eventpy -- Python library for event dispatcher and callback list

eventpy is a Python event library that provides tools that enable your application components to communicate with each other by dispatching events and listening for them. With eventpy you can easily implement signal/slot mechanism, or observer pattern.
This library is the Python version rewritten from the C++ library eventpp, both are developed by the same developer.

Facts and features

• Powerful
  • Supports synchronous event dispatching and asynchronous event queue.
  • Configurable and extensible with policies.
• Robust
  • Supports nested event. During the process of handling an event, a listener can safely dispatch event and append/prepend/insert/remove other listeners.
  • Thread safety. Supports multi-threading.
  • Well tested. Backed by unit tests.
• Flexible and easy to use
  • Listeners and events can be of any type and do not need to be inherited from any base class.
  • Requires Python 3. Tested with Python 3.7 and Cython.

License

Apache License, Version 2.0

Version 0.0.1

eventpy is currently usable and stable.

Source code

https://github.com/wqking/eventpy

Quick start

Install

pip install eventpy

Package

eventpy

Using CallbackList

# create a CallbackList
callbackList = CallbackList()
callbackList.append(lambda s, b : print("Got callback 1, s is %s b is %d" % (s, b)))
def anotherCallback(s, b) :
	print("Got callback 2, s is %s b is %d" % (s, b))
callbackList.append(anotherCallback)
# Invoke the callback list
callbackList("Hello world", True)

Using EventDispatcher

# create an EventDispatcher
dispatcher = EventDispatcher()

dispatcher.appendListener(3, lambda s, b : print("Got event 3, s is %s b is %d" % (s, b)))
dispatcher.appendListener(5, lambda s, b : print("Got event 5, s is %s b is %d" % (s, b)))
dispatcher.appendListener(5, lambda s, b : print("Got another event 5, s is %s b is %d" % (s, b)))

# Dispatch the events, the first argument is always the event type.
dispatcher.dispatch(3, "Hello", True)
dispatcher.dispatch(5, "World", False)

Using EventQueue

# create an EventQueue
queue = eventqueue.EventQueue()
queue.appendListener(3, lambda s, n : print("Got event 3, s is %s n is %d" % (s, n)))
queue.appendListener(5, lambda s, n : print("Got event 5, s is %s n is %d" % (s, n)))
queue.appendListener(5, lambda s, n : print("Got another event 5, s is %s n is %d" % (s, n)))

# Enqueue the events, the first argument is always the event type.
# The listeners are not triggered during enqueue.
queue.enqueue(3, "Hello", 38)
queue.enqueue(5, "World", 58)

# Process the event queue, dispatch all queued events.
queue.process();

Documentations

• Overview
• Tutorials of CallbackList
• Tutorials of EventDispatcher
• Tutorials of EventQueue
• Class CallbackList
• Class EventDispatcher
• Class EventQueue
• Policies -- configure eventpy
• There are runnable tutorials in the unit tests.

Run the unit tests

Go to the root folder of eventpy, run python -m pytest