python - 具有唯一约束的 Django 添加到购物车功能失败

Question

我有一个添加到购物车的功能，它在触发时会引发错误。如果用户使用管理员帐户，则该功能有效，但是当用户拥有普通帐户时，它会显示以下错误。

视图.py

@login_required
def add_to_cart(request, slug):
    item = get_object_or_404(Item, slug=slug)
    order_item, created = OrderItem.objects.get_or_create(
        item=item,
        user=request.user,
        ordered=False,
    )
    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.quantity += 1
            order_item.save()

            order.save()
            messages.success(request, "This item was updated to your cart.")
        else:
            messages.success(request, "This item was added to your cart.")
            order.items.add(order_item)
            order.save()
    else:
        ordered_date = timezone.now()
        order = Order.objects.get_or_create(id=item.id,
            user=request.user, ordered_date=ordered_date)
        order.items.add(order_item)
        order.save()
        messages.success(request, "This item was added to your cart.")
    return redirect("product", slug=slug)

模型.py

class Item(models.Model):
    title = models.CharField(max_length=100)
    description = models.TextField()
    price = models.FloatField()
    stored = models.DateTimeField(auto_now_add=True)
    item_quantity = models.IntegerField(default=1)
    img = models.ImageField(upload_to='images/')
    category = models.CharField(choices=CATEGORY_CHOICES, max_length=15)
    slug = models.SlugField(unique=True, default=uuid.uuid1)
    
    def __str__(self) -> str:
        return self.title
    
    def save(self, *args, **kwargs):
        self.slug = slugify(self.title)
        super(Item, self).save(*args, **kwargs)
    
    def get_absolute_url(self):
        return reverse("product", kwargs={"slug": self.slug})
    
    def get_add_to_cart_url(self):
        return reverse("add-to-cart", kwargs={
            'slug': self.slug
        })
    
    def get_remove_from_cart_url(self):
        return reverse("remove_from_cart", kwargs={
            'slug': self.slug
        })
        
    def get_add_single_item_to_cart_url(self):
        return reverse("add_single_item_to_cart", kwargs={
            'slug': self.slug
        })
    
    def get_remove_single_item_from_cart_url(self):
        return reverse("remove_single_item_from_cart", kwargs={
            'slug': self.slug
        })
        

class OrderItem(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL,
                            on_delete=models.CASCADE)
    item = models.ForeignKey(Item, on_delete=models.CASCADE)
    quantity = models.IntegerField(default=1)
    ordered = models.BooleanField(default=False)
    
    def __str__(self):
        return f"{self.quantity} of {self.item.title}"
    
    def get_total_item_price(self):
        return self.quantity * self.item.price
    
    def get_final_price(self):
        return self.get_total_item_price()
    
    def get_quantity(self):
        return self.quantity
    
      
class Order(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL,
                             on_delete=models.CASCADE)
    items = models.ManyToManyField(OrderItem)
    start_date = models.DateTimeField(auto_now_add=True)
    ordered_date = models.DateTimeField()
    ordered = models.BooleanField(default=False)
    total_price = models.FloatField(default=0)

    def __str__(self):
        return self.user.username
    
    def get_total(self):
        total = 0
        for order_item in self.items.all():
            total += order_item.get_final_price()
        return total
    
    def save(self, *args, **kwargs):
        total = 0
        self.total_price = self.get_total()
        return super().save(*args, **kwargs)

错误信息：

/add-to-cart/start-with-why/ UNIQUE 约束处的 IntegrityError 失败：ecommpage_order.id 请求方法：GET 请求 URL：http: //127.0.0.1 :8000/add-to-cart/start-with-why / Django 版本：3.1.7 异常类型：IntegrityError 异常值：UNIQUE 约束失败：ecommpage_order.id

标签： pythondjango

Answer 1