ActivePreview

active_preview is a Ruby on Rails plugin that makes it easy to create previews of updates to records. The previews don't interact with the database but otherwise behave like ActiveRecord objects.

To preview a model, first run the generator:

$ rails generate active_preview:preview --model MyModel

This will create my_model_preview.rb in app/previews. If you have methods that touch the database in your model that need to be used with previewed data, override them there.

Next, add the #preview method to your model:

class MyModel < ActiveRecord::Base
  include ActivePreview::Previewing
end

Now you can pass an attribute hash or ActionController::Parameters object to my_model.preview to get a preview object with updated attributes that behaves exactly like your model.

For models with associations, run the generator for each associated model and add include ActivePreview::Previewing to each model class.

Add this line to your application's Gemfile:

gem 'active_preview'

And then execute:

$ bundle

Or install it yourself as:

$ gem install active_preview

Contribution directions go here.

The gem is available as open source under the terms of the MIT License.