From f6b1a845455e3e739100e0fbcf1cd7b094bc9179 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Norman=20J=C3=A4ckel?= <openslides@normanjaeckel.de>
Date: Mon, 22 Dec 2014 18:09:05 +0100
Subject: [PATCH] Cleaned up utils.views to increase performance when fetching
 single objects from the database for a view. Fixed #1378.

---
 CHANGELOG                                     |   4 +
 openslides/agenda/views.py                    |  98 ++++++------
 openslides/assignment/views.py                |  52 +++---
 openslides/mediafile/views.py                 |   4 +-
 openslides/motion/views.py                    | 150 ++++++++----------
 openslides/participant/views.py               |  33 ++--
 openslides/poll/views.py                      |  13 +-
 openslides/utils/views.py                     |  47 ++++--
 tests/mediafile/tests.py                      |   4 +-
 tests/settings.py                             |   1 +
 tests/utils/models.py                         |   8 +
 .../templates/utils/dummymodel_detail.html    |   5 +
 tests/utils/test_views.py                     |  13 ++
 tests/utils/urls.py                           |   3 +
 tests/utils/views.py                          |  14 ++
 15 files changed, 249 insertions(+), 200 deletions(-)
 create mode 100644 tests/utils/models.py
 create mode 100644 tests/utils/templates/utils/dummymodel_detail.html

diff --git a/CHANGELOG b/CHANGELOG
index e09e3d91a..001b7d0db 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -8,6 +8,10 @@ Version 1.6.2 (unreleased)
 ==========================
 [https://github.com/OpenSlides/OpenSlides/milestones/1.6.2]
 
+Other:
+- Cleaned up utils.views to increase performance when fetching single objects
+  from the database for a view (#1378).
+
 
 Version 1.6.1 (2014-12-08)
 ==========================
diff --git a/openslides/agenda/views.py b/openslides/agenda/views.py
index 5133755d0..bba1582fc 100644
--- a/openslides/agenda/views.py
+++ b/openslides/agenda/views.py
@@ -183,15 +183,14 @@ class AgendaItemView(SingleObjectMixin, FormView):
         return check_permission
 
     def get_context_data(self, **kwargs):
-        self.object = self.get_object()
-        list_of_speakers = self.object.get_list_of_speakers()
+        list_of_speakers = self.get_object().get_list_of_speakers()
         active_slide = get_active_slide()
         active_type = active_slide.get('type', None)
         kwargs.update({
-            'object': self.object,
+            'object': self.get_object(),
             'list_of_speakers': list_of_speakers,
             'is_on_the_list_of_speakers': Speaker.objects.filter(
-                item=self.object, begin_time=None, person=self.request.user).exists(),
+                item=self.get_object(), begin_time=None, person=self.request.user).exists(),
             'active_type': active_type,
         })
         return super(AgendaItemView, self).get_context_data(**kwargs)
@@ -206,7 +205,7 @@ class AgendaItemView(SingleObjectMixin, FormView):
         return kwargs
 
 
-class SetClosed(RedirectView, SingleObjectMixin):
+class SetClosed(SingleObjectMixin, RedirectView):
     """
     Close or open an item.
     """
@@ -218,15 +217,14 @@ class SetClosed(RedirectView, SingleObjectMixin):
     def get_ajax_context(self, **kwargs):
         closed = self.kwargs['closed']
         if closed:
-            link = reverse('item_open', args=[self.object.pk])
+            link = reverse('item_open', args=[self.get_object().pk])
         else:
-            link = reverse('item_close', args=[self.object.pk])
+            link = reverse('item_close', args=[self.get_object().pk])
         return super(SetClosed, self).get_ajax_context(closed=closed, link=link)
 
     def pre_redirect(self, request, *args, **kwargs):
-        self.object = self.get_object()
         closed = kwargs['closed']
-        self.object.set_closed(closed)
+        self.get_object().set_closed(closed)
         return super(SetClosed, self).pre_redirect(request, *args, **kwargs)
 
     def get_url_name_args(self):
@@ -245,7 +243,7 @@ class ItemUpdate(UpdateView):
     url_name_args = []
 
     def get_form_class(self):
-        if self.object.content_object:
+        if self.get_object().content_object:
             form = RelatedItemForm
         else:
             form = ItemForm
@@ -286,7 +284,7 @@ class ItemDelete(DeleteView):
         try:
             options = self.item_delete_answer_options
         except AttributeError:
-            if self.object.children.exists():
+            if self.get_object().children.exists():
                 options = [('all', _("Yes, with all child items."))] + self.answer_options
             else:
                 options = self.answer_options
@@ -297,13 +295,13 @@ class ItemDelete(DeleteView):
         """
         Deletes the item but not its children.
         """
-        self.object.delete(with_children=False)
+        self.get_object().delete(with_children=False)
 
     def on_clicked_all(self):
         """
         Deletes the item and its children.
         """
-        self.object.delete(with_children=True)
+        self.get_object().delete(with_children=True)
 
     def get_final_message(self):
         """
@@ -312,9 +310,9 @@ class ItemDelete(DeleteView):
         # OpenSlidesError (invalid answer) should never be raised here because
         # this method should only be called if the answer is 'yes' or 'all'.
         if self.get_answer() == 'yes':
-            message = _('Item %s was successfully deleted.') % html_strong(self.object)
+            message = _('Item %s was successfully deleted.') % html_strong(self.get_object())
         else:
-            message = _('Item %s and its children were successfully deleted.') % html_strong(self.object)
+            message = _('Item %s and its children were successfully deleted.') % html_strong(self.get_object())
         return message
 
 
@@ -329,18 +327,11 @@ class CreateRelatedAgendaItemView(SingleObjectMixin, RedirectView):
     url_name = 'item_overview'
     url_name_args = []
 
