Hub

class glue.core.hub.Hub(*args)

Bases: object

The hub manages communication between subscribers.

Objects subscribe() to receive specific message types. When a message is passed to broadcast(), the hub observes the following protocol:

• For each subscriber, it looks for a message class subscription that is a parent class of the input message type (if several are found, the most-subclassed one is chosen)

• If one is found, it calls the subscriptions filter(message) class (if provided)

• If filter(message) == True, it calls handler(message) (or notify(message) if handler wasn’t provided).

Any arguments that are passed to Hub will be registered to the new hub object.

Methods Summary

broadcast(self, message)	Broadcasts a message to all subscribed objects.
delay_callbacks(self)
get_handler(self, subscriber, message)
ignore_callbacks(self, ignore_type)
is_subscribed(self, subscriber, message)	Test whether the subscriber has subscribed to a given message class
subscribe(self, subscriber, message_class[, …])	Subscribe an object to a type of message class.
unsubscribe(self, subscriber, message)	Remove a (subscriber,message) pair from subscription list.
unsubscribe_all(self, subscriber)	Unsubscribe the object from any subscriptions.

Methods Documentation

broadcast(self, message)

Broadcasts a message to all subscribed objects.

Parameters

message (Message) – The message to broadcast

delay_callbacks(self)

get_handler(self, subscriber, message)

ignore_callbacks(self, ignore_type)

is_subscribed(self, subscriber, message)

Test whether the subscriber has subscribed to a given message class

Parameters

• subscriber – The subscriber to test

• message – The message class to test

Returns:

True if the subscriber/message pair have been subscribed to the hub

subscribe(self, subscriber, message_class, handler=None, filter=<function Hub.<lambda> at 0x7f08ffb5b400>)

Subscribe an object to a type of message class.

Parameters

• subscriber (HubListener) – The subscribing object

• message_class – A Message class to subscribe to

• handler – An optional function of the form handler(message) that will receive the message on behalf of the subscriber. If not provided, this defaults to the HubListener’s notify method

• filter – An optional function of the form filter(message). Messages are only passed to the subscriber if filter(message) == True. The default is to always pass messages.

Raises:

InvalidMessage: If the input class isn’t a Message class

InvalidSubscriber: If the input subscriber isn’t a HubListener object.

unsubscribe(self, subscriber, message)

Remove a (subscriber,message) pair from subscription list. The handler originally attached to the subscription will no longer be called when broadcasting messages of type message

unsubscribe_all(self, subscriber)

Unsubscribe the object from any subscriptions.