Make pagination tunable through the settings panel

This patch set expands on the fine work done in https://review.openstack.org/26022

It makes the number of items displayed a per-user tunable through
the "Settings" panel and a session cookie, with the default/max
values being the values set in django.conf.settings

Fixes Bug: 1046915
Change-Id: I38ef4845d46bce62e44209865885aff8eb0bac83

openstack_dashboard/api/nova.py

@@ -362,7 +362,9 @@ def server_get(request, instance_id):
 
 
 def server_list(request, search_opts=None, all_tenants=False):
-    page_size = getattr(settings, 'API_RESULT_PAGE_SIZE', 20)
+    page_size = request.session.get('horizon_pagesize',
+                                    getattr(settings, 'API_RESULT_PAGE_SIZE',
+                                            20))
     paginate = False
     if search_opts is None:
         search_opts = {}
@@ -382,6 +384,9 @@ def server_list(request, search_opts=None, all_tenants=False):
     if paginate and len(servers) > page_size:
         servers.pop(-1)
         has_more_data = True
+    elif paginate and len(servers) == getattr(settings, 'API_RESULT_LIMIT',
+                                              1000):
+        has_more_data = True
     return (servers, has_more_data)
 
 

openstack_dashboard/dashboards/settings/user/forms.py

@@ -28,6 +28,13 @@
 class UserSettingsForm(forms.SelfHandlingForm):
     language = forms.ChoiceField()
     timezone = forms.ChoiceField()
+    pagesize = forms.IntegerField(label=translation.ugettext("Items Per Page"),
+                                  min_value=1,
+                                  max_value=getattr(settings,
+                                                    'API_RESULT_LIMIT',
+                                                    1000),
+                                  help_text=translation.ugettext(
+                                      "Number of items to show per page"))
 
     def __init__(self, *args, **kwargs):
         super(UserSettingsForm, self).__init__(*args, **kwargs)
@@ -70,6 +77,8 @@ def handle(self, request, data):
         request.session['django_timezone'] = pytz.timezone(
             data['timezone']).zone
 
+        request.session['horizon_pagesize'] = data['pagesize']
+
         messages.success(request, translation.ugettext("Settings saved."))
 
         return response

openstack_dashboard/dashboards/settings/user/views.py

@@ -14,6 +14,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from django.conf import settings
 from horizon import forms
 
 from .forms import UserSettingsForm
@@ -25,7 +26,10 @@ class UserSettingsView(forms.ModalFormView):
 
     def get_initial(self):
         return {'language': self.request.LANGUAGE_CODE,
-                'timezone': self.request.session.get('django_timezone', 'UTC')}
+                'timezone': self.request.session.get('django_timezone', 'UTC'),
+                'pagesize': self.request.session.get(
+                        'horizon_pagesize',
+                        getattr(settings, 'API_RESULT_PAGE_SIZE', 20))}
 
     def form_valid(self, form):
         return form.handle(self.request, form.cleaned_data)