events-manager 0.1.0

An event system extension for Python

events-manager

Python event system support implementation package.

Getting started

Requirements

• Python >= 3.8

Installation

pip install events-manager

Usage

Creating an event

from events_manager import Event

class FooEvent(Event):
    pass

Listening and emitting an Event

Listen means that when an event of the type passed as the first argument to the listen method is emitted, the callable passed as second argument will be invoked passing the event emitted.

from events_manager import Event, listen, emit

def on_foo_event(event: Event):
    print(f"Callable invoked on {type(event).__name__}")

if __name__ == '__main__':    
    listen(FooEvent, on_foo_event)   
    
    foo_event = FooEvent()

    print("Emitting event...")
    emit(foo_event)

Emitting event...
Callable invoked on FooEvent

Process finished with exit code 0

The Events Manager supports both sync and async listeners.

from events_manager import Event, listen, emit
from asyncio import sleep

async def on_foo_event(event: Event) -> None:
    await sleep(10)
    print(f"Awaitable awaited on {type(event).__name__}")

if __name__ == '__main__':    
    listen(FooEvent, on_foo_event)
    
    foo_event = FooEvent()
    
    print("Emitting event...")
    emit(foo_event)

Emitting event...
Awaitable awaited on FooEvent

Process finished with exit code 0

args and kwargs support

The listen method supports also args and kwargs that will be passed to the listened listener.

from __future__ import annotations
from events_manager import Event, listen, emit

class Bar:
    @staticmethod
    def on_foo_event(event: Event, self: Bar) -> None:
        self.__do_something(event)
        
    def __do_something(self, event: Event) -> None:
        print(self)

if __name__ == '__main__':    
    bar = Bar()
    print(bar)
    
    listen(FooEvent, Bar.on_foo_event, bar)
    
    foo_event = FooEvent()
    
    print("Emitting event...")
    emit(foo_event)

<__main__.Bar object at 0x000001E4541FB4C0> 
Emitting event...
<__main__.Bar object at 0x000001E4541FB4C0>

Process finished with exit code 0

@on decorator

Instead of calling listen method, you can also use the @on decorator.

from events_manager import Event, emit, on

@on(FooEvent)
def on_foo_event(event: Event):
    print(f"Callable invoked on {type(event).__name__}")

if __name__ == '__main__':    
    foo_event = FooEvent()

    print("Emitting event...")
    emit(foo_event)

Emitting event...
Callable invoked on FooEvent

Process finished with exit code 0

Unregister an event listener

Call unregister method passing the event type that you want to stop listening and the listener.

from events_manager import Event, emit, listen, unregister

def on_foo_event(event: Event):
    print(f"Callable invoked on {type(event).__name__}")

if __name__ == '__main__':    
    foo_event = FooEvent()
    
    listen(FooEvent, on_foo_event)

    print("Emitting first event...")
    emit(foo_event)
    
    unregister(FooEvent, on_foo_event)
    
    print("Emitting second event...")
    emit(foo_event)

Emitting first event...
Callable invoked on FooEvent
Emitting second event...

Process finished with exit code 0

License

Distributed under the MIT License. See LICENSE file for more information.