Moksha+TurboGears2 - Hello World Tutorial

Note

You can find the source for this tutorial on github.

Bootstrapping

Set up a virtualenv and install Moksha and TurboGears2 (install virtualenvwrapper if you haven’t already).

$ mkvirtualenv tutorial
$ pip install -i http://tg.gy/current tg.devtools
$ pip install moksha.wsgi moksha.hub

Use paster to setup the default TurboGears2 quickstart, install dependencies, and verify that its working.

$ paster quickstart --auth --mako --sqlalchemy -p tutorial tutorial
$ cd tutorial/
$ python setup.py develop
$ nosetests
$ paster setup-app development.ini
$ paster serve development.ini

Visit http://localhost:8080 to check it out. Success.

Enable ToscaWidgets2

Some versions of TurboGears2 start with ToscaWidgets1 turned on by default. You’ll want to disable that and enable ToscaWidgets2.

Edit tutorial/config/app_cfg.py and add the following two lines to the bottom.

base_config.use_toscawidgets = False
base_config.use_toscawidgets2 = True

Enabling the Moksha Middleware

Edit tutorial/config/middleware.py and remove the line that reads app = make_base_app(global_conf, full_stack=True, **app_conf). In its place, put the following

from moksha.wsgi.middleware import make_moksha_middleware
wrap_app = lambda app: make_moksha_middleware(app, app_conf)
app = make_base_app(global_conf, full_stack=True,
                    wrap_app=wrap_app, **app_conf)

See also

• Moksha Middleware

Provide some configuration for Moksha

Edit development.ini and add the following lines under the [app:main] section:

moksha.domain = localhost

moksha.livesocket = True
moksha.livesocket.backend = websocket
moksha.livesocket.websocket.port = 9998

moksha.socket.notify = True

zmq_enabled = True
zmq_strict = False
zmq_publish_endpoints = tcp://*:3000
zmq_subscribe_endpoints = tcp://127.0.0.1:3000

Your first Polling Producer

Add a new file in tutorial/producers.py. In it, add the following definition:

import datetime
import moksha.hub.api.producer


class HelloWorldProducer(moksha.hub.api.producer.PollingProducer):
    frequency = datetime.timedelta(seconds=2)

    def poll(self):
        self.send_message('hello_world', "Hello World!")

As well, edit setup.py and modify the entry_points section to include a declaration of this new producer like so:

[moksha.producer]
hello = tutorial.producers:HelloWorldProducer

Open up a second terminal, activate your virtualenv with workon tutorial and run the moksha-hub:

$ workon tutorial
$ python setup.py develop
$ moksha-hub

This will start up the hub which should pick up and load your HelloWorldProducer. Keep this running in your second terminal as you go on to create the frontend components.

Your first LiveWidget

Create a new file in tutorial/widgets.py. In it, add the following definition:

import moksha.wsgi.widgets.api
import tw2.jqplugins.gritter

class PopupNotification(moksha.wsgi.widgets.api.LiveWidget):
    topic = "*"
    onmessage = "$.gritter.add({'title': 'Received', 'text': json});"
    resources = moksha.wsgi.widgets.api.LiveWidget.resources + \
            tw2.jqplugins.gritter.gritter_resources
    backend = "websocket"

    # Don't actually produce anything when you call .display() on this widget.
    inline_engine_name = "mako"
    template = ""

You’ll need to expose this widget and the moksha global resources to your templates. You could do this with some logic in a controller, but instead we’ll just stuff it on every page for simplicity here.

Edit tutorial/lib/base.py and add the following inside the __call__ method:

import tutorial.widgets
from moksha.wsgi.ext.turbogears import global_resources

tmpl_context.notification_widget = tutorial.widgets.PopupNotification
tmpl_context.moksha_global_resources = global_resources

Finally, display the widget on your page by editing tutorial/templates/master.mak and adding the following at the end but just inside of the </body> tag:

${tmpl_context.notification_widget.display() |n}
${tmpl_context.moksha_global_resources() | n}

Go restart your paster server and check out http://localhost:8080 again. You should see popups from your PollingProducer.

See also

• Live Widgets