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python - Django AttributeError：'Cart' 对象没有属性'get'

问题描述

我的 django 项目出现此错误：

   Request Method: GET
   Request URL: http://127.0.0.1:8000/cart/
   Exception Type: AttributeError at /cart/
   Exception Value: 'Cart' object has no attribute 'get'

这是carts.views.py：

from django.shortcuts import render, redirect, get_object_or_404
from store.models import Product
from .models import Cart, CartItem



# Create your views here.

def _cart_id(request):
    cart = request.session.session_key
    if not cart:
        cart = request.session.create()
    return cart

def add_cart(request, product_id):
    product = Product.objects.get(id=product_id)

    try:
        cart = Cart.objects.get(cart_id=_cart_id(request))
    except Cart.DoesNotExist:
        cart = Cart.objects.create(
            cart_id = _cart_id(request)
            )
        cart.save()
    
    try:
        cart_item = CartItem.objects.get(product=product, cart=cart)
        cart_item.quantity += 1
        cart_item.save()
    except CartItem.DoesNotExist:
        cart_item = CartItem.objects.create(
            product= product,
            quantity= 1,
            cart= cart,
        )
        cart_item.save()
    return redirect('cart')


def cart(request):
    return render(request, 'store/cart.html')

我试过了：

  1. 重写类'Cart'的名称
  2. 使用 objectDoesnotexist 而不是 DoesnotExit
  3. 仔细检查 models.py 中类的名称

我无法调试此错误。我多次忽略了我的代码，但无法理解错误在哪里产生。提前致谢。

编辑：

模型.py：

from django.db import models
from store.models import Product

# Create your models here.

class Cart(models.Model):
    cart_id         = models.CharField(max_length=250, blank=True)
    date_added      = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return self.cart_id

class CartItem(models.Model):
    product         = models.ForeignKey(Product, on_delete=models.CASCADE)
    cart            = models.ForeignKey(Cart, on_delete=models.CASCADE, related_name='cart')
    quantity        = models.IntegerField()
    is_active       = models.BooleanField(default=True)

    def __str__(self):
        return self.product

编辑：完整追溯：

Environment:


Request Method: GET
Request URL: http://127.0.0.1:8000/cart/

Django Version: 3.2.3
Python Version: 3.9.1
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'category',
 'accounts',
 'store',
 'carts']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware']



Traceback (most recent call last):
  File "D:\greatkart\env\lib\site-packages\django\core\handlers\exception.py", line 47, in inner
    response = get_response(request)
  File "D:\greatkart\env\lib\site-packages\django\utils\deprecation.py", line 119, in __call__
    response = self.process_response(request, response)
  File "D:\greatkart\env\lib\site-packages\django\middleware\clickjacking.py", line 26, in process_response
    if response.get('X-Frame-Options') is not None:

Exception Type: AttributeError at /cart/
Exception Value: 'Cart' object has no attribute 'get'

编辑：urls.py：

from django.urls import path
from . import views

urlpatterns = [
    path('', views.Cart, name='cart'),
    path('add_cart/<int:product_id>/', views.add_cart, name='add_cart'),
]

标签： pythondjango

解决方案

由于这些错误，我开始使用“Model.objects.filter().first()”而不是“Model.objects.get()”。

你可以试试这个：

 cart = Cart.objects.filter(cart_id=_cart_id(request).first()

 if not cart:
     new_cart = Cart(cart_id = _cart_id(request))
     new_cart.save()

此方法为您提供具有正确“cart_id”的所有对象。使用“.first()”，您会将给定查询集转换为一个对象（即使查询集中只有一个对象，您也需要这样做）

而不是这个

    try:
        cart = Cart.objects.get(cart_id=_cart_id(request))
    except Cart.DoesNotExist:
        cart = Cart.objects.create(
            cart_id = _cart_id(request)
            )
        cart.save()

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