StripAttributes

StripAttributes is an ActiveModel extension that automatically strips all attributes of leading and trailing whitespace before validation. If the attribute is blank, it strips the value to nil by default.

It works by adding a before_validation hook to the record. By default, all attributes are stripped of whitespace, but :only and :except options can be used to limit which attributes are stripped. Both options accept a single attribute (only: :field) or arrays of attributes (except: [:field1, :field2, :field3]).

It's also possible to skip stripping the attributes altogether per model using the :if and :unless options.

Installation

Include the gem in your Gemfile:

gem "strip_attributes"

Examples

Default Behavior

class DrunkPokerPlayer < ActiveRecord::Base
  strip_attributes
end

Using except

# all attributes will be stripped except :boxers
class SoberPokerPlayer < ActiveRecord::Base
  strip_attributes except: :boxers
end

Using only

# only :shoe, :sock, and :glove attributes will be stripped
class ConservativePokerPlayer < ActiveRecord::Base
  strip_attributes only: [:shoe, :sock, :glove]
end

Using if

# Only records with odd ids will be stripped
class OddPokerPlayer < ActiveRecord::Base
  strip_attributes if: :strip_me?

  def strip_me?
    id.odd?
  end
end

Using unless

# strip_attributes will be applied randomly
class RandomPokerPlayer < ActiveRecord::Base
  strip_attributes unless: :strip_me?

  def strip_me?
    [true, false].sample
  end
end

Using allow_empty

# Empty attributes will not be converted to nil
class BrokePokerPlayer < ActiveRecord::Base
  strip_attributes allow_empty: true
end

Using collapse_spaces

# Sequential spaces in attributes will be collapsed to one space
class EloquentPokerPlayer < ActiveRecord::Base
  strip_attributes collapse_spaces: true
end

Using replace_newlines

# Newlines in attributes will be replaced with a space
class EloquentPokerPlayer < ActiveRecord::Base
  strip_attributes replace_newlines: true
end

Using regex

class User < ActiveRecord::Base
  # Strip off characters defined by RegEx
  strip_attributes only: [:first_name, :last_name], regex: /[^[:alpha:]\s]/

  # Strip off non-integers
  strip_attributes only: :phone, regex: /[^0-9]/

  # Strip off all spaces and keep only alphabetic and numeric characters
  strip_attributes only: :nickname, regex: /[^[:alnum:]_-]/

  # Remove trailing whitespace from a multi-line string
  strip_attributes only: :code, regex: /[[:blank:]]+$/)
end

Usage Patterns

Other ORMs implementing ActiveModel

It also works on other ActiveModel classes, such as Mongoid documents:

class User
  include Mongoid::Document
  strip_attributes only: :email
end

Using it with ActiveAttr

class Person
  include ActiveAttr::Model
  include ActiveModel::Validations::Callbacks

  attribute :name
  attribute :email

  strip_attributes
end

Using it directly

# where record is an ActiveModel instance
StripAttributes.strip(record, collapse_spaces: true)

# works directly on Strings too
StripAttributes.strip(" foo \t") #=> "foo"
StripAttributes.strip(" foo   bar", collapse_spaces: true) #=> "foo bar"

Testing

StripAttributes provides an RSpec/Shoulda-compatible matcher for easier testing of attribute assignment. You can use this with RSpec, Shoulda, Minitest-MatchersVaccine (preferred), or Minitest-Matchers.

Setup spec_helper.rb or test_helper.rb

To initialize RSpec, add this to your spec_helper.rb:

require "strip_attributes/matchers"
RSpec.configure do |config|
  config.include StripAttributes::Matchers
end

To initialize Shoulda (with test-unit), add this to your test_helper.rb:

require "strip_attributes/matchers"
class Test::Unit::TestCase
  extend StripAttributes::Matchers
end

OR if in a Rails environment, you might prefer this:

require "strip_attributes/matchers"
class ActiveSupport::TestCase
  extend StripAttributes::Matchers
end

To initialize Minitest-MatchersVaccine, add this to your test_helper.rb:

require "strip_attributes/matchers"
class MiniTest::Spec
  include StripAttributes::Matchers
end

OR if in a Rails environment, you might prefer this:

require "strip_attributes/matchers"
class ActiveSupport::TestCase
  include StripAttributes::Matchers
end

To initialize Minitest-Matchers, add this to your test_helper.rb:

require "strip_attributes/matchers"
class MiniTest::Spec
  include StripAttributes::Matchers
end

Writing Tests

RSpec:

describe User do
  it { is_expected.to strip_attribute(:name).collapse_spaces }
  it { is_expected.to strip_attribute(:name).replace_newlines }
  it { is_expected.to strip_attribute :email }
  it { is_expected.to strip_attributes(:name, :email) }
  it { is_expected.not_to strip_attribute :password }
  it { is_expected.not_to strip_attributes(:password, :encrypted_password)  }
end

Shoulda (with test-unit):

class UserTest < ActiveSupport::TestCase
  should strip_attribute(:name).collapse_spaces
  should strip_attribute(:name).replace_newlines
  should strip_attribute :email
  should strip_attributes(:name, :email)
  should_not strip_attribute :password
  should_not strip_attributes(:password, :encrypted_password)
end

Minitest-MatchersVaccine:

describe User do
  subject { User.new }

  it "should strip attributes" do
    must strip_attribute(:name).collapse_spaces
    must strip_attribute(:name).replace_newlines
    must strip_attribute :email
    must strip_attributes(:name, :email)
    wont strip_attribute :password
    wont strip_attributes(:password, :encrypted_password)
  end
end

Minitest-Matchers:

describe User do
  subject { User.new }

  must { strip_attribute(:name).collapse_spaces }
  must { strip_attribute(:name).replace_newlines }
  must { strip_attribute :email }
  must { strip_attributes(:name, :email) }
  wont { strip_attribute :password }
  wont { strip_attributes(:password, :encrypted_password) }
end

Support

Submit suggestions or feature requests as a GitHub Issue or Pull Request (preferred). If you send a pull request, remember to update the corresponding unit tests. In fact, I prefer new features to be submitted in the form of new unit tests.

Credits

The idea was originally triggered by the information at the (now defunct) Rails Wiki but was modified from the original to include more idiomatic ruby and rails support.

Versioning

Semantic Versioning 2.0 as defined at http://semver.org.

License

MIT License