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import datetime
from django.db import models
from django.core.exceptions import ImproperlyConfigured
from django.http import Http404
from django.utils.encoding import force_unicode
from django.utils.translation import ugettext as _
from django.utils import timezone
from django.views.generic.base import View
from django.views.generic.detail import BaseDetailView, SingleObjectTemplateResponseMixin
from django.views.generic.list import MultipleObjectMixin, MultipleObjectTemplateResponseMixin
class YearMixin(object):
year_format = '%Y'
year = None
def get_year_format(self):
"""
Get a year format string in strptime syntax to be used to parse the
year from url variables.
"""
return self.year_format
def get_year(self):
"Return the year for which this view should display data"
year = self.year
if year is None:
try:
year = self.kwargs['year']
except KeyError:
try:
year = self.request.GET['year']
except KeyError:
raise Http404(_(u"No year specified"))
return year
class MonthMixin(object):
month_format = '%b'
month = None
def get_month_format(self):
"""
Get a month format string in strptime syntax to be used to parse the
month from url variables.
"""
return self.month_format
def get_month(self):
"Return the month for which this view should display data"
month = self.month
if month is None:
try:
month = self.kwargs['month']
except KeyError:
try:
month = self.request.GET['month']
except KeyError:
raise Http404(_(u"No month specified"))
return month
def get_next_month(self, date):
"""
Get the next valid month.
"""
first_day, last_day = _month_bounds(date)
next = (last_day + datetime.timedelta(days=1)).replace(day=1)
return _get_next_prev_month(self, next, is_previous=False, use_first_day=True)
def get_previous_month(self, date):
"""
Get the previous valid month.
"""
first_day, last_day = _month_bounds(date)
prev = (first_day - datetime.timedelta(days=1))
return _get_next_prev_month(self, prev, is_previous=True, use_first_day=True)
class DayMixin(object):
day_format = '%d'
day = None
def get_day_format(self):
"""
Get a day format string in strptime syntax to be used to parse the day
from url variables.
"""
return self.day_format
def get_day(self):
"Return the day for which this view should display data"
day = self.day
if day is None:
try:
day = self.kwargs['day']
except KeyError:
try:
day = self.request.GET['day']
except KeyError:
raise Http404(_(u"No day specified"))
return day
def get_next_day(self, date):
"""
Get the next valid day.
"""
next = date + datetime.timedelta(days=1)
return _get_next_prev_month(self, next, is_previous=False, use_first_day=False)
def get_previous_day(self, date):
"""
Get the previous valid day.
"""
prev = date - datetime.timedelta(days=1)
return _get_next_prev_month(self, prev, is_previous=True, use_first_day=False)
class WeekMixin(object):
week_format = '%U'
week = None
def get_week_format(self):
"""
Get a week format string in strptime syntax to be used to parse the
week from url variables.
"""
return self.week_format
def get_week(self):
"Return the week for which this view should display data"
week = self.week
if week is None:
try:
week = self.kwargs['week']
except KeyError:
try:
week = self.request.GET['week']
except KeyError:
raise Http404(_(u"No week specified"))
return week
class DateMixin(object):
"""
Mixin class for views manipulating date-based data.
"""
date_field = None
allow_future = False
def get_date_field(self):
"""
Get the name of the date field to be used to filter by.
"""
if self.date_field is None:
raise ImproperlyConfigured(u"%s.date_field is required." % self.__class__.__name__)
return self.date_field
def get_allow_future(self):
"""
Returns `True` if the view should be allowed to display objects from
the future.
"""
return self.allow_future
class BaseDateListView(MultipleObjectMixin, DateMixin, View):
"""
Abstract base class for date-based views display a list of objects.
"""
allow_empty = False
def get(self, request, *args, **kwargs):
self.date_list, self.object_list, extra_context = self.get_dated_items()
context = self.get_context_data(object_list=self.object_list,
date_list=self.date_list)
context.update(extra_context)
return self.render_to_response(context)
def get_dated_items(self):
"""
Obtain the list of dates and itesm
"""
raise NotImplementedError('A DateView must provide an implementation of get_dated_items()')
def get_dated_queryset(self, **lookup):
"""
Get a queryset properly filtered according to `allow_future` and any
extra lookup kwargs.
"""
qs = self.get_queryset().filter(**lookup)
date_field = self.get_date_field()
allow_future = self.get_allow_future()
allow_empty = self.get_allow_empty()
if not allow_future:
qs = qs.filter(**{'%s__lte' % date_field: timezone.now()})
if not allow_empty and not qs:
raise Http404(_(u"No %(verbose_name_plural)s available") % {
'verbose_name_plural': force_unicode(qs.model._meta.verbose_name_plural)
})
return qs
def get_date_list(self, queryset, date_type):
"""
Get a date list by calling `queryset.dates()`, checking along the way
for empty lists that aren't allowed.
