Horizon UI message when browser cookies disabled

Used dijango's CSRF_FAILURE_VIEW setting to create
a view indicating the reason the request was rejected.
This information is passed on to the login page so it
can render the error.

Change-Id: I61c7195c9bafb269816fde12b058e19ebc69953c
Closes-Bug: #1412483

horizon/templates/auth/_login_form.html

@@ -59,6 +59,11 @@
               <p>{{ request.COOKIES.logout_reason }}</p>
             </div>
         {% endif %}
+        {% if csrf_failure %}
+            <div class="form-group clearfix error help-block alert alert-danger" id="logout_reason">
+              <p>{{ csrf_failure }}</p>
+            </div>
+        {% endif %}
         {% if next %}
           <input type="hidden" name="{{ redirect_field_name }}" value="{{ next }}" />
         {% endif %}

openstack_auth/views.py

@@ -90,6 +90,8 @@ def login(request, template_name=None, extra_context=None, **kwargs):
     if extra_context is None:
         extra_context = {'redirect_field_name': auth.REDIRECT_FIELD_NAME}
 
+    extra_context['csrf_failure'] = request.GET.get('csrf_failure')
+
     if not template_name:
         if request.is_ajax():
             template_name = 'auth/_login.html'

openstack_dashboard/settings.py

@@ -214,6 +214,8 @@ SESSION_COOKIE_MAX_SIZE = 4093
 #                https://bugs.launchpad.net/horizon/+bug/1349463
 SESSION_SERIALIZER = 'django.contrib.sessions.serializers.PickleSerializer'
 
+CSRF_FAILURE_VIEW = 'openstack_dashboard.views.csrf_failure'
+
 LANGUAGES = (
     ('cs', 'Czech'),
     ('de', 'German'),

openstack_dashboard/views.py

@@ -17,7 +17,9 @@ import logging
 
 from django.conf import settings
 from django.core import urlresolvers
+from django import http
 from django import shortcuts
+from django.utils.translation import ugettext as _
 import django.views.decorators.vary
 from django.views.generic import TemplateView
 from six.moves import urllib
@@ -118,3 +120,14 @@ class ExtensibleHeaderView(TemplateView):
 
         context['header_sections'] = header_sections
         return context
+
+
+def csrf_failure(request, reason=""):
+    if reason:
+        reason += " "
+    reason += _("Cookies may be turned off. "
+                "Make sure cookies are enabled and try again.")
+
+    url = settings.LOGIN_URL + "?csrf_failure=%s" % urllib.parse.quote(reason)
+    response = http.HttpResponseRedirect(url)
+    return response