canvas

Not abandoned, but temporarily dormant

A full-stack web application framework for building modern web products simply.

What's it like?

canvas is designed for minimalism and extensibility. Especially its documentation... (I'm working on this).

The following code samples define a web application consisting of a breakfast model, an API endpoint that serves an instance of it, and a page which contains a view that displays it.

The model and controllers (breakfast/__init__.py):

#   Import canvas.
import canvas as cv

#   Create a breakfast model.
@cv.model('breakfasts', {
    'id': cv.Column('uuid', primary_key=True),
    'name': cv.Column('text', nullable=False),
    'ingredients': cv.Column('json')
})
class Breakfast:

    def __init__(self, name, ingredients):
        self.name, self.ingredients = name, ingredients

#   Create an initialization function that cooks a breakfast if there isn't
#   one already.
@cv.on_post_init
def cook_breakfast():
    session = cv.create_session()
	
    if not session.query(Breakfast, one=True):
        breakfast = Breakfast('Bacon and Eggs', ['Bacon', 'Eggs'])
        session.save(breakfast).commit()

#   Create an API endpoint that serves breakfast.
@cv.endpoint('/api/breakfast')
class BreakfastEndpoint:

    def on_get(self, context):
        breakfast = context.session.query(Breakfast, one=True)
        return cv.create_json('success', cv.dictize(breakfast))

#	Create a page that will contain our view.
@cv.page('/', title='Breakfast!', assets=('breakfast.js',))
class Homepage: pass

The view (assets/breakfast.jsx):

//  Define a breakfast view that renders on '/' and retrieves its data from
//	the endpoint.
@cv.page('/')
@cv.view({
    data: cv.fetch('/api/breakfast'),
    template: breakfast => 
        <article class="col-6 breakfast">
            <em>Breakfast is served...</em>
            <h1>{ breakfast.name }</h1>
            <ul>
                { cv.comp(breakfast.ingredients, ingredient => <li>{ ingredient }</li>) }
            </ul>
            <button>Eat!</button>
        </article>
})
class BreakfastView {
    @cv.event('button')
    eat() {
        alert('Yum!');
    }
}

Setup

The following setup instructions are intended for Ubuntu 14.04 LTS+.

Download and install canvas:

#   Download and enter this repository.
git clone https://github.com/robinsax/canvas.git
cd canvas

#   Install Python 3, Pip, Node JS, NPM, and PostgreSQL.
sudo ./etc/install_dependencies.sh
#   Initialize the canvas installation.
sudo -H python3 canvas --init

You can now configure canvas by editing settings.json.

If you have not already created your database and user, you can run the following to do so:

python3 canvas --write-setup-sql | sudo -u postgres psql

Note: To see the complete list of command line options, simply run python3 canvas.

Running the tests

canvas's unit tests are invoked with:

python3 canvas --test

Serving for development

You can start canvas's development server with:

python3 canvas --serve 80

An empty canvas instance will then be served at http://localhost.

Use

Plugins

canvas web applications are implemented as one or more plugins. Plugins are stored in a shared plugin folder (by default ../canvas_plugins) and activated in configuration.

To create a plugin in the configured plugin directory, run:

python3 canvas --make-plugin <plugin_name>

To activate a plugin, modify the appropriate entry of settings.json, or run:

python3 canvas --config "plugins.activated=<plugin_name>,"