"""
date_field = self.get_date_field()
allow_empty = self.get_allow_empty()
date_list = queryset.dates(date_field, date_type)[::-1]
if date_list is not None and not date_list and not allow_empty:
name = force_unicode(queryset.model._meta.verbose_name_plural)
raise Http404(_(u"No %(verbose_name_plural)s available") %
{'verbose_name_plural': name})
return date_list
def get_context_data(self, **kwargs):
"""
Get the context. Must return a Context (or subclass) instance.
"""
items = kwargs.pop('object_list')
context = super(BaseDateListView, self).get_context_data(object_list=items)
context.update(kwargs)
return context
class BaseArchiveIndexView(BaseDateListView):
"""
Base class for archives of date-based items.
Requires a response mixin.
"""
context_object_name = 'latest'
def get_dated_items(self):
"""
Return (date_list, items, extra_context) for this request.
"""
qs = self.get_dated_queryset()
date_list = self.get_date_list(qs, 'year')
if date_list:
object_list = qs.order_by('-' + self.get_date_field())
else:
object_list = qs.none()
return (date_list, object_list, {})
class ArchiveIndexView(MultipleObjectTemplateResponseMixin, BaseArchiveIndexView):
"""
Top-level archive of date-based items.
"""
template_name_suffix = '_archive'
class BaseYearArchiveView(YearMixin, BaseDateListView):
"""
List of objects published in a given year.
"""
make_object_list = False
def get_dated_items(self):
"""
Return (date_list, items, extra_context) for this request.
"""
# Yes, no error checking: the URLpattern ought to validate this; it's
# an error if it doesn't.
year = self.get_year()
date_field = self.get_date_field()
qs = self.get_dated_queryset(**{date_field+'__year': year})
date_list = self.get_date_list(qs, 'month')
if self.get_make_object_list():
object_list = qs.order_by('-'+date_field)
else:
# We need this to be a queryset since parent classes introspect it
# to find information about the model.
object_list = qs.none()
return (date_list, object_list, {'year': year})
def get_make_object_list(self):
"""
Return `True` if this view should contain the full list of objects in
the given year.
"""
return self.make_object_list
class YearArchiveView(MultipleObjectTemplateResponseMixin, BaseYearArchiveView):
"""
List of objects published in a given year.
"""
template_name_suffix = '_archive_year'
class BaseMonthArchiveView(YearMixin, MonthMixin, BaseDateListView):
"""
List of objects published in a given year.
"""
def get_dated_items(self):
"""
Return (date_list, items, extra_context) for this request.
"""
year = self.get_year()
month = self.get_month()
date_field = self.get_date_field()
date = _date_from_string(year, self.get_year_format(),
month, self.get_month_format())
# Construct a date-range lookup.
first_day, last_day = _month_bounds(date)
lookup_kwargs = {
'%s__gte' % date_field: first_day,
'%s__lt' % date_field: last_day,
}
qs = self.get_dated_queryset(**lookup_kwargs)
date_list = self.get_date_list(qs, 'day')
return (date_list, qs, {
'month': date,
'next_month': self.get_next_month(date),
'previous_month': self.get_previous_month(date),
})
class MonthArchiveView(MultipleObjectTemplateResponseMixin, BaseMonthArchiveView):
"""
List of objects published in a given year.
"""
template_name_suffix = '_archive_month'
class BaseWeekArchiveView(YearMixin, WeekMixin, BaseDateListView):
"""
List of objects published in a given week.
"""
def get_dated_items(self):
"""
Return (date_list, items, extra_context) for this request.
"""
year = self.get_year()
week = self.get_week()
date_field = self.get_date_field()
week_format = self.get_week_format()
week_start = {
'%W': '1',
'%U': '0',
}[week_format]
date = _date_from_string(year, self.get_year_format(),
week_start, '%w',
week, week_format)
# Construct a date-range lookup.
first_day = date
last_day = date + datetime.timedelta(days=7)
lookup_kwargs = {
'%s__gte' % date_field: first_day,
'%s__lt' % date_field: last_day,
}
qs = self.get_dated_queryset(**lookup_kwargs)
return (None, qs, {'week': date})
class WeekArchiveView(MultipleObjectTemplateResponseMixin, BaseWeekArchiveView):
"""
List of objects published in a given week.
"""
template_name_suffix = '_archive_week'
class BaseDayArchiveView(YearMixin, MonthMixin, DayMixin, BaseDateListView):
"""
List of objects published on a given day.
"""
def get_dated_items(self):
"""
Return (date_list, items, extra_context) for this request.
"""
year = self.get_year()
month = self.get_month()
day = self.get_day()
date = _date_from_string(year, self.get_year_format(),
month, self.get_month_format(),
day, self.get_day_format())
return self._get_dated_items(date)
def _get_dated_items(self, date):
"""
Do the actual heavy lifting of getting the dated items; this accepts a
date object so that TodayArchiveView can be trivial.