-    def get(self, request, *args, **kwargs):
-        """
-        Set self.object to the relevant object.
-        """
-        self.object = self.get_object()
-        return super(CreateRelatedAgendaItemView, self).get(request, *args, **kwargs)
-
     def pre_redirect(self, request, *args, **kwargs):
         """
         Create the agenda item.
         """
-        self.item = Item.objects.create(content_object=self.object)
+        self.item = Item.objects.create(content_object=self.get_object())
 
 
 class AgendaNumberingView(QuestionView):
@@ -388,12 +379,11 @@ class SpeakerAppendView(SingleObjectMixin, RedirectView):
     model = Item
 
     def pre_redirect(self, request, *args, **kwargs):
-        self.object = self.get_object()
-        if self.object.speaker_list_closed:
+        if self.get_object().speaker_list_closed:
             messages.error(request, _('The list of speakers is closed.'))
         else:
             try:
-                Speaker.objects.add(item=self.object, person=request.user)
+                Speaker.objects.add(item=self.get_object(), person=request.user)
             except OpenSlidesError, e:
                 messages.error(request, e)
             else:
@@ -418,11 +408,10 @@ class SpeakerDeleteView(DeleteView):
             return True
 
     def get(self, *args, **kwargs):
-        try:
-            return super(SpeakerDeleteView, self).get(*args, **kwargs)
-        except Speaker.DoesNotExist:
-            messages.error(self.request, _('You are not on the list of speakers.'))
+        if self.get_object() is None:
             return super(RedirectView, self).get(*args, **kwargs)
+        else:
+            return super(SpeakerDeleteView, self).get(*args, **kwargs)
 
     def get_object(self):
         """
@@ -432,10 +421,22 @@ class SpeakerDeleteView(DeleteView):
         object with the request.user as speaker.
         """
         try:
-            return Speaker.objects.get(pk=self.kwargs['speaker'])
-        except KeyError:
-            return Speaker.objects.filter(
-                item=self.kwargs['pk'], person=self.request.user).exclude(weight=None).get()
+            speaker = self._object
+        except AttributeError:
+            speaker_pk = self.kwargs.get('speaker')
+            if speaker_pk is not None:
+                queryset = Speaker.objects.filter(pk=speaker_pk)
+            else:
+                queryset = Speaker.objects.filter(
+                    item=self.kwargs['pk'], person=self.request.user).exclude(weight=None)
+            try:
+                speaker = queryset.get()
+            except Speaker.DoesNotExist:
+                speaker = None
+                if speaker_pk is not None:
+                    messages.error(self.request, _('You are not on the list of speakers.'))
+            self._object = speaker
+        return speaker
 
     def get_url_name_args(self):
         return [self.kwargs['pk']]
@@ -456,22 +457,21 @@ class SpeakerSpeakView(SingleObjectMixin, RedirectView):
     model = Item
 
     def pre_redirect(self, *args, **kwargs):
-        self.object = self.get_object()
         try:
             speaker = Speaker.objects.filter(
                 person=kwargs['person_id'],
-                item=self.object,
+                item=self.get_object(),
                 begin_time=None).get()
         except Speaker.DoesNotExist:  # TODO: Check the MultipleObjectsReturned error here?
             messages.error(
                 self.request,
                 _('%(person)s is not on the list of %(item)s.')
-                % {'person': kwargs['person_id'], 'item': self.object})
+                % {'person': kwargs['person_id'], 'item': self.get_object()})
         else:
             speaker.begin_speach()
 
     def get_url_name_args(self):
-        return [self.object.pk]
+        return [self.get_object().pk]
 
 
 class SpeakerEndSpeachView(SingleObjectMixin, RedirectView):
@@ -483,21 +483,20 @@ class SpeakerEndSpeachView(SingleObjectMixin, RedirectView):
     model = Item
 
     def pre_redirect(self, *args, **kwargs):
-        self.object = self.get_object()
         try:
             speaker = Speaker.objects.filter(
-                item=self.object,
+                item=self.get_object(),
                 end_time=None).exclude(begin_time=None).get()
         except Speaker.DoesNotExist:
             messages.error(
                 self.request,
                 _('There is no one speaking at the moment according to %(item)s.')
-                % {'item': self.object})
+                % {'item': self.get_object()})
         else:
             speaker.end_speach()
 
     def get_url_name_args(self):
-        return [self.object.pk]
+        return [self.get_object().pk]
 
 
 class SpeakerListCloseView(SingleObjectMixin, RedirectView):
@@ -510,12 +509,11 @@ class SpeakerListCloseView(SingleObjectMixin, RedirectView):
     url_name = 'item_view'
 
     def pre_redirect(self, *args, **kwargs):
-        self.object = self.get_object()
-        self.object.speaker_list_closed = not self.reopen
-        self.object.save()
+        self.get_object().speaker_list_closed = not self.reopen
+        self.get_object().save()
 
     def get_url_name_args(self):
-        return [self.object.pk]
+        return [self.get_object().pk]
 
 
 class SpeakerChangeOrderView(SingleObjectMixin, RedirectView):
@@ -528,9 +526,6 @@ class SpeakerChangeOrderView(SingleObjectMixin, RedirectView):
     model = Item
     url_name = 'item_view'
 
-    def pre_redirect(self, args, **kwargs):
-        self.object = self.get_object()
-
     @transaction.commit_manually
     def pre_post_redirect(self, request, *args, **kwargs):
         """
@@ -538,7 +533,6 @@ class SpeakerChangeOrderView(SingleObjectMixin, RedirectView):
 
         Take the string 'sort_order' from the post-data, and use this order.
         """
-        self.object = self.get_object()
         transaction.commit()
         for (counter, speaker) in enumerate(self.request.POST['sort_order'].split(',')):
             try:
@@ -547,7 +541,7 @@ class SpeakerChangeOrderView(SingleObjectMixin, RedirectView):
                 transaction.rollback()
                 break
             try:
-                speaker = Speaker.objects.filter(item=self.object).get(pk=speaker_pk)
+                speaker = Speaker.objects.filter(item=self.get_object()).get(pk=speaker_pk)
             except:
                 transaction.rollback()
                 break
@@ -559,7 +553,7 @@ class SpeakerChangeOrderView(SingleObjectMixin, RedirectView):
         messages.error(request, _('Could not change order. Invalid data.'))
 
