In Rails4, using Trailblazer, how do I access the current_user - ruby-on-rails-4

Question

We are building a Rails4 app using Trailblazer. I have never worked with Trailblazer before and I am confused about how to do things.
We are building an auction site. I was previously using a traditional controller, and this route endpoint was working fine:
def bill
#profile = Profile.find_by user_id: current_user_id
#current_order = Order.order(created_at: :desc).find_by(user_id: current_user_id)
#batch = #current_order.batch
if #batch.nil?
puts "There was no batch linked to the current order of #{#current_order.id}"
flash[:error] = "We are sorry, but we could not determine which batch your order belongs to."
else
#price_shown_to_customer = #batch.price + ENV["FUELBID_FEE_PER_GALLON"].to_f
#amount = #current_order.quantity * #price_shown_to_customer
end
But now I'm suppose to create this as a Trailblazer api, using a Representer class.
So in routes.rb I added something for "charges":
namespace :api do
get '/price' => 'info#info'
post '/order' => 'orders#create'
get '/charges' => 'charges#bill'
end
I created this Api but copying-and-pasting another:
module Api
class ChargesController < ApiApplicationController
respond_to :json
def bill
respond_with OpenStruct.new.extend(ChargesRepresenter)
end
end
end
I tested the above with a simple Representer and it all worked fine, so everything is good up to this point. If I return simple data from the Representer, then I can see it fine here:
http://localhost:3000/api/charges.json
But I need to get the current_user. How is this done? Right now, this does not work:
module ChargesRepresenter
include Roar::JSON
collection :price_shown_to_customer
def price_shown_to_customer
current_order = Order.order(created_at: :desc).find_by(user_id: current_user_id)
puts "current_order"
puts current_order.id
batch = current_order.batch
batch.price + ENV["FUELBID_FEE_PER_GALLON"].to_f
end
end
current_user_id exists in my traditional controllers because we set up Devise and so my traditional controllers inherit it:
class ChargesController < SecuredController
But is there any way to get it in a Trailblazer Representer?

Answer 1

Hope this answer is not too late.
If you can switch to Decorator pattern instead of a Module.
Representer really doesn't need to know and doesn't care if it is called from controller or console or test. All it needs is a hash to build your json object from. So you can just pass another attribute called current_user_id to your Representer and then use it inside r presenter like you do.
FYI:
If you need a more immediate response you can also copy your question to https://gitter.im/trailblazer/chat . There are usually several people hanging out there. But it's also good to post a question here for posterity.