Add template support

homeassistant/util/template.py

@@ -0,0 +1,58 @@
+"""
+homeassistant.util.template
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Template utility methods for rendering strings with HA data.
+"""
+# pylint: disable=too-few-public-methods
+from jinja2.sandbox import SandboxedEnvironment
+
+ENV = SandboxedEnvironment()
+
+
+def forgiving_round(value, precision):
+    """ Rounding method that accepts strings. """
+    try:
+        return round(float(value), precision)
+    except ValueError:
+        # If value can't be converted to float
+        return value
+
+
+ENV.filters['round'] = forgiving_round
+
+
+def render(hass, template):
+    """ Render given template. """
+    return ENV.from_string(template).render(
+        states=AllStates(hass))
+
+
+class AllStates(object):
+    """ Class to expose all HA states as attributes. """
+    def __init__(self, hass):
+        self._hass = hass
+
+    def __getattr__(self, name):
+        return DomainStates(self._hass, name)
+
+    def __iter__(self):
+        return iter(sorted(self._hass.states.all(),
+                           key=lambda state: state.entity_id))
+
+
+class DomainStates(object):
+    """ Class to expose a specific HA domain as attributes. """
+
+    def __init__(self, hass, domain):
+        self._hass = hass
+        self._domain = domain
+
+    def __getattr__(self, name):
+        return self._hass.states.get('{}.{}'.format(self._domain, name))
+
+    def __iter__(self):
+        return iter(sorted(
+            (state for state in self._hass.states.all()
+             if state.domain == self._domain),
+            key=lambda state: state.entity_id))

tests/util/test_template.py

@@ -0,0 +1,57 @@
+"""
+tests.test_util
+~~~~~~~~~~~~~~~~~
+
+Tests Home Assistant util methods.
+"""
+# pylint: disable=too-many-public-methods
+import unittest
+import homeassistant.core as ha
+
+from homeassistant.util import template
+
+
+class TestUtilTemplate(unittest.TestCase):
+
+    def setUp(self):  # pylint: disable=invalid-name
+        self.hass = ha.HomeAssistant()
+
+    def tearDown(self):  # pylint: disable=invalid-name
+        """ Stop down stuff we started. """
+        self.hass.stop()
+
+    def test_referring_states_by_entity_id(self):
+        self.hass.states.set('test.object', 'happy')
+        self.assertEqual(
+            'happy',
+            template.render(self.hass, '{{ states.test.object.state }}'))
+
+    def test_iterating_all_states(self):
+        self.hass.states.set('test.object', 'happy')
+        self.hass.states.set('sensor.temperature', 10)
+
+        self.assertEqual(
+            '10happy',
+            template.render(
+                self.hass,
+                '{% for state in states %}{{ state.state }}{% endfor %}'))
+
+    def test_iterating_domain_states(self):
+        self.hass.states.set('test.object', 'happy')
+        self.hass.states.set('sensor.back_door', 'open')
+        self.hass.states.set('sensor.temperature', 10)
+
+        self.assertEqual(
+            'open10',
+            template.render(
+                self.hass,
+                '{% for state in states.sensor %}{{ state.state }}{% endfor %}'))
+
+    def test_rounding_value(self):
+        self.hass.states.set('sensor.temperature', 12.34)
+
+        self.assertEqual(
+            '12.3',
+            template.render(
+                self.hass,
+                '{{ states.sensor.temperature.state | round(1) }}'))