Pass widget_data to new tab even if 3rd-party cookies are disabled (Z#23176995)

src/pretix/presale/templates/pretixpresale/event/index.html

@@ -182,7 +182,7 @@
                     data-asynctask-headline="{% trans "We're now trying to reserve this for you!" %}"
                     data-asynctask-text="{% blocktrans with time=event.settings.reservation_time %}Once the items are in your cart, you will have {{ time }} minutes to complete your purchase.{% endblocktrans %}"
                     class="{% if event.seating_plan_id %}has-seating{% endif %}"
-                    action="{% eventurl request.event "presale:event.cart.add" cart_namespace=cart_namespace %}?next={{ cart_redirect|urlencode }}&next_error={{ request.path|urlencode }}">
+                    action="{% eventurl request.event "presale:event.cart.add" cart_namespace=cart_namespace %}?next={{ cart_redirect|urlencode }}&next_error={{ request.path|urlencode }}{{ take_cart_id_param }}">
                 {% csrf_token %}
                 <input type="hidden" name="subevent" value="{{ subevent.id|default_if_none:"" }}" />
                 {% if ev.seating_plan_id and event.settings.seating_choice %}

src/pretix/presale/views/cart.py

@@ -307,7 +307,7 @@ def create_empty_cart_id(request, replace_current=True):
     return new_id
 
 
-def get_or_create_cart_id(request, create=True):
+def get_or_create_cart_id(request, create=True, cache_widget_data=False):
     """
     This method returns the cart ID in use for this request or creates a new cart ID if required.
 
@@ -404,6 +404,9 @@ def get_or_create_cart_id(request, create=True):
             cart_data['widget_data'] = json.loads(request.GET.get('widget_data'))
         except ValueError:
             pass
+        else:
+            if cache_widget_data:
+                widget_data_cache.set('widget_data_{}'.format(new_id), cart_data['widget_data'], 600)
 
     if 'carts' not in request.session:
         request.session['carts'] = {}

src/pretix/presale/views/event.py

@@ -505,7 +505,7 @@ class EventIndex(EventViewMixin, EventListMixin, CartMixin, TemplateView):
             get_or_create_cart_id(request)
             return redirect_to_url(eventreverse(request.event, 'presale:event.index', kwargs=kwargs) + '?' + urlencode(utm_params))
         elif request.GET.get('iframe', '') == '1' and 'take_cart_id' in request.GET:
-            # Widget just opened, a cart already exists. Let's to a stupid redirect to check if cookies are disabled
+            # Widget just opened, a cart already exists. Let's do a stupid redirect to check if cookies are disabled
             get_or_create_cart_id(request)
             return redirect_to_url(eventreverse(request.event, 'presale:event.index', kwargs=kwargs) + '?' + urlencode({
                 'require_cookie': 'true',
@@ -515,7 +515,7 @@ class EventIndex(EventViewMixin, EventListMixin, CartMixin, TemplateView):
             }))
         elif request.GET.get('iframe', '') == '1' and len(self.request.GET.get('widget_data', '{}')) > 3:
             # We've been passed data from a widget, we need to create a cart session to store it.
-            get_or_create_cart_id(request)
+            get_or_create_cart_id(request, cache_widget_data=True)
         elif 'require_cookie' in request.GET and settings.SESSION_COOKIE_NAME not in request.COOKIES and \
                 '__Host-' + settings.SESSION_COOKIE_NAME not in self.request.COOKIES:
             # Cookies are in fact not supported
@@ -644,6 +644,10 @@ class EventIndex(EventViewMixin, EventListMixin, CartMixin, TemplateView):
         else:
             context['cart_redirect'] = self.request.path
 
+        if 'cart_namespace' in self.kwargs and self.request.GET.get('iframe') == '1' and 'take_cart_id' in self.request.GET:
+            from pretix.presale.views.cart import get_or_create_cart_id
+            context['take_cart_id_param'] = '&take_cart_id=' + get_or_create_cart_id(self.request)
+
         return context
 
     def _subevent_list_cachekey(self):