pwa-launcher 0.3.2

Cross-platform PWA launcher using Chromium

py-pwa-launcher

Launch Progressive Web Apps from Python

A Python library for launching Progressive Web Apps (PWAs) using Chromium-based browsers. Automatically finds or downloads a Chromium browser and launches PWAs in app mode with all necessary flags.

Features

• 🚀 Launch PWAs with a single function call
• 🔍 Auto-detect system Chrome/Edge browsers
• 📥 Auto-download portable Chromium if needed
• ⚙️ PWA-optimized flags for installation and features
• 🔒 Custom profiles for isolated PWA data
• ✅ Check PWA support before launching
• 🧪 Fully tested with comprehensive test suite

Installation

pip install pwa-launcher

Quick Start

Launch a PWA

from pwa_launcher import open_pwa

# Launch a PWA - that's it!
open_pwa("https://weatherlite.app")

Check PWA Support

from pwa_launcher import check_pwa_support

# Check if a URL supports PWA
result = check_pwa_support("https://weatherlite.app")

if result.is_pwa_supported:
    print(f"✓ {result.url} is PWA-ready!")
    print(f"  Manifest: {result.manifest_url}")
    print(f"  Service Worker: {result.service_worker_url}")
else:
    print(f"✗ Not a PWA")
    for error in result.errors:
        print(f"  - {error}")

Launch with Custom Options

from pwa_launcher import open_pwa
from pathlib import Path

# Launch with custom profile and flags
process = open_pwa(
    "https://excalidraw.com",
    user_data_dir=Path("./my_pwa_profile"),
    additional_flags=["--start-maximized"]
)

print(f"Launched PWA (PID: {process.pid})")

Keep Process Alive

By default, each PWA runs in an isolated profile to keep the process alive:

from pwa_launcher import open_pwa

# Auto-generates isolated profile - process stays alive!
process = open_pwa("https://example.com")
print(f"PID: {process.pid}")  # Process won't exit immediately

# To disable auto-profile (may cause process to exit if Chrome is already running):
process = open_pwa("https://example.com", auto_profile=False)

Why this matters: When Chrome reuses an existing profile, it hands off to an already-running Chrome instance and the new process exits immediately. With auto_profile=True (default), each PWA gets its own isolated profile, keeping the process running.

API Reference

open_pwa(url, **kwargs)

Launch a PWA using Chromium browser.

Parameters:

• url (str): URL to open as PWA (required)
• chromium_path (Path, optional): Path to Chromium executable
• allow_system (bool, default=True): Allow using system Chrome/Edge
• allow_download (bool, default=True): Allow downloading portable Chromium
• install_dir (Path, optional): Directory for portable Chromium
• user_data_dir (Path, optional): Custom browser profile directory
• additional_flags (List[str], optional): Extra Chromium flags
• wait (bool, default=False): Wait for browser to exit
• auto_profile (bool, default=True): Auto-generate isolated profile (keeps process alive)

Returns: subprocess.Popen - Browser process

Raises:

• ChromiumNotFoundError: No browser found
• ValueError: Invalid URL

Note: When auto_profile=True, each PWA gets its own isolated profile based on the URL hostname. This prevents Chrome from handing off to an existing instance and keeps your process alive.

check_pwa_support(url, timeout=10)

Check if a URL supports PWA features.

Parameters:

• url (str): URL to check
• timeout (int): Request timeout in seconds

Returns: PWACheckResult with:

• is_pwa_supported (bool): Whether PWA is supported
• has_manifest (bool): Has web manifest
• manifest_url (str): URL of manifest file
• manifest_data (dict): Parsed manifest data
• has_service_worker (bool): Has service worker
• service_worker_url (str): URL of service worker
• has_https (bool): Uses HTTPS
• errors (list): List of error messages
• warnings (list): List of warnings

get_chromium_install(**options)

Get a single Chromium browser executable path (tries system → portable → download).

Parameters:

• allow_system (bool, default=True): Search for system Chrome/Edge
• allow_download (bool, default=True): Allow downloading portable Chrome
• install_dir (Path, optional): Directory for portable Chrome
• force_reinstall (bool, default=False): Force download even if exists

Returns: Path - Path to Chromium executable

Raises: ChromiumNotFoundError - No browser found

get_chromium_installs(**options)

Get all available Chromium browser executable paths.

Parameters:

• allow_system (bool, default=True): Search for system Chrome/Edge
• allow_download (bool, default=True): Allow downloading portable Chrome
• install_dir (Path, optional): Directory for portable Chrome

Returns: List[Path] - List of paths to Chromium executables

Examples

See the examples/ directory for more examples:

• examples/check_pwa.py - Check PWA support

Command Line Usage

Launch a PWA

python -m pwa_launcher.open_pwa https://weatherlite.app

Check PWA Support

python -m pwa_launcher.pwa_support https://weatherlite.app

How It Works

1. Get Chromium: Finds system Chrome/Edge or downloads portable Chromium
2. Build Command: Creates command with --app={url} and PWA flags
3. Launch: Starts browser in app mode with PWA features enabled

PWA Flags Included

• --app={url}: Launch in app mode (no browser UI)
• --enable-features=WebAppInstallation: Enable PWA installation
• --enable-features=DesktopPWAsTabStrip: Enable tab strip in PWAs
• --enable-features=FileSystemAccessAPI: Enable file system access
• --enable-features=NotificationTriggers: Enable notifications
• --no-default-browser-check: Skip default browser check
• --no-first-run: Skip first run experience

Development

Setup

# Clone the repository
git clone https://github.com/yourusername/py-pwa-launcher.git
cd py-pwa-launcher

# Create virtual environment
python -m venv venv
source venv/bin/activate  # On Windows: venv\Scripts\activate

# Install dependencies
pip install -r requirements-dev.txt

Run Tests

# Run all tests
pytest

# Run with coverage
pytest --cov=pwa_launcher

# Run specific test file
pytest tests/test_open_pwa.py -v

License

MIT License - see LICENSE file for details.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.