A Python async web framework built with aiohttp

Dazzler

Dazzler is a Python async web framework built with aiohttp. Create dazzling fast pages with a layout of Python components and bindings to update from the backend.

Install

Install with pip: $ pip install dazzler

Features

Fast WebSocket based communication, deliver updates in realtime to thousands of connected clients at once.
Lightweight bundles for fast initial page load.
Support for third party integrations via middlewares.
Session & authentication systems.
No HTML/CSS/JS knowledge required, write everything with Python.
Multi page based.
Hot reload.
Tons of components.
Tie & Transform API to perform updates on the client side.

Basic example

Create a page with a layout and assign bindings to save & load a visitor name with the session system. The button to save the visitor name is disabled if no input value via tie & transform.

from dazzler import Dazzler
from dazzler.system import Page, BindingContext, transforms as t
from dazzler.components import core

app = Dazzler(__name__)
page = Page(
    __name__,
    core.Container([
        core.Html('H2', 'My dazzler page'),
        core.Container('Please enter a name', identity='visitor-name'),
        core.Input(value='', identity='input'),
        core.Button('Save name', identity='save-btn', disabled=True),
    ], identity='layout', id='layout'),
    title='My Page',
    url='/'
)

# UI updates via tie & transforms
page.tie('value@input', 'disabled@save-btn').transform(
    t.Length().t(t.Lesser(1))
)


# Bindings executes on the server via websockets.
@page.bind('clicks@save-btn')
async def on_click(context: BindingContext):
    # Save the visitor name via session system
    name = await context.get_aspect('input', 'value')
    await context.session.set('visitor', name)
    await context.set_aspect(
        'visitor-name', children=f'Saved {name}'
    )


# Aspects defined on the layout trigger on initial render and
# allows to insert initial data.
@page.bind('id@layout')
async def on_layout(context: BindingContext):
    visitor = await context.session.get('visitor')
    if visitor:
        await context.set_aspect(
            'visitor-name', children=f'Welcome back {visitor}!'
        )


app.add_page(page)

if __name__ == '__main__':
    app.start()