mirror of https://github.com/ae-utbm/sith3.git
176 lines
7.1 KiB
Python
176 lines
7.1 KiB
Python
# -*- coding:utf-8 -*
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#
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# Copyright 2022
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# - Maréchal <thgirod@hotmail.com
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#
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# Ce fichier fait partie du site de l'Association des Étudiants de l'UTBM,
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# http://ae.utbm.fr.
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#
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# This program is free software; you can redistribute it and/or modify it under
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# the terms of the GNU General Public License a published by the Free Software
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# Foundation; either version 3 of the License, or (at your option) any later
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# version.
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#
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# This program is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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# details.
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#
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# You should have received a copy of the GNU General Public License along with
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# this program; if not, write to the Free Sofware Foundation, Inc., 59 Temple
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# Place - Suite 330, Boston, MA 02111-1307, USA.
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#
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#
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import json
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import re
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import typing
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from django.http import HttpRequest
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from django.utils.translation import gettext as _
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from eboutic.models import get_eboutic_products
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class BasketForm:
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"""
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Class intended to perform checks on the request sended to the server when
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the user submits his basket from /eboutic/
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Because it must check an unknown number of fields, coming from a cookie
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and needing some databases checks to be performed, inheriting from forms.Form
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or using formset would have been likely to end in a big ball of wibbly-wobbly hacky stuff.
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Thus this class is a pure standalone and performs its operations by its own means.
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However, it still tries to share some similarities with a standard django Form.
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Example:
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::
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def my_view(request):
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form = BasketForm(request)
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form.clean()
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if form.is_valid():
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# perform operations
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else:
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errors = form.get_error_messages()
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# return the cookie that was in the request, but with all
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# incorrects elements removed
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cookie = form.get_cleaned_cookie()
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You can also use a little shortcut by directly calling `form.is_valid()`
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without calling `form.clean()`. In this case, the latter method shall be
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implicitly called.
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"""
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# check the json is an array containing non-nested objects.
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# values must be strings or numbers
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# this is matched :
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# [{"id": 4, "name": "[PROMO 22] badges", "unit_price": 2.3, "quantity": 2}]
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# but this is not :
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# [{"id": {"nested_id": 10}, "name": "[PROMO 22] badges", "unit_price": 2.3, "quantity": 2}]
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# and neither does this :
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# [{"id": ["nested_id": 10], "name": "[PROMO 22] badges", "unit_price": 2.3, "quantity": 2}]
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# and neither does that :
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# [{"id": null, "name": "[PROMO 22] badges", "unit_price": 2.3, "quantity": 2}]
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json_cookie_re = re.compile(
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r"^\[\s*(\{\s*(\"[^\"]*\":\s*(\"[^\"]{0,64}\"|\d{0,5}\.?\d+),?\s*)*\},?\s*)*\s*\]$"
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)
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def __init__(self, request: HttpRequest):
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self.user = request.user
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self.cookies = request.COOKIES
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self.error_messages = set()
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self.correct_cookie = []
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def clean(self) -> None:
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"""
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Perform all the checks, but return nothing.
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To know if the form is valid, the `is_valid()` method must be used.
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The form shall be considered as valid if it meets all the following conditions :
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- it contains a "basket_items" key in the cookies of the request given in the constructor
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- this cookie is a list of objects formatted this way : `[{'id': <int>, 'quantity': <int>,
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'name': <str>, 'unit_price': <float>}, ...]`. The order of the fields in each object does not matter
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- all the ids are positive integers
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- all the ids refer to products available in the EBOUTIC
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- all the ids refer to products the user is allowed to buy
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- all the quantities are positive integers
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"""
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basket = self.cookies.get("basket_items", None)
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if basket is None or basket in ("[]", ""):
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self.error_messages.add(_("You have no basket."))
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return
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# check that the json is not nested before parsing it to make sure
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# malicious user can't ddos the server with deeply nested json
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if not BasketForm.json_cookie_re.match(basket):
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self.error_messages.add(_("The request was badly formatted."))
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return
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try:
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basket = json.loads(basket)
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except json.JSONDecodeError:
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self.error_messages.add(_("The basket cookie was badly formatted."))
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return
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if type(basket) is not list or len(basket) == 0:
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self.error_messages.add(_("Your basket is empty."))
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return
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for item in basket:
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expected_keys = {"id", "quantity", "name", "unit_price"}
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if type(item) is not dict or set(item.keys()) != expected_keys:
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self.error_messages.add("One or more items are badly formatted.")
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continue
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# check the id field is a positive integer
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if type(item["id"]) is not int or item["id"] < 0:
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self.error_messages.add(
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_("%(name)s : this product does not exist.")
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% {"name": item["name"]}
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)
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continue
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# check a product with this id does exist
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ids = {product.id for product in get_eboutic_products(self.user)}
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if not item["id"] in ids:
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self.error_messages.add(
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_(
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"%(name)s : this product does not exist or may no longer be available."
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)
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% {"name": item["name"]}
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)
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continue
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if type(item["quantity"]) is not int or item["quantity"] < 0:
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self.error_messages.add(
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_("You cannot buy %(nbr)d %(name)%s.")
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% {"nbr": item["quantity"], "name": item["name"]}
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)
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continue
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# if we arrive here, it means this item has passed all tests
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self.correct_cookie.append(item)
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# for loop for item checking ends here
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# this function does not return anything.
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# instead, it fills a set containing the collected error messages
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# an empty set means that no error was seen thus everything is ok
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# and the form is valid.
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# a non-empty set means there was at least one error thus
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# the form is invalid
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def is_valid(self) -> bool:
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"""
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return True if the form is correct else False.
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If the `clean()` method has not been called beforehand, call it
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"""
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if self.error_messages == set() and self.correct_cookie == []:
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self.clean()
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if self.error_messages:
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return False
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return True
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def get_error_messages(self) -> typing.List[str]:
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# return [msg for msg in self.error_messages]
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return list(self.error_messages)
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def get_cleaned_cookie(self) -> str:
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if not self.correct_cookie:
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return ""
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return json.dumps(self.correct_cookie)
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