     def get_url_name_args(self):
-        return [self.object.pk]
+        return [self.get_object().pk]
 
 
 class CurrentListOfSpeakersView(RedirectView):
diff --git a/openslides/assignment/views.py b/openslides/assignment/views.py
index e2b0b1319..4f0391f56 100644
--- a/openslides/assignment/views.py
+++ b/openslides/assignment/views.py
@@ -43,31 +43,30 @@ class AssignmentDetail(DetailView):
             context['form'] = self.form_class(self.request.POST)
         else:
             context['form'] = self.form_class()
-        polls = self.object.poll_set.all()
+        polls = self.get_object().poll_set.all()
         if not self.request.user.has_perm('assignment.can_manage_assignment'):
-            polls = self.object.poll_set.filter(published=True)
-            vote_results = self.object.vote_results(only_published=True)
+            polls = self.get_object().poll_set.filter(published=True)
+            vote_results = self.get_object().vote_results(only_published=True)
         else:
-            polls = self.object.poll_set.all()
-            vote_results = self.object.vote_results(only_published=False)
+            polls = self.get_object().poll_set.all()
+            vote_results = self.get_object().vote_results(only_published=False)
 
         blocked_candidates = [
             candidate.person for candidate in
-            self.object.assignment_candidates.filter(blocked=True)]
+            self.get_object().assignment_candidates.filter(blocked=True)]
         context['polls'] = polls
         context['vote_results'] = vote_results
         context['blocked_candidates'] = blocked_candidates
-        context['user_is_candidate'] = self.object.is_candidate(self.request.user)
+        context['user_is_candidate'] = self.get_object().is_candidate(self.request.user)
         return context
 
     def post(self, *args, **kwargs):
-        self.object = self.get_object()
         if self.request.user.has_perm('assignment.can_nominate_other'):
             form = self.form_class(self.request.POST)
             if form.is_valid():
                 user = form.cleaned_data['candidate']
                 try:
-                    self.object.run(user, self.request.user)
+                    self.get_object().run(user, self.request.user)
                 except NameError, e:
                     messages.error(self.request, e)
                 else:
@@ -101,18 +100,17 @@ class AssignmentSetStatusView(SingleObjectMixin, RedirectView):
     url_name = 'assignment_detail'
 
     def pre_redirect(self, *args, **kwargs):
-        self.object = self.get_object()
         status = kwargs.get('status')
         if status is not None:
             try:
-                self.object.set_status(status)
+                self.get_object().set_status(status)
             except ValueError, e:
                 messages.error(self.request, e)
             else:
                 messages.success(
                     self.request,
                     _('Election status was set to: %s.') %
-                    html_strong(self.object.get_status_display())
+                    html_strong(self.get_object().get_status_display())
                 )
 
 
@@ -137,11 +135,10 @@ class AssignmentRunDeleteView(SingleObjectMixin, RedirectView):
     url_name = 'assignment_detail'
 
     def pre_redirect(self, *args, **kwargs):
-        self.object = self.get_object()
-        if self.object.status == 'sea' or self.request.user.has_perm(
+        if self.get_object().status == 'sea' or self.request.user.has_perm(
                 "assignment.can_manage_assignment"):
             try:
-                self.object.delrun(self.request.user, blocked=True)
+                self.get_object().delrun(self.request.user, blocked=True)
             except Exception, e:
                 messages.error(self.request, e)
             else:
@@ -167,7 +164,7 @@ class AssignmentRunOtherDeleteView(SingleObjectMixin, QuestionView):
     def on_clicked_yes(self):
         self._get_person_information()
         try:
-            self.object.delrun(self.person, blocked=False)
+            self.get_object().delrun(self.person, blocked=False)
         except Exception, e:
             self.error = e
         else:
@@ -186,9 +183,8 @@ class AssignmentRunOtherDeleteView(SingleObjectMixin, QuestionView):
         return message
 
     def _get_person_information(self):
-        self.object = self.get_object()
         self.person = get_person(self.kwargs.get('user_id'))
-        self.is_blocked = self.object.is_blocked(self.person)
+        self.is_blocked = self.get_object().is_blocked(self.person)
 
 
 class PollCreateView(SingleObjectMixin, RedirectView):
@@ -197,8 +193,7 @@ class PollCreateView(SingleObjectMixin, RedirectView):
     url_name = 'assignment_detail'
 
     def pre_redirect(self, *args, **kwargs):
-        self.object = self.get_object()
-        self.object.gen_poll()
+        self.get_object().gen_poll()
         messages.success(self.request, _("New ballot was successfully created."))
 
 
@@ -233,15 +228,15 @@ class SetPublishStatusView(SingleObjectMixin, RedirectView):
 
     def pre_redirect(self, *args, **kwargs):
         try:
-            self.object = self.get_object()
+            poll = self.get_object()
         except self.model.DoesNotExist:
             messages.error(self.request, _('Ballot ID %d does not exist.') %
                            int(kwargs['poll_id']))
         else:
-            if self.object.published:
-                self.object.set_published(False)
+            if poll.published:
+                poll.set_published(False)
             else:
-                self.object.set_published(True)
+                poll.set_published(True)
 
 
 class SetElectedView(SingleObjectMixin, RedirectView):
@@ -251,19 +246,18 @@ class SetElectedView(SingleObjectMixin, RedirectView):
     allow_ajax = True
 
     def pre_redirect(self, *args, **kwargs):
-        self.object = self.get_object()
         self.person = get_person(kwargs['user_id'])
         self.elected = kwargs['elected']
-        self.object.set_elected(self.person, self.elected)
+        self.get_object().set_elected(self.person, self.elected)
 
     def get_ajax_context(self, **kwargs):
         if self.elected:
             link = reverse('assignment_user_not_elected',
-                           args=[self.object.id, self.person.person_id])
+                           args=[self.get_object().id, self.person.person_id])
             text = _('not elected')
         else:
             link = reverse('assignment_user_elected',
-                           args=[self.object.id, self.person.person_id])
+                           args=[self.get_object().id, self.person.person_id])
             text = _('elected')
         return {'elected': self.elected, 'link': link, 'text': text}
 
