add onsolved problem for help

django/didgeridoo/webshop/models.py

@@ -111,7 +111,7 @@ class CartPosition(models.Model):
     """ Items in Cart """
     article = models.ForeignKey(Article, on_delete=models.CASCADE)
     amount = models.FloatField(max_length=5)
-    cart = models.ForeignKey(ShoppingCart)
+    cart = models.ForeignKey(ShoppingCart, on_delete=models.CASCADE)
 
 
 class City(models.Model):

django/didgeridoo/webshop/views.py

@@ -148,8 +148,15 @@ def article_details(request, article_id):
                 print("amount:", amount,
                       "article_id:", article_id,
                       "currency_id:", currency_id)
+                article = Article.objects.get(id=article_id)
+                try:
+                    cart_id = ShoppingCart.objects.get(user=request.user)
+                except:
+                    cart_id = ShoppingCart.objects.create(user=request.user)
+                    cart_id.save()
+                if cart_id:
                     cart_position = CartPosition.objects.create(
-                    article=article_id,
+                        article=article,
                         amount=amount,
                         cart=ShoppingCart.objects.get(user=request.user)
                         )
@@ -215,6 +222,7 @@ def registration(request):
 
 
 def cart(request):
+    category_list = get_categories()
     currencies_form = CurrenciesForm
     rate = ExchangeRate
     article_view = True
@@ -234,14 +242,17 @@ def cart(request):
             else:
                 request.session['currency'] = None
 
-    cart_id = ShoppingCart.objects.get(user=request.user)
+    try:
+        cart_id = ShoppingCart.objects.filter(user=request.user)
+    except Exception as e:
+        message = "You have no items in the Basket"
+    if cart_id:
         articles = CartPosition.objects.filter(cart=cart_id)
         articles_list = list(articles)
         for idx, article in enumerate(articles_list):
             article.price_in_chf = rate.exchange(
                 currency, article.price_in_chf)
             articles_list[idx] = article
-
             currency_name = ExchangeRate_name.objects.get(id=currency)
             article.price_in_chf = rate.exchange(currency, article.price_in_chf)
 
@@ -250,4 +261,6 @@ def cart(request):
                    'currencies_form': currencies_form,
                    'article_view': article_view,
                    'currency_name': currency_name,
+                   'category_list': category_list,
+                   'message': message,
                    })