Sith/eboutic/forms.py
2024-08-06 16:49:20 +02:00

131 lines
5.1 KiB
Python

#
# Copyright 2022
# - Maréchal <thgirod@hotmail.com
#
# Ce fichier fait partie du site de l'Association des Étudiants de l'UTBM,
# http://ae.utbm.fr.
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License a published by the Free Software
# Foundation; either version 3 of the License, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Sofware Foundation, Inc., 59 Temple
# Place - Suite 330, Boston, MA 02111-1307, USA.
#
#
from functools import cached_property
from urllib.parse import unquote
from django.http import HttpRequest
from django.utils.translation import gettext as _
from pydantic import ValidationError
from eboutic.models import get_eboutic_products
from eboutic.schemas import PurchaseItemList, PurchaseItemSchema
class BasketForm:
"""Class intended to perform checks on the request sended to the server when
the user submits his basket from /eboutic/.
Because it must check an unknown number of fields, coming from a cookie
and needing some databases checks to be performed, inheriting from forms.Form
or using formset would have been likely to end in a big ball of wibbly-wobbly hacky stuff.
Thus this class is a pure standalone and performs its operations by its own means.
However, it still tries to share some similarities with a standard django Form.
Examples:
::
def my_view(request):
form = BasketForm(request)
form.clean()
if form.is_valid():
# perform operations
else:
errors = form.get_error_messages()
# return the cookie that was in the request, but with all
# incorrects elements removed
cookie = form.get_cleaned_cookie()
You can also use a little shortcut by directly calling `form.is_valid()`
without calling `form.clean()`. In this case, the latter method shall be
implicitly called.
"""
def __init__(self, request: HttpRequest):
self.user = request.user
self.cookies = request.COOKIES
self.error_messages = set()
self.correct_items = []
def clean(self) -> None:
"""Perform all the checks, but return nothing.
To know if the form is valid, the `is_valid()` method must be used.
The form shall be considered as valid if it meets all the following conditions :
- it contains a "basket_items" key in the cookies of the request given in the constructor
- this cookie is a list of objects formatted this way : `[{'id': <int>, 'quantity': <int>,
'name': <str>, 'unit_price': <float>}, ...]`. The order of the fields in each object does not matter
- all the ids are positive integers
- all the ids refer to products available in the EBOUTIC
- all the ids refer to products the user is allowed to buy
- all the quantities are positive integers
"""
try:
basket = PurchaseItemList.validate_json(
unquote(self.cookies.get("basket_items", "[]"))
)
except ValidationError:
self.error_messages.add(_("The request was badly formatted."))
return
if len(basket) == 0:
self.error_messages.add(_("Your basket is empty."))
return
existing_ids = {product.id for product in get_eboutic_products(self.user)}
for item in basket:
# check a product with this id does exist
if item.product_id in existing_ids:
self.correct_items.append(item)
else:
self.error_messages.add(
_(
"%(name)s : this product does not exist or may no longer be available."
)
% {"name": item.name}
)
continue
# this function does not return anything.
# instead, it fills a set containing the collected error messages
# an empty set means that no error was seen thus everything is ok
# and the form is valid.
# a non-empty set means there was at least one error thus
# the form is invalid
def is_valid(self) -> bool:
"""Return True if the form is correct else False.
If the `clean()` method has not been called beforehand, call it.
"""
if not self.error_messages and not self.correct_items:
self.clean()
if self.error_messages:
return False
return True
@cached_property
def errors(self) -> list[str]:
return list(self.error_messages)
@cached_property
def cleaned_data(self) -> list[PurchaseItemSchema]:
return self.correct_items