Awesome

Viewtastic

Installation

Install the gem

gem install viewtastic

Load the gem in your environment.rb file

config.gem "viewtastic"

Usage

My presenters go into the app/presenters directory of the application so this is added to the load_path in Rails by default by Viewtastic.

Presenters

A Presenter inherits from Viewtastic::Base and should use the presents method to declare presented objects.

class CommentPresenter < Viewtastic::Base
  presents :comment
end

This gives you several 'magic' methods:

All attributes of comment with the prefix 'comment'. For instance: comment_body, comment_post, comment_created_at.
comment_dom_id is the same as calling dom_id(comment) in a view.

If you want to skip the prefix and just have the attribute name, you can declare:

presents :comment => [:body, :created_at]

and you get presenter.body and presenter.created_at.

Assuming you have a Comment model and your controller has a helper method current_user that returns the user currently logged in, you could make the following presenter to help in presenting products.

class CommentPresenter < Viewtastic::Base
  presents :comment
  
  def dom_id
    comment_dom_id
  end
  
  def owner?
    controller.current_user.comments.include?(comment)
  end
  
  def links
    returning([]) do |links|
      links << link_to("Edit", [:edit, comment]) if owner?
      links << link_to("Reply", [:new, :comment]) if controller.current_user
    end
  end
end

Convenience

each_with_presenter is available on any Array, and it is designed to reuse a single Presenter instance and pass every element in the array as the presented object.

In your view (maybe posts/show.html.erb):

<ul>
<% @post.comments.each_with_presenter(CommentPresenter, :comment) do |comment| %>
  <li id="<%= comment.dom_id %>">
    <%= comment.body %>
    <%= comment.links %>
  </li>
<% end %>
</ul>

Credits

ActivePresenter was the inspiration for this project and some of the presenter code was used from ActivePresenter.
Authlogic -- the Authlogic activation code is used to activate Viewtastic on each request.