from asgiref.sync import async_to_sync
from channels.layers import get_channel_layer
from django.dispatch import Signal
from djangochannelsrestframework.observer.base_observer import BaseObserver
class Observer(BaseObserver):
def __init__(self, func, signal: Signal = None, kwargs=None):
super().__init__(func)
if kwargs is None:
kwargs = {}
self.signal = signal
self.signal_kwargs = kwargs
self._serializer = None
self.signal.connect(self.handle, **self.signal_kwargs)
def handle(self, signal, *args, **kwargs):
message = self.serialize(signal, *args, **kwargs)
channel_layer = get_channel_layer()
for group_name in self.group_names_for_signal(*args, message=message, **kwargs):
async_to_sync(channel_layer.group_send)(group_name, message)
def group_names(self, *args, **kwargs):
yield "{}-{}-signal-{}".format(
self._uuid,
self.func.__name__.replace("_", "."),
".".join(
arg.lower().replace("_", ".") for arg in self.signal.providing_args
),
)
