symposion_app Changeset - 587e6e20b284

Changeset - 587e6e20b284

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Christopher Neugebauer - 8 years ago 2016-04-29 01:08:45
chrisjrn@gmail.com

Adds an operations_batch context manager that allows batches of modifying operations to be nested. Closes #44.

2 files changed with 75 insertions and 18 deletions:

registrasion/controllers/cart.py

registrasion/controllers/invoice.py

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registrasion/controllers/cart.py

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 import collections
 import contextlib
 import datetime
 import functools
 import itertools
@@ ... / @@ -23,12 +24,19 @@ from .product import ProductController @@
 def _modifies_cart(func):
     ''' Decorator that makes the wrapped function raise ValidationError
     if we're doing something that could modify the cart. '''
     if we're doing something that could modify the cart.
     It also wraps the execution of this function in a database transaction,
     and marks the boundaries of a cart operations batch.
     '''
     @functools.wraps(func)
     def inner(self, *a, **k):
         self._fail_if_cart_is_not_active()
         return func(self, *a, **k)
         with transaction.atomic():
             with CartController.operations_batch(self.cart.user) as mark:
                 mark.mark = True  # Marker that we've modified the cart
                 return func(self, *a, **k)
     return inner
@@ ... / @@ -56,13 +64,57 @@ class CartController(object): @@
+            )
         return cls(existing)
     # Marks the carts that are currently in batches
     _BATCH_COUNT = collections.defaultdict(int)
     _MODIFIED_CARTS = set()
     class _ModificationMarker(object):
         pass
     @classmethod
     @contextlib.contextmanager
     def operations_batch(cls, user):
         ''' Marks the boundary for a batch of operations on a user's cart.
         These markers can be nested. Only on exiting the outermost marker will
         a batch be ended.
         When a batch is ended, discounts are recalculated, and the cart's
         revision is increased.
         '''
         ctrl = cls.for_user(user)
         _id = ctrl.cart.id
         cls._BATCH_COUNT[_id] += 1
         try:
             success = False
             marker = cls._ModificationMarker()
             yield marker
             if hasattr(marker, "mark"):
                 cls._MODIFIED_CARTS.add(_id)
             success = True
         finally:
             cls._BATCH_COUNT[_id] -= 1
             # Only end on the outermost batch marker, and only if
             # it excited cleanly, and a modification occurred
             modified = _id in cls._MODIFIED_CARTS
             if modified and cls._BATCH_COUNT[_id] == 0 and success:
                 ctrl._end_batch()
                 cls._MODIFIED_CARTS.remove(_id)
     def _fail_if_cart_is_not_active(self):
         self.cart.refresh_from_db()
         if self.cart.status != commerce.Cart.STATUS_ACTIVE:
             raise ValidationError("You can only amend active carts.")
     @_modifies_cart
     def extend_reservation(self):
     def _autoextend_reservation(self):
         ''' Updates the cart's time last updated value, which is used to
         determine whether the cart has reserved the items and discounts it
         holds. '''
@@ ... / @@ -84,21 +136,26 @@ class CartController(object): @@
         self.cart.time_last_updated = timezone.now()
         self.cart.reservation_duration = max(reservations)
     @_modifies_cart
     def end_batch(self):
     def _end_batch(self):
         ''' Performs operations that occur occur at the end of a batch of
         product changes/voucher applications etc.
         THIS SHOULD BE PRIVATE
         You need to call this after you've finished modifying the user's cart.
         This is normally done by wrapping a block of code using
         ``operations_batch``.
         '''
         self.recalculate_discounts()
         self.extend_reservation()
         self.cart.refresh_from_db()
         self._recalculate_discounts()
         self._autoextend_reservation()
         self.cart.revision += 1
         self.cart.save()
     @_modifies_cart
     @transaction.atomic
     def set_quantities(self, product_quantities):
         ''' Sets the quantities on each of the products on each of the
         products specified. Raises an exception (ValidationError) if a limit
@@ ... / @@ -140,8 +197,6 @@ class CartController(object): @@
         items_in_cart.filter(quantity=0).delete()
         self.end_batch()
     def _test_limits(self, product_quantities):
         ''' Tests that the quantity changes we intend to make do not violate
         the limits and flag conditions imposed on the products. '''
@@ ... / @@ -213,7 +268,6 @@ class CartController(object): @@
         # If successful...
         self.cart.vouchers.add(voucher)
         self.end_batch()
     def _test_voucher(self, voucher):
         ''' Tests whether this voucher is allowed to be applied to this cart.
@@ ... / @@ -331,7 +385,6 @@ class CartController(object): @@
             raise ValidationError(errors)
     @_modifies_cart
     @transaction.atomic
     def fix_simple_errors(self):
         ''' This attempts to fix the easy errors raised by ValidationError.
         This includes removing items from the cart that are no longer
@@ ... / @@ -363,11 +416,9 @@ class CartController(object): @@
         self.set_quantities(zeros)
     @_modifies_cart
     @transaction.atomic
     def recalculate_discounts(self):
         ''' Calculates all of the discounts available for this product.
         '''
     def _recalculate_discounts(self):
         ''' Calculates all of the discounts available for this product.'''
         # Delete the existing entries.
         commerce.DiscountItem.objects.filter(cart=self.cart).delete()

registrasion/controllers/invoice.py

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@@ ... / @@ -29,6 +29,7 @@ class InvoiceController(ForId, object): @@
         If such an invoice does not exist, the cart is validated, and if valid,
         an invoice is generated.'''
         cart.refresh_from_db()
         try:
             invoice = commerce.Invoice.objects.exclude(
                 status=commerce.Invoice.STATUS_VOID,
@@ ... / @@ -74,6 +75,8 @@ class InvoiceController(ForId, object): @@
     def _generate(cls, cart):
         ''' Generates an invoice for the given cart. '''
         cart.refresh_from_db()
         issued = timezone.now()
         reservation_limit = cart.reservation_duration + cart.time_last_updated
         # Never generate a due time that is before the issue time
@@ ... / @@ -251,6 +254,9 @@ class InvoiceController(ForId, object): @@
     def _invoice_matches_cart(self):
         ''' Returns true if there is no cart, or if the revision of this
         invoice matches the current revision of the cart. '''
         self._refresh()
         cart = self.invoice.cart
         if not cart:
             return True

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