RenderingEngine

gem 'rendering_engine'

$ bundle

$ gem install rendering_engine

$ file_repo        = RenderingEngine::FileRepo.new(base_path)
$ content_provider = RenderingEngine::Provider.new(file_repo)
$ content = content_provider.get(relative_file_path)
$ content.source #gets source of file (rendered or not :D)
$ content.kind return (:orginal, :template, :unknown)

In controller can looks like this:

---
def show
  path = "#{params[:client]}/#{params[:path]}"
  data = params[:data]

  content = content_provider.get(path, data: data)
  return not_found if content.unknown?

  render text: content.source
end

def content_provider
  @content_provider ||= RenderingEngine::Provider.new(file_repo)
end

def file_repo
  @file_repo ||= RenderingEngine::FileRepo(Rails.root.join('app/content'))
end
---

class MongoFileRepo
  def initilaize(mongo)
    @mongo = mongo
  end

  def get(file_path)
    bucket.open(file_path, 'r+')
  end

  def read(file_path)
    bucket.open(file_path, 'r').read
  end

  def exist?(file_path)
    bucket.files.select { |f| f.filename == file_path }.count > 0
  end

  def save(file_path, body, opts = {})
    file_opts = opts.merge(filename: file_path)
    bucket.open(file_opts , 'w+').write(body)
  end

  def delete(file_path)
    bucket.delete(file_path)
  end

  def file_dirname(file_path)
    File.dirname(file_path)
  end

  private

  attr_reader :mongo

  def bucket
    @bucket ||= mongo.bucket
  end
end

mongo = Moped::Session.new(['127.0.0.1:27017'], database: 'test')
file_repo = MongoFileRepo(mongo)
provider = RenderingEngine::Provider.new(file_repo)
provider.get(path, custom_helper: ContentCustomHelpers).source

class ContentCustomHelpers
  def initialize(opts={})
    @base_path = opts.fetch(:base_path)
    @data      = opts[:data]
  end

  def make_some_stuff
    "best line ever!"
  end

  def render(file_relative_path)
    file_path = File.join(base_path, file_relative_path)

    RenderingEngine::Content.new(file_path, data: data, custom_helper: self.class).source
  end

  attr_reader :data

  private

  attr_reader :base_path
end

file_repo = RenderingEngine::FileRepo.new(Rails.root.join('app/content'))
provider = RenderingEngine::Provider.new(file_repo, custom_helper: ContentCustomHelpers)
provider.get(path).source

file_repo = RenderingEngine::FileRepo.new(Rails.root.join('app/content'))
provider = RenderingEngine::Provider.new(file_repo)
provider.get(path, custom_helper: ContentCustomHelpers).source