@@ -284,7 +278,7 @@ class AssignmentPollDeleteView(DeleteView):
         super(AssignmentPollDeleteView, self).pre_post_redirect(request, *args, **kwargs)
 
     def set_assignment(self):
-        self.assignment = self.object.assignment
+        self.assignment = self.get_object().assignment
 
     def get_redirect_url(self, **kwargs):
         return reverse('assignment_detail', args=[self.assignment.id])
diff --git a/openslides/mediafile/views.py b/openslides/mediafile/views.py
index cfe27bd24..7ee4ce09c 100644
--- a/openslides/mediafile/views.py
+++ b/openslides/mediafile/views.py
@@ -86,7 +86,7 @@ class MediafileUpdateView(MediafileViewMixin, UpdateView):
 
     def get_form_kwargs(self, *args, **kwargs):
         form_kwargs = super(MediafileUpdateView, self).get_form_kwargs(*args, **kwargs)
-        form_kwargs['initial'].update({'uploader': self.object.uploader.person_id})
+        form_kwargs['initial'].update({'uploader': self.get_object().uploader.person_id})
         return form_kwargs
 
 
@@ -103,7 +103,7 @@ class MediafileDeleteView(DeleteView):
 
     def on_clicked_yes(self, *args, **kwargs):
         """Deletes the file in the filesystem, if user clicks "Yes"."""
-        self.object.mediafile.delete()
+        self.get_object().mediafile.delete()
         return super(MediafileDeleteView, self).on_clicked_yes(*args, **kwargs)
 
 
diff --git a/openslides/motion/views.py b/openslides/motion/views.py
index 97da9976d..9a5a382bc 100644
--- a/openslides/motion/views.py
+++ b/openslides/motion/views.py
@@ -55,14 +55,14 @@ class MotionDetailView(DetailView):
         version_number = self.kwargs.get('version_number', None)
         if version_number is not None:
             try:
-                version = self.object.versions.get(version_number=int(version_number))
+                version = self.get_object().versions.get(version_number=int(version_number))
             except MotionVersion.DoesNotExist:
                 raise Http404('Version %s not found' % version_number)
         else:
-            version = self.object.get_active_version()
+            version = self.get_object().get_active_version()
 
         kwargs.update({
-            'allowed_actions': self.object.get_allowed_actions(self.request.user),
+            'allowed_actions': self.get_object().get_allowed_actions(self.request.user),
             'version': version,
             'title': version.title,
             'text': version.text,
@@ -302,21 +302,25 @@ class VersionDeleteView(DeleteView):
 
     def get_object(self):
         try:
-            motion = Motion.objects.get(pk=int(self.kwargs.get('pk')))
-        except Motion.DoesNotExist:
-            raise Http404('Motion %s not found.' % self.kwargs.get('pk'))
-        try:
-            version = MotionVersion.objects.get(
-                motion=motion,
-                version_number=int(self.kwargs.get('version_number')))
-        except MotionVersion.DoesNotExist:
-            raise Http404('Version %s not found.' % self.kwargs.get('version_number'))
-        if version == motion.active_version:
-            raise Http404('You can not delete the active version of a motion.')
+            version = self._object
+        except AttributeError:
+            try:
+                motion = Motion.objects.get(pk=int(self.kwargs.get('pk')))
+            except Motion.DoesNotExist:
+                raise Http404('Motion %s not found.' % self.kwargs.get('pk'))
+            try:
+                version = MotionVersion.objects.get(
+                    motion=motion,
+                    version_number=int(self.kwargs.get('version_number')))
+            except MotionVersion.DoesNotExist:
+                raise Http404('Version %s not found.' % self.kwargs.get('version_number'))
+            if version == motion.active_version:
+                raise Http404('You can not delete the active version of a motion.')
+            self._object = version
         return version
 
     def get_url_name_args(self):
-        return (self.object.motion_id, )
+        return (self.get_object().motion_id, )
 
 version_delete = VersionDeleteView.as_view()
 
@@ -332,12 +336,11 @@ class VersionPermitView(SingleObjectMixin, QuestionView):
 
     def get(self, *args, **kwargs):
         """
-        Set self.object to a motion.
+        Sets self.version to a motion version.
         """
-        self.object = self.get_object()
         version_number = self.kwargs.get('version_number', None)
         try:
-            self.version = self.object.versions.get(version_number=int(version_number))
+            self.version = self.get_object().versions.get(version_number=int(version_number))
         except MotionVersion.DoesNotExist:
             raise Http404('Version %s not found.' % version_number)
         return super(VersionPermitView, self).get(*args, **kwargs)
@@ -346,7 +349,7 @@ class VersionPermitView(SingleObjectMixin, QuestionView):
         """
         Returns a list with arguments to create the success- and question_url.
         """
-        return [self.object.pk, self.version.version_number]
+        return [self.get_object().pk, self.version.version_number]
 
     def get_question_message(self):
         """
@@ -358,9 +361,9 @@ class VersionPermitView(SingleObjectMixin, QuestionView):
         """
         Activate the version, if the user chooses 'yes'.
         """
-        self.object.active_version = self.version
-        self.object.save(update_fields=['active_version'])
-        self.object.write_log(
+        self.get_object().active_version = self.version
+        self.get_object().save(update_fields=['active_version'])
+        self.get_object().write_log(
             message_list=[ugettext_noop('Version'),
                           ' %d ' % self.version.version_number,
                           ugettext_noop('permitted')],
@@ -384,8 +387,8 @@ class VersionDiffView(DetailView):
         try:
             rev1 = int(self.request.GET['rev1'])
             rev2 = int(self.request.GET['rev2'])
-            version_rev1 = self.object.versions.get(version_number=rev1)
-            version_rev2 = self.object.versions.get(version_number=rev2)
+            version_rev1 = self.get_object().versions.get(version_number=rev1)
+            version_rev2 = self.get_object().versions.get(version_number=rev2)
             diff_text = htmldiff(version_rev1.text, version_rev2.text)
             diff_reason = htmldiff(version_rev1.reason, version_rev2.reason)
         except (KeyError, ValueError, MotionVersion.DoesNotExist):
@@ -419,18 +422,11 @@ class SupportView(SingleObjectMixin, QuestionView):
     model = Motion
     support = True
 
