broadcast-areas: only load geojson when needed

Signed-off-by: Toby Lorne <toby.lornewelch-richards@digital.cabinet-office.gov.uk>

notifications_utils/broadcast_areas/__init__.py

@@ -1,3 +1,4 @@
+import geojson
 import itertools
 
 from notifications_utils.serialised_model import SerialisedModelCollection
@@ -39,8 +40,8 @@ class BroadcastArea(IdentifiableMixin):
 
         self.id = id
         self.name = name
-        self.feature = feature
-        self.simple_feature = simple_feature
+        self._feature = feature
+        self._simple_feature = simple_feature
 
         for coordinates in self.polygons:
             if coordinates[0] != coordinates[-1]:
@@ -91,6 +92,14 @@ class BroadcastArea(IdentifiableMixin):
     def simple_unenclosed_polygons(self):
         return self._unenclosed_polygons(self.simple_feature)
 
+    @property
+    def feature(self):
+        return geojson.loads(self._feature)
+
+    @property
+    def simple_feature(self):
+        return geojson.loads(self._simple_feature)
+
 
 class BroadcastAreaLibrary(SerialisedModelCollection, IdentifiableMixin, IdFromNameMixin, GetItemByIdMixin):
 

notifications_utils/broadcast_areas/repo.py

@@ -1,4 +1,3 @@
-import geojson
 import os
 from pathlib import Path
 import sqlite3
@@ -129,7 +128,7 @@ class BroadcastAreasRepository(object):
             results = cursor.fetchall()
 
             areas = [
-                (row[0], row[1], geojson.loads(row[2]), geojson.loads(row[3]))
+                (row[0], row[1], row[2], row[3])
                 for row in results
             ]
 
@@ -145,7 +144,7 @@ class BroadcastAreasRepository(object):
         results = self.query(q, library_id)
 
         areas = [
-            (row[0], row[1], geojson.loads(row[2]), geojson.loads(row[3]))
+            (row[0], row[1], row[2], row[3])
             for row in results
         ]