GreenRocket 0.11

A simple implementation of Observer pattern via Signals

Green Rocket is a simple implementation of Observer (or Publish/Subscribe)

design pattern using Signals.

Create specific signal from base class:

>>> from greenrocket import Signal
>>> class MySignal(Signal):
...     pass
...

Subscribe handler:

>>> @MySignal.subscribe
... def handler(signal):
...     print('handler: ' + repr(signal))
...

Fire signal:

>>> MySignal().fire()
handler: MySignal()

Note, that signal propagates over inheritance, i.e. all subscribes of base signal will be called when child signal fired:

>>> @Signal.subscribe
... def base_hadler(signal):
...     print('base_handler: ' + repr(signal))
...
>>> MySignal().fire()
handler: MySignal()
base_handler: MySignal()

Unsubscribe handler:

>>> MySignal.unsubscribe(handler)
>>> MySignal().fire()
base_handler: MySignal()

Any keyword argument passed to signal constructor becomes its attribute:

>>> s = Signal(a=1, b=2)
>>> s.a
1
>>> s.b
2