Question

我的购物车会话有问题。每次上传购物车页面时，都会创建一个新的购物车会话！即使用户已通过身份验证。

这是我的购物车应用模型中的代码。py：

from django.conf import settings
from django.db import models
from django.db.models.signals import pre_save, post_save, m2m_changed

from products.models import Product


User = settings.AUTH_USER_MODEL

class CartManager(models.Manager):
    def new_or_get(self, request):
        cart_id = request.session.get("cart_id", None)
        qs = self.get_queryset().filter(id=cart_id)
        if qs.count() == 1:
            new_obj = False
            cart_obj = qs.first()
            if request.user.is_authenticated and cart_obj.user is None:
                cart_obj.user = request.user
                cart_obj.save()
        else:
            cart_obj = Cart.objects.new(user=request.user)
            new_obj = True  
            request.session['card_id'] = cart_obj.id
        return cart_obj, new_obj

    def new(self, user=None):
        user_obj = None
        if user is not None:
            if user.is_authenticated:
                user_obj = user
        return self.model.objects.create(user=user_obj)



class Cart(models.Model):
    user        = models.ForeignKey(User, null=True, blank=True, on_delete=models.CASCADE)
    products    = models.ManyToManyField(Product, blank=True)
    subtotal    = models.DecimalField(default=0.00, max_digits=100, decimal_places=2)
    total       = models.DecimalField(default=0.00, max_digits=100, decimal_places=2)
    updated     = models.DateTimeField(auto_now=True)
    timestamp   = models.DateTimeField(auto_now_add=True)

    objects = CartManager()

    def __str__(self):
        return str(self.id)


def m2m_changed_cart_receiver(sender, instance, action, *args, **kwargs):
    if action == 'post_add' or action == 'post_remove' or action == 'post_clear':
        products = instance.products.all()
        total = 0
        for x in products:
            total += x.price
        if instance.subtotal !=total: 
            instance.subtotal = total
            instance.save()

m2m_changed.connect(m2m_changed_cart_receiver, sender=Cart.products.through)

def pre_save_cart_receiver(sender, instance, *args, **kwargs):
    if instance.subtotal > 0:
        instance.total = instance.subtotal 
    else:
        instance.total = 0.00

pre_save.connect(pre_save_cart_receiver, sender=Cart)

这是我的购物车应用view.py中的代码：

from django.shortcuts import render

# Create your views here.

from django.shortcuts import render, redirect

from products.models import Product
from .models import Cart


def cart_home(request):
    cart_obj, new_obj = Cart.objects.new_or_get(request)
    return render(request, 'carts/home.html', {"cart": cart_obj})

def cart_update(request):
    product_id = request.POST.get('product_id')
    if product_id is not None:
        try:
            product_obj = Product.objects.get(id=product_id)
        except Product.DoesNotExist:
            return redirect("cart:home")
        cart_obj, new_obj = Cart.objects.new_or_get(request)
        if product_obj in cart_obj.products.all():
            cart_obj.products.remove(product_obj)
        else:
            cart_obj.products.add(product_obj)

    return redirect("cart:home")

在设置中，我有以下内容：

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',

    #my apps
    'carts',
    'products',
    'search',
    'tags',
]

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',
]

能否帮助我找出代码中的问题并加以解决？

还是您有可以共享的购物车会话示例？

谢谢。

Django 2.2会话在我的购物车应用中不起作用

0 个答案: