core/homeassistant/remote.py

481 lines
14 KiB
Python

"""
homeassistant.remote
~~~~~~~~~~~~~~~~~~~~
A module containing drop in replacements for core parts that will interface
with a remote instance of home assistant.
If a connection error occurs while communicating with the API a
HomeAssistantError will be raised.
"""
import threading
import logging
import json
import enum
import urllib.parse
import requests
import homeassistant.core as ha
from homeassistant.exceptions import HomeAssistantError
import homeassistant.bootstrap as bootstrap
from homeassistant.const import (
SERVER_PORT, HTTP_HEADER_HA_AUTH, URL_API, URL_API_STATES,
URL_API_STATES_ENTITY, URL_API_EVENTS, URL_API_EVENTS_EVENT,
URL_API_SERVICES, URL_API_SERVICES_SERVICE, URL_API_EVENT_FORWARD)
METHOD_GET = "get"
METHOD_POST = "post"
METHOD_DELETE = "delete"
_LOGGER = logging.getLogger(__name__)
class APIStatus(enum.Enum):
""" Represents API status. """
# pylint: disable=no-init,invalid-name,too-few-public-methods
OK = "ok"
INVALID_PASSWORD = "invalid_password"
CANNOT_CONNECT = "cannot_connect"
UNKNOWN = "unknown"
def __str__(self):
return self.value
class API(object):
""" Object to pass around Home Assistant API location and credentials. """
# pylint: disable=too-few-public-methods
def __init__(self, host, api_password=None, port=None):
self.host = host
self.port = port or SERVER_PORT
self.api_password = api_password
self.base_url = "http://{}:{}".format(host, self.port)
self.status = None
self._headers = {}
if api_password is not None:
self._headers[HTTP_HEADER_HA_AUTH] = api_password
def validate_api(self, force_validate=False):
""" Tests if we can communicate with the API. """
if self.status is None or force_validate:
self.status = validate_api(self)
return self.status == APIStatus.OK
def __call__(self, method, path, data=None):
""" Makes a call to the Home Assistant api. """
if data is not None:
data = json.dumps(data, cls=JSONEncoder)
url = urllib.parse.urljoin(self.base_url, path)
try:
if method == METHOD_GET:
return requests.get(
url, params=data, timeout=5, headers=self._headers)
else:
return requests.request(
method, url, data=data, timeout=5, headers=self._headers)
except requests.exceptions.ConnectionError:
_LOGGER.exception("Error connecting to server")
raise HomeAssistantError("Error connecting to server")
except requests.exceptions.Timeout:
error = "Timeout when talking to {}".format(self.host)
_LOGGER.exception(error)
raise HomeAssistantError(error)
def __repr__(self):
return "API({}, {}, {})".format(
self.host, self.api_password, self.port)
class HomeAssistant(ha.HomeAssistant):
""" Home Assistant that forwards work. """
# pylint: disable=super-init-not-called,too-many-instance-attributes
def __init__(self, remote_api, local_api=None):
if not remote_api.validate_api():
raise HomeAssistantError(
"Remote API at {}:{} not valid: {}".format(
remote_api.host, remote_api.port, remote_api.status))
self.remote_api = remote_api
self.pool = pool = ha.create_worker_pool()
self.bus = EventBus(remote_api, pool)
self.services = ha.ServiceRegistry(self.bus, pool)
self.states = StateMachine(self.bus, self.remote_api)
self.config = ha.Config()
self.config.api = local_api
def start(self):
# Ensure a local API exists to connect with remote
if self.config.api is None:
if not bootstrap.setup_component(self, 'api'):
raise HomeAssistantError(
'Unable to setup local API to receive events')
ha.create_timer(self)
self.bus.fire(ha.EVENT_HOMEASSISTANT_START,
origin=ha.EventOrigin.remote)
# Setup that events from remote_api get forwarded to local_api
# Do this after we fire START, otherwise HTTP is not started
if not connect_remote_events(self.remote_api, self.config.api):
raise HomeAssistantError((
'Could not setup event forwarding from api {} to '
'local api {}').format(self.remote_api, self.config.api))
def stop(self):
""" Stops Home Assistant and shuts down all threads. """
