Merge pull request #66 from Qabel/m/trafficfx

query DB only once

drop_service/models.py

@@ -17,7 +17,7 @@ class Drop(ExportModelOperationsMixin('Drop'), models.Model):
     class Meta:
         # Force un-prefixed table name for compatibility
         db_table = 'drops'
-        get_latest_by = 'created_at'
+        ordering = ['created_at']
 
     def __repr__(self):
         return u'<{0} for {1} created at {2} >'.format(self.drop_id, self.message, self.created_at)

drop_service/views.py

@@ -34,8 +34,6 @@ def _get_drops(self, drop_id):
             return error('Invalid drop id'), None
 
         drops = Drop.objects.filter(drop_id=drop_id)
-        if not drops:
-            return HttpResponse(status=status.HTTP_204_NO_CONTENT), None
 
         try:
             have_since, since = self.get_if_modified_since()
@@ -45,10 +43,15 @@ def _get_drops(self, drop_id):
 
         if have_since:
             drops = drops.filter(created_at__gt=since)
-        if have_since and not drops:
-            return HttpResponseNotModified(), None
 
-        return None, drops
+
+        if not drops.exists():
+            if have_since:
+                return HttpResponseNotModified(), None
+            else:
+                return HttpResponse(status=status.HTTP_204_NO_CONTENT), None
+
+        return None, list(drops)
 
     def get(self, request, drop_id):
         response, drops = self._get_drops(drop_id)
@@ -61,7 +64,7 @@ def get(self, request, drop_id):
         body = self.generate_body(drops, boundary)
         response = HttpResponse(body, content_type=content_type)
         if drops:
-            self.set_latest(response, drops.latest())
+            self.set_latest(response, drops[-1])
         return response
 
     def head(self, request, drop_id):