[](https://travis-ci.org/jek/blinker)

# Blinker

Blinker provides a fast dispatching system that allows any number of interested parties to subscribe to events, or “signals”.

Signal receivers can subscribe to specific senders or receive signals sent by any sender.

>>> from blinker import signal
>>> started = signal('round-started')
>>> def each(round):
...     print "Round %s!" % round
...
>>> started.connect(each)

>>> def round_two(round):
...     print "This is round two."
...
>>> started.connect(round_two, sender=2)

>>> for round in range(1, 4):
...     started.send(round)
...
Round 1!
Round 2!
This is round two.
Round 3!

See the [Blinker documentation](https://pythonhosted.org/blinker/) for more information.

## Requirements

Blinker requires Python 2.4 or higher, Python 3.0 or higher, or Jython 2.5 or higher.

## Changelog Summary

1.3 (July 3, 2013)

• The global signal stash behind blinker.signal() is now backed by a regular name-to-Signal dictionary. Previously, weak references were held in the mapping and ephemeral usage in code like signal('foo').connect(...) could have surprising program behavior depending on import order of modules.

• blinker.Namespace is now built on a regular dict. Use blinker.WeakNamespace for the older, weak-referencing behavior.

• Signal.connect(‘text-sender’) uses an alternate hashing strategy to avoid sharp edges in text identity.

1.2 (October 26, 2011)

• Added Signal.receiver_connected and Signal.receiver_disconnected per-Signal signals.

• Deprecated the global ‘receiver_connected’ signal.

• Verified Python 3.2 support (no changes needed!)

1.1 (July 21, 2010)

• Added @signal.connect_via(sender) decorator

• Added signal.connected_to shorthand name for the temporarily_connected_to context manager.

1.0 (March 28, 2010)

• Python 3.x compatibility

0.9 (February 26, 2010)

• Sphinx docs, project website

• Added with a_signal.temporarily_connected_to(receiver): ... support