Source code for soco.events_asyncio

"""Classes to handle Sonos UPnP Events and Subscriptions using asyncio.

The `Subscription` class from this module will be used in
:py:mod:`soco.services` if `config.EVENTS_MODULE` is set
to point to this module.

Example:

    Run this code, and change your volume, tracks etc::

        import logging

        logging.basicConfig()
        import soco
        import asyncio
        from pprint import pprint

        from soco import events_asyncio

        soco.config.EVENTS_MODULE = events_asyncio


        def print_event(event):
            try:
                pprint(event.variables)
            except Exception as e:
                print("There was an error in print_event:", e)


        def _get_device():
            device = soco.discover().pop().group.coordinator
            print(device.player_name)
            return device


        async def main():
            # pick a device at random and use it to get
            # the group coordinator
            loop = asyncio.get_event_loop()
            device = await loop.run_in_executor(None, _get_device)
            sub = await device.renderingControl.subscribe()
            sub2 = await device.avTransport.subscribe()
            sub.callback = print_event
            sub2.callback = print_event

            async def before_shutdown():
                await sub.unsubscribe()
                await sub2.unsubscribe()
                await events_asyncio.event_listener.async_stop()

            await asyncio.sleep(1)
            print("Renewing subscription..")
            await sub.renew()

            await asyncio.sleep(100)
            await before_shutdown()


        if __name__ == "__main__":
            asyncio.run(main())

"""

import logging
import socket
import sys
import time
import asyncio

try:
    from aiohttp import ClientSession, ClientTimeout, web
except ImportError as error:
    print(
        """ImportError: {}:
    Use of the SoCo events_asyncio module requires the 'aiohttp'
    package and its dependencies to be installed. aiohttp is not
    installed with SoCo by default due to potential issues installing
    the dependencies 'multidict' and 'yarl' on some platforms.
    See: https://github.com/SoCo/SoCo/issues/819""".format(
            error
        )
    )
    sys.exit(1)

# Event is imported for compatibility with events.py
# pylint: disable=unused-import
from .events_base import Event  # noqa: F401

from .events_base import (  # noqa: E402
    get_listen_ip,
    parse_event_xml,
    EventNotifyHandlerBase,
    EventListenerBase,
    SubscriptionBase,
    SubscriptionsMap,
)

from .exceptions import SoCoException  # noqa: E402

log = logging.getLogger(__name__)  # pylint: disable=C0103


[docs]class EventNotifyHandler(EventNotifyHandlerBase): """Handles HTTP ``NOTIFY`` Verbs sent to the listener server. Inherits from `soco.events_base.EventNotifyHandlerBase`. """ def __init__(self): super().__init__() # The SubscriptionsMapAio instance created when this module is # imported. This is referenced by # soco.events_base.EventNotifyHandlerBase. self.subscriptions_map = subscriptions_map
[docs] async def notify(self, request): """Serve a ``NOTIFY`` request by calling `handle_notification` with the headers and content. """ content = await request.text() seq = request.headers["seq"] # Event sequence number sid = request.headers["sid"] # Event Subscription Identifier # find the relevant service from the sid # pylint: disable=no-member subscription = self.subscriptions_map.get_subscription(sid) # It might have been removed by another thread if subscription: timestamp = time.time() service = subscription.service self.log_event(seq, service.service_id, timestamp) log.debug("Event content: %s", content) if "x-sonos-http" in content: # parse_event_xml will generate I/O if # x-sonos-http is in the content variables = await asyncio.get_event_loop().run_in_executor( None, parse_event_xml, content ) else: variables = parse_event_xml(content) # Build the Event object event = Event(sid, seq, service, timestamp, variables) # pass the event details on to the service so it can update # its cache. # pylint: disable=protected-access service._update_cache_on_event(event) # Pass the event on for handling subscription.send_event(event) else: log.debug("No service registered for %s", sid) return web.Response(text="OK", status=200)
# pylint: disable=no-self-use, missing-docstring def log_event(self, seq, service_id, timestamp): log.debug("Event %s received for %s service at %s", seq, service_id, timestamp)
[docs]class EventListener(EventListenerBase): # pylint: disable=too-many-instance-attributes """The Event Listener. Runs an http server which is an endpoint for ``NOTIFY`` requests from Sonos devices. Inherits from `soco.events_base.EventListenerBase`. """ def __init__(self): super().__init__() self.sock = None self.ip_address = None self.port = None self.runner = None self.site = None self.session = None self.start_lock = None
[docs] def start(self, any_zone): """A stub since the first subscribe calls async_start.""" return
[docs] def listen(self, ip_address): """A stub since since async_listen is used.""" return
[docs] async def async_start(self, any_zone): """Start the event listener listening on the local machine under the lock. Args: any_zone (SoCo): Any Sonos device on the network. It does not matter which device. It is used only to find a local IP address reachable by the Sonos net. """ if not self.start_lock: self.start_lock = asyncio.Lock() async with self.start_lock: if self.is_running: return # Use configured IP address if there is one, else detect # automatically. ip_address = get_listen_ip(any_zone.ip_address) if not ip_address: log.exception("Could not start Event Listener: check network.") # Otherwise, no point trying to start server return port = await self.async_listen(ip_address) if not port: return self.address = (ip_address, port) client_timeout = ClientTimeout(total=10) self.session = ClientSession(raise_for_status=True, timeout=client_timeout) self.is_running = True log.debug("Event Listener started")
[docs] async def async_listen(self, ip_address): """Start the event listener listening on the local machine at port 1400 (default). If this port is unavailable, the listener will attempt to listen on the next available port, within a range of 100. Make sure that your firewall allows connections to this port. This method is called by `soco.events_base.EventListenerBase.start` Handling of requests is delegated to an instance of the `EventNotifyHandler` class. Args: ip_address (str): The local network interface on which the server should start listening. Returns: int: The port on which the server is listening. Note: The port on which the event listener listens is configurable. See `config.EVENT_LISTENER_PORT` """ for port_number in range( self.requested_port_number, self.requested_port_number + 100 ): try: if port_number > self.requested_port_number: log.debug("Trying next port (%d)", port_number) # pylint: disable=no-member sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.bind((ip_address, port_number)) sock.listen(200) self.sock = sock self.port = port_number break # pylint: disable=invalid-name except socket.error as e: log.warning("Could not bind to %s:%s: %s", ip_address, port_number, e) continue if not self.port: return None self.ip_address = ip_address await self._async_start() return self.port
async def _async_start(self): """Start the site.""" handler = EventNotifyHandler() app = web.Application() app.add_routes([web.route("notify", "", handler.notify)]) self.runner = web.AppRunner(app) await self.runner.setup() self.site = web.SockSite(self.runner, self.sock) await self.site.start() log.debug("Event listener running on %s", (self.ip_address, self.port))
[docs] async def async_stop(self): """Stop the listener.""" if self.site: await self.site.stop() self.site = None if self.runner: await self.runner.cleanup() self.runner = None if self.session: await self.session.close() self.session = None if self.sock: self.sock.close() self.sock = None self.port = None self.ip_address = None
# pylint: disable=unused-argument
[docs] def stop_listening(self, address): """Stop the listener.""" asyncio.ensure_future(self.async_stop())
[docs]class Subscription(SubscriptionBase): """A class representing the subscription to a UPnP event. Inherits from `soco.events_base.SubscriptionBase`. """ def __init__(self, service, callback=None): """ Args: service (Service): The SoCo `Service` to which the subscription should be made. event_queue (:class:`~queue.Queue`): A queue on which received events will be put. If not specified, a queue will be created and used. """ super().__init__(service, None) #: :py:obj:`function`: callback function to be called whenever an #: `Event` is received. If it is set and is callable, the callback #: function will be called with the `Event` as the only parameter and #: the Subscription's event queue won't be used. self.callback = callback # The SubscriptionsMapAio instance created when this module is # imported. This is referenced by soco.events_base.SubscriptionBase. self.subscriptions_map = subscriptions_map # The EventListener instance created when this module is imported. # This is referenced by soco.events_base.SubscriptionBase. self.event_listener = event_listener # Used to keep track of the auto_renew loop self._auto_renew_task = None # pylint: disable=arguments-differ
