scrubby

It’s so simple! scrubby makes sure that all your attributes are cleaned up before they make their way into your models.

Installation

In environment.rb:

Rails::Initializer.run do |config|
  ...
  config.gem 'scrubby'
  ...
end

At your application root, run:

$ sudo rake gems:install

Example

By default, scrubby will strip extra whitespace from strings, and turn blank strings into nil values:

class User < ActiveRecord::Base
  scrub :first_name, :middle_name, :last_name
end

>> u = User.new(:first_name => " Steve", :middle_name => "  ", :last_name => "Richert ")
=> #<User first_name: "Steve", middle_name: nil, last_name: "Richert">

Or you can override the default behavior, just by defining a scrub instance method:

class User < ActiveRecord::Base
  scrub :first_name, :middle_name, :last_name

  def scrub(value)
    value.to_s.upcase
  end
end

>> u = User.new(:first_name => "Steve", :last_name => "Richert")
=> #<User first_name: "STEVE", middle_name: "", last_name: "RICHERT">

And defining your own scrubbers inline is super easy:

class User < ActiveRecord::Base
  scrub(:first_name, :last_name){|v| v.blank? ? nil : v.titleize }

  scrub :middle_name do |value|
    initials = value.split(" ").map{|n| n.first.upcase + "." }
    initials.empty? ? nil : initials.join(" ")
  end
end

class Admin < User
  scrub(:middle_name){ nil }
end

>> u = User.new(:first_name => "stephen", :middle_name => "joel michael", :last_name => "richert")
=> #<User first_name: "Stephen", middle_name: "J. M.", last_name: "Richert">
>> a = Admin.new(:first_name => "stephen", :middle_name => "joel michael", :last_name => "richert")
=> #<Admin first_name: "Stephen", middle_name: nil, last_name: "Richert">

How It Works

It’s pretty straightforward, and there’s nothing all that fancy happening behind the scenes.

Scrubbing happens only when attributes are set. That way, no time is wasted scrubbing every time an attribute is retrieved.

For column attributes, the scrubbing is done at the write_attribute level, without stepping on ActiveRecord’s toes by creating a bunch of unnecessary setter methods.

scrubby also works with virtual attributes, simply by adding an alias_method_chain to the corresponding setter method, so the original can still be accessed via attribute_without_scrub=.

Inheritance is respected, just as you’d expect, down through model subclasses. Scrubbers are overridden in subclasses with no problem.

Inspiration

Those of you who are familiar with attribute_normalizer[http://github.com/mdeering/attribute_normalizer] will recognize the how scrubby looks and feels, and that’s no accident! attribute_normalizer has a simple, clean and effective interface.

But scrubby was written to be an improvement on what’s happening behind the scenes, particularly with regards to inheritance and avoiding unnecessary method definitions. Basically, the idea was to really clean up and simplify the back-end of an already awesome interface.

Contributing