[TASK] Backend publisher/subscriber architecture

[Turnlings]

We should use a proper publisher/subscriber architecture for communication between controllers and endpoints. Currently callbacks containing socketio emit commands are passed through which is not a proper separation of concerns. Controllers having publishers would allow for a proper signalling of intent rather than executing the command themselves and pushing directly to the frontend.

This would most likely result in a V0.3.X release.

[1Blademaster]

How would this look in the code for example? Would the controllers "register" publishers or something?

[Turnlings]

Yep exactly, there are many existing solutions, I think blinker is pretty common in flask but could also use something like redis. They both should let you publish on specific channels with messages, pretty much the same as using socketio.

[1Blademaster]

Interesting I've not heard of Blinker. Quick Google search led me to Signals which seems to be what we want I think?

[Turnlings]

Yep, I'm pretty sure you can use decorators to mark a function just like socketio so if we follow all the same conventions as we want to use for that then everything should be pretty familiar.

[1Blademaster]

Can you make a branch and test it out? I'm curious to see what the implementation is like. We won't merge this branch, we'll implement it in one go (mostly I think..).