Question

美好的一天，我收到以下错误：不是JSON可序列化

但我不确定为什么我会得到它。一切都工作正常，直到我决定开始使用会话启动我的用户购物车添加和删除项目这是我的观点：

def add_or_update_cart(request, slug):
    request.session.set_expiry(180)
    new_total = 0.00
    try:
        # check that session exists
        the_cart_id = request.session['cart_id']
    except:
        new_cart_id = Cart()
        new_cart_id.save()
        request.session['cart_id'] = new_cart_id
        the_cart_id = new_cart_id.id

    cart = Cart.objects.get(id=the_cart_id)
    try:
        product = Product.objects.get(slug=slug)
    except Product.DoesNotExist:
        pass
    except:
        pass

    if not product in cart.products.all():
        cart.products.add(product)
    else:
        cart.products.remove(product)

    for item in cart.products.all():
        new_total += float(item.price)

    request.session['items_total'] = cart.products.count()
    cart.total = new_total
    cart.save()
    print(cart.products.count())
    return HttpResponseRedirect(reverse('cart:cart'))

型号：

class Cart(models.Model):
    products = models.ManyToManyField(Product, null=True, blank=True)
    total = models.DecimalField(max_digits=100, decimal_places=2, default=0.00)
    timestamp = models.DateTimeField(auto_now_add=True, auto_now=False)
    updated = models.DateTimeField(auto_now_add=False, auto_now=True)
    cart_status = models.BooleanField(default=False)

    def __str__(self):
        return '%s' % self.id

    def item_name(self):
        return " ".join([str(p) for p in self.product.all()])

并在我的模板中：

<li role="presentation"><a href="{% url 'cart:cart' %}">Cart <span class="badge">{{ request.session.items_total }}</span></a></li>

追溯：

Internal Server Error: /my-cart/puma/
Traceback (most recent call last):
  File "/home/drcongo/.virtualenvs/eCommerce/lib/python3.4/site-packages/django/core/handlers/base.py", line 235, in get_response
    response = middleware_method(request, response)
  File "/home/drcongo/.virtualenvs/eCommerce/lib/python3.4/site-packages/django/contrib/sessions/middleware.py", line 50, in process_response
    request.session.save()
  File "/home/drcongo/.virtualenvs/eCommerce/lib/python3.4/site-packages/django/contrib/sessions/backends/db.py", line 82, in save
    obj = self.create_model_instance(data)
  File "/home/drcongo/.virtualenvs/eCommerce/lib/python3.4/site-packages/django/contrib/sessions/backends/db.py", line 68, in create_model_instance
    session_data=self.encode(data),
  File "/home/drcongo/.virtualenvs/eCommerce/lib/python3.4/site-packages/django/contrib/sessions/backends/base.py", line 88, in encode
    serialized = self.serializer().dumps(session_dict)
  File "/home/drcongo/.virtualenvs/eCommerce/lib/python3.4/site-packages/django/core/signing.py", line 95, in dumps
    return json.dumps(obj, separators=(',', ':')).encode('latin-1')
  File "/usr/lib/python3.4/json/__init__.py", line 237, in dumps
    **kw).encode(obj)
  File "/usr/lib/python3.4/json/encoder.py", line 192, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/lib/python3.4/json/encoder.py", line 250, in iterencode
    return _iterencode(o, 0)
  File "/usr/lib/python3.4/json/encoder.py", line 173, in default
    raise TypeError(repr(o) + " is not JSON serializable")
TypeError: <Cart: 31> is not JSON serializable

我将不胜感激。

Answer 1

当Django尝试在此处序列化模型实例时出现错误

request.session['cart_id'] = new_cart_id

new_cart_id是一个模型实例，无法序列化您似乎想要将实例的主键分配给键cart_id。

request.session['cart_id'] = new_cart_id.id

我错过了什么来得到这个错误：<cart：22 =“”>不是JSON可序列化的？

1 个答案: