def discard(cls, callback, sender=None):
"""Similar to `Message.unsubscribe`, but does not raise an error if the
callback has not been registered before.
"""
if sender:
MessageBus().discard_locally(cls, sender, callback)
else:
MessageBus().discard_globally(cls, callback)
def subscribe(cls, callback, sender=None):
"""Register a callback to be called whenever a message of this type is send.
callback - Callable that receives an instance of a message as only argument.
sender - If specified, the callback receives only messages that originated
from sender. By default, all messages are received.
Example:
>>> def cb(msg):
... print 'Received', msg
>>> MessageClass.subscribe(cb) # Global
>>> MessageClass.subscribe(cb, sender=foo) # Specific sender
"""
if sender:
MessageBus().subscribe_locally(cls, sender, callback)
else:
MessageBus().subscribe_globally(cls, callback)
def unsubscribe(cls, callback, sender=None):
"""Stop your subscription of this message type for the specified callback.
callback - Callable that receives an instance of a message as only argument.
The same you've been using with `Message.subscribe`.
sender - If specified, the subscription will only be stopped for messages
from this sender. By default, all subscriptions are ended.
Note: There has to be a subscription, otherwise an error will be raised.
Example:
>>> MessageClass.subscribe(cb)
>>> MessageClass.broadcast('sender')
message received
>>> MessageClass.unsubscribe(cb)
>>> MessageClass.broadcast('sender')
"""
if sender:
MessageBus().unsubscribe_locally(cls, sender, callback)
else:
MessageBus().unsubscribe_globally(cls, callback)
def broadcast(cls, *args):
"""Send a message that is initialized with `args`.
The first argument is always a sender, the number of arguments has to be
N + 1, with N being the number of arguments defined on the message class.
Example:
>>> class Foo(Message):
... arguments = ('a', 'b', )
>>> Foo.broadcast('sender', 1, 2)
"""
MessageBus().broadcast(cls(*args))
def discard(cls, callback):
"""Similar to `Message.unsubscribe`, but does not raise an error if the
callback has not been registered before.
"""
MessageBus().discard_globally(cls, callback)
