This project demonstrates how to build a browser push notification system using Node.js, Express, and the Web Push API. It leverages Service Workers to receive push notifications in the browser and uses the web-push library on the server to send notifications.

• Service Worker Registration:
  Registers a service worker to enable background processing of push events.

• Push Subscription:
  Uses the Push API to subscribe the browser for push notifications.

• VAPID Authentication:
  Utilizes VAPID keys to securely send notifications.

• Express Server:
  Handles subscription storage and notification dispatching.

• Node.js (v12 or later)
• A modern browser (Chrome, Firefox, etc.) that supports Service Workers and the Push API

project-root/ ├── public/ │ ├── index.html # Client-side HTML and JavaScript │ └── sw.js # Service Worker file ├── generateVapidKeys.js # Script to generate VAPID keys ├── server.js # Express server code ├── package.json └── README.md 

git clone <repository-url> cd <repository-folder>

npm install

Run the following command to generate your VAPID keys:

node generateVapidKeys.js

This will output an object containing publicKey and privateKey. Update your code in both server.js and index.html:

• In server.js: Replace 'YOUR_PUBLIC_VAPID_KEY_HERE' and 'YOUR_PRIVATE_VAPID_KEY_HERE' with the generated keys.
• In index.html: Replace 'YOUR_PUBLIC_VAPID_KEY_HERE' with your public key.

Run the Express server:

node server.js

Your server will start on http://localhost:3000.

1. Open your browser and navigate to http://localhost:3000.

2. Click the "Subscribe for Notifications" button. This will register the service worker and subscribe your browser for push notifications.

3. To send a push notification, use a tool like curl or Postman to send a POST request to the /notify endpoint:

   curl -X POST http://localhost:3000/notify

You should receive a push notification in your browser.

• Client Side:

  • Service Worker Registration:
    The browser registers sw.js as a service worker.

  • Subscription:
    The browser subscribes for push notifications using the Push API. The subscription object (including endpoint and keys) is sent to the server via the /subscribe endpoint.

  • Handling Push Events:
    The service worker listens for push events and displays notifications using the Notifications API.

• Server Side:

  • Subscription Storage:
    The server stores incoming subscription objects (for demo purposes, these are kept in memory; consider using a database in production).

  • Sending Notifications:
    The /notify endpoint uses the web-push library to send notifications to all stored subscriptions using the VAPID keys for authentication.

• HTTPS:
  Service Workers and push notifications require HTTPS in production environments (except on localhost during development).

• Subscription Storage:
  Replace the in-memory storage with a database for persistent storage of subscription objects.

• Error Handling:
  Enhance error handling and logging for a production-ready system.