Prevented flatpage view from directly accessing settings.SITE_ID

Refs #15089

django/contrib/flatpages/views.py

@@ -1,9 +1,10 @@
-from django.contrib.flatpages.models import FlatPage
-from django.template import loader, RequestContext
-from django.shortcuts import get_object_or_404
-from django.http import Http404, HttpResponse, HttpResponsePermanentRedirect
 from django.conf import settings
+from django.contrib.flatpages.models import FlatPage
+from django.contrib.sites.models import get_current_site
 from django.core.xheaders import populate_xheaders
+from django.http import Http404, HttpResponse, HttpResponsePermanentRedirect
+from django.shortcuts import get_object_or_404
+from django.template import loader, RequestContext
 from django.utils.safestring import mark_safe
 from django.views.decorators.csrf import csrf_protect
 
@@ -30,14 +31,15 @@ def flatpage(request, url):
     """
     if not url.startswith('/'):
         url = '/' + url
+    site_id = get_current_site(request).id
     try:
         f = get_object_or_404(FlatPage,
-            url__exact=url, sites__id__exact=settings.SITE_ID)
+            url__exact=url, sites__id__exact=site_id)
     except Http404:
         if not url.endswith('/') and settings.APPEND_SLASH:
             url += '/'
             f = get_object_or_404(FlatPage,
-                url__exact=url, sites__id__exact=settings.SITE_ID)
+                url__exact=url, sites__id__exact=site_id)
             return HttpResponsePermanentRedirect('%s/' % request.path)
         else:
             raise