Shellac Webview

A Selenium wrapper for building desktop applications using web technologies. It uses FastAPI for backend communication and Selenium for browser automation.

Installation

pip install shellac-webview

Basic Usage

from shellac import Window

win = Window()

@win.bind
def my_function(event):
    return "Data from Python"

html = """
<button onclick="run()">Run</button>
<script>
    async function run() {
        const result = await webui.call("my_function");
        console.log(result);
    }
</script>
"""

win.show(html)
win.wait()

Binding

You can bind functions in python to be called from js using webui.call("func_name")

Function Binding

You can bind a specific function to a name.

def my_function(event):
    return f"Hello, {event.data[0]}!"

win.bind("greet", my_function)

JS Usage:

const response = await webui.call("greet", "Alice");
console.log(response); // "Hello, Alice!"

Decorator Binding

Use the @bind decorator for a cleaner syntax.

@win.bind
def calculate(event):
    return event.data[0] * 2

JS Usage: webui.call("calculate", 21);

Class/Namespace Binding

You can bind an entire class or instance. All public methods (not starting with _) will be available in JavaScript.

@win.bind("db")
class Database:
    def get_user(self, event):
        return {"id": event.data[0], "name": "John Doe"}

or with

win.bind("db", Database())

JS Usage:

const user = await webui.call("db.get_user", 1);

Class Mapping

If you bind a class without a prefix, its methods are mapped to the top-level.

class API:
    def status(self, event):
        return "Online"

win.bind(API)

JS Usage: webui.call("status");

The Event Object

Every bound Python function receives an Event object as its first argument.

• event.window: The Window instance.
• event.data: A list of arguments passed from JavaScript.
• event.element: The name of the function called.

Window Configuration

You can configure the window size and behavior before calling show().

win = Window()
win.config.width = 1200
win.config.height = 900
win.config.hide_controls = True # Hides address bar/tabs (App Mode)
win.config.kiosk = False        # Fullscreen mode

Browser Selection

By default, the library looks for Chrome, Edge, or Firefox. You can force a specific browser:

from webui import Browser

win.show("index.html", browser=Browser.Firefox)

Available options: Chrome, Firefox, Edge, Chromium, Brave, Vivaldi.

Other functions

Once the window is running, you can navigate to new pages or execute JavaScript from Python.

# Navigate to a new URL
win.navigate("https://google.com")

# Execute JS directly
win.run_js("alert('Hello from Python!')")

# Change title
win.set_title("New Title")