Refs #765 -- Display warning if cookies are blocked

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

@@ -107,6 +107,28 @@
         </div>
     {% endif %}
 
+    {% if cookie_warning %}
+        <div class="alert alert-danger">
+            {% if cart_namespace %}
+                {% blocktrans trimmed %}
+                    Your browser does not accept cookies from us. However, we need to set a cookie to remember who
+                    you are and what is in your cart. Please try to open the ticket shop in a new tab or change your
+                    browser settings.
+                {% endblocktrans %}
+                <br>
+                <a href="{% eventurl event "presale:event.index" %}" class="btn btn-default" target="_blank">
+                    {% trans "Open ticket shop in new tab" %}
+                </a>
+                <div class="clearfix"></div>
+            {% else %}
+                {% blocktrans trimmed %}
+                    Your browser does not accept cookies from us. However, we need to set a cookie to remember who
+                    you are and what is in your cart. Please change your browser settings accordingly.
+                {% endblocktrans %}
+            {% endif %}
+        </div>
+    {% endif %}
+
     {% if subevent or not event.has_subevents %}
         {% if not ev.presale_is_running %}
             <div class="alert alert-info">

src/pretix/presale/views/cart.py

@@ -37,12 +37,17 @@ class CartActionMixin:
 
     def get_next_url(self):
         if "next" in self.request.GET and is_safe_url(self.request.GET.get("next")):
-            return self.request.GET.get('next')
+            u = self.request.GET.get('next')
         else:
             kwargs = {}
             if 'cart_namespace' in self.kwargs:
                 kwargs['cart_namespace'] = self.kwargs['cart_namespace']
-            return eventreverse(self.request.event, 'presale:event.index', kwargs=kwargs)
+            u = eventreverse(self.request.event, 'presale:event.index', kwargs=kwargs)
+        if '?' in u:
+            u += '&require_cookie=true'
+        else:
+            u += '?require_cookie=false'
+        return u
 
     def get_success_url(self, value=None):
         return self.get_next_url()

src/pretix/presale/views/checkout.py

@@ -23,7 +23,7 @@ class CheckoutView(View):
         kwargs = {}
         if 'cart_namespace' in self.kwargs:
             kwargs['cart_namespace'] = self.kwargs['cart_namespace']
-        return eventreverse(self.request.event, 'presale:event.index', kwargs=kwargs)
+        return eventreverse(self.request.event, 'presale:event.index', kwargs=kwargs) + '?require_cookie=false'
 
     def dispatch(self, request, *args, **kwargs):
         self.request = request

src/pretix/presale/views/event.py

@@ -274,6 +274,11 @@ class EventIndex(EventViewMixin, CartMixin, TemplateView):
             )
         )
 
+        context['cookie_warning'] = (
+            'require_cookie' in self.request.GET and
+            settings.SESSION_COOKIE_NAME not in self.request.COOKIES
+        )
+
         return context