"""
date_field = self.get_date_field()
field = self.get_queryset().model._meta.get_field(date_field)
lookup_kwargs = _date_lookup_for_field(field, date)
qs = self.get_dated_queryset(**lookup_kwargs)
return (None, qs, {
'day': date,
'previous_day': self.get_previous_day(date),
'next_day': self.get_next_day(date),
'previous_month': self.get_previous_month(date),
'next_month': self.get_next_month(date)
})
class DayArchiveView(MultipleObjectTemplateResponseMixin, BaseDayArchiveView):
"""
List of objects published on a given day.
"""
template_name_suffix = "_archive_day"
class BaseTodayArchiveView(BaseDayArchiveView):
"""
List of objects published today.
"""
def get_dated_items(self):
"""
Return (date_list, items, extra_context) for this request.
"""
return self._get_dated_items(datetime.date.today())
class TodayArchiveView(MultipleObjectTemplateResponseMixin, BaseTodayArchiveView):
"""
List of objects published today.
"""
template_name_suffix = "_archive_day"
class BaseDateDetailView(YearMixin, MonthMixin, DayMixin, DateMixin, BaseDetailView):
"""
Detail view of a single object on a single date; this differs from the
standard DetailView by accepting a year/month/day in the URL.
"""
def get_object(self, queryset=None):
"""
Get the object this request displays.
"""
year = self.get_year()
month = self.get_month()
day = self.get_day()
date = _date_from_string(year, self.get_year_format(),
month, self.get_month_format(),
day, self.get_day_format())
# Use a custom queryset if provided
qs = queryset or self.get_queryset()
if not self.get_allow_future() and date > datetime.date.today():
raise Http404(_(u"Future %(verbose_name_plural)s not available because %(class_name)s.allow_future is False.") % {
'verbose_name_plural': qs.model._meta.verbose_name_plural,
'class_name': self.__class__.__name__,
})
# Filter down a queryset from self.queryset using the date from the
# URL. This'll get passed as the queryset to DetailView.get_object,
# which'll handle the 404
date_field = self.get_date_field()
field = qs.model._meta.get_field(date_field)
lookup = _date_lookup_for_field(field, date)
qs = qs.filter(**lookup)
return super(BaseDetailView, self).get_object(queryset=qs)
class DateDetailView(SingleObjectTemplateResponseMixin, BaseDateDetailView):
"""
Detail view of a single object on a single date; this differs from the
standard DetailView by accepting a year/month/day in the URL.
"""
template_name_suffix = '_detail'
def _date_from_string(year, year_format, month, month_format, day='', day_format='', delim='__'):
"""
Helper: get a datetime.date object given a format string and a year,
month, and possibly day; raise a 404 for an invalid date.
"""
format = delim.join((year_format, month_format, day_format))
datestr = delim.join((year, month, day))
try:
return datetime.datetime.strptime(datestr, format).date()
except ValueError:
raise Http404(_(u"Invalid date string '%(datestr)s' given format '%(format)s'") % {
'datestr': datestr,
'format': format,
})
def _month_bounds(date):
"""
Helper: return the first and last days of the month for the given date.
"""
first_day = date.replace(day=1)
if first_day.month == 12:
last_day = first_day.replace(year=first_day.year + 1, month=1)
else:
last_day = first_day.replace(month=first_day.month + 1)
return first_day, last_day
def _get_next_prev_month(generic_view, naive_result, is_previous, use_first_day):
"""
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.
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,
reguardless of object existence.)
* If allow_empty is true, allow_future is false, and the naive month
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()
# If allow_empty is True the naive value will be valid
if allow_empty:
result = naive_result
# 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__lte' % date_field: naive_result}
ordering = '-%s' % date_field
else:
lookup = {'%s__gte' % date_field: naive_result}
ordering = date_field
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:
result = None
# Convert datetimes to a dates
if hasattr(result, 'date'):
result = result.date()
# For month views, we always want to have a date that's the first of the
# month for consistency's sake.
if result and use_first_day:
result = result.replace(day=1)
# Check against future dates.
if result and (allow_future or result < datetime.date.today()):
return result
else:
return None
def _date_lookup_for_field(field, date):
"""
Get the lookup kwargs for looking up a date against a given Field. If the
date field is a DateTimeField, we can't just do filter(df=date) because
that doesn't take the time into account. So we need to make a range lookup
in those cases.
"""
if isinstance(field, models.DateTimeField):
date_range = (
datetime.datetime.combine(date, datetime.time.min),
datetime.datetime.combine(date, datetime.time.max)
)
return {'%s__range' % field.name: date_range}
else:
return {field.name: date}
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