-    def get(self, request, *args, **kwargs):
-        """
-        Set self.object to a motion.
-        """
-        self.object = self.get_object()
-        return super(SupportView, self).get(request, *args, **kwargs)
-
     def check_permission(self, request):
         """
         Return True if the user can support or unsupport the motion. Else: False.
         """
-        allowed_actions = self.object.get_allowed_actions(request.user)
+        allowed_actions = self.get_object().get_allowed_actions(request.user)
         if self.support and not allowed_actions['support']:
             messages.error(request, _('You can not support this motion.'))
             return False
@@ -459,11 +455,11 @@ class SupportView(SingleObjectMixin, QuestionView):
         if self.check_permission(self.request):
             user = self.request.user
             if self.support:
-                self.object.support(person=user)
-                self.object.write_log([ugettext_noop('Motion supported')], user)
+                self.get_object().support(person=user)
+                self.get_object().write_log([ugettext_noop('Motion supported')], user)
             else:
-                self.object.unsupport(person=user)
-                self.object.write_log([ugettext_noop('Motion unsupported')], user)
+                self.get_object().unsupport(person=user)
+                self.get_object().write_log([ugettext_noop('Motion unsupported')], user)
 
     def get_final_message(self):
         """
@@ -486,26 +482,19 @@ class PollCreateView(SingleObjectMixin, RedirectView):
     model = Motion
     url_name = 'motionpoll_detail'
 
-    def get(self, request, *args, **kwargs):
-        """
-        Set self.object to a motion.
-        """
-        self.object = self.get_object()
-        return super(PollCreateView, self).get(request, *args, **kwargs)
-
     def pre_redirect(self, request, *args, **kwargs):
         """
         Create the poll for the motion.
         """
-        self.poll = self.object.create_poll()
-        self.object.write_log([ugettext_noop("Poll created")], request.user)
+        self.poll = self.get_object().create_poll()
+        self.get_object().write_log([ugettext_noop("Poll created")], request.user)
         messages.success(request, _("New vote was successfully created."))
 
     def get_redirect_url(self, **kwargs):
         """
         Return the URL to the UpdateView of the poll.
         """
-        return reverse('motionpoll_update', args=[self.object.pk, self.poll.poll_number])
+        return reverse('motionpoll_update', args=[self.get_object().pk, self.poll.poll_number])
 
 poll_create = PollCreateView.as_view()
 
@@ -525,16 +514,21 @@ class PollMixin(object):
         Use the motion id and the poll_number from the url kwargs to get the
         object.
         """
-        queryset = MotionPoll.objects.filter(
-            motion=self.kwargs['pk'],
-            poll_number=self.kwargs['poll_number'])
-        return get_object_or_404(queryset)
+        try:
+            obj = self._object
+        except AttributeError:
+            queryset = MotionPoll.objects.filter(
+                motion=self.kwargs['pk'],
+                poll_number=self.kwargs['poll_number'])
+            obj = get_object_or_404(queryset)
+            self._object = obj
+        return obj
 
     def get_url_name_args(self):
         """
         Return the arguments to create the url to the success_url.
         """
-        return [self.object.motion.pk]
+        return [self.get_object().motion.pk]
 
 
 class PollUpdateView(PollMixin, PollFormView):
@@ -566,7 +560,7 @@ class PollUpdateView(PollMixin, PollFormView):
         Write a log message, if the form is valid.
         """
         value = super(PollUpdateView, self).form_valid(form)
-        self.object.write_log([ugettext_noop('Poll updated')], self.request.user)
+        self.get_object().write_log([ugettext_noop('Poll updated')], self.request.user)
         return value
 
 poll_update = PollUpdateView.as_view()
@@ -584,13 +578,13 @@ class PollDeleteView(PollMixin, DeleteView):
         Write a log message, if the form is valid.
         """
         super(PollDeleteView, self).on_clicked_yes()
-        self.object.motion.write_log([ugettext_noop('Poll deleted')], self.request.user)
+        self.get_object().motion.write_log([ugettext_noop('Poll deleted')], self.request.user)
 
     def get_redirect_url(self, **kwargs):
         """
         Return the URL to the DetailView of the motion.
         """
-        return reverse('motion_detail', args=[self.object.motion.pk])
+        return reverse('motion_detail', args=[self.get_object().motion.pk])
 
 poll_delete = PollDeleteView.as_view()
 
@@ -603,15 +597,11 @@ class PollPDFView(PollMixin, PDFView):
     required_permission = 'motion.can_manage_motion'
     top_space = 0
 
-    def get(self, *args, **kwargs):
-        self.object = self.get_object()
-        return super(PollPDFView, self).get(*args, **kwargs)
-
     def get_filename(self):
         """
         Return the filename for the PDF.
         """
-        return u'%s%s_%s' % (_("Motion"), str(self.object.poll_number), _("Poll"))
+        return u'%s%s_%s' % (_("Motion"), str(self.get_object().poll_number), _("Poll"))
 
     def get_template(self, buffer):
         return SimpleDocTemplate(
@@ -625,7 +615,7 @@ class PollPDFView(PollMixin, PDFView):
         """
         Append PDF objects.
         """
-        motion_poll_to_pdf(pdf, self.object)
+        motion_poll_to_pdf(pdf, self.get_object())
 
 poll_pdf = PollPDFView.as_view()
 
