Support for pushing to WebPush compatible servers would be very useful. It would allow pushing to the web app even when the tab is closed, and to the F-Droid version of Nextcloud Android using UnifiedPush.

Implementation

The primary things that need to be changed are:

1. Create a v3 API endpoint to register devices with WebPush style keys
2. Change the encrypt function to handle the WebPush keys in case the device is v3
3. Minor changes to headers on sending the push request

Advantages

Can push to Web and open source Android apps (using a fully self-hosted notification stack) through existing push channels (no need to keep a new connection open).

Previous relevant discussions

This repo is the first step before such a feature could be used in apps. See nextcloud/talk-android#257 nextcloud/android#8684

#1054 mentioned https://github.com/nextcloud/notify_push as a solution, however, it doesn't solve the problem of receiving notifications when either the web app is not open, or on Android without a persistent connection.

Would you be interested in receiving a PR for such a feature?