django-2.0 - django 2.0：不使用正确的视图
问题描述
我正在关注基于 django 1.8 的 django 图书项目。它有点过时了，但我尝试并将某些部分翻译成 django 2.0 并取得了一定的成功。
截至目前，该项目有 2 个应用程序，商店，然后是购物车。商店应用程序正常运行；当我介绍购物车应用程序时，我现在卡住了好几天，但现在没有经过艰苦的审查来尝试纠正错误。单击产品项目链接时会触发该错误，据说它应该像在购物车应用之前一样显示产品详细信息页面，但现在会生成以下错误：
NoReverseMatch at /1/coke-375ml
Reverse for 'cart_add' with arguments '('',)' not found. 1 pattern(s) tried: ['cart\\/add\\/(?P<product_id>[0-9]+)$']
我不明白为什么 django坚持使用cart_add购物车应用程序的product_detail视图而不是商店应用程序的视图。代码有什么问题？
以下是相关文件。
项目范围的 urls.py
from django.contrib import admin
from django.urls import path, include
from django.conf import settings
from django.conf.urls.static import static
urlpatterns = [
path('admin/', admin.site.urls),
path('cart/', include('cart.urls')),
path('', include('shop.urls')),
]
if settings.DEBUG:
urlpatterns += static(settings.MEDIA_URL,
document_root=settings.MEDIA_ROOT)
商店/urls.py
from django.urls import path
from . import views
app_name = 'shop'
urlpatterns = [
path('', views.product_list, name='product_list'),
path('<slug:category_slug>',
views.product_list,
name='product_list_by_category'),
path('<int:id>/<slug:slug>',
views.product_detail,
name='product_detail'),
]
商店/views.py
from django.shortcuts import render, get_object_or_404
from .models import Category, Product
from cart.forms import CartAddProductForm
def product_list(request, category_slug=None):
category = None
categories = Category.objects.all()
products = Product.objects.filter(available=True)
if category_slug:
category = get_object_or_404(Category, slug=category_slug)
products = products.filter(category=category)
return render(request,
'shop/product/list.html',
{'category': category,
'categories': categories,
'products': products})
def product_detail(request, id, slug):
product = get_object_or_404(Product,
id=id,
slug=slug,
available=True)
cart_product_form = CartAddProductForm()
return render(request,
'shop/product/detail.html',
{'product': product,
'cart_product_form': cart_product_form})
shop/product/details.html 模板
{% extends "base.html" %}
{% load static %}
{% block title %}
{% if category %}{{ category.title }}{% else %}Products{% endif %}
{% endblock %}
{% block content %}
<div class="product-detail">
<img src="{% if product.image %}{{ product.image.url }}{% else %}
{% static "img/no_image.png" %}{% endif %}">
<h1>{{ product.name }}</h1>
<h2><a href="{{ product.category.get_absolute_url }}">{{ product.category }}</a></h2>
<p class="price">${{ product.price }}</p>
<form action="{% url "cart:cart_add" product_id %}" method="post">
{{ cart_product_form }}
{% csrf_token %}
<input type="submit" value="Add to cart">
</form>
{{ product.description|linebreaks }}
</div>
{% endblock %}
购物车/urls.py
from django.urls import path
from cart import views
app_name = 'cart'
urlpatterns = [
path('', views.cart_detail, name='cart_detail'),
path('add/<int:product_id>', views.cart_add, name='cart_add'),
path('remove/<int:product_id>', views.cart_remove, name='cart_remove'),
]
购物车/views.py
from django.shortcuts import render, redirect, get_object_or_404
from django.views.decorators.http import require_POST
from shop.models import Product
from .cart import Cart
from .forms import CartAddProductForm
@require_POST
def cart_add(request, product_id):
cart = Cart(request)
product = get_object_or_404(Product, id=product_id)
form = CartAddProductForm(request.POST)
if form.is_valid():
cd = form.cleaned_data
cart.add(product=product,
quantity=cd['quantity'],
update_quantity=cd['update'])
return redirect('cart:cart_detail')
def cart_remove(request, product_id):
cart = Cart(request)
product = get_object_or_404(Product, id=product_id)
cart.remove(product)
return redirect('cart:cart_detail')
def cart_detail(request):
cart = Cart(request)
return render(request, 'cart/detail.html', {'cart': cart})
购物车/cart.py
from decimal import Decimal
from django.conf import settings
from shop.models import Product
class Cart(object):
def __init__(self, request):
"""
Initialize the cart.
"""
self.session = request.session
cart = self.session.get(settings.CART_SESSION_ID)
if not cart:
# save an empty cart in the session
cart = self.session[settings.CART_SESSION_ID] = {}
self.cart = cart
def add(self, product, quantity=1, update_quantity=False):
"""
Add a product to the cart or update its quantity
"""
product_id = str(product.id)
if product_id not in self.cart:
self.cart[product_id] = {'quantity': 0,
'price': str(product.price)}
if update_quantity:
self.cart[product_id]['quantity'] = quantity
else:
self.cart[product_id]['quantity'] += quantity
self.save()
def save(self):
# update the session cart
self.session[settings.CART_SESSION_ID] = self.cart
# mark the session as "modified" to make sure it is saved
self.session.modified = True
def remove(self, product):
"""
Remove a product from the cart.
"""
product_id = str(product.id)
if product_id in self.cart:
del self.cart[prodcut_id]
self.save()
def __iter__(self):
"""
Iterate over the items in the cart and get the products
from the database
"""
product_ids = self.cart.keys()
# get the product objects and add them to the cart
products = Product.objects.filter(id__in=product_ids)
for product in products:
self.cart[str(product.id)]['product'] = product
for item in self.cart.values():
item['price'] = Decimal(item['price'])
item['total_price'] = item['price'] * item['quantity']
yield item
def __len__(self):
"""
Count all items in the cart.
"""
return sum(item['quantity'] for item in self.cart.values())
def get_total_price(self):
return sum(Decimal(item['price']) * item['quantity'] for item in self.cart.values())
def clear(self):
# remove cart from session
del self.session[settings.CART_SESSION_ID]
self.session.modified = True
解决方案
shop/product/details.html模板引用了 中不product_id存在的{% url "cart:cart_add" product_id %}。它可能应该是product.id匹配cart/urls.py.