@@ -646,26 +636,25 @@ class MotionSetStateView(SingleObjectMixin, RedirectView):
         """
         Save the new state and write a log message.
         """
-        self.object = self.get_object()
         success = False
         if self.reset:
-            self.object.reset_state()
+            self.get_object().reset_state()
             success = True
-        elif self.object.state.id == int(kwargs['state']):
+        elif self.get_object().state.id == int(kwargs['state']):
             messages.error(request, _('You can not set the state of the motion. It is already done.'))
-        elif int(kwargs['state']) not in [state.id for state in self.object.state.next_states.all()]:
+        elif int(kwargs['state']) not in [state.id for state in self.get_object().state.next_states.all()]:
             messages.error(request, _('You can not set the state of the motion to %s.') % _(State.objects.get(pk=int(kwargs['state'])).name))
         else:
-            self.object.set_state(int(kwargs['state']))
+            self.get_object().set_state(int(kwargs['state']))
             success = True
         if success:
-            self.object.save(update_fields=['state', 'identifier'])
-            self.object.write_log(
-                message_list=[ugettext_noop('State changed to'), ' ', self.object.state.name],  # TODO: Change string to 'State set to ...'
+            self.get_object().save(update_fields=['state', 'identifier'])
+            self.get_object().write_log(
+                message_list=[ugettext_noop('State changed to'), ' ', self.get_object().state.name],  # TODO: Change string to 'State set to ...'
                 person=self.request.user)
             messages.success(request,
                              _('The state of the motion was set to %s.')
-                             % html_strong(_(self.object.state.name)))
+                             % html_strong(_(self.get_object().state.name)))
 
 set_state = MotionSetStateView.as_view()
 reset_state = MotionSetStateView.as_view(reset=True)
@@ -682,7 +671,7 @@ class CreateRelatedAgendaItemView(_CreateRelatedAgendaItemView):
         Create the agenda item.
         """
         super(CreateRelatedAgendaItemView, self).pre_redirect(request, *args, **kwargs)
-        self.object.write_log([ugettext_noop('Agenda item created')], self.request.user)
+        self.get_object().write_log([ugettext_noop('Agenda item created')], self.request.user)
 
 create_agenda_item = CreateRelatedAgendaItemView.as_view()
 
@@ -701,13 +690,12 @@ class MotionPDFView(SingleObjectMixin, PDFView):
     top_space = 0
     print_all_motions = False
 
-    def get(self, request, *args, **kwargs):
-        """
-        Set self.object to a motion.
-        """
-        if not self.print_all_motions:
-            self.object = self.get_object()
-        return super(MotionPDFView, self).get(request, *args, **kwargs)
+    def get_object(self, *args, **kwargs):
+        if self.print_all_motions:
+            obj = None
+        else:
+            obj = super(MotionPDFView, self).get_object(*args, **kwargs)
+        return obj
 
     def get_filename(self):
         """
@@ -716,10 +704,10 @@ class MotionPDFView(SingleObjectMixin, PDFView):
         if self.print_all_motions:
             return _("Motions")
         else:
-            if self.object.identifier:
-                suffix = self.object.identifier.replace(' ', '')
+            if self.get_object().identifier:
+                suffix = self.get_object().identifier.replace(' ', '')
             else:
-                suffix = self.object.title.replace(' ', '_')
+                suffix = self.get_object().title.replace(' ', '_')
                 suffix = slugify(suffix)
             return '%s-%s' % (_("Motion"), suffix)
 
@@ -730,7 +718,7 @@ class MotionPDFView(SingleObjectMixin, PDFView):
         if self.print_all_motions:
             motions_to_pdf(pdf)
         else:
-            motion_to_pdf(pdf, self.object)
+            motion_to_pdf(pdf, self.get_object())
 
 motion_list_pdf = MotionPDFView.as_view(print_all_motions=True)
 motion_detail_pdf = MotionPDFView.as_view(print_all_motions=False)
diff --git a/openslides/participant/views.py b/openslides/participant/views.py
index aa02bbfad..1c7055f0f 100644
--- a/openslides/participant/views.py
+++ b/openslides/participant/views.py
@@ -162,13 +162,13 @@ class UserDeleteView(DeleteView):
     url_name_args = []
 
     def pre_redirect(self, request, *args, **kwargs):
-        if self.object == self.request.user:
+        if self.get_object() == self.request.user:
             messages.error(request, _("You can not delete yourself."))
         else:
             super(UserDeleteView, self).pre_redirect(request, *args, **kwargs)
 
     def pre_post_redirect(self, request, *args, **kwargs):
-        if self.object == self.request.user:
+        if self.get_object() == self.request.user:
             messages.error(self.request, _("You can not delete yourself."))
         else:
             super(UserDeleteView, self).pre_post_redirect(request, *args, **kwargs)
@@ -185,23 +185,22 @@ class SetUserStatusView(SingleObjectMixin, RedirectView):
     model = User
 
     def pre_redirect(self, request, *args, **kwargs):
-        self.object = self.get_object()
         action = kwargs['action']
         if action == 'activate':
-            self.object.is_active = True
+            self.get_object().is_active = True
         elif action == 'deactivate':
-            if self.object.user == self.request.user:
+            if self.get_object().user == self.request.user:
                 messages.error(request, _("You can not deactivate yourself."))
             else:
-                self.object.is_active = False
+                self.get_object().is_active = False
         elif action == 'toggle':
-            self.object.is_active = not self.object.is_active
-        self.object.save()
+            self.get_object().is_active = not self.get_object().is_active
+        self.get_object().save()
         return super(SetUserStatusView, self).pre_redirect(request, *args, **kwargs)
 
     def get_ajax_context(self, **kwargs):
         context = super(SetUserStatusView, self).get_ajax_context(**kwargs)
-        context['active'] = self.object.is_active
+        context['active'] = self.get_object().is_active
         return context
 
 
@@ -257,18 +256,14 @@ class ResetPasswordView(SingleObjectMixin, QuestionView):
     allow_ajax = True
     question_message = ugettext_lazy('Do you really want to reset the password?')
 
