在视图中定义get_queryset，属性错误

如何解决在视图中定义get_queryset，属性错误

我试图编写一个自定义get_queryset函数，因为我想从'request.user.email'访问用户的电子邮件，并使用它来形成另一个查询，我想使用我的视图显示该查询cartv(generic.ListView)。第一次在这里提出问题时，在网站上进行了搜索，但没有找到任何类似的东西，但是如果您确实找到了一些东西，请直接将我指向我，我会尽快删除

环境：

Request Method: GET
Request URL: http://192.168.24.169:8000/products/cart/

    Django Version: 3.1.2
    Python Version: 3.6.9
    Installed Applications:
    ['products.apps.ProductsConfig','accounts.apps.AccountsConfig','django.contrib.admin','django.contrib.auth','django.contrib.contenttypes','django.contrib.sessions','django.contrib.messages','django.contrib.staticfiles']
    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 "/home/nirman/.local/lib/python3.6/site-packages/django/core/handlers/exception.py",line 47,in inner
    response = get_response(request)
  File "/home/nirman/.local/lib/python3.6/site-packages/django/core/handlers/base.py",line 179,in _get_response
    response = wrapped_callback(request,*callback_args,**callback_kwargs)
  File "/home/nirman/.local/lib/python3.6/site-packages/django/views/generic/base.py",line 70,in view
    return self.dispatch(request,*args,**kwargs)
  File "/home/nirman/.local/lib/python3.6/site-packages/django/views/generic/base.py",line 98,in dispatch
    return handler(request,**kwargs)
  File "/home/nirman/.local/lib/python3.6/site-packages/django/views/generic/list.py",line 142,in get
    self.object_list = self.get_queryset()
  File "/home/nirman/Desktop/login/products/views.py",line 91,in get_queryset
    self.user = request.user

Exception Type: AttributeError at /products/cart/
Exception Value: 'cartv' object has no attribute 'user'

观看次数：

class cartv(generic.ListView):
    model = cart
    context_object_name = 'cart_list'   
    template_name='products/cartview.html'

    def get_queryset(request):
        qs = cart.objects.filter(user__email=request.user.email) #error points here
        if qs.exists():
            c = qs[0]
            return c.items.all()

        else:
            return redirect('failure')

型号：

class cart_item(models.Model): 
products = models.ManyToManyField(product) 
quantity = models.IntegerField(null=False,default=1) 
user = models.ManyToManyField(User) 

class cart(models.Model): 
items = models.ManyToManyField(cart_item) 
user = models.ManyToManyField(User) 
ordered = models.BooleanField(null=False,default=False)

解决方法

您应该将self参数传递给get_queryset方法。然后，在self参数内，您可以通过request访问self.request。

您的情况应如下所示：

class cartv(generic.ListView):
    model = cart
    context_object_name = 'cart_list'   
    template_name='products/cartview.html'

    def get_queryset(self):
        qs = cart.objects.filter(user__email=self.request.user.email)
        if qs.exists():
            c = qs[0]
            return c.items.all()

        else:
            return redirect('failure')

,

get_queryset(…) method [Django-doc]不使用参数request，它具有参数self（类似于任何对象方法）。

此外，redirect在这种情况下将不起作用。 get_queryset应该返回QuerySet，而不是redirect。例如，在这种情况下，您可以引发Http404异常：

from django.http import Http404

class cartv(generic.ListView):
    model = cart_item
    context_object_name = 'cart_list'   
    template_name='products/cartview.html'

    def get_queryset(self):
        cart = cart.objects.filter(user=self.request.user)
        try:
            cart[0].items.all()
        except IndexError:
            raise Http404

但是首先使用cart[0]有点“奇怪”。如果用户有多个购物车，那么为什么要退回第一个购物车？