The notification system of Pillar was rather troublesome, as clients polled for new notifications every 30 seconds on every open page, and the query for constructing the response wasn't too simple either. Because of the nature of the Apache/mod_wsgi/Flask stack, it was hard to implement things like long polls or server-sent events (SSE), and thus caused a big performance bottleneck. Furthermore, back then Internet Explorer was incompatible with SSE, which is no longer an issue since it got replaced by Edge.

Will the notification system get a much-deserved redesign, so that such issues will not occur in the future? How will notifications be sent to the client? What is the overall design of the system?

In D9488#235396, @Sybren A. Stüvel (sybren) wrote:

The notification system of Pillar was rather troublesome, as clients polled for new notifications every 30 seconds on every open page, and the query for constructing the response wasn't too simple either. Because of the nature of the Apache/mod_wsgi/Flask stack, it was hard to implement things like long polls or server-sent events (SSE), and thus caused a big performance bottleneck. Furthermore, back then Internet Explorer was incompatible with SSE, which is no longer an issue since it got replaced by Edge.

Will the notification system get a much-deserved redesign, so that such issues will not occur in the future? How will notifications be sent to the client? What is the overall design of the system?

We taking an incremental approach. The steps are:

• Leverage the actstream library to record likes, comments, replies etc.
• Provide a context variable that notifies a user if any unread activity is available
• Provide a dedicated endpoint to visualize, browse (paginate) and interact with notifications, without any JS

This is straightforward to implement, test and deploy. We will look into a more integrated and "interactive" notification system once we adopt a modern JS framework like Vue.

I have never worked with actstream, so I can't really review the code. I'd have no idea whether it's doing the right thing or not.