Simple python events library
Project description
PyEventEmitter
Python events library, heavily inspired by Node.js’ EventEmitter.
Installation
$ pip install PyEventEmitter
How to use
The library provides an EventEmitter class. This class let you bind listeners to events and trigger events.
import event_emitter as events
em = events.EventEmitter()
def hello(who):
print('Hello {}'.format(who))
em.on('hello', hello)
em.emit('hello', who='World') # prints Hello World
You can also use on decorator :
import event_emitter as events
em = events.EventEmitter()
@events.on(emitter=em, event='hello')
def hello(who):
print('Hello {}'.format(who))
em.emit('hello', who='World') # prints Hello World
Using once instead of on may be usefull if you want your listener to be called once :
import event_emitter as events
em = events.EventEmitter()
def hello(who):
print('Hello {}'.format(who))
em.once('hello', hello)
em.emit('hello', who='World') # prints Hello World
em.emit('hello', who='World') # nothing happens
Of course, there is also a decorator for this :
import event_emitter as events
em = events.EventEmitter()
@events.once(emitter=em, event='hello')
def hello(who):
print('Hello {}'.format(who))
em.emit('hello', who='World') # prints Hello World
You can remove a listener bound to an event :
import event_emitter as events
em = events.EventEmitter()
def hello(who):
print('Hello {}'.format(who))
em.on('hello', hello)
em.remove('hello', hello)
em.emit('hello', who='World') # nothing happens
Please note that this method will remove at moste one listener from the list. If the same listener was bound multiple times to the event, this method has to be invoked multiple times to remove all the occurences.
You can also remove all listeners bound to an event thanks to remove_all.
The count method returns the number of listeners bound to an event :
import event_emitter as events
em = events.EventEmitter()
def hello(who):
print('Hello {}'.format(who))
em.on('hello', hello)
print(em.count('hello')) # prints 1
Project details
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