问题
We need to develop something similar to OneSignal (only web, no native apps) for private use. Where can we start? Is there some open source project we can use?
回答1:
Each browser implements their own Push Service, so using a private/custom Push Service necessitates re-creating (at least portions of) the Push & Service Worker API's to achieve similar behavior client-side. Google has a nicely-written high-level overview; see the "Who and What is the Push Service?" section of Step 2. It's also worth noting that while the Push Service itself may be created, you will lose the functionality the browser provides the web app (e.g. waking the service worker on receiving a notification, even if the web app isn't in the foreground), because the browser will only be looking to its own Push Service.
Outside the browser (e.g. an Electron app), you will still need to re-create (portions of) the Push & Service Worker API's to achieve similar behavior client-side. In this case, you're likely still better off using a native Push Service for the target platform, if available.
If content privacy is the ultimate goal: the WebPush protocol provides a means of encryption between the client and application server, so the Push Service can't read the notification content. This, combined with the acceptance of a standard Push API, makes using a 3rd party Push Service allowable for most scenarios, and trivial compared to building everything from scratch.
However, if you absolutely need to make a custom Push Service, Mozilla's Push Service is the only fully open-source solution I've found. It may not be exactly what you need "out of the box", but may be close. Only the client and admin SDK's are open-source for Firebase, so far.
来源：https://stackoverflow.com/questions/51538371/create-a-web-push-notification-service-like-onesignal