deb-python-autobahn/examples/running-the-examples.md

Running the Examples

Setting up a Router

To run the following examples, you need a WAMP router.

By default, all examples are set up to use a local Crossbar instance. You can change the URI used with the environment variable AUTOBAHN_DEMO_ROUTER (by default it is ws://localhost:8080/ws). Please see [Running Crossbar Locally] below.

Creating a virtualenv

If you do not yet have a virtualenv to run the examples with, you can do something like:

git clone https://github.com/crossbario/autobahn-python.git
cd ./AutobahnPython/
virtualenv venv-autobahn
source venv-autobahn/bin/activate
pip install -e ./

For all the examples, we presume that you are in the ./examples directory of your autobahn clone, and that the virtualenv in which you've installed Autobahn is activated. If you're running your own Crossbar, it runs from ./examples/router in its own virtualenv.

The examples usually contain two components:

• frontend
• backend

Each component is (usually) provided in two languages:

• Python
• JavaScript

The JavaScript version can run on the browser or in NodeJS.

To run an example, you can have two (or three) terminal sessions open with:

1. frontend
2. backend
3. the router (e.g. crossbar)

You can also run the frontend/backend in the same shell by putting one in the background. This makes tbe examples less clear, however:

python twisted/wamp/pubsub/basic/frontend.py &
python twisted/wamp/pubsub/basic/backend.py

Some things to try: open a new terminal and run a second frontend; leave the backend running for a while and then run the frontend; disconnect a frontend and reconnect (re-run) it; mix and match the examples (e.g. twisted/wamp/pubsub/basic/backend.py with twisted/wamp/pubsub/decorators/frontend.py) to see how the topic URIs interact.

Running Crossbar Locally

If you want to use your own local Crossbar instance you must have a Python2-based virtualenv and pip install crossbar in it. See also crossbar.io's platform-specific installation instructions as you may need to install some native libraries as well.

Once you have crossbar installed, use the provided router configuration in examples/router/.crossbar/config.json. Starting your router is then:

cd ./examples/router
crossbar start

There should now be a router listening on localhost:8080 so you can change the URI in all the demos to ws://localhost:8080/ws or set the environment variable AUTOBAHN_DEMO_ROUTER=ws://localhost:8080/ws Obviously, this environment variable isn't used by in-browser JavaScript so you'll have to change .js files by hand.

If you are running the router successfully, you should see a Crossbar page at http://localhost:8080/. We've added enough configuration to serve the HTML, JavaScript and README files from all the examples; you should see a list of links at the page.

Hosting

Crossbar.io is a WAMP router that can also act as a host for WAMP application components. So, for example, to let Crossbar.io host one of the examples as a backend application component, you can add a "components" section to examples/router/.crossbar/config.json at the same level as "realms":

{
         ...
         "options": {
             "pythonpath": ["../../twisted/wamp/"]
         },
         "components": [
            {
               "type": "class",
               "classname": "pubsub.complex.backend.Component",
               "realm": "crossbardemo"
            }
         ],
         ...
}

For the above exact configuration to work you'll need the ./examples/twisted/wamp/ directory in your PYTHONPATH (that configuration is provided in the "options" above).