Features

Features is a nice little gem for associating application features with an active record model in a Rails app.

Developed and used on zendesk.com for account owners to switch different application features on and off.

Description

If the feature set of your application grows, some customers would like to limit the features to only include what they need. To enable your customers at Zendesk to customize their help desk to their needs, we developed this nice lille feature management system, that we thought someone else out there might find useful.

You can define your feature set in a nice directly in the class that should be associated with features:

class Account < ActiveRecord::Base
  has_features do
    feature :archive
    feature :ssl
  end
end

Which would enable code like:

account.features.archive? # checks weather an account has the archive feature.
account.features.archive.create # adds the archive feature to the account
account.features.archive.destroy # removes the archive feature to the account
account.features?(:account, :ssl) # checks if the account has both the archive and ssl features

You can also define feature dependencies:

class Account < ActiveRecord::Base
  has_features do
    feature :archive
    feature :premium
    feature :ssl, :requires => [:premium]
  end
end

Which would enable code like:

account.features.ssl.available? # returns true if all the required features of the ssl feature are met.
account.features.ssl.create # raises a Features::RequirementsError if the account doesn't have the premium feature
account.features.premium.destroy # would also destroy the ssl feature

Features can also be updated with the update_attributes and update_attributes! methods.

#assuming params include { :account => { :features => { :archive => '1', :ssl => '0' } } }
account.update_attributes(params[:account]) # would add the archive feature and remove the ssl feature

WARNING: You might want to protect some features from being updated with update_attributes. You can do this with:

class Account < ActiveRecord::Base
  has_features do
    feature :archive
    feature :premium, :protected => true
    feature :ssl, :requires => [:premium]
  end
end

This would protect the premium feature from being updated with update_attributes and update_attributes! The premium feature can only be updated with account.features.premium.create and account.features.premium.destroy.

We also created a view helper to help you generate the UI for enabling and disabling features:

<% form_for(:account, :html => { :method => :put }) do |f| %>
  <h3>
    <%= f.feature_check_box :ssl %> Enable SSL on your account
  </h3>
<% end %>

Installation

Install the gem in your rails project by putting it in your environment.rb:

config.gem 'zendesk-features', :lib => 'features', :source => 'http://gems.github.com'

and do a sudo rake gems:install

Also remember to create the features table. Depending on the name of the model you choose to associate with features in your project, you could create the table like:

create_table :features do |t|
  t.string :type, :null => false
  t.integer :account_id, :null => false
  t.timestamps
end

Known issues

Let us know if you find any.

Requirements

ActiveRecord
ActionPack

LICENSE:

(The MIT License)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.