Use Cases pattern spike - part 3

transactions_controller.rb

# 3. This would enable a really focused TransactionsController
# that just handled sending off a use_case to the handler and
# dealing with renders or redirects on the way back in.
# 
# In this example we have a context that is per action - but 
# maybe we just pass in a broad context of request params,
# any authorization/authentication object and self as a listener
# in to the use_cases handler as a context. This could be a
# method in application controller to clean this up even 
# further.

class TransactionsController < ApplicationController
  attr_writer :new_transaction_form

  def create
    use_cases.execute :create,
      context: new_transaction_form,
      on_success: :create_succeeded,
      on_failure: :create_failed
  end

  def new; end

  def show
    use_cases.execute :show,
      context: show_context,
      on_success: :transaction_found,
      on_failure: :transaction_not_found
  end

  # Callbacks

  def create_failed(form_with_errors)
    self.new_transaction_form = form_with_errors
    render new
  end

  def create_succeeded(_new_transaction_form)
    flash[:notice] = "Transaction successfully created."
    redirect_to transactions_path
  end

  def transaction_found(transaction)
    render transaction
  end

  def transaction_not_found(_return_value)
    render file: "#{Rails.root}/public/404", status: :not_found
  end


  private

  def create_params
    params.permit(:to_wallet_id, :from_wallet_id, :amount)
  end

  def new_transaction_form
    @new_transaction_form ||= NewTransactionForm.new(create_params)
  end

  def show_context
    params.permit(:id)
  end

  def use_cases
    UseCases::TransactionsUseCases.new(self)
  end

end