[FR] Simplify / optimize setting loading (#4152)

* [FR] Simplify / optimize setting loading
Cache config.yaml data on load and use cached  for get_settings
Fixes #4149

* move the cache setting to config

* add docstring

* spell fix

* Add lookup where settings come from
Fixes #3982

* Fix spelling

InvenTree/common/api.py

@@ -18,9 +18,11 @@ from rest_framework.views import APIView
 import common.models
 import common.serializers
 from InvenTree.api import BulkDeleteMixin
+from InvenTree.config import CONFIG_LOOKUPS
 from InvenTree.helpers import inheritors
 from InvenTree.mixins import (ListAPI, RetrieveAPI, RetrieveUpdateAPI,
                               RetrieveUpdateDestroyAPI)
+from InvenTree.permissions import IsSuperuser
 from plugin.models import NotificationUserSetting
 from plugin.serializers import NotificationUserSettingSerializer
 
@@ -360,6 +362,29 @@ class NewsFeedEntryDetail(NewsFeedMixin, RetrieveUpdateDestroyAPI):
     """Detail view for an individual news feed object."""
 
 
+class ConfigList(ListAPI):
+    """List view for all accessed configurations."""
+
+    queryset = CONFIG_LOOKUPS
+    serializer_class = common.serializers.ConfigSerializer
+    permission_classes = [IsSuperuser, ]
+
+
+class ConfigDetail(RetrieveAPI):
+    """Detail view for an individual configuration."""
+
+    serializer_class = common.serializers.ConfigSerializer
+    permission_classes = [IsSuperuser, ]
+
+    def get_object(self):
+        """Attempt to find a config object with the provided key."""
+        key = self.kwargs['key']
+        value = CONFIG_LOOKUPS.get(key, None)
+        if not value:
+            raise NotFound()
+        return {key: value}
+
+
 settings_api_urls = [
     # User settings
     re_path(r'^user/', include([
@@ -415,3 +440,9 @@ common_api_urls = [
     ])),
 
 ]
+
+admin_api_urls = [
+    # Admin
+    path('config/', ConfigList.as_view(), name='api-config-list'),
+    path('config/<str:key>/', ConfigDetail.as_view(), name='api-config-detail'),
+]

InvenTree/common/serializers.py

@@ -222,3 +222,16 @@ class NewsFeedEntrySerializer(InvenTreeModelSerializer):
             'summary',
             'read',
         ]
+
+
+class ConfigSerializer(serializers.Serializer):
+    """Serializer for the InvenTree configuration.
+
+    This is a read-only serializer.
+    """
+
+    def to_representation(self, instance):
+        """Return the configuration data as a dictionary."""
+        if not isinstance(instance, str):
+            instance = list(instance.keys())[0]
+        return {'key': instance, **self.instance[instance]}

InvenTree/common/tests.py

@@ -827,7 +827,7 @@ class NotificationTest(InvenTreeAPITestCase):
         self.assertEqual(NotificationMessage.objects.filter(user=self.user).count(), 3)
 
 
-class LoadingTest(TestCase):
+class CommonTest(InvenTreeAPITestCase):
     """Tests for the common config."""
 
     def test_restart_flag(self):
@@ -844,6 +844,30 @@ class LoadingTest(TestCase):
         # now it should be false again
         self.assertFalse(common.models.InvenTreeSetting.get_setting('SERVER_RESTART_REQUIRED'))
 
+    def test_config_api(self):
+        """Test config URLs."""
+        # Not superuser
+        self.get(reverse('api-config-list'), expected_code=403)
+
+        # Turn into superuser
+        self.user.is_superuser = True
+        self.user.save()
+
+        # Successfull checks
+        data = [
+            self.get(reverse('api-config-list'), expected_code=200).data[0],                                    # list endpoint
+            self.get(reverse('api-config-detail', kwargs={'key': 'INVENTREE_DEBUG'}), expected_code=200).data,  # detail endpoint
+        ]
+
+        for item in data:
+            self.assertEqual(item['key'], 'INVENTREE_DEBUG')
+            self.assertEqual(item['env_var'], 'INVENTREE_DEBUG')
+            self.assertEqual(item['config_key'], 'debug')
+
+        # Turn into normal user again
+        self.user.is_superuser = False
+        self.user.save()
+
 
 class ColorThemeTest(TestCase):
     """Tests for ColorTheme."""