将商品添加到购物车 Django Python

Question

编辑当我点击添加到购物车时，这是终端的输出

[22/Mar/2016 07:07:44] "GET /store/add/7 HTTP/1.1" 302 0
[22/Mar/2016 07:07:44] "GET /store/ HTTP/1.1" 200 4888

我有两个功能，一个是将商品添加到购物车，另一个是删除。

我在想问题是我的 URL 请求没有正确形成。所以我很感激比我更有经验的人向我解释预期的 URL 应该是什么。

我正在像这样创建我的 URL，

url(r'^add/(\d+)', views.add_to_cart, name='add_to_cart'),  
    url(r'^remove/(\d+)', views.remove_from_cart, name='remove_from_cart'),
    url(r'^cart/', views.cart, name='cart'),

将商品添加到购物车的链接位于 base.html 文件中，如下所示，

  {% if request.user.is_authenticated %}
         <span class="storefront_add_to_cart">
             <a href="{% url 'add_to_cart' book.id %}">[Add to Cart]</a>
         </span>
         {% endif %}

因此，当您从购物车中添加或删除项目时，它会调用相应的函数。

视图.py

def add_to_cart(request,book_id):
        if request.user.is_authenticated():
            try:
                book = Book.objects.get(pk=book_id)
            except ObjectDoesNotExist:
                pass
            else :
                try:
                    cart = Cart.objects.get(user = request.user, active = True)
                except ObjectDoesNotExist:
                    cart = Cart.objects.create(user = request.user)
                    cart.save()
                    cart.add_to_cart(book_id)
                    return redirect('cart')
                else:
                    return redirect('index')


def remove_from_cart(request, book_id):
    if request.user.is_authenticated():
        try:
            book = Book.objects.get(pk = book_id)
        except ObjectDoesNotExist:
            pass 
        else:
            cart = Cart.objects.get(user = request.user, active = True)
            cart.remove_from_cart(book_id)
        return redirect('cart')
    else:
        return redirect('index')

当我点击添加到购物车时，网址看起来像这样（这给了我错误）

http://localhost:8000/store/add/4

当我点击从购物车中删除时，网址看起来像这样，但我没有收到任何错误。（购物车中的商品会保留且不会移除。）

http://localhost:8000/store/cart/%7B%20url%20'remove_from_cart'%20item.book.id%20%%7D

如果它有帮助，这里是 models.py 中的相应模型

class Cart(models.Model):
    user = models.ForeignKey(User)
    active = models.BooleanField(default=True)
    order_date = models.DateField(null=True)
    payment_type = models.CharField(max_length=100, null=True)
    payment_id = models.CharField(max_length=100, null=True)

    def __unicode__(self): 
            return "%s" % (self.user)

    def add_to_cart(self, book_id):
        book = Book.objects.get(pk=book_id)
        try:
            preexisting_order = BookOrder.objects.get(book=book, cart=self)
            preexisting_order.quantity += 1
            preexisting_order.save()
        except BookOrder.DoesNotExist:
            new_order = BookOrder.objects.create(
                book=book,
                cart=self,
                quantity=1
                )
            new_order.save()

            def __unicode__(self):
                return "%s" % (self.book_id)


    def remove_from_cart(self, book_id):
        book = Book.objects.get(pk=book_id)
        try:
            preexisting_order = BookOrder.objects.get(book=book, cart=self)
            if preexisting_order.quantity > 1:
                preexisting_order.quantity -= 1
                preexisting_order.save()
            else:
                preexisting_order.delete()
        except BookOrder.DoesNotExist:
            pass

Answer 1

让我们及时解决这个问题。

首先，您需要使用login_required装饰器；您也不应该接受将无效书籍添加到购物车（您当前正在数据库级别检查，并且不会向客户显示此错误）。

from django.contrib.auth.decorators import login_required
from django.shortcuts import get_object_or_404

@login_required
def add_to_cart(request,book_id):
    book = get_object_or_404(Book, pk=book_id)
    cart,created = Cart.objects.get_or_create(user=request.user, active=True)
    cart.add_to_cart(book_id)
    return redirect('cart')

接下来，您需要修复生成链接以从购物车中删除商品的模板。你的链接应该是：

<a href="{% url 'remove_from_cart' args=(item.book.id,) %}">Remove item</a>

在您的模型中，您有两种__unicode__方法，我认为这是复制粘贴中的错误，否则您需要add_to_cart从您的models.py.

无论如何，您不需要该方法，您应该将整个逻辑保留在您的视图中。这是修改后的方法：

from django.contrib.auth.decorators import login_required
from django.shortcuts import get_object_or_404
from django.contrib import messages

from .models import Cart, BookOrder, Book

@login_required
def add_to_cart(request,book_id):
    book = get_object_or_404(Book, pk=book_id)
    cart,created = Cart.objects.get_or_create(user=request.user, active=True)
    order,created = BookOrder.objects.get_or_create(book=book,cart=cart)
    order.quantity += 1
    order.save()
    messages.success(request, "Cart updated!")
    return redirect('cart')