-    def get(self, request, *args, **kwargs):
-        self.object = self.get_object()
-        return super(ResetPasswordView, self).get(request, *args, **kwargs)
-
     def get_redirect_url(self, **kwargs):
-        return reverse('user_edit', args=[self.object.id])
+        return reverse('user_edit', args=[self.get_object().id])
 
     def on_clicked_yes(self):
-        self.object.reset_password()
+        self.get_object().reset_password()
 
     def get_final_message(self):
-        return _('The Password for %s was successfully reset.') % html_strong(self.object)
+        return _('The Password for %s was successfully reset.') % html_strong(self.get_object())
 
 
 class GroupOverview(ListView):
@@ -361,12 +356,12 @@ class GroupDeleteView(DeleteView):
         """
         Checks whether the group is protected.
         """
-        if self.object.pk in [1, 2]:
+        if self.get_object().pk in [1, 2]:
             messages.error(self.request, _('You can not delete this group.'))
             return True
         if (not self.request.user.is_superuser and
-            get_protected_perm() in self.object.permissions.all() and
-            not Group.objects.exclude(pk=self.object.pk).filter(
+            get_protected_perm() in self.get_object().permissions.all() and
+            not Group.objects.exclude(pk=self.get_object().pk).filter(
                 permissions__in=[get_protected_perm()],
                 user__pk=self.request.user.pk).exists()):
             messages.error(
diff --git a/openslides/poll/views.py b/openslides/poll/views.py
index 41ee176d5..7bb0bed17 100644
--- a/openslides/poll/views.py
+++ b/openslides/poll/views.py
@@ -11,11 +11,11 @@ class PollFormView(FormMixin, TemplateView):
     poll_class = None
 
     def get(self, request, *args, **kwargs):
-        self.poll = self.object = self.get_object()
+        self.poll = self.get_object()
         return super(PollFormView, self).get(request, *args, **kwargs)
 
     def post(self, request, *args, **kwargs):
-        self.poll = self.object = self.get_object()
+        self.poll = self.get_object()
         option_forms = self.poll.get_vote_forms(data=self.request.POST)
 
         FormClass = self.get_modelform_class()
@@ -57,8 +57,13 @@ class PollFormView(FormMixin, TemplateView):
         """
         Returns the poll object. Raises Http404 if the poll does not exist.
         """
-        queryset = self.get_poll_class().objects.filter(pk=self.kwargs['poll_id'])
-        return get_object_or_404(queryset)
+        try:
+            obj = self._object
+        except AttributeError:
+            queryset = self.get_poll_class().objects.filter(pk=self.kwargs['poll_id'])
+            obj = get_object_or_404(queryset)
+            self._object = obj
+        return obj
 
     def get_context_data(self, **kwargs):
         context = super(PollFormView, self).get_context_data(**kwargs)
diff --git a/openslides/utils/views.py b/openslides/utils/views.py
index 6bf5b983e..be43de7e0 100644
--- a/openslides/utils/views.py
+++ b/openslides/utils/views.py
@@ -14,7 +14,6 @@ from django.utils.decorators import method_decorator
 from django.utils.translation import ugettext as _
 from django.utils.translation import ugettext_lazy
 from django.views import generic as django_views
-from django.views.generic.detail import SingleObjectMixin
 from reportlab.lib.units import cm
 from reportlab.platypus import SimpleDocTemplate, Spacer
 
@@ -166,6 +165,32 @@ class UrlMixin(object):
         return value
 
 
+class SingleObjectMixin(django_views.detail.SingleObjectMixin):
+    """
+    Mixin for single objects from the database.
+    """
+
+    def dispatch(self, *args, **kwargs):
+        if not hasattr(self, 'object'):
+            # Save the object not only in the cache but in the public
+            # attribute self.object because Django expects this later.
+            # Because get_object() has an internal cache this line is not a
+            # performance problem.
+            self.object = self.get_object()
+        return super(SingleObjectMixin, self).dispatch(*args, **kwargs)
+
+    def get_object(self, *args, **kwargs):
+        """
+        Returns the single object from database or cache.
+        """
+        try:
+            obj = self._object
+        except AttributeError:
+            obj = super(SingleObjectMixin, self).get_object(*args, **kwargs)
+            self._object = obj
+        return obj
+
+
 class FormMixin(UrlMixin):
     """
     Mixin for views with forms.
@@ -442,14 +467,14 @@ class FormView(PermissionMixin, ExtraContextMixin, FormMixin,
 
 
 class UpdateView(PermissionMixin, ExtraContextMixin,
-                 ModelFormMixin, django_views.UpdateView):
+                 ModelFormMixin, SingleObjectMixin, django_views.UpdateView):
     """
     View to update an model object.
     """
 
     def get_success_message(self):
         if self.success_message is None:
-            message = _('%s was successfully modified.') % html_strong(self.object)
+            message = _('%s was successfully modified.') % html_strong(self.get_object())
         else:
             message = self.success_message
         return message
@@ -459,6 +484,10 @@ class CreateView(PermissionMixin, ExtraContextMixin,
                  ModelFormMixin, django_views.CreateView):
     """
     View to create a model object.
+
+    Note: This class has a django method get_object() which is different form
+          the method in openslides.utils.views.SingleObjectMixin. The result
+          is not cached.
     """
 
     def get_success_message(self):
@@ -477,10 +506,6 @@ class DeleteView(SingleObjectMixin, QuestionView):
     success_url = None
     success_url_name = None
 
