Allow to pass user data to the widget (#1095)

- [x] Logic
- [x] Tests
- [x] Docs
- [x] find a way to integrate with tracking

src/pretix/presale/checkoutflow.py

@@ -309,7 +309,10 @@ class QuestionsStep(QuestionsViewMixin, CartMixin, TemplateFlowStep):
     @cached_property
     def contact_form(self):
         initial = {
-            'email': self.cart_session.get('email', '')
+            'email': (
+                self.cart_session.get('email', '') or
+                self.cart_session.get('widget_data', {}).get('email', '')
+            )
         }
         initial.update(self.cart_session.get('contact_form_data', {}))
         return ContactForm(data=self.request.POST if self.request.method == "POST" else None,

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

@@ -237,6 +237,9 @@
                     <div class="clearfix"></div>
                 </div>
             {% endif %}
+            {% if "widget_data" in request.GET %}
+                <input type="hidden" value="{{ request.GET.widget_data }}" name="widget_data">
+            {% endif %}
         </form>
     {% endif %}
 {% endblock %}

src/pretix/presale/views/cart.py

@@ -1,8 +1,10 @@
+import json
 import mimetypes
 import os
 
 from django.conf import settings
 from django.contrib import messages
+from django.core.cache import caches
 from django.db.models import Q
 from django.http import FileResponse, Http404, JsonResponse
 from django.shortcuts import get_object_or_404, redirect
@@ -33,6 +35,11 @@ from pretix.presale.views.event import (
 )
 from pretix.presale.views.robots import NoSearchIndexViewMixin
 
+try:
+    widget_data_cache = caches['redis']
+except:
+    widget_data_cache = caches['default']
+
 
 class CartActionMixin:
 
@@ -266,11 +273,20 @@ def get_or_create_cart_id(request, create=True):
         cart_data = {}
         if prefix and 'take_cart_id' in request.GET and current_id:
             new_id = current_id
+            cached_widget_data = widget_data_cache.get('widget_data_{}'.format(current_id))
+            if cached_widget_data:
+                cart_data['widget_data'] = cached_widget_data
         else:
             if not create:
                 return None
             new_id = generate_cart_id(request, prefix=prefix)
 
+        if 'widget_data' not in cart_data and 'widget_data' in request.GET:
+            try:
+                cart_data['widget_data'] = json.loads(request.GET.get('widget_data'))
+            except ValueError:
+                pass
+
         if 'carts' not in request.session:
             request.session['carts'] = {}
         if new_id not in request.session['carts']:
@@ -349,10 +365,24 @@ class CartAdd(EventViewMixin, CartActionMixin, AsyncAction, View):
         }
 
     def post(self, request, *args, **kwargs):
+        cart_id = get_or_create_cart_id(self.request)
+        if "widget_data" in request.POST:
+            try:
+                widget_data = json.loads(request.POST.get("widget_data", "{}"))
+            except ValueError:
+                widget_data = {}
+            else:
+                widget_data_cache.set('widget_data_{}'.format(cart_id), widget_data, 600)
+                cs = cart_session(request)
+                cs['widget_data'] = widget_data
+        else:
+            cs = cart_session(request)
+            widget_data = cs.get('widget_data', {})
+
         items = self._items_from_post_data()
         if items:
-            return self.do(self.request.event.id, items, get_or_create_cart_id(self.request), translation.get_language(),
-                           self.invoice_address.pk)
+            return self.do(self.request.event.id, items, cart_id, translation.get_language(),
+                           self.invoice_address.pk, widget_data)
         else:
             if 'ajax' in self.request.GET or 'ajax' in self.request.POST:
                 return JsonResponse({
@@ -449,6 +479,10 @@ class RedeemView(NoSearchIndexViewMixin, EventViewMixin, TemplateView):
     def get(self, request, *args, **kwargs):
         if 'iframe' in request.GET and 'require_cookie' not in request.GET:
             return redirect(request.get_full_path() + '&require_cookie=1')
+
+        if 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)
         return super().get(request, *args, **kwargs)
 
 

src/pretix/presale/views/event.py

@@ -189,6 +189,9 @@ class EventIndex(EventViewMixin, CartMixin, TemplateView):
             return redirect(eventreverse(request.event, 'presale:event.index', kwargs=kwargs) + '?require_cookie=true&cart_id={}'.format(
                 request.GET.get('take_cart_id')
             ))
+        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)
         elif 'require_cookie' in request.GET and settings.SESSION_COOKIE_NAME not in request.COOKIES:
             # Cookies are in fact not supported
             r = render(request, 'pretixpresale/event/cookies.html', {