gistfile1.txt

class ContractsController
  jsonapi resource: ContractResource
end

class TransactionsController
  jsonapi resource: TransactionResource
end

class ContractResource < JsonapiCompliable::Resource
  type :contracts
  use_adapter JsonapiCompliable::Adapters::ActiveRecord
  
  has_many :transactions,
    foreign_key: :contract_id,
    scope: -> { Transaction.all },
    resource: TransactionResource
    
  polymorphic_belongs_to :workspace,
    group_by: proc { |contract| contract.workspace_type },
    groups: {
      'SpecialWorkspace' => {
        resource: WorkspaceResource
      },
      'AnotherSpecialWorkspace' => {
        resource: WorkspaceResource
      |
    }
end

class TransactionResource < JsonapiCompliable::Resource
  type :transactions
end







allow_sideload :workspace, resource: WorkspaceResource do
  scope do |contracts|
    BasService.call({ 'Filter' => { 'ContractIDs' => contracts.map(&:id) } })
  end
  
  assign do |contracts, transactions|
    contracts.
  end
end