Cells-4.0.4 : uninitialized constant Cell::Concept (NameError)

Question

Environment:

CentOS-6.7 / OSX-10.9.5
Ruby 2.2.3p173
Rails 4.2.5.1
Trailblazer 1.1.0

I am working through the examples in the Trailblazer book mapping them to a current project. I had things working more or less as expected up to the point when I switched from ActionView to Cells. I moved the templates into app/concepts/ar_invoice/views and created app/concepts/ar_invoice/cell.rb. Following this change when I start the rails server I get this error:

app/concepts/ar_invoice/cell.rb:1:in `<top (required)>': 
  uninitialized constant Cell::Concept (NameError)

The code involved is this:

The Gemfile:

Gems included by the bundle:
  * ISO3166P2 (0.0.1)
  * actionmailer (4.2.5.1)
  * actionpack (4.2.5.1)
  * actionview (4.2.5.1)
  * activejob (4.2.5.1)
  * activemodel (4.2.5.1)
  * activerecord (4.2.5.1)
  * activesupport (4.2.5.1)
  * addressable (2.4.0)
  * annotate (2.7.0)
  * ansi (1.5.0)
  * arel (6.0.3)
  * autoprefixer-rails (6.3.1)
  * axiom-types (0.1.1)
  * bcrypt (3.1.10)
  * bootstrap-sass (3.3.6)
  * bootstrap3-datetimepicker-rails (4.17.37)
  * builder (3.2.2)
  * bundler (1.11.2)
  * byebug (8.2.2)
  * capistrano (3.4.0)
  * capistrano-bundler (1.1.4)
  * capistrano-rails (1.1.6)
  * capybara (2.6.2)
  * cells (4.0.4)
  * cells-hamlit (0.1.1)
  * coercible (1.0.0)
  * coffee-rails (4.1.1)
  * coffee-script (2.4.1)
  * coffee-script-source (1.10.0)
  * concurrent-ruby (1.0.0)
  * cucumber (2.3.2)
  * cucumber-core (1.4.0)
  * cucumber-rails (1.4.3)
  * cucumber-wire (0.0.1)
  * daemons (1.2.3)
  * database_cleaner (1.5.1)
  * debug_inspector (0.0.2)
  * declarative (0.0.5)
  * declarative_authorization (0.5.7)
  * descendants_tracker (0.0.4)
  * devise (3.5.6)
  * devise-encryptable (0.2.0)
  * devise_security_extension (0.9.2)
  * diff-lcs (1.2.5)
  * disposable (0.2.5)
  * equalizer (0.0.11)
  * erubis (2.7.0)
  * eventmachine (1.0.9.1)
  * execjs (2.6.0)
  * gherkin (3.2.0)
  * globalid (0.3.6)
  * hamlit (2.2.1)
  * hamlit-block (0.3.0)
  * hamlit-rails (0.1.0)
  * humanize (1.1.0)
  * i18n (0.7.0)
  * ice_nine (0.11.2)
  * jbuilder (2.4.0)
  * jquery-rails (4.1.0)
  * json (1.8.3)
  * loofah (2.0.3)
  * mail (2.6.3)
  * mime-types (2.99)
  * mini_portile2 (2.0.0)
  * minitest (5.8.4)
  * minitest-capybara (0.7.2)
  * minitest-metadata (0.5.3)
  * minitest-rails (2.2.0)
  * minitest-rails-capybara (2.1.1)
  * minitest-reporters (1.1.7)
  * modernizr-rails (2.7.1)
  * momentjs-rails (2.11.0)
  * multi_json (1.11.2)
  * multi_test (0.1.2)
  * net-scp (1.2.1)
  * net-ssh (3.0.2)
  * nokogiri (1.6.7)
  * orm_adapter (0.5.0)
  * paper_trail (4.1.0)
  * partially_useful (0.2.2)
  * pg (0.18.4)
  * rack (1.6.4)
  * rack-test (0.6.3)
  * rails (4.2.5.1)
  * rails-deprecated_sanitizer (1.0.3)
  * rails-dom-testing (1.0.7)
  * rails-html-sanitizer (1.0.3)
  * railties (4.2.5.1)
  * rake (10.5.0)
  * rdoc (4.2.1)
  * reform (2.1.0)
  * representable (3.0.0)
  * request_store (1.3.0)
  * responders (2.1.1)
  * ruby-progressbar (1.7.5)
  * sass (3.4.21)
  * sass-rails (5.0.4)
  * sdoc (0.4.1)
  * smarter_csv (1.1.0)
  * spring (1.6.2)
  * sprockets (3.5.2)
  * sprockets-rails (3.0.1)
  * sqlite3 (1.3.10)
  * sshkit (1.8.1)
  * temple (0.7.6)
  * thin (1.6.4)
  * thor (0.19.1)
  * thread_safe (0.3.5)
  * tilt (2.0.2)
  * trailblazer (1.1.0)
  * trailblazer-loader (0.0.9)
  * trailblazer-rails (0.2.4)
  * turbolinks (2.5.3)
  * tzinfo (1.2.2)
  * uber (0.0.15)
  * uglifier (2.7.2)
  * virtus (1.0.5)
  * warden (1.2.6)
  * web-console (3.1.1)
  * xpath (2.0.0)

