Source code for spotify.eventloop

from __future__ import unicode_literals

import logging
import threading

try:
    # Python 3
    import queue
except ImportError:
    # Python 2
    import Queue as queue

import spotify


__all__ = ['EventLoop']

logger = logging.getLogger(__name__)


[docs]class EventLoop(threading.Thread): """Event loop for automatically processing events from libspotify. The event loop is a :class:`~threading.Thread` that listens to :attr:`~spotify.SessionEvent.NOTIFY_MAIN_THREAD` events and calls :meth:`~spotify.Session.process_events` when needed. To use it, pass it your :class:`~spotify.Session` instance and call :meth:`start`:: >>> session = spotify.Session() >>> event_loop = spotify.EventLoop(session) >>> event_loop.start() The event loop thread is a daemon thread, so it will not stop your application from exiting. If you wish to stop the event loop without stopping your entire application, call :meth:`stop`. You may call :meth:`~threading.Thread.join` to block until the event loop thread has finished, just like for any other thread. .. warning:: If you use :class:`EventLoop` to process the libspotify events, any event listeners you've registered will be called from the event loop thread. pyspotify itself is thread safe, but you'll need to ensure that you have proper synchronization in your own application code, as always when working with threads. """ daemon = True name = 'SpotifyEventLoop' def __init__(self, session): threading.Thread.__init__(self) self._session = session self._runnable = True self._queue = queue.Queue()
[docs] def start(self): """Start the event loop.""" self._session.on( spotify.SessionEvent.NOTIFY_MAIN_THREAD, self._on_notify_main_thread ) threading.Thread.start(self)
[docs] def stop(self): """Stop the event loop.""" self._runnable = False self._session.off( spotify.SessionEvent.NOTIFY_MAIN_THREAD, self._on_notify_main_thread )
[docs] def run(self): logger.debug('Spotify event loop started') timeout = self._session.process_events() / 1000.0 while self._runnable: try: logger.debug('Waiting %.3fs for new events', timeout) self._queue.get(timeout=timeout) except queue.Empty: logger.debug('Timeout reached; processing events') else: logger.debug('Notification received; processing events') finally: timeout = self._session.process_events() / 1000.0 logger.debug('Spotify event loop stopped')
def _on_notify_main_thread(self, session): # WARNING: This event listener is called from an internal libspotify # thread. It must not block. try: self._queue.put_nowait(1) except queue.Full: logger.warning( 'pyspotify event loop queue full; dropped notification event' )