62 lines
1.9 KiB
Python
62 lines
1.9 KiB
Python
import inspect
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import logging
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import threading
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class EventGenerator(object):
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"""
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Abstract class for event generators. It allows to fire events to the bus and
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trigger/register/unregister custom callback handlers associated to event
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types. Both plugins and backends extend this class.
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"""
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logger = logging.getLogger('platypush')
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def __init__(self, *args, **kwargs):
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self._event_handlers = {} # Event type => callback map
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def fire_event(self, event):
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# Fires an event (instance of :class:`platypush.message.event.Event` or a
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# subclass) to the internal bus and triggers any handler callback
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# associated to the event type or any of its super-classes.
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def hndl_thread(handler):
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handler(event)
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from platypush.backend import Backend
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from platypush.context import get_bus
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bus = self.bus if isinstance(self, Backend) else get_bus()
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if not bus:
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self.logger.warning('No bus available to post the event: {}'.format(event))
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else:
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bus.post(event)
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handlers = set()
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for cls in inspect.getmro(event.__class__):
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if cls in self._event_handlers:
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handlers.update(self._event_handlers[cls])
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for hndl in handlers:
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threading.Thread(target=hndl_thread, args=(hndl,)).start()
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def register_handler(self, event_type, callback):
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if event_type not in self._event_handlers:
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self._event_handlers[event_type] = set()
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self._event_handlers[event_type].add(callback)
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def unregister_handler(self, event_type, callback):
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if event_type not in self._event_handlers:
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return
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if callback not in self._event_handlers[event_type]:
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return
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self._event_handlers[event_type].remove(callback)
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if not self._event_handlers[event_type]:
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del self._event_handlers[event_type]
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# vim:sw=4:ts=4:et:
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