Reference steps to use Trailblazer inside a Lotus app. Only includes important parts for Lotus 0.5, not full files.

application.rb

# apps/web/application.rb

# include in your load paths whatever directories
# you want to use for creating your trailblazer
# related classes, this is just an example

load_paths << [
    'controllers',
    'views',
    'operations',
    'policies'
  ]

# include in every action the controller helpers
# so that you have access to `run MyOperation`...
controller.prepare do
  include ::Trailblazer::Operation::Controller
end

environment.rb

# config/environment.rb

# Load the gems in your application config/environment.rb
require 'trailblazer'
require 'trailblazer/autoloading'
require 'lotus/validations'
require "reform/form/lotus"

# Make reform use lotus validations
Reform::Form.class_eval do
  include Reform::Form::Lotus
end

Gemfile

# add this gems to your Gemfile
gem 'trailblazer', '~> 1.0.4'
gem 'lotus-validations', '~> 0.3.3'
gem 'hashie'

operation.rb

module Web::Comment
  class Create < Trailblazer::Operation
    include Policy::Guard

    policy do |params|
      not params[:greeting].blank?
    end

    contract do
      property :greeting, validates: {presence: true}
      property :name
    end

    def process(params)
      validate(params) do |pm|
        pm.save and return
      end
    end

    private

    def setup_params!(params)
      # Params are Lotus Params, not a hash
      # we convert it to_h and used only symbols
      # to access the fields, e.g. in the policy
      @params = Hashie.symbolize_keys! params.to_h
    end

  end
end

sample_action.rb

module Web::Controllers::Root
  class Index
    include Web::Action
    
    # give access to the view
    # from there use the objects as any other in a view
    expose :model, :operation

    def call(params)
      run Web::Comment::Create
    rescue ::Trailblazer::NotAuthorizedError
      unauthorized!
    end

    private

    def unauthorized!
      status 401, "UNAUTHORIZED"
    end

  end
end