Simple Presenter System

application_helper.rb

module ApplicationHelper
  def present(object, klass = nil)
    klass ||= "#{object.class}Presenter".constantize
    presenter = klass.new(object, self)
    yield presenter if block_given?
    presenter
  end
end

base_presenter.rb

class BasePresenter
  def initialize(object, template)
    @object = object
    @template = template
  end

  private

  def self.presents(name)
    define_method(name) do
      @object
    end
  end

  def view
    @template
  end
  
  def method_missing(*args, &block)
    @template.send(*args, &block)
  end
end

user_presenter.rb

class UserPresenter < BasePresenter
  presents :user
  delegate :username, to: :user

  def avatar
    site_link image_tag("avatars/#{avatar_name}", class: "avatar")
  end

  def linked_name
    site_link(user.full_name.present? ? user.full_name : user.username)
  end

  def member_since
    user.created_at.strftime("%B %e, %Y")
  end
  
  # ...
  
end