python - 将产品添加到购物车无法正常工作

Question

我遇到了代码问题，一个更具体的错误，那就是当我第一次将一个项目添加到购物车时(比如绿色和中等版本)，它被很好地添加了。然后当我添加另一个项目(假设蓝色和小)时，它也可以工作。但是，当我从 order_summary.html 增加项目数量时，它增加了另一个项目的数量，而不是我点击的项目(如果我点击了红色和中号，蓝色和大号的数量会增加)并说:请指定所需的变化。为什么会这样？还值得注意的是，当我从我的单个产品页面添加具有相同变体的相同项目时，它工作正常。我认为这个错误的发生是因为我的观点的编写方式。我试图自己解决它，但我迷路了。任何人都可以帮我吗？提前致谢!

我的models.py:

class Item(models.Model):
   title = models.CharField(max_length=120)
   price = models.FloatField()

class Variation(models.Model):
   item = models.ForeignKey(Item, on_delete=models.CASCADE)
   name = models.CharField(max_length=50) # size, color

class ItemVariation(models.Model):
   variation  = models.ForeignKey(Variation, on_delete=models.CASCADE)
   value = models.CharField(max_length=50) # small, medium large etc

class OrderItem(models.Model):
   user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
   item  = models.ForeignKey(Item, on_delete=models.CASCADE)
   item_variations = models.ManyToManyField(ItemVariation)
   quantity = models.IntegerField(default=1)
   ordered = models.BooleanField(default=False)

class Order(models.Model):
   user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
   ref_code = models.CharField(max_length=20)
   ordered = models.BooleanField(default=False)
   items = models.ManyToManyField(OrderItem)
   start_date = models.DateTimeField(auto_now_add= True)
   ordered_date = models.DateTimeField()

我的意见.py:

@login_required
def add_to_cart(request, slug):
    item = get_object_or_404(Item, slug=slug)
    variations = request.POST.getlist('variations', [])
    print(variations)
    print(request.POST)
    minimum_variation_count = Variation.objects.filter(item=item).count()
    print(minimum_variation_count)
    print(len(variations))
    if len(variations) < minimum_variation_count:
        messages.info(request, "Please specify the required variations.")


    order_item_qs = OrderItem.objects.filter(
        item=item,
        user= request.user,
        ordered=False,
    )

    for v in variations:
        print(v)
        order_item_qs = order_item_qs.filter(
            item_variations__value=v
        )

    if order_item_qs.exists():
        order_item = order_item_qs.first()
        order_item.quantity += 1
        # messages.success(request, "Product quantity was updated.")
        order_item.save()
    else:
        order_item = OrderItem.objects.create(
            item=item,
            user= request.user,
            ordered=False,
        )

        # order_item.item_variations.add(*variations)
        item_variations_to_add = ItemVariation.objects.filter(
                variation__item=item,
                value__in=variations
            ).values_list('id', flat=True)
        order_item.item_variations.add(*item_variations_to_add)
        order_item.save()

    order_qs = Order.objects.filter(user=request.user, ordered=False)
    if order_qs.exists():
        order = order_qs[0]
        if not order.items.filter(item__id=order_item.id).exists():
            order.items.add(order_item)
            # print(request.POST.getlist('variations', None)) 
            messages.success(request, "Product added to cart.")
            return redirect("order-summary")
    else:
        ordered_date = timezone.now()
        order = Order.objects.create(user=request.user, ordered_date=ordered_date)
        order.items.add(order_item)
        # print(request.POST.getlist('variations', None)) 
        messages.success(request, "Product added to cart.")
        return redirect("order-summary")
    return redirect("order-summary")


@login_required
def remove_single_item_from_cart(request, slug):
    item = get_object_or_404(Item, slug=slug)
    variations = request.POST.getlist('variations', [])
    order_qs = Order.objects.filter(
        user=request.user,
        ordered=False
    )
    if order_qs.exists():
        order = order_qs[0]
        # check if the order item is in the order
        if order.items.filter(item__slug=item.slug).exists():
            order_item = OrderItem.objects.filter(
                item=item,
                user=request.user,
                ordered=False
            )[0]
            if order_item.quantity > 1:
                order_item.quantity -= 1
                order_item.save()
                messages.info(request, "Product quantity was updated.")
            else:
                order.items.remove(order_item)
                order_item.delete()
                messages.info(request, "Product was removed from cart.")
            return redirect("order-summary")
        else:
            messages.info(request, "Product was not in your cart")
            return redirect("product", slug=slug)
    else:
        messages.info(request, "You do not have an active order")
        return redirect("product", slug=slug)
    return redirect("order-summary")

