How to implement a messenger using Push and WebSockets?

Question

Mobile development

There is a goal - to implement a messenger.
Each time a dialog is opened, a websocket connection is created. We receive when the user writes a message, when it was delivered and viewed. This is all when the dialog is open.
When we exit the dialog, the websocket connection is closed. Let's move on to push notifications. And here is the nuance - if the user has banned notifications - is it possible to receive them as system ones?
A request to receive notifications usually means receiving notifications when the application is closed. In my case, I need to receive and process them when the application is open.

Answer 1

On iOS, it cannot be accepted if the user has forbidden it, and in general, notifications do not guarantee delivery. Do a longpoll and get everything through it. Or if you have your own protocol on sockets, keep the connection open all the time and receive and send all messages through it.