Examples

Hello World

A complete example of use:

'''
One listener is subscribed to a topic called 'rootTopic'.
One 'rootTopic' message gets sent. 
'''

from pubsub import pub

# ------------ create a listener ------------------

def listener1(arg1, arg2=None):
    print 'Function listener1 received:\n  arg1="%s"\n  arg2="%s"' % (arg1, arg2)

# ------------ register listener ------------------

pub.subscribe(listener1, 'rootTopic')

#------ create a function that sends a message ----

def doSomethingAndSendResult():
    print 'lahdida... have result, publishing it via pubsub'
    pub.sendMessage('rootTopic', arg1=123, arg2=dict(a='abc', b='def'))

# --------- define the main part of application --------

if __name__ == '__main__':
    doSomethingAndSendResult()

Running the above as a script (already saved for your convenience as helloworld.py in the docs folder of the source distribution) will produce the result:

lahdida... have result, publishing it via pubsub
Function listener1 received:
  arg1="123"
  arg2="{'a': 'abc', 'b': 'def'}"

More Examples

There are several examples that can be found in the source distribution in the examples folder. There are some “basic” examples that focus on syntax, and more advanced examples that hint at some design pattern. In most cases, there are both “console”-based and GUI (wxPython) based examples.

On Windows, the whole set of examples in the examples folder can be executed automatically as a form of regression testing. Run runall.bat from a console window once cd’d to the examples folder. Read the text in the console for instructions.

The examples described below can be browsed online.

Basic, Kwargs messaging

These two examples demonstrate a simple use of pubsub with the kwargs messaging protocol (default). There are two examples that can be run from this folder:

console_main.py: basic console based, uses the console_senders.py and

console_listeners.py modules, giving example of the kwargs messaging protocol.

wx_main.py: wxPython GUI application with two windows (win1 and win2)

that exchange data without any reference to the other. This example looks for pubsub on your system path so default install ok.

Basic, Arg1 messaging

These two examples demonstrate a simple use of pubsub with the arg1 messaging protocol. There are two examples that can be run from this folder:

console_main.py: basic console based, uses the console_senders.py and

console_listeners.py modules, giving basic example of the arg1 messaging protocol.

wx.py: basic wxPython GUI application that uses the arg1 messaging

protocol. Note that it imports pubsub from wxPython’s wx.lib package. Therefore you must have (a copy of) pubsub installed there for this example to work (pubsub can be installed in multiple places independently and they will all work without interfering with each other).

Note that this example is copied almost verbatim from the wxPython wiki site and is probably not a good model of how an application should be structured.

Basic, old API

These examples demonstrate the use of the legacy (version 1) pubsub API. There are two examples that can be run from this folder:

main.py: basic console based, all in one module (so not very realistic).

wx_main.py: using pubsub within wxPython application, all in one module.

Advanced

These two examples demonstrate a more advanced use of pubsub. One of the examples uses the kwargs messaging protocol, the other uses the arg1 messaging protocol. There are two examples that can be run from this folder:

kwargs_main.py: advanced example that shows other capabilities of

pubsub such as pubsub notification and listener exception handling, in the ‘kwargs’ messaging protocol. All modules that start with ‘kwargs_’ are used, as well as some modules that are independent of protocol and are shared with the arg1_main example.

arg1_main.py: same as kwargs_main but using the ‘arg1’ protocol.

All modules that start with ‘kwargs_’ are used, as well as some modules that are independent of protocol and are shared with the kwargs_main example.