我的 order_summary.html(我可以在其中增加数量):

<th scope="row" class="border-0">
  <div class="p-2">
    <img src="{{ order_item.item.image_url }}" alt="" width="70" class="img-fluid rounded shadow-sm">
      <div class="ml-3 d-inline-block align-middle">
        <h5 class="mb-1"> <a href="{{ order_item.item.get_absolute_url }}" class="text-dark
        -inline-block align-middle">{{ order_item.item.title }}</a>
        {% for var in order_item.item_variations.all %}
          <!-- <h6>{{ order_item.item_variations.all }}</h6> -->
          <!-- <ul> -->
            <!-- <li><h6>{{ var.variation.name }}: {{ var.value }}</h6></li> -->
          <!-- </ul> -->
          <h6>{{ var.variation.name }}: {{ var.value }}</h6>
        {% endfor %}
      </div>
  </div>
</th>
{% if order_item.item.discount_price %}
  <td class="border-0 align-middle"><strong>${{ order_item.get_total_discount_item_price }} <span class="badge badge-warning">Saving ${{ order_item.get_amount_saved }}</span></strong></td>
{% else %}
  <td class="border-0 align-middle"><strong>${{ order_item.get_total_item_price }}</strong></td>
{% endif %}
    <td class="border-0 align-middle"><strong>
      <div class="pull-center">
          <a href="{% url 'remove-single-item-from-cart' order_item.item.slug %}" class="btn mr-2"><i class="fa fa-minus"></i></a>
          {{ order_item.quantity }}<a href="{% url 'add-to-cart' order_item.item.slug %}" class="btn ml-2"><i class="fa fa-plus"></i></a>
        </div>      
      </div>
      </strong></td>
    <td class="border-0 align-middle"><a href="{% url 'remove-from-cart' order_item.item.slug %}" class="text-dark"><i class="fa fa-trash"></i></a></td>
  </tr>

我的 single_product.html(我可以从这里增加我的产品数量，并且它工作正常):

<form class="form" method="POST" action="{{ object.get_add_to_cart_url }}">
                    {% csrf_token %}
                      {% for var in object.variation_set.all %}
                        <h5>Choose {{ var.name }}</h5>
                        <select class="form-control mb-4 col-md-4" name="variations">
                          {% for item in var.itemvariation_set.all %}
                            <option value="{{ item.value }}">{{ item.value|capfirst }}</option>
                          {% endfor %}
                        </select> 
                      {% endfor %}


                    <div class="action">
                      <button class="btn btn-success">Add to Cart</button>
                      <button class="like btn btn-danger" type="button"><span class="fa fa-heart"></span></button>
                    </div>
                  </form>

我的 admin.py:

from django.contrib import admin
from .models import Item, Variation, ItemVariation


class ItemVariationAdmin(admin.ModelAdmin):
    list_display = ['variation',
                    'value']

    list_filter = ['variation', 'variation__item']
    search_fields = ['value']


class ItemVariationInLineAdmin(admin.TabularInline):
    model = ItemVariation
    extra = 1


class VariationAdmin(admin.ModelAdmin):
    list_display = ['item',
                    'name']
    list_filter = ['item']
    search_fields = ['name']
    inlines = [ItemVariationInLineAdmin]

admin.site.register(Item)
admin.site.register(ItemVariation, ItemVariationAdmin)
admin.site.register(Variation, VariationAdmin)

我的 urls.py:

path('add_to_cart/<slug>/', orders_views.add_to_cart, name='add-to-cart'),
path('remove_from_cart/<slug>/', orders_views.remove_from_cart, name='remove-from-cart'),

Answer 1

我希望 variations为空，因为您不是通过 POST 请求发送，也不是从您的 html 表单发送任何变体输入。这就是您获得 "Please specify the required variations." 的原因信息。 ( len(variations) == 0 )

因为 variations为空，for v in variations没有做任何过滤工作。所以当你到达 order_item_qs.first() ，您不一定会得到您期望的 OrderItem，并且可能是 +=1在错误的 OrderItem 上。

修理:

最简单的方法是添加 increase_quantity url 端点，您可以在其中将 OrderItem id 传递到 View 中。这样您就可以确切地知道要增加数量的 OrderItem，并且不需要进行任何过滤来找到它。

否则，您需要弄清楚如何将变体发送到 View 。如果使用 POST，那么您希望使用某种输入。如果 GET，那么您可以附加 url 或类似的内容。 (我强烈建议作为 POST 请求发送。)