Overview

Chrome/Edge extension that uses Native Messaging to execute code from the browser.

A Chrome/Edge extension that leverages the Native Messaging API to bridge the browser and the host operating system — demonstrated here by launching Notepad, but designed with a broader execution scope in mind.

GitHub Repository

Components

Extension Files

File	Purpose
manifest.json	Extension configuration and permissions
background.js	Service worker — handles native messaging connection
popup.html	Extension popup UI
popup.js	Popup interaction logic
icon*.png	Extension icons (16, 48, 128px)

Native Host Files

File	Purpose
native_host.py	Python script that receives messages and executes commands
native_host.bat	Windows batch wrapper for Python (optional)
com.notepad.launcher.json	Native messaging host manifest
install_host.reg	Registry installer for Windows

How It Works

1. Extension → Native Host: The extension calls chrome.runtime.connectNative() to open a persistent connection.
2. Message Format: JSON messages prefixed with a 4-byte length header (standard Native Messaging protocol).
3. Native Host → System: The Python script receives the JSON command and executes it via subprocess.Popen().
4. Response: The native host sends a JSON status message back to the extension.

Customization

Edit native_host.py to launch different applications, execute custom commands, process files before opening, or return richer status information — the extension shell stays the same.