#255 Undo with Paper Trail

Feb 28, 2011 | 13 minutes | Plugins

Undo and redo behavior is easy to add with a versioning gem such as Paper Trail. Learn how to add an undo link to any model's flash message.

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          bash
        
bundle
rails g paper_trail:install
rake db:migrate
rails g controller versions

          Gemfile
        
gem 'paper_trail'

          models/product.rb
        
has_paper_trail

          products_controller.rb
        
def undo_link
  view_context.link_to("undo", revert_version_path(@product.versions.scoped.last), :method => :post)
end

          routes.rb
        
post "versions/:id/revert" => "versions#revert", :as => "revert_version"

          versions_controller.rb
        
def revert
  @version = Version.find(params[:id])
  if @version.reify
    @version.reify.save!
  else
    @version.item.destroy
  end
  link_name = params[:redo] == "true" ? "undo" : "redo"
  link = view_context.link_to(link_name, revert_version_path(@version.next, :redo => !params[:redo]), :method => :post)
  redirect_to :back, :notice => "Undid #{@version.event}. #{link}"
end