_LOGGER.info("Stopping")
self.bus.fire(ha.EVENT_HOMEASSISTANT_STOP,
origin=ha.EventOrigin.remote)
# Disconnect master event forwarding
disconnect_remote_events(self.remote_api, self.config.api)
# Wait till all responses to homeassistant_stop are done
self.pool.block_till_done()
self.pool.stop()
class EventBus(ha.EventBus):
""" EventBus implementation that forwards fire_event to remote API. """
# pylint: disable=too-few-public-methods
def __init__(self, api, pool=None):
super().__init__(pool)
self._api = api
def fire(self, event_type, event_data=None, origin=ha.EventOrigin.local):
""" Forward local events to remote target,
handles remote event as usual. """
# All local events that are not TIME_CHANGED are forwarded to API
if origin == ha.EventOrigin.local and \
event_type != ha.EVENT_TIME_CHANGED:
fire_event(self._api, event_type, event_data)
else:
super().fire(event_type, event_data, origin)
class EventForwarder(object):
""" Listens for events and forwards to specified APIs. """
def __init__(self, hass, restrict_origin=None):
self.hass = hass
self.restrict_origin = restrict_origin
# We use a tuple (host, port) as key to ensure
# that we do not forward to the same host twice
self._targets = {}
self._lock = threading.Lock()
def connect(self, api):
"""
Attach to a HA instance and forward events.
Will overwrite old target if one exists with same host/port.
"""
with self._lock:
if len(self._targets) == 0:
# First target we get, setup listener for events
self.hass.bus.listen(ha.MATCH_ALL, self._event_listener)
key = (api.host, api.port)
self._targets[key] = api
def disconnect(self, api):
""" Removes target from being forwarded to. """
with self._lock:
key = (api.host, api.port)
did_remove = self._targets.pop(key, None) is None
if len(self._targets) == 0:
# Remove event listener if no forwarding targets present
self.hass.bus.remove_listener(ha.MATCH_ALL,
self._event_listener)
return did_remove
def _event_listener(self, event):
""" Listen and forwards all events. """
with self._lock:
# We don't forward time events or, if enabled, non-local events
if event.event_type == ha.EVENT_TIME_CHANGED or \
(self.restrict_origin and event.origin != self.restrict_origin):
return
for api in self._targets.values():
fire_event(api, event.event_type, event.data)
class StateMachine(ha.StateMachine):
"""
Fires set events to an API.
Uses state_change events to track states.
"""
def __init__(self, bus, api):
super().__init__(None)
self._api = api
self.mirror()
bus.listen(ha.EVENT_STATE_CHANGED, self._state_changed_listener)
def set(self, entity_id, new_state, attributes=None):
""" Calls set_state on remote API . """
set_state(self._api, entity_id, new_state, attributes)
def mirror(self):
""" Discards current data and mirrors the remote state machine. """
self._states = {state.entity_id: state for state
in get_states(self._api)}
def _state_changed_listener(self, event):
""" Listens for state changed events and applies them. """
self._states[event.data['entity_id']] = event.data['new_state']
class JSONEncoder(json.JSONEncoder):
""" JSONEncoder that supports Home Assistant objects. """
# pylint: disable=too-few-public-methods,method-hidden
def default(self, obj):
""" Converts Home Assistant objects and hands
other objects to the original method. """
if hasattr(obj, 'as_dict'):
return obj.as_dict()
try:
return json.JSONEncoder.default(self, obj)
except TypeError:
# If the JSON serializer couldn't serialize it
# it might be a generator, convert it to a list
try:
return [self.default(child_obj)
for child_obj in obj]
except TypeError:
# Ok, we're lost, cause the original error
return json.JSONEncoder.default(self, obj)
def validate_api(api):
""" Makes a call to validate API. """
try:
req = api(METHOD_GET, URL_API)
if req.status_code == 200:
return APIStatus.OK
elif req.status_code == 401:
return APIStatus.INVALID_PASSWORD
else:
return APIStatus.UNKNOWN
except HomeAssistantError:
return APIStatus.CANNOT_CONNECT
def connect_remote_events(from_api, to_api):
""" Sets up from_api to forward all events to to_api. """
data = {
'host': to_api.host,
'api_password': to_api.api_password,
'port': to_api.port
}
try:
req = from_api(METHOD_POST, URL_API_EVENT_FORWARD, data)
if req.status_code == 200:
return True
else:
_LOGGER.error(
"Error setting up event forwarding: %s - %s",
req.status_code, req.text)
return False
except HomeAssistantError:
_LOGGER.exception("Error setting up event forwarding")
return False
def disconnect_remote_events(from_api, to_api):
""" Disconnects forwarding events from from_api to to_api. """
data = {
'host': to_api.host,
'port': to_api.port
}
try:
req = from_api(METHOD_DELETE, URL_API_EVENT_FORWARD, data)
if req.status_code == 200:
return True
else:
_LOGGER.error(
"Error removing event forwarding: %s - %s",
req.status_code, req.text)
return False
except HomeAssistantError:
_LOGGER.exception("Error removing an event forwarder")
return False
def get_event_listeners(api):
""" List of events that is being listened for. """
try:
req = api(METHOD_GET, URL_API_EVENTS)
return req.json() if req.status_code == 200 else {}
except (HomeAssistantError, ValueError):
# ValueError if req.json() can't parse the json
_LOGGER.exception("Unexpected result retrieving event listeners")
return {}
def fire_event(api, event_type, data=None):
""" Fire an event at remote API. """
try:
req = api(METHOD_POST, URL_API_EVENTS_EVENT.format(event_type), data)
if req.status_code != 200:
_LOGGER.error("Error firing event: %d - %d",
req.status_code, req.text)
except HomeAssistantError:
_LOGGER.exception("Error firing event")
def get_state(api, entity_id):
""" Queries given API for state of entity_id. """
try:
req = api(METHOD_GET,
URL_API_STATES_ENTITY.format(entity_id))
# req.status_code == 422 if entity does not exist
return ha.State.from_dict(req.json()) \
if req.status_code == 200 else None
except (HomeAssistantError, ValueError):
# ValueError if req.json() can't parse the json
_LOGGER.exception("Error fetching state")
return None
def get_states(api):
""" Queries given API for all states. """
try:
req = api(METHOD_GET,
URL_API_STATES)
return [ha.State.from_dict(item) for
item in req.json()]
except (HomeAssistantError, ValueError, AttributeError):
# ValueError if req.json() can't parse the json
_LOGGER.exception("Error fetching states")
return []
def set_state(api, entity_id, new_state, attributes=None):
"""
Tells API to update state for entity_id.
Returns True if success.
"""
attributes = attributes or {}
data = {'state': new_state,
'attributes': attributes}
try:
req = api(METHOD_POST,
URL_API_STATES_ENTITY.format(entity_id),
data)
if req.status_code not in (200, 201):
_LOGGER.error("Error changing state: %d - %s",
req.status_code, req.text)
return False
else:
return True
except HomeAssistantError:
_LOGGER.exception("Error setting state")
return False
def is_state(api, entity_id, state):
""" Queries API to see if entity_id is specified state. """
cur_state = get_state(api, entity_id)
return cur_state and cur_state.state == state
def get_services(api):
"""
Returns a list of dicts. Each dict has a string "domain" and
a list of strings "services".
"""
try:
req = api(METHOD_GET, URL_API_SERVICES)
return req.json() if req.status_code == 200 else {}
except (HomeAssistantError, ValueError):
# ValueError if req.json() can't parse the json
_LOGGER.exception("Got unexpected services result")
return {}
def call_service(api, domain, service, service_data=None):
""" Calls a service at the remote API. """
try:
req = api(METHOD_POST,
URL_API_SERVICES_SERVICE.format(domain, service),
service_data)
if req.status_code != 200:
_LOGGER.error("Error calling service: %d - %s",
req.status_code, req.text)
except HomeAssistantError:
_LOGGER.exception("Error calling service")