-    def get(self, request, *args, **kwargs):
-        self.object = self.get_object()
-        return super(DeleteView, self).get(request, *args, **kwargs)
-
     def get_redirect_url(self, **kwargs):
         """
         Returns the url on which the delete dialog is shown and the url after
@@ -510,22 +535,22 @@ class DeleteView(SingleObjectMixin, QuestionView):
         """
         Returns the question for the delete dialog.
         """
-        return _('Do you really want to delete %s?') % html_strong(self.object)
+        return _('Do you really want to delete %s?') % html_strong(self.get_object())
 
     def on_clicked_yes(self):
         """
         Deletes the object.
         """
-        self.object.delete()
+        self.get_object().delete()
 
     def get_final_message(self):
         """
         Prints the success message to the user.
         """
-        return _('%s was successfully deleted.') % html_strong(self.object)
+        return _('%s was successfully deleted.') % html_strong(self.get_object())
 
 
-class DetailView(PermissionMixin, ExtraContextMixin, django_views.DetailView):
+class DetailView(PermissionMixin, ExtraContextMixin, SingleObjectMixin, django_views.DetailView):
     """
     View to show an model object.
     """
diff --git a/tests/mediafile/tests.py b/tests/mediafile/tests.py
index 507c4691a..315743a2a 100644
--- a/tests/mediafile/tests.py
+++ b/tests/mediafile/tests.py
@@ -203,8 +203,8 @@ class MediafileTest(TestCase):
         response = clients['client_normal_user'].get('/mediafile/1/del/')
         self.assertEqual(response.status_code, 403)
         bad_client = Client()
-        response = bad_client.get('/mediafile/2/del/')
-        self.assertRedirects(response, expected_url='/login/?next=/mediafile/2/del/', status_code=302, target_status_code=200)
+        response = bad_client.get('/mediafile/1/del/')
+        self.assertRedirects(response, expected_url='/login/?next=/mediafile/1/del/', status_code=302, target_status_code=200)
 
     def test_delete_mediafile_get_request_own_file(self):
         self.object.uploader = self.vip_user
diff --git a/tests/settings.py b/tests/settings.py
index f9b58b5ac..d913376e7 100644
--- a/tests/settings.py
+++ b/tests/settings.py
@@ -29,6 +29,7 @@ DATABASES = {
 # Add OpenSlides plugins to this list
 INSTALLED_PLUGINS = (
     'tests.person_api',
+    'tests.utils',
 )
 
 INSTALLED_APPS += INSTALLED_PLUGINS
diff --git a/tests/utils/models.py b/tests/utils/models.py
new file mode 100644
index 000000000..cd5c87cb9
--- /dev/null
+++ b/tests/utils/models.py
@@ -0,0 +1,8 @@
+from django.db import models
+
+
+class DummyModel(models.Model):
+    """
+    Dummy model to test some model views.
+    """
+    title = models.CharField(max_length=255)
diff --git a/tests/utils/templates/utils/dummymodel_detail.html b/tests/utils/templates/utils/dummymodel_detail.html
new file mode 100644
index 000000000..1a8a594f6
--- /dev/null
+++ b/tests/utils/templates/utils/dummymodel_detail.html
@@ -0,0 +1,5 @@
+<html>
+<body>
+    {{ object.title }}
+</body>
+</html>
diff --git a/tests/utils/test_views.py b/tests/utils/test_views.py
index fe468538c..8229dbd2b 100644
--- a/tests/utils/test_views.py
+++ b/tests/utils/test_views.py
@@ -3,6 +3,7 @@
 from django.contrib.auth.models import AnonymousUser
 from django.core.exceptions import ImproperlyConfigured
 from django.core.urlresolvers import clear_url_caches
+from django.db import connection, reset_queries
 from django.test import RequestFactory
 from django.test.client import Client
 from django.test.utils import override_settings
@@ -13,6 +14,7 @@ from openslides.utils.signals import template_manipulation
 from openslides.utils.test import TestCase
 
 from . import views as test_views
+from .models import DummyModel
 
 
 @override_settings(ROOT_URLCONF='tests.utils.urls')
@@ -194,6 +196,17 @@ class QuestionViewTest(ViewTestCase):
         self.assertIn('the question', question)
 
 
+class DetailViewTest(ViewTestCase):
+    def test_get_object_cache(self):
+        with self.settings(DEBUG=True):
+            DummyModel.objects.create(title='title_ooth8she7yos1Oi8Boh3')
+            reset_queries()
+            client = Client()
+            response = client.get('/dummy_detail_view/1/')
+            self.assertContains(response, 'title_ooth8she7yos1Oi8Boh3')
+            self.assertEqual(len(connection.queries), 3)
+
+
 def set_context(sender, request, context, **kwargs):
     """
     receiver for testing the ExtraContextMixin
diff --git a/tests/utils/urls.py b/tests/utils/urls.py
index c31d30303..181a5db59 100644
--- a/tests/utils/urls.py
+++ b/tests/utils/urls.py
@@ -28,4 +28,7 @@ urlpatterns += patterns(
 
     url(r'^permission_mixin3/$',
         views.PermissionMixinView.as_view(required_permission='agenda.can_see_agenda')),
+
+    url(r'^dummy_detail_view/(?P<pk>\d+)/$',
+        views.DummyDetailView.as_view()),
 )
diff --git a/tests/utils/views.py b/tests/utils/views.py
index 8af2be1ac..c9e7c4579 100644
--- a/tests/utils/views.py
+++ b/tests/utils/views.py
@@ -2,6 +2,8 @@ from django.http import HttpResponse
 
 from openslides.utils import views
 
+from .models import DummyModel
+
 
 class GetAbsoluteUrl(object):
     """
@@ -45,3 +47,15 @@ class UrlMixinView(views.UrlMixin, views.View):
 
 class UrlMixinViewWithObject(views.UrlMixin, views.View):
     object = GetAbsoluteUrl()
+
+
+class DummyDetailView(views.DetailView):
+    model = DummyModel
+
+    def get_context_data(self, **context):
+        context = super(DummyDetailView, self).get_context_data(**context)
+        # Just call get_object() some times to test the cache
+        self.get_object()
+        self.get_object()
+        self.get_object()
+        return context