Setup Modules

There are two setup modules for pubsub; only one can be imported in an application.

pubsub.setupkwargs

The kwargs protocol is defined as follows:

• the sender provides message data via keyword (i.e. named) arguments. The keywords must be the same for all messages of the same topic.

• the listener must be callable as listener(*req_data, **opt_data): the parameter names must be the same for all listeners of a topic, and must be the same as the message data items.

Example:

from pubsub import pub

def listener1(msg):
    assert msg == 'hi'

def listener(r1, o1=None):
    assert r1 == 123
    assert o1 is None

pub.subscribe(listener1, 'someTopic_1')
pub.subscribe(listener2, 'someTopic_2')

pub.sendMessage('someTopic_1', msg='hi')
pub.sendMessage('someTopic_2', r1=123) # ok: o1 optional

pubsub.setuparg1

The arg1 protocol is defined as follows:

• the sender only provides one data, or nothing. This one data can be any object: a string, a tuple, a dictionary, etc.

• the listener must be callable as listener(message): the message.data is the data given by the sender. The message contains other information such as topic.

An important consequence of the freedom of this protocol is that the same listener can subscribe to any topic; it is the listener’s responsibility to determine what data is packaged in message.data and use properly.

Example:

from pubsub import setuparg1
from pubsub import pub

def listener1(msg):
    assert msg.data == 'hi'

def listener2(msg):
    assert msg.data['r1'] == 123

pub.subscribe(listener1, 'someTopic')
pub.subscribe(listener2, 'someTopic') # same topic ok despite differing message data

pub.sendMessage('someTopic', 'hi')

data = {'r1':123, ...} # replace ... with whatever you want
pub.sendMessage('someTopic', data)