The application.rb:

#config/application.rb
require File.expand_path('../boot', __FILE__)

require "rails"
# Pick the frameworks you want:
require "active_model/railtie"
require "active_job/railtie"
require "active_record/railtie"
require "action_controller/railtie"
require "action_mailer/railtie"
require "action_view/railtie"
require "sprockets/railtie"
# require "rails/test_unit/railtie"

# Require the gems listed in Gemfile, including any gems
# you've limited to :test, :development, or :production.
Bundler.require(*Rails.groups)

module HllThMain
  class Application < Rails::Application
    # Use the responders controller from the responders gem
    config.app_generators.scaffold_controller :responders_controller

    . . .         

    # Do not swallow errors in after_commit/after_rollback callbacks.
    config.active_record.raise_in_transactional_callbacks = true
  end
  require( "hll_th_main" )
end

# For trailBlazer
# railties have to be loaded here.

require 'trailblazer/rails/railtie'

The controller (ar_invoices_controller.rb):

class ARInvoicesController < ApplicationController
  def create
    run( ARInvoice::Create )
  end

# route => ar_invoices#new
  def new
    form( ARInvoice::Create )
  end
end

The operation.rb:

class ARInvoice < GLTransaction

  class Create < Trailblazer::Operation
    include( Model )

    model( ARInvoice, :create )

    contract() do
      property( :invoice_number )
      property( :currency_code )
      property( :forex_rate )
      property( :gl_account_id )
      property( :effective_from )

      validates( :invoice_number, :presence => true )
      validates( :currency_code, :presence => true )
    end

    def process( params )
      # must use instance variable @model
      @model = ARInvoice.new
      validate( params[ :ar_invoice ], @model ) do |f|
        f.save
      end
    end
  end
end

The cell.rb:

class ARInvoice::Cell < Cell::Concept

  def new()
    render
  end

  def show()
    render
  end

  private
  def body()
    model.body
  end
end

And the view (new.haml):

= simple_form_for( @form ) do |f|
  = f.input( :invoice_number )
  = f.input( :currency_code )
  = f.input( :forex_rate )
  = f.input( :gl_account_id )

  = f.submit

I do not use any Trailblazer/Cells initializers. Can someone point out my error that is causing the exception reported above?

Answer 1

Explicitly adding the gem cells into the project Gemfile solved the issue.

Because cells is a dependency of cells-hamlit I only listed cells-hamlit in the Gemfile. This did indeed cause the cells gem to be included in the project, which was verified by running bundle list. But it was not enough to have the gem loaded into the application.

This is a side-effect of Bundler of which I was previously unaware.

Answer 2

Here is the Trailblazer related part from a project already in production some gems declarations might be an overkill but, well it works:

gem "trailblazer",       "1.1.0"
gem "trailblazer-rails", ">= 0.2.3"
gem "representable",     "3.0.0"
gem "reform",            "2.1.0"
gem "reform-rails"
gem "disposable"

gem "virtus"

gem "tyrant", github: "apotonick/tyrant"

gem "cells", "4.0.3"
gem "cells-haml", "0.0.8"
gem "haml", github: "haml/haml", ref: "7c7c169"
gem "kaminari-cells"

gem "paperdragon", ">= 0.0.10"
gem "file_validators", "~> 1.2"
gem "dragonfly-s3_data_store"

gem "roar", github: "apotonick/roar"

gem "pundit"

gem "rails-timeago"
gem "email_validator"

Application.rb

require File.expand_path('../boot', __FILE__)
require 'rails/all'

# Require the gems listed in Gemfile, including any gems
# you've limited to :test, :development, or :production.
Bundler.require(*Rails.groups)

module Appname
  class Application < Rails::Application
    ...
  end
end

# railties have to be loaded here.
require 'trailblazer/rails/railtie'

Trailblazer initializer

require "trailblazer/operation/dispatch"
# require "trailblazer/operation/representer"
# require "trailblazer/operation/responder"

Trailblazer::Operation.class_eval do
  include Trailblazer::Operation::Dispatch
end

require "roar/json/hal"

::Roar::Representer.module_eval do
  include Rails.application.routes.url_helpers
  # include Rails.app.routes.mounted_helpers

  def default_url_options
    {}
  end
end

Cells initializer:

ActiveSupport::Notifications.subscribe "read_fragment.cells" do |name, start, finish, id, payload|
  Rails.logger.debug "CACHE: #{payload}"
end

ActiveSupport::Notifications.subscribe "write_fragment.cells" do |name, start, finish, id, payload|
  Rails.logger.debug "CACHE write: #{payload}"
end

Answer 3

You have to say ::Cell::Concept not Cell::Concept, Ruby will look it up in the wrong namespace otherwise.