Added support to Yahoo Finance to track the stock market within Home Assistant (#3446)

* Added support to Yahoo Finance to track the stock market within Home Assistant

* Fixed pylint issues

* Fixed formatting issues

* Fixed pep257 issues

*   - Fixed URL link
  - Added attributes for Yahoo Finance

* Removed price sales ATTR

* Fixed lint and flake8 issues. Added attribution to Yahoo! per https://developer.yahoo.com/attribution/

.coveragerc

@@ -260,6 +260,7 @@ omit =
     homeassistant/components/sensor/uber.py
     homeassistant/components/sensor/worldclock.py
     homeassistant/components/sensor/xbox_live.py
+    homeassistant/components/sensor/yahoo_finance.py
     homeassistant/components/sensor/yweather.py
     homeassistant/components/switch/acer_projector.py
     homeassistant/components/switch/arest.py

homeassistant/components/sensor/yahoo_finance.py

@@ -0,0 +1,125 @@
+"""
+Currency exchange rate support that comes from Yahoo Finance.
+
+For more details about this platform, please refer to the documentation at
+https://home-assistant.io/components/sensor.yahoo_finance/
+"""
+import logging
+from datetime import timedelta
+
+import voluptuous as vol
+
+from homeassistant.components.sensor import PLATFORM_SCHEMA
+from homeassistant.const import CONF_NAME
+from homeassistant.helpers.entity import Entity
+from homeassistant.util import Throttle
+import homeassistant.helpers.config_validation as cv
+
+REQUIREMENTS = ['yahoo-finance==1.2.1']
+
+_LOGGER = logging.getLogger(__name__)
+
+CONF_SYMBOL = 'symbol'
+DEFAULT_SYMBOL = 'YHOO'
+DEFAULT_NAME = 'Yahoo Stock'
+
+ICON = 'mdi:currency-usd'
+
+MIN_TIME_BETWEEN_UPDATES = timedelta(minutes=1)
+
+ATTR_CHANGE = 'Change'
+ATTR_OPEN = 'Open'
+ATTR_PREV_CLOSE = 'Prev. Close'
+
+PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
+    vol.Optional(CONF_SYMBOL, default=DEFAULT_SYMBOL): cv.string,
+    vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
+})
+
+
+def setup_platform(hass, config, add_devices, discovery_info=None):
+    """Setup the Yahoo Finance sensor."""
+    name = config.get(CONF_NAME)
+    symbol = config.get(CONF_SYMBOL)
+
+    data = YahooFinanceData(name, symbol)
+    add_devices([YahooFinanceSensor(name, data, symbol)])
+
+
+# pylint: disable=too-few-public-methods
+class YahooFinanceSensor(Entity):
+    """Representation of a Yahoo Finance sensor."""
+
+    def __init__(self, name, data, symbol):
+        """Initialize the sensor."""
+        self._name = name
+        self.data = data
+        self._symbol = symbol
+        self._state = None
+        self._unit_of_measurement = None
+        self.update()
+
+    @property
+    def name(self):
+        """Return the name of the sensor."""
+        return self._name
+
+    @property
+    def unit_of_measurement(self):
+        """Return the unit of measurement of this entity, if any."""
+        return self._symbol
+
+    @property
+    def state(self):
+        """Return the state of the sensor."""
+        return self._state
+
+    @property
+    def device_state_attributes(self):
+        """Return the state attributes."""
+        if self._state is not None:
+            return {
+                ATTR_CHANGE: self.data.price_change,
+                ATTR_OPEN: self.data.price_open,
+                ATTR_PREV_CLOSE: self.data.prev_close,
+                'About': "Stock market information delivered by Yahoo!"
+                         " Inc. are provided free of charge for use"
+                         " by individuals and non-profit organizations"
+                         " for personal, non-commercial uses."
+            }
+
+    @property
+    def icon(self):
+        """Return the icon to use in the frontend, if any."""
+        return ICON
+
+    def update(self):
+        """Get the latest data and updates the states."""
+        _LOGGER.debug('Updating sensor %s - %s', self._name, self._state)
+        self.data.update()
+        self._state = self.data.state
+
+
+class YahooFinanceData(object):
+    """Get data from Yahoo Finance."""
+
+    def __init__(self, name, symbol):
+        """Initialize the data object."""
+        from yahoo_finance import Share
+
+        self._name = name
+        self._symbol = symbol
+        self.state = None
+        self.price_change = None
+        self.price_open = None
+        self.prev_close = None
+        self.stock = Share(symbol)
+
+    @Throttle(MIN_TIME_BETWEEN_UPDATES)
+    def update(self):
+        """Get the latest data and updates the states."""
+        self.stock.refresh()
+        self.state = self.stock.get_price()
+        self.price_change = self.stock.get_change()
+        self.price_open = self.stock.get_open()
+        self.prev_close = self.stock.get_prev_close()

requirements_all.txt

@@ -516,6 +516,9 @@ xboxapi==0.1.1
 # homeassistant.components.sensor.yr
 xmltodict==0.10.2
 
+# homeassistant.components.sensor.yahoo_finance
+yahoo-finance==1.2.1
+
 # homeassistant.components.sensor.yweather
 yahooweather==0.8