Pi-Hole statistics sensor (#3158)

* Add Pi-Hole sensor

* Update docstrings and remove print()

* Use None for payload

.coveragerc

@@ -235,6 +235,7 @@ omit =
     homeassistant/components/sensor/onewire.py
     homeassistant/components/sensor/openexchangerates.py
     homeassistant/components/sensor/openweathermap.py
+    homeassistant/components/sensor/pi_hole.py
     homeassistant/components/sensor/plex.py
     homeassistant/components/sensor/rest.py
     homeassistant/components/sensor/sabnzbd.py

homeassistant/components/sensor/pi_hole.py

@@ -0,0 +1,101 @@
+"""
+Support for getting statistical data from a Pi-Hole system.
+
+For more details about this platform, please refer to the documentation at
+https://home-assistant.io/components/sensor.pi_hole/
+"""
+import logging
+import json
+
+import voluptuous as vol
+
+from homeassistant.helpers.entity import Entity
+from homeassistant.components.sensor import PLATFORM_SCHEMA
+from homeassistant.components.sensor.rest import RestData
+from homeassistant.const import (
+    CONF_NAME, CONF_HOST, CONF_SSL, CONF_VERIFY_SSL)
+import homeassistant.helpers.config_validation as cv
+
+_LOGGER = logging.getLogger(__name__)
+_ENDPOINT = '/admin/api.php'
+
+ATTR_BLOCKED_DOMAINS = 'domains_blocked'
+ATTR_PERCENTAGE_TODAY = 'percentage_today'
+ATTR_QUERIES_TODAY = 'queries_today'
+
+DEFAULT_HOST = 'localhost'
+DEFAULT_METHOD = 'GET'
+DEFAULT_NAME = 'Pi-hole'
+DEFAULT_SSL = False
+DEFAULT_VERIFY_SSL = True
+
+PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
+    vol.Optional(CONF_HOST, default=DEFAULT_HOST): cv.string,
+    vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
+    vol.Optional(CONF_SSL, default=DEFAULT_SSL): cv.boolean,
+    vol.Optional(CONF_VERIFY_SSL, default=DEFAULT_VERIFY_SSL): cv.boolean,
+})
+
+
+def setup_platform(hass, config, add_devices, discovery_info=None):
+    """Setup the Pi-Hole sensor."""
+    name = config.get(CONF_NAME)
+    host = config.get(CONF_HOST)
+    method = 'GET'
+    payload = None
+    verify_ssl = config.get(CONF_VERIFY_SSL)
+    use_ssl = config.get(CONF_SSL)
+
+    if use_ssl:
+        uri_scheme = 'https://'
+    else:
+        uri_scheme = 'http://'
+
+    resource = "{}{}{}".format(uri_scheme, host, _ENDPOINT)
+
+    rest = RestData(method, resource, payload, verify_ssl)
+    rest.update()
+
+    if rest.data is None:
+        _LOGGER.error('Unable to fetch REST data')
+        return False
+
+    add_devices([PiHoleSensor(hass, rest, name)])
+
+
+class PiHoleSensor(Entity):
+    """Representation of a Pi-Hole sensor."""
+
+    def __init__(self, hass, rest, name):
+        """Initialize a Pi-Hole sensor."""
+        self._hass = hass
+        self.rest = rest
+        self._name = name
+        self._state = False
+        self.update()
+
+    @property
+    def name(self):
+        """Return the name of the sensor."""
+        return self._name
+
+    # pylint: disable=no-member
+    @property
+    def state(self):
+        """Return the state of the device."""
+        return self._state.get('ads_blocked_today')
+
+    # pylint: disable=no-member
+    @property
+    def state_attributes(self):
+        """Return the state attributes of the GPS."""
+        return {
+            ATTR_BLOCKED_DOMAINS: self._state.get('domains_being_blocked'),
+            ATTR_PERCENTAGE_TODAY: self._state.get('ads_percentage_today'),
+            ATTR_QUERIES_TODAY: self._state.get('dns_queries_today'),
+        }
+
+    def update(self):
+        """Get the latest data from REST API and updates the state."""
+        self.rest.update()
+        self._state = json.loads(self.rest.data)