Allow jinja namespace command to work. (#18011)

homeassistant/helpers/template.py

@@ -9,6 +9,7 @@ import re
 import jinja2
 from jinja2 import contextfilter
 from jinja2.sandbox import ImmutableSandboxedEnvironment
+from jinja2.utils import Namespace
 
 from homeassistant.const import (
     ATTR_LATITUDE, ATTR_LONGITUDE, ATTR_UNIT_OF_MEASUREMENT, MATCH_ALL,
@@ -618,6 +619,11 @@ class TemplateEnvironment(ImmutableSandboxedEnvironment):
         """Test if callback is safe."""
         return isinstance(obj, AllStates) or super().is_safe_callable(obj)
 
+    def is_safe_attribute(self, obj, attr, value):
+        """Test if attribute is safe."""
+        return isinstance(obj, Namespace) or \
+            super().is_safe_attribute(obj, attr, value)
+
 
 ENV = TemplateEnvironment()
 ENV.filters['round'] = forgiving_round

tests/helpers/test_template.py

@@ -963,6 +963,23 @@ class TestHelpersTemplate(unittest.TestCase):
                 "{{ is_state('media_player.' ~ where , 'playing') }}",
                 {'where': 'livingroom'})
 
+    def test_jinja_namespace(self):
+        """Test Jinja's namespace command can be used."""
+        test_template = template.Template(
+            (
+                "{% set ns = namespace(a_key='') %}"
+                "{% set ns.a_key = states.sensor.dummy.state %}"
+                "{{ ns.a_key }}"
+            ),
+            self.hass
+        )
+
+        self.hass.states.set('sensor.dummy', 'a value')
+        assert 'a value' == test_template.render()
+
+        self.hass.states.set('sensor.dummy', 'another value')
+        assert 'another value' == test_template.render()
+
 
 @asyncio.coroutine
 def test_state_with_unit(hass):