Skip to main content

Lightweight Event Handling

Project description

python-dispatch

Lightweight event handling for Python

Build StatusCoverage StatusPyPI versionGitHub license

Description

This is an implementation of the "Observer Pattern" with inspiration from the Kivy framework. Many of the features though are intentionally stripped down and more generalized. The goal is to have a simple drop-in library with no dependencies that stays out of the programmer's way.

Installation

pip install python-dispatch

Links

Project Home https://github.com/nocarryr/python-dispatch
PyPI https://pypi.python.org/pypi/python-dispatch
Documentation https://nocarryr.github.io/python-dispatch

Usage

Events

from pydispatch import Dispatcher

class MyEmitter(Dispatcher):
    # Events are defined in classes and subclasses with the '_events_' attribute
    _events_ = ['on_state', 'new_data']
    def do_some_stuff(self):
        # do stuff that makes new data
        data = self.get_some_data()
        # Then emit the change with optional positional and keyword arguments
        self.emit('new_data', data=data)

# An observer - could inherit from Dispatcher or any other class
class MyListener(object):
    def on_new_data(self, *args, **kwargs):
        data = kwargs.get('data')
        print('I got data: {}'.format(data))
    def on_emitter_state(self, *args, **kwargs):
        print('emitter state changed')

emitter = MyEmitter()
listener = MyListener()

emitter.bind(on_state=listener.on_emitter_state)
emitter.bind(new_data=listener.on_new_data)

emitter.do_some_stuff()
# >>> I got data: ...

emitter.emit('on_state')
# >>> emitter state changed

Properties

from pydispatch import Dispatcher, Property

class MyEmitter(Dispatcher):
    # Property objects are defined and named at the class level.
    # They will become instance attributes that will emit events when their values change
    name = Property()
    value = Property()

class MyListener(object):
    def on_name(self, instance, value, **kwargs):
        print('emitter name is {}'.format(value))
    def on_value(self, instance, value, **kwargs):
        print('emitter value is {}'.format(value))

emitter = MyEmitter()
listener = MyListener()

emitter.bind(name=listener.on_name, value=listener.on_value)

emitter.name = 'foo'
# >>> emitter name is foo
emitter.value = 42
# >>> emitter value is 42

Project details


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Files for python-dispatch, version 0.1.2
Filename, size File type Python version Upload date Hashes
Filename, size python_dispatch-0.1.2-py2.py3-none-any.whl (14.6 kB) File type Wheel Python version py2.py3 Upload date Hashes View hashes
Filename, size python-dispatch-0.1.2.tar.gz (13.8 kB) File type Source Python version None Upload date Hashes View hashes

Supported by

Elastic Elastic Search Pingdom Pingdom Monitoring Google Google BigQuery Sentry Sentry Error logging AWS AWS Cloud computing DataDog DataDog Monitoring Fastly Fastly CDN SignalFx SignalFx Supporter DigiCert DigiCert EV certificate StatusPage StatusPage Status page