Refactored date arithmetic

in date based generic views, in order to deal properly with both
DateFields and DateTimeFields.
This commit is contained in:
Aymeric Augustin 2012-05-17 17:41:37 +02:00
parent dcd4383107
commit 20e6973682
1 changed files with 136 additions and 60 deletions

View File

@ -23,7 +23,9 @@ class YearMixin(object):
return self.year_format
def get_year(self):
"Return the year for which this view should display data"
"""
Return the year for which this view should display data.
"""
year = self.year
if year is None:
try:
@ -35,6 +37,20 @@ class YearMixin(object):
raise Http404(_(u"No year specified"))
return year
def _get_next_year(self, date):
"""
Return the start date of the next interval.
The interval is defined by start date <= item date < next start date.
"""
return date.replace(year=date.year + 1, month=1, day=1)
def _get_current_year(self, date):
"""
Return the start date of the current interval.
"""
return date.replace(month=1, day=1)
class MonthMixin(object):
month_format = '%b'
@ -48,7 +64,9 @@ class MonthMixin(object):
return self.month_format
def get_month(self):
"Return the month for which this view should display data"
"""
Return the month for which this view should display data.
"""
month = self.month
if month is None:
try:
@ -64,20 +82,30 @@ class MonthMixin(object):
"""
Get the next valid month.
"""
# next must be the first day of the next month.
if date.month == 12:
next = date.replace(year=date.year + 1, month=1, day=1)
else:
next = date.replace(month=date.month + 1, day=1)
return _get_next_prev(self, next, is_previous=False, period='month')
return _get_next_prev(self, date, is_previous=False, period='month')
def get_previous_month(self, date):
"""
Get the previous valid month.
"""
# prev must be the last day of the previous month.
prev = date.replace(day=1) - datetime.timedelta(days=1)
return _get_next_prev(self, prev, is_previous=True, period='month')
return _get_next_prev(self, date, is_previous=True, period='month')
def _get_next_month(self, date):
"""
Return the start date of the next interval.
The interval is defined by start date <= item date < next start date.
"""
if date.month == 12:
return date.replace(year=date.year + 1, month=1, day=1)
else:
return date.replace(month=date.month + 1, day=1)
def _get_current_month(self, date):
"""
Return the start date of the previous interval.
"""
return date.replace(day=1)
class DayMixin(object):
@ -92,7 +120,9 @@ class DayMixin(object):
return self.day_format
def get_day(self):
"Return the day for which this view should display data"
"""
Return the day for which this view should display data.
"""
day = self.day
if day is None:
try:
@ -108,15 +138,27 @@ class DayMixin(object):
"""
Get the next valid day.
"""
next = date + datetime.timedelta(days=1)
return _get_next_prev(self, next, is_previous=False, period='day')
return _get_next_prev(self, date, is_previous=False, period='day')
def get_previous_day(self, date):
"""
Get the previous valid day.
"""
prev = date - datetime.timedelta(days=1)
return _get_next_prev(self, prev, is_previous=True, period='day')
return _get_next_prev(self, date, is_previous=True, period='day')
def _get_next_day(self, date):
"""
Return the start date of the next interval.
The interval is defined by start date <= item date < next start date.
"""
return date + datetime.timedelta(days=1)
def _get_current_day(self, date):
"""
Return the start date of the current interval.
"""
return date
class WeekMixin(object):
@ -131,7 +173,9 @@ class WeekMixin(object):
return self.week_format
def get_week(self):
"Return the week for which this view should display data"
"""
Return the week for which this view should display data
"""
week = self.week
if week is None:
try:
@ -147,19 +191,34 @@ class WeekMixin(object):
"""
Get the next valid week.
"""
# next must be the first day of the next week.
next = date + datetime.timedelta(days=7 - self._get_weekday(date))
return _get_next_prev(self, next, is_previous=False, period='week')
return _get_next_prev(self, date, is_previous=False, period='week')
def get_previous_week(self, date):
"""
Get the previous valid week.
"""
# prev must be the last day of the previous week.
prev = date - datetime.timedelta(days=self._get_weekday(date) + 1)
return _get_next_prev(self, prev, is_previous=True, period='week')
return _get_next_prev(self, date, is_previous=True, period='week')
def _get_next_week(self, date):
"""
Return the start date of the next interval.
The interval is defined by start date <= item date < next start date.
"""
