Files
pretix_cgo/src/pretix/presale/views/cart.py
2015-02-21 17:00:52 +01:00

238 lines
10 KiB
Python

from datetime import timedelta
import json
from django.contrib import messages
from django.contrib.auth.views import redirect_to_login
from django.core.urlresolvers import reverse
from django.db.models import Q
from django.shortcuts import redirect
from django.utils.timezone import now
from django.views.generic import View
from django.utils.translation import ugettext_lazy as _
from pretix.base.models import Item, ItemVariation, Quota, CartPosition
from pretix.presale.views import EventLoginRequiredMixin, EventViewMixin
class CartActionMixin:
def get_next_url(self):
if "next" in self.request.GET and '://' not in self.request.GET:
return self.request.GET.get('next')
elif "HTTP_REFERER" in self.request.META:
return self.request.META.get('HTTP_REFERER')
else:
return reverse('presale:event.index', kwargs={
'event': self.request.event.slug,
'organizer': self.request.event.organizer.slug,
})
def get_success_url(self):
return self.get_next_url()
def get_failure_url(self):
return self.get_next_url()
def _items_from_post_data(self):
"""
Parses the POST data and returns a list of tuples in the
form (item id, variation id or None, number)
"""
items = []
for key, value in self.request.POST.items():
if value.strip() == '':
continue
if key.startswith('item_'):
try:
items.append((key.split("_")[1], None, int(value)))
except ValueError:
messages.error(self.request, _('Please enter numbers only.'))
return []
elif key.startswith('variation_'):
try:
items.append((key.split("_")[1], key.split("_")[2], int(value)))
except ValueError:
messages.error(self.request, _('Please enter numbers only.'))
return []
if len(items) == 0:
messages.warning(self.request, _('You did not select any items.'))
return []
return items
def _re_add_position(self, items, position):
for i, tup in enumerate(items):
if tup[0] == position.item_id and tup[1] == position.variation_id:
items[i] = (tup[0], tup[1], tup[2] + 1)
return items
items.append((position.item_id, position.variation_id, 1))
return items
class CartRemove(EventViewMixin, CartActionMixin, EventLoginRequiredMixin, View):
def post(self, *args, **kwargs):
items = self._items_from_post_data()
if not items:
return redirect(self.get_failure_url())
qw = Q(user=self.request.user)
for item, variation, cnt in items:
cw = qw & Q(item_id=item)
if variation:
cw &= Q(variation_id=variation)
else:
cw &= Q(variation__isnull=True)
for cp in CartPosition.objects.current.filter(cw).order_by("-price")[:cnt]:
cp.delete()
messages.success(self.request, _('Your cart has been updated.'))
return redirect(self.get_success_url())
class CartAdd(EventViewMixin, CartActionMixin, View):
error_messages = {
'unavailable': _('Some of the items you selected were no longer available. '
'Please see below for details.'),
'in_part': _('Some of the items you selected were no longer available in '
'the quantity you selected. Please see below for details.'),
'busy': _('We were not able to process your request completely as the '
'server was too busy. Please try again.'),
'not_for_sale': _('You selected an item which is not available for sale.'),
'max_items': _("You cannot select more than %s items per order"),
}
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.msg_some_unavailable = False
def post(self, request, *args, **kwargs):
items = self._items_from_post_data()
# We do not use EventLoginRequiredMixin here, as we want to store stuff into the
# session beforehand
if not request.user.is_authenticated() or \
(request.user.event is not None and request.user.event != request.event):
request.session['cart_tmp'] = json.dumps(items)
return redirect_to_login(
self.get_success_url(), reverse('presale:event.checkout.login', kwargs={
'organizer': request.event.organizer.slug,
'event': request.event.slug,
}), 'next'
)
return self.process(items)
def error_message(self, msg, important=False):
if not self.msg_some_unavailable or important:
self.msg_some_unavailable = True
messages.error(self.request, msg)
def process(self, items):
# Extend this user's cart session to 30 minutes from now to ensure all items in the
# cart expire at the same time
# We can extend the reservation of items which are not yet expired without risk
CartPosition.objects.current.filter(
Q(user=self.request.user) & Q(event=self.request.event) & Q(expires__gt=now())
).update(expires=now() + timedelta(minutes=30))
# For items that are already expired, we have to delete and re-add them, as they might
# be no longer available. Sorry!
for cp in CartPosition.objects.current.filter(
Q(user=self.request.user) & Q(event=self.request.event) & Q(expires__lte=now())):
items = self._re_add_position(items, cp)
cp.delete()
if not items:
return redirect(self.get_failure_url())
existing = CartPosition.objects.current.filter(user=self.request.user, event=self.request.event).count()
if sum(i[2] for i in items) + existing > int(self.request.event.settings.max_items_per_order):
# TODO: i18n plurals
self.error_message(self.error_messages['max_items'] % self.request.event.settings.max_items_per_order)
return redirect(self.get_failure_url())
# Fetch items from the database
items_cache = {
i.identity: i for i
in Item.objects.current.filter(
event=self.request.event,
identity__in=[i[0] for i in items]
).prefetch_related("quotas")
}
variations_cache = {
v.identity: v for v
in ItemVariation.objects.current.filter(
item__event=self.request.event,
identity__in=[i[1] for i in items if i[1] is not None]
).select_related("item", "item__event").prefetch_related("quotas", "values", "values__prop")
}
# Process the request itself
for i in items:
# Check whether the specified items are part of what we just fetched from the database
# If they are not, the user supplied item IDs which either do not exist or belong to
# a different event
if i[0] not in items_cache or (i[1] is not None and i[1] not in variations_cache):
self.error_message(self.error_messages['not_for_sale'])
return redirect(self.get_failure_url())
item = items_cache[i[0]]
variation = variations_cache[i[1]] if i[1] is not None else None
# Execute restriction plugins to check whether they (a) change the price or
# (b) make the item/variation unavailable. If neither is the case, check_restriction
# will correctly return the default price
price = item.check_restrictions() if variation is None else variation.check_restrictions()
if price is False:
self.error_message(self.error_messages['unavailable'])
continue
# Fetch all quotas. If there are no quotas, this item is not allowed to be sold.
quotas = list(item.quotas.all()) if variation is None else list(variation.quotas.all())
if len(quotas) == 0:
self.error_message(self.error_messages['unavailable'])
continue
# Assume that all quotas allow us to buy i[2] instances of the object
quota_ok = i[2]
try:
for quota in quotas:
# Lock the quota, so no other thread is allowed to perform sales covered by this
# quota while we're doing so.
quota.lock()
avail = quota.availability()
if avail[0] != Quota.AVAILABILITY_OK:
# This quota is sold out/currently unavailable, so do not sell this at all
self.error_message(self.error_messages['unavailable'])
quota_ok = 0
break
elif avail[1] < i[2]:
# This quota is available, but with less than i[2] items left, so we have to
# reduce the number of bought items
self.error_message(self.error_messages['in_part'])
quota_ok = min(quota_ok, avail[1])
# Create a CartPosition for as much items as we can
for k in range(quota_ok):
CartPosition.objects.create(
event=self.request.event,
user=self.request.user,
item=item,
variation=variation,
price=price,
expires=now() + timedelta(minutes=30)
)
except Quota.LockTimeoutException:
# Is raised when there are too many threads asking for quota locks and we were
# unaible to get one
self.error_message(self.error_messages['busy'], important=True)
finally:
# Release the locks. This is important ;)
for quota in quotas:
quota.release()
if not self.msg_some_unavailable:
messages.success(self.request, _('The items have been successfully added to your cart.'))
return redirect(self.get_success_url())