Quick Start

Installation

You can install the library from PyPI using typical methods, such as pip:

python3 -m pip install harami

Usage

Let’s try a “learn by example” approach. The following code is a Widget Factory implementation. The Widget Factory raises an event on Widget Creation, it also emits the Widgets it creates through an Observable. The MyApp class creates an instance of the Widget Factory, adds an event handler, adds an observer, and finally requests the factory create a Widget.

from harami import *

class Widget:
    color:str
    def __init__(self, color: str = None) -> None:
        self.color = color

class WidgetEventArgs(EventArgs):
    @property
    def widget(self) -> Widget:
        return self.args[0]

class WidgetFactory:
    def __init__(self) -> None:
        self.widget_emitter = Observable[Widget]()

    @event(WidgetEventArgs)
    def on_widget_created(self, widget: Widget) -> None:
        # this is an "Event Source", it does not require an
        # implementation, but one can be provided if it
        # makes sense for your application
        pass

    def create_widget(color: str) -> None:
        widget = Widget(color)
        self.on_widget_created(widget)
        self.widget_emitter(widget)

class MyApp:
    def __init__(self) -> None:
        self.__widget_factory = WidgetFactory()
        self.__widget_factory.on_widget_created += self.__on_widget_created_handler
        self.__widget_factory.widget_emitter += self.__widget_observer

    def __on_widget_created_handler(sender:object, e: WidgetEventArgs) -> None:
        print(f'Widget Created: color is {e.widget.color}')

    def __widget_observer(widget: Widget) -> None:
        print(f'Widget Emitted: color is {e.widget.color}')

    def run(self) -> None:
        self.__widget_factory.create_widget('red')

MyApp().run()

When executed the program outputs the following:

Widget Created: color is red
Widget Emitted: color is red