core/homeassistant/components/sensor/scrape.py

"""
Support for getting data from websites with scraping.

For more details about this platform, please refer to the documentation at
https://home-assistant.io/components/sensor.scrape/
"""
import logging

import voluptuous as vol

from homeassistant.components.sensor import PLATFORM_SCHEMA
from homeassistant.components.sensor.rest import RestData
from homeassistant.const import (
    CONF_NAME, CONF_RESOURCE, CONF_UNIT_OF_MEASUREMENT, STATE_UNKNOWN,
    CONF_VALUE_TEMPLATE, CONF_VERIFY_SSL)
from homeassistant.helpers.entity import Entity
import homeassistant.helpers.config_validation as cv

REQUIREMENTS = ['beautifulsoup4==4.6.0']

_LOGGER = logging.getLogger(__name__)

CONF_SELECT = 'select'
CONF_ATTR = 'attribute'

DEFAULT_NAME = 'Web scrape'
DEFAULT_VERIFY_SSL = True

PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
    vol.Required(CONF_RESOURCE): cv.string,
    vol.Required(CONF_SELECT): cv.string,
    vol.Optional(CONF_ATTR): cv.string,
    vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
    vol.Optional(CONF_UNIT_OF_MEASUREMENT): cv.string,
    vol.Optional(CONF_VALUE_TEMPLATE): cv.template,
    vol.Optional(CONF_VERIFY_SSL, default=DEFAULT_VERIFY_SSL): cv.boolean,
})


def setup_platform(hass, config, add_devices, discovery_info=None):
    """Set up the Web scrape sensor."""
    name = config.get(CONF_NAME)
    resource = config.get(CONF_RESOURCE)
    method = 'GET'
    payload = auth = headers = None
    verify_ssl = config.get(CONF_VERIFY_SSL)
    select = config.get(CONF_SELECT)
    attr = config.get(CONF_ATTR)
    unit = config.get(CONF_UNIT_OF_MEASUREMENT)
    value_template = config.get(CONF_VALUE_TEMPLATE)
    if value_template is not None:
        value_template.hass = hass

    rest = RestData(method, resource, auth, headers, payload, verify_ssl)
    rest.update()

    if rest.data is None:
        _LOGGER.error("Unable to fetch data from %s", resource)
        return False

    add_devices([
        ScrapeSensor(hass, rest, name, select, attr, value_template, unit)
    ], True)


class ScrapeSensor(Entity):
    """Representation of a web scrape sensor."""

    def __init__(self, hass, rest, name, select, attr, value_template, unit):
        """Initialize a web scrape sensor."""
        self.rest = rest
        self._name = name
        self._state = STATE_UNKNOWN
        self._select = select
        self._attr = attr
        self._value_template = value_template
        self._unit_of_measurement = unit

    @property
    def name(self):
        """Return the name of the sensor."""
        return self._name

    @property
    def unit_of_measurement(self):
        """Return the unit the value is expressed in."""
        return self._unit_of_measurement

    @property
    def state(self):
        """Return the state of the device."""
        return self._state

    def update(self):
        """Get the latest data from the source and updates the state."""
        self.rest.update()

        from bs4 import BeautifulSoup

        raw_data = BeautifulSoup(self.rest.data, 'html.parser')
        _LOGGER.debug(raw_data)
        if self._attr is not None:
            value = raw_data.select(self._select)[0][self._attr]
        else:
            value = raw_data.select(self._select)[0].text
        _LOGGER.debug(value)

        if self._value_template is not None:
            self._state = self._value_template.render_with_possible_json_value(
                value, STATE_UNKNOWN)
        else:
            self._state = value