Allow to access not-yet-live shop on different domain

src/pretix/control/templates/pretixcontrol/event/index.html

@@ -3,12 +3,21 @@
 {% load eventurl %}
 {% block title %}{{ request.event.name }}{% endblock %}
 {% block content %}
-    <h1>
-        {{ request.event.name }}
-        <a href="{% eventurl request.event "presale:event.index" %}" class="btn btn-default btn-sm" target="_blank">
-            {% trans "Go to shop" %}
-        </a>
-    </h1>
+    <form action="{% eventurl request.event "presale:event.auth" %}" method="post" target="_blank">
+        <h1>
+            {{ request.event.name }}
+            {% if has_domain and not request.event.live %}
+                <input type="hidden" value="{{ new_session }}" name="session">
+                <button type="submit" class="btn btn-default btn-sm">
+                    {% trans "Go to shop" %}
+                </button>
+            {% else %}
+                <a href="{% eventurl request.event "presale:event.index" %}" class="btn btn-default btn-sm" target="_blank">
+                    {% trans "Go to shop" %}
+                </a>
+            {% endif %}
+        </h1>
+    </form>
 
     {% if actions|length > 0 %}
         <div class="panel panel-danger">

src/pretix/control/views/dashboards.py

@@ -1,5 +1,7 @@
 from decimal import Decimal
+from importlib import import_module
 
+from django.conf import settings
 from django.contrib.contenttypes.models import ContentType
 from django.core.urlresolvers import reverse
 from django.db.models import Sum
@@ -17,6 +19,7 @@ from pretix.control.signals import (
 
 from ..logdisplay import OVERVIEW_BLACKLIST
 
+SessionStore = import_module(settings.SESSION_ENGINE).SessionStore
 NUM_WIDGET = '<div class="numwidget"><span class="num">{num}</span><span class="text">{text}</span></div>'
 
 
@@ -167,11 +170,21 @@ def event_index(request, organizer, event):
 
     a_qs = request.event.requiredaction_set.filter(done=False)
 
+    has_domain = request.event.organizer.domains.exists()
+
     ctx = {
         'widgets': rearrange(widgets),
         'logs': qs[:5],
-        'actions': a_qs[:5] if request.eventperm.can_change_orders else []
+        'actions': a_qs[:5] if request.eventperm.can_change_orders else [],
+        'has_domain': has_domain
     }
+
+    if not request.event.live and has_domain:
+        s = SessionStore()
+        s['pretix_event_access_{}'.format(request.event.pk)] = request.session.session_key
+        s.create()
+        ctx['new_session'] = s.session_key
+
     for a in ctx['actions']:
         a.display = a.display(request)