event emitter python

Author: jordanpaulchan

event-emitter/event-emitter.py

@@ -0,0 +1,44 @@
+class EventEmitter:
+ def __init__(self):
+ self.events = {}
+
+ def subscribe(self, event, callback):
+ if event in self.events:
+ self.events[event].append(callback)
+ else:
+ self.events[event] = [callback]
+
+ def unsubscribe(self, event, callback=None):
+ if event not in self.events:
+ return
+
+ if not callback:
+ self.events.pop(event, None)
+ else:
+ self.events[event] = list(
+ filter(lambda c: c != callback, self.events[event]))
+
+ def emit(self, event, *args):
+ if event not in self.events:
+ return
+
+ for callback in self.events[event]:
+ callback(*args)
+
+
+def print_callback(*args):
+ for arg in args:
+ print(arg)
+
+
+eventEmitter = EventEmitter()
+eventEmitter.subscribe("print", print_callback)
+eventEmitter.emit("print", "Hello World")
+eventEmitter.subscribe("print", print_callback)
+eventEmitter.emit("print", "Test")
+eventEmitter.unsubscribe("print")
+eventEmitter.emit("print", "Don't print")
+eventEmitter.subscribe("print", print_callback)
+eventEmitter.emit("print", "Print")
+eventEmitter.unsubscribe("print", print_callback)
+eventEmitter.emit("print", "Don't print")