Publishers and subscribers with backpressure

[falcowinkler]

I'm having a great time with composable architecture but ran into a situation i find hard to implement with Effects

Basically want to achieve the following

• One component in my app is capable of producing an arbitrary amount of some Content for my app.
• Producing this content can take a bit, so it should be buffered, in order to present the next content right away, on demand
• A view (view store) can request a single value from the buffer on demand

I started to read into how this would be achievable in pure Combine. There i would create my custom Publisher and Subscriber instances and handle backpressure within request(_ demand: Subscribers.Demand) etc.

What i don't understand is this: After i managed to code up a Subscriber, i have a Subscription instance that i hold internally, on which i can .request(Demand) more data. But how do i wire this up with the view store exactly? On the view store i need to return an effect that just produces a single value, that is just displayed when it arrives.

I thought about storing the subscription somewhere, and returning the custom Publisher as Effect when the view initializes. Then i could just request more data on the subscription, and wait for the event to come in?

If you know of any example of something similar, that would also greatly help. I didn't find anything in the case studies.

Right now, i simply wrote a function that returns an Effect, which produces a single Content value. The problem with that, is that i can not buffer the values, i always have to request a new one after the user action happened. Perhaps i can hack around that with keeping a buffer in my Reducer state, but that seems like a hack to me and i'm interested in the best practice solution.

[falcowinkler]

I ended up leaving the "Effect" architecture as it is, and just handling the buffering in the view store, if it's helpful for anyone. I don't think it's very elegant, but it works nicely.