HasHistory

This gem adds a simple but effective changes history to your ActiveRecord models. It is designed with Rails on mind but it can be used without it as well.

Installation

Add this line to your application's Gemfile:

gem 'has_history'

And then execute:

$ bundle

Or install it yourself as:

$ gem install has_history

Usage

First you have to set up has_history:

$ rails g has_history:install

and then migrate your database (rake db:migrate).

From then on whenever you add has_history to your ActiveRecord model like this:

class MyModel < ActiveRecord::Base
  ...
  has_history
  ...
end

then you 'magically' have history for the changes. You can access history via

MyModel.history_entries

Each entry has a modifications attribute that contains the changes in array of hashes:

[{ attribute1 => {:before => value1_before, :after => value1_after} }, ..., { attributeN => {:before => valueN_before, :after => valueN_after} }]

Other useful attributes:

• modified_by_id is a reference to the user who made the changes
• entity is the model instance affected
• created_at is the time when the change took place

Configuration

has_history has a few options to control its behavior:

• ignore_attributes controls which attributes are not included in the history tracking
• updater_id sets the user who made the changes (it can be taken from the record or set via some other method, such as the widespread User.current_user hack)
• resolution_map holds foreign key references to attributes whose value is to be materializes (that is instead of post_id it is possible to save the title of the referenced post)

For more details see config/initializers/has_history.rb.

Configuration options have defaults, can be set through the initializer, or can be passed in on a per-model base (as params to the has_model method).

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Added some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request