[docs] def subscribe(self, requested_timeout=None, auto_renew=False, strict=True): """Subscribe to the service. If requested_timeout is provided, a subscription valid for that number of seconds will be requested, but not guaranteed. Check `timeout` on return to find out what period of validity is actually allocated. This method calls `events_base.SubscriptionBase.subscribe`. Note: SoCo will try to unsubscribe any subscriptions which are still subscribed on program termination, but it is good practice for you to clean up by making sure that you call :meth:`unsubscribe` yourself. Args: requested_timeout(int, optional): The timeout to be requested. auto_renew (bool, optional): If `True`, renew the subscription automatically shortly before timeout. Default `False`. strict (bool, optional): If True and an Exception occurs during execution, the Exception will be raised or, if False, the Exception will be logged and the Subscription instance will be returned. Default `True`. Returns: `Subscription`: The Subscription instance. """ self.subscriptions_map.subscribing() future = asyncio.Future() subscribe = super().subscribe async def _async_wrap_subscribe(): try: if not self.event_listener.is_running: await self.event_listener.async_start(self.service.soco) await subscribe(requested_timeout, auto_renew) future.set_result(self) except SoCoException as ex: future.set_exception(ex) except Exception as exc: # pylint: disable=broad-except self._cancel_subscription(exc) if strict: future.set_exception(exc) else: self._log_exception(exc) future.set_result(self) finally: self.subscriptions_map.finished_subscribing() asyncio.ensure_future(_async_wrap_subscribe()) return future
def _log_exception(self, exc): """Log an exception during subscription.""" msg = ( "An Exception occurred: {}.".format(exc) + " Subscription to {},".format( self.service.base_url + self.service.event_subscription_url ) + " sid: {} has been cancelled".format(self.sid) ) log.exception(msg)
[docs] async def renew( self, requested_timeout=None, is_autorenew=False, strict=True ): # pylint: disable=invalid-overridden-method """renew(requested_timeout=None) Renew the event subscription. You should not try to renew a subscription which has been unsubscribed, or once it has expired. This method calls `events_base.SubscriptionBase.renew`. Args: requested_timeout (int, optional): The period for which a renewal request should be made. If None (the default), use the timeout requested on subscription. is_autorenew (bool, optional): Whether this is an autorenewal. Default `False`. strict (bool, optional): If True and an Exception occurs during execution, the Exception will be raised or, if False, the Exception will be logged and the Subscription instance will be returned. Default `True`. Returns: `Subscription`: The Subscription instance. """ try: return await super().renew(requested_timeout, is_autorenew) except Exception as exc: # pylint: disable=broad-except self._cancel_subscription(exc) if self.auto_renew_fail is not None and hasattr( self.auto_renew_fail, "__call__" ): # pylint: disable=not-callable self.auto_renew_fail(exc) else: self._log_exception(exc) if strict: raise return self
[docs] async def unsubscribe( self, strict=True ): # pylint: disable=invalid-overridden-method """unsubscribe() Unsubscribe from the service's events. Once unsubscribed, a Subscription instance should not be reused This method calls `events_base.SubscriptionBase.unsubscribe`. Args: strict (bool, optional): If True and an Exception occurs during execution, the Exception will be raised or, if False, the Exception will be logged and the Subscription instance will be returned. Default `True`. Returns: `Subscription`: The Subscription instance. """ try: unsub = super().unsubscribe() if unsub is None: return await unsub except Exception as exc: # pylint: disable=broad-except self._cancel_subscription(exc) if strict: raise self._log_exception(exc) return self
def _auto_renew_start(self, interval): """Starts the auto_renew loop.""" self._auto_renew_task = asyncio.get_event_loop().call_later( interval, self._auto_renew_run, interval ) def _auto_renew_run(self, interval): asyncio.ensure_future(self.renew(is_autorenew=True, strict=False)) self._auto_renew_start(interval) def _auto_renew_cancel(self): """Cancels the auto_renew loop""" if self._auto_renew_task: self._auto_renew_task.cancel() self._auto_renew_task = None # pylint: disable=no-self-use, too-many-branches, too-many-arguments def _request(self, method, url, headers, success, unconditional=None): """Sends an HTTP request. Args: method (str): 'SUBSCRIBE' or 'UNSUBSCRIBE'. url (str): The full endpoint to which the request is being sent. headers (dict): A dict of headers, each key and each value being of type `str`. success (function): A function to be called if the request succeeds. The function will be called with a dict of response headers as its only parameter. unconditional (function): An optional function to be called after the request is complete, regardless of its success. Takes no parameters. """ async def _async_make_request(): response = await self.event_listener.session.request( method, url, headers=headers ) if response.ok: success(response.headers) if unconditional: unconditional() return _async_make_request()
[docs]class nullcontext: # pylint: disable=invalid-name """Context manager that does no additional processing. Backport from python 3.7+ for older pythons. """ def __init__(self, enter_result=None): self.enter_result = enter_result def __enter__(self): return self.enter_result def __exit__(self, *excinfo): pass
[docs]class SubscriptionsMapAio(SubscriptionsMap): """Maintains a mapping of sids to `soco.events_asyncio.Subscription` instances. Registers each subscription to be unsubscribed at exit. Inherits from `soco.events_base.SubscriptionsMap`. """ def __init__(self): super().__init__() # A counter of calls to Subscription.subscribe # that have started but not completed. This is # to prevent the event listener from being stopped prematurely self._pending = 0 self.subscriptions_lock = nullcontext()
[docs] def register(self, subscription): """Register a subscription by updating local mapping of sid to subscription and registering it to be unsubscribed at exit. Args: subscription(`soco.events_asyncio.Subscription`): the subscription to be registered. """ # Add the subscription to the local dict of subscriptions so it # can be looked up by sid self.subscriptions[subscription.sid] = subscription
[docs] def subscribing(self): """Called when the `Subscription.subscribe` method commences execution. """ # Increment the counter self._pending += 1
[docs] def finished_subscribing(self): """Called when the `Subscription.subscribe` method completes execution. """ # Decrement the counter self._pending -= 1
@property def count(self): """ `int`: The number of active or pending subscriptions. """ return len(self.subscriptions) + self._pending
subscriptions_map = SubscriptionsMapAio() # pylint: disable=C0103 event_listener = EventListener() # pylint: disable=C0103