Calculating Free Spins and Cascades.

I am making a slot machine game for fun and i was wondering how Free Spins and Cascading reels are calculated.
in my architecture i have a client and a server the client tells the server to give him a spin result and the server makes this result.
i was wondering what the server should answer to the client when he gets free spins or anything else that has a recursive nature like cascades.
is it common practice for the server to send a result containing all the free spins? for example if i get 5 free spins in the result of my spin i will also send the 5 free spins as a part of this result. this makes sense in a way because those 5 free spins are a result of the spin and are not betted on.

I don't know whats industry standard. For slots you basically have no user interaction, so there is no need to have some kind of fancy communication - keep it simple. I would send a single seed number from the server to the client. Use it on the client to display the animation, including all free spins and cascades (again including all free spins and cascades). Use it on the server to calculate the monetary result. That's it, simple as that. Make sure you use the same slot algorithms and patterns both on client and server, and everything should be fine.

This sounds like an online game or class II to me, which necessitates the communication. It is my experience that the free spin outcomes are sent individually, but you could package them into a single message if you want. For cascading reels, you just need to send the initial reel stops, but the server should pre-compute the total win and send that info to the game as well. This way, the game can calculate the win and verify the win amount.