EddM/preferential

Extract preference data from your ActiveRecord models quickly and painlessly

Preferential

Sometimes storing preference data for users (or other types of object) can result in database tables with tons of very infrequently-accessed columns. This isn't always a problem, especially if you optimise your queries everywhere - but sometimes doing this is unwieldy. Preferential is a Rails gem that can make the extraction of this "metadata" to another table quick and painless.

Installation

In your Gemfile:

gem "preferential"

Usage

First, you'll need to generate a migration to create the preferences table:

$ [bundle exec] rails generate preferential:migration
$ [bundle exec] rake db:migrate

You can then define preferences for your models like this:

class User < ActiveAdmin::Base
  has_preference :time_zone
  has_preference :language
  has_preference :send_newsletter
end

That's it! You can then read and write this preference as you would a normal model attribute:

user = User.find(3)
user.time_zone # => "JST"
user.language = "Japanese"
user.language # => "Japanese"
user.send_newsletter? # => true

Advanced Configuration

Along with the name of the preference attribute, you can also (optionally) provide a default value for preferences and a type. A preference's type will be inferred from its default if no type is provided but a default is.

If no default or type is provided, values will (as you'd expect) default to nil and will be typecast as a string when being accessed.

class User < ActiveAdmin::Base
  has_preference time_zone: { type: :string }
  has_preference language: { type: :string, default: "Japanese" }
  has_preference send_newsletter: { default: false }
end

The accepted values for type are:

• :boolean
• :string
• :float
• :integer

You can also define multiple preferences at once:

class User < ActiveAdmin::Base
  has_preference time_zone: { type: :string }, language: { type: :string, default: "Japanese" }
end