return date + datetime.timedelta(days=7 - self._get_weekday(date))
def _get_current_week(self, date):
"""
Return the start date of the current interval.
"""
return date - datetime.timedelta(self._get_weekday(date))
def _get_weekday(self, date):
"""
Return the weekday for a given date.
The first day according to the week format is 0 and the last day is 6.
"""
week_format = self.get_week_format()
if week_format == '%W': # week starts on Monday
return date.weekday()
@ -168,6 +227,7 @@ class WeekMixin(object):
else:
raise ValueError("unknown week format: %s" % week_format)
class DateMixin(object):
"""
Mixin class for views manipulating date-based data.
@ -267,7 +327,7 @@ class BaseDateListView(MultipleObjectMixin, DateMixin, View):
paginate_by = self.get_paginate_by(qs)
if not allow_future:
now = timezone.now() if self.uses_datetime_field else datetime.date.today()
now = timezone.now() if self.uses_datetime_field else timezone_today()
qs = qs.filter(**{'%s__lte' % date_field: now})
if not allow_empty:
@ -344,7 +404,7 @@ class BaseYearArchiveView(YearMixin, BaseDateListView):
date = _date_from_string(year, self.get_year_format())
since = self._make_date_lookup_arg(date)
until = self._make_date_lookup_arg(datetime.date(date.year + 1, 1, 1))
until = self._make_date_lookup_arg(self._get_next_year(date))
lookup_kwargs = {
'%s__gte' % date_field: since,
'%s__lt' % date_field: until,
@ -392,12 +452,8 @@ class BaseMonthArchiveView(YearMixin, MonthMixin, BaseDateListView):
date = _date_from_string(year, self.get_year_format(),
month, self.get_month_format())
# Construct a date-range lookup.
since = self._make_date_lookup_arg(date)
if date.month == 12:
until = self._make_date_lookup_arg(datetime.date(date.year + 1, 1, 1))
else:
until = self._make_date_lookup_arg(datetime.date(date.year, date.month + 1, 1))
until = self._make_date_lookup_arg(self._get_next_month(date))
lookup_kwargs = {
'%s__gte' % date_field: since,
'%s__lt' % date_field: until,
@ -442,9 +498,8 @@ class BaseWeekArchiveView(YearMixin, WeekMixin, BaseDateListView):
week_start, '%w',
week, week_format)
# Construct a date-range lookup.
since = self._make_date_lookup_arg(date)
until = self._make_date_lookup_arg(date + datetime.timedelta(days=7))
until = self._make_date_lookup_arg(self._get_next_week(date))
lookup_kwargs = {
'%s__gte' % date_field: since,
'%s__lt' % date_field: until,
@ -585,22 +640,22 @@ def _date_from_string(year, year_format, month='', month_format='', day='', day_
})
def _get_next_prev(generic_view, naive_result, is_previous, period):
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 both next and previous months
and days (for MonthArchiveView and DayArchiveView); hence the coupling to generic_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 or month,
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 month
* 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
@ -616,9 +671,23 @@ def _get_next_prev(generic_view, naive_result, is_previous, period):
allow_empty = generic_view.get_allow_empty()
allow_future = generic_view.get_allow_future()
# If allow_empty is True the naive value will be valid
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:
result = naive_result
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
@ -627,12 +696,22 @@ def _get_next_prev(generic_view, naive_result, is_previous, period):
# 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__lte' % date_field: generic_view._make_date_lookup_arg(naive_result)}
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(naive_result)}
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
@ -640,26 +719,23 @@ def _get_next_prev(generic_view, naive_result, is_previous, period):
try:
result = getattr(qs[0], date_field)
except IndexError:
result = None
return None
# Convert datetimes to a dates
if result and generic_view.uses_datetime_field:
# 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()
if result:
if period == 'month':
# first day of the month
result = result.replace(day=1)
elif period == 'week':
# monday of the week
result = result - datetime.timedelta(days=generic_view._get_weekday(result))
elif period != 'day':
raise ValueError('invalid period: %s' % period)
# Return the first day of the period.
return get_current(result)
# Check against future dates.
if result and (allow_future or result < datetime.date.today()):
return result
def timezone_today():
"""
Return the current date in the current time zone.
"""
if settings.USE_TZ:
return timezone.localtime(timezone.now()).date()
else:
return None
return datetime.date.today()