README

asyncio_dispatch is a is a signal dispatcher for the asyncio event loop found in Python versions 3.4 and up.

Check out the official documentation

Synopsis

Many callbacks can be connected to a Signal. When the Signal is triggered using its send() method, all connected callbacks will be scheduled for asynchronous execution.

Connections can optionally be made with two types of filters, senders and keys. If filters are used, the callback is only scheduled for execution if the Signal is sent with at least one matching sender or key. A sender can be any object, while a key is more likely to be a string. Under the hood, they use id() and hash() respectively.

Callbacks are invoked with keyword arguments that allow the callback to determine which Signal is calling it and which senders and keys were specified. Additional keyword arguments can be added to the Signal when it is instantiated, and their default values can be replaced when the Signal is sent.

Example

import asyncio
from asyncio_dispatch import Signal


@asyncio.coroutine
def callback(**kwargs):
    print('callback was called!')


loop = asyncio.get_event_loop()

# create the signal
signal = Signal(loop=loop)

# connect the callback to the Signal - This is a coroutine!
loop.run_until_complete(signal.connect(callback))

# send the signal - This is also a coroutine!
print('sending the signal.')
loop.run_until_complete(signal.send())

The above example will print the following:

sending the signal.
callback was called!

Features

• Supports the new async/await syntax found in python 3.5 and up
• Callbacks can be a function, asyncio.coroutine, async def, class method, @staticmethod, or @classmethod
• Multiple callbacks can be connected to the same signal
• Callbacks can be called with additional keyword arguments containing references to arbitrary objects
• Callbacks can be disconnected from a signal
• Signals can hold weak or strong references to callbacks, allowing for automatic disconnection if a reference to a callback is not maintained, or conversely to persist one-off lambda expressions without needing to maintain a reference
• Callbacks receive the Signal object that was used to schedule it, so multiple signals can be attached to the same callback and handled differently
• Callbacks can be connected with senders or keys which cause the Signal to ignore the callback unless the signal is sent with a matching Object or str

License

Released under the MIT license.

Installation

pip install asyncio_dispatch