Application structure question

This is a very interesting project and executes well something that many other projects have attempted in the past.

I have seen the sample contacts application, read the documentation, and I am currently reading through the gem source but there are still some things which are unclear to me. The most significant of which is where non-CRUD behaviour should be included.

For example, if I were building an application to sell T-shirts using Stripe, I might have an Order class with various LineItems that would consist of Products with corresponding quantities. Now, I could easily manage to create all of the relevant records via a create request to the OrdersController. However, where would I put the call to create my Stripe charge, schedule fulfilment, etc.?

Normally, I would leave my Order and corresponding models fairly simple, and organize charging and fulfilment via services. I would have, say, a PurchaseService which would be instantiated by a PurchaseController. This would arrange for the various models to be created, trigger the Stripe charge, and if successful, schedule fulfilment (possibly by delegating to another service).

The code in the PurchaseController would be very minimal and would not do anything more than pass parameters to the PurchaseService, make a single call on it, and then take care of response and error handling.

It seems like the intention with JR would be to leave the default implementation for the resource controllers, and add charging and purchasing behaviour to the resource code. For example, I would do:

class PurchaseController < JSONAPI::ResourceController
end

and

class PurchaseResource < JSONAPI::Resource
  def create
    # call to Stripe, etc. goes here
  end
end

Does this make sense? Would you structure things differently?

One the one hand this seems like a good place to include the behaviour without needing to reproduce a lot of error and response handling code if I were to override the corresponding controller method. On the other, I've seen the callback support in JSONAPI::Resource but I'm not clear if/when the corresponding lifecycle methods are actually called within the resource code. Additionally, if the code were structured this way, the PurchaseResource would also have to coordinate validating and creating Orders, LineItems, etc. rather than relying on the default JSONAPI::Resource functionality to do so.

Anyhow, apologies for the long-winded and naive question but I feel like I am missing something obvious. Any help in clarifying would be appreciated.

Start with JSONAPI::ResourceController, JSONAPI::Resource, and the resource callback and lifecycle entry points mentioned in the discussion. Trace when create-related methods and callbacks run, then document where non-CRUD work such as charging and fulfilment should live and what the recommended structure is.