bitbake: toaster: Don't HTTP cache ToasterTable responses

Django allows generated pages to be cached by default by the
browser. This can result in stale data displaying for some pages.

Instead, disable HTTP caching of ToasterTable responses, so that
each time a ToasterTable view is displayed, its data is
refreshed. This carries a performance penalty, but ensures that
ToasterTable views (e.g. compatible layers) are correctly
refreshed if the user navigates their history with forward/back.

[YOCTO #7660]

(Bitbake rev: 44dccd3018554915868d6c8fe5e22624a2fcdec5)

Signed-off-by: Elliot Smith <elliot.smith@intel.com>
Signed-off-by: Michael Wood <michael.g.wood@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/toaster/toastergui/widgets.py

@@ -20,6 +20,7 @@
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
 from django.views.generic import View, TemplateView
+from django.views.decorators.cache import cache_control
 from django.shortcuts import HttpResponse
 from django.http import HttpResponseBadRequest
 from django.core import serializers
@@ -64,6 +65,11 @@ class ToasterTable(TemplateView):
                         orderable=True,
                         field_name="id")
 
+        # prevent HTTP caching of table data
+    @cache_control(must_revalidate=True, max_age=0, no_store=True, no_cache=True)
+    def dispatch(self, *args, **kwargs):
+        return super(ToasterTable, self).dispatch(*args, **kwargs)
+
     def get_context_data(self, **kwargs):
         context = super(ToasterTable, self).get_context_data(**kwargs)
         context['title'] = self.title