mediator 0.2.0

A library implements the Mediator pattern to make your code extensible

A library implements the Mediator pattern to make your code extensible.

Inspired by symfony/event-dispatcher component.

Installation

Using pip:

# pip install mediator

Manually:

$ git clone https://github.com/Kilte/mediator
$ cd mediator
# python setup.py install

Usage

from mediator import Mediator

m = Mediator()

Adding a listener

def event_listener(event):
    print('Got event: %r' % event)

m.add_listener('event_name', event_listener)

Triggering events

event = m.dispatch('event_name')
# Got event: <mediator.Event object at 0x7f954bc2b250>
print(event)
# <mediator.Event object at 0x7f954bc2b250>

Removing a listener

def another_listener(event):
    print('Got another event: %r' % event)

m.add_listener('event_name', another_listener)
m.remove_listener('event_name', event_listener)
m.dispatch('event_name')
# Got another event: <mediator.Event object at 0x7f954bbbd510>

Removing all listeners

m.remove_listener('event_name')
m.dispatch('event_name')
# Nothing was happened

Using priorities

m.add_listener('test_event', another_listener, -255)
m.add_listener('test_event', event_listener, 255)
m.dispatch('test_event')
# Got another event: <mediator.Event object at 0x7f954bbbd510>
# Got event: <mediator.Event object at 0x7f954bbbd510>

Defining custom events

from mediator import Event

def my_event_listener(event):
    event.params = 'params'


class MyEvent(Event):
    def __init__(self):
        super(MyEvent, self).__init__('my_event')
        self.params = None

event = MyEvent()
m.add_listener('my_event', my_event_listener)
m.dispatch(event)
print(event.params)
# params

Using Subscribers

from mediator import SubscriberInterface


class Subscriber(SubscriberInterface):
    def first(self, event):
        event.first = True

    def middle(self, event):
        event.middle = True

    def last(self, event):
        event.last = True

    def event2_handler(self, event):
        event.success = True

    def event3_handler(self, event):
        event.success = True

    def get_subscribed_events(self):
        return {
            'event1': [
                ['middle'],
                ['first', -100],
                ['last', 100]
            ],
            'event2': 'event2_handler',
            'event3': ['event3_handler']
        }

class Event1(Event):
     def __init__(self):
         super(Event1, self).__init__('event1')
         self.first = False
         self.middle = False
         self.last = False

class Event2(Event):
     def __init__(self):
         super(Event2, self).__init__('event2')
         self.success = True

class Event3(Event2):
    pass

subscriber = Subscriber()
event1 = Event1()
event2 = Event2()
event3 = Event3()

m.add_subscriber(subscriber)

m.dispatch(event1)
print('%s;%s;%s' % (event1.first, event1.middle, event1.last))
# True;True;True

m.dispatch(event2)
print(event2.success)
# True

m.dispatch(event3)
print(event3.success)
# True

Using a class name as event name

class EventWithoutName(Event):
     def __init__(self):
         super(Event1, self).__init__()
         self.attr = 'val'


 def on_event_without_name(event):
    event.attr = 'new-val'

 m.add_listener('EventWithoutName', on_event_without_name)
 m.dispatch(EventWithoutName())

Adding listeners using decorator

import sys


@EventWithoutName.listen(priority=255)  # Priority is optional
def another_event_without_name_listener(event):
    event.attr = 'another-val'

# Don't forget to call Mediator.scan(module)!
m.scan(sys.modules[__name__])
m.dispatch(EventWithoutName())

See source code and tests for more information.

Changelog

0.2.0 (17.12.2015)

• Automatic event name detection based on a class name.

• Added %Event%.listen decorator.

0.1.0 (19.11.2015)

• First release.

Contributing

• Fork and clone it

• Create your feature branch (git checkout -b awesome-feature)

• Make your changes

• Write/update tests, if it’s necessary (make buildout && make tests)

• Update README.md, if it’s necessary

• Push your branch (git push origin awesome-feature)

• Send a pull request

LICENSE

The MIT License (MIT)