Common Rails validations wrapped in a gem.
Latest commit 664b7c8 May 16, 2015 @mdespuits Update to v0.9
Failed to load latest commit information.
README.markdown Add Ruby 2.2 support to README May 15, 2015


Build Status Dependency Status Code Climate

Validates Formatting Of

The validates_formatting_of gem adds several convenient methods to validate things such as emails, urls, and phone numbers in a Rails application.

Supported Ruby Versions

  • 1.9.3
  • 2.0.0
  • 2.1.0
  • 2.2.0


To install validates_formatting_of, add the following to your Gemfile:

gem 'validates_formatting_of'

Then bundle install:

bundle install


Using validates_formatting_of is as simple as using Rails' built-in validation methods in models.

class User < ActiveRecord::Base
  validates_formatting_of :email

If the name of the column is identical to the validation method you would use, it auto-selects that validation method. Thus, this is a shortcut for the following:

class User < ActiveRecord::Base
  validates_formatting_of :email, :using => :email

This call will ensure that the user-provided email is a valid email. This way, you will not need to find or write your own regex to validate. All of that logic is contained within validates_formatting_of.

Rails validation options still available

You can still add the following options when using validates_formatting_of:

  • :allow_nil
  • :allow_blank
  • :on
  • :if
  • :unless
  • You can also specify the :message option to use a custom validation message.

Share your Validations

Say, for example, you have identical plain-old regex validations for different columns or even on different models entirely. You can easily alleviate this problem by simply adding the validation(s) in an initializer file.

While very unrealistic, these examples should serve their purpose in demonstrating this ability.

# config/initializers/validates_formatting_of.rb
ValidatesFormattingOf::Method.add :loweralpha, /[a-z]/, "must be lowercase and no spaces"
ValidatesFormattingOf::Method.add :upperalpha, /[A-Z]/, "must be uppercase and no spaces"
ValidatesFormattingOf::Method.add :weak_password, /[a-zA-Z0-9]{8,}/, "must contain only letters and numbers and be at least 8 characters long".

Keep in mind, since this gem is only ActiveModel-dependent, you should be able to do this in whatever non-Rails application classes you have that include ActiveModel::Validations in some way (and that extend the ValidatesFormattingOf::ModelAdditons module).

Built-in Validations

validates_formatting_of has the following built-in validations:

class ExampleModel < ActiveRecord::Base
  validates_formatting_of :email, :using => :email      # Email
  validates_formatting_of :first_name, :using => :alpha # Letters
  validates_formatting_of :website, :using => :url      # URLs
  validates_formatting_of :text, :using => :alphanum    # Alpha-numeric
  validates_formatting_of :zipcode, :using => :us_zip   # US Zip Code
  validates_formatting_of :phone, :using => :us_phone   # US Phone Numbers
  validates_formatting_of :ip, :using => :ip_address_v4 # IPv4
  validates_formatting_of :ssn, :using => :ssn          # Social Security Numbers
  validates_formatting_of :color, :using => :hex_color  # Hexadecimal Colors
  validates_formatting_of :amount, :using => :dollars   # Dollars

  # Credit Card (Visa, Mastercard, Discover, and American Express)
  validates_formatting_of :cc, :using => :credit_card

Note: If you use client_side_validations then you need to use the following validation method:

class User < ActiveRecord::Base
  validates_formatting_of :email, :using => :simple_email

Plain Old Ruby Objects

If you are not using ActiveRecord or want to use it on some other type of object, this is the least you need to get validations running.

class User
  include ActiveModel::Validations
  extend ValidatesFormattingOf::ModelAdditions

  attr_accessor :email

  validates_formatting_of :email, :using => :email


If, for any reason, you want to overwrite the regex specified in the gem, you can using the :with option just like in ActiveModel's built-in validates_format_of.

class Person < ActiveRecord::Base
  validates_formatting_of :first_name, :with => /[A-Z]/i

Development and Contribution

To add a simple regex validation, all that is necessary is to add a single line to the ValidatesFormattingOf::Method module in the lib/method.rb file (with a line or two of documentation explaining it's use).

For example:

module ValidatesFormattingOf::Method
  # This :validation_name method is for example purposes only.
  # You can use this in production, but it would require a value of 'example regex' to pass.
  add :validation_name, %r{example regex}iux, "is a message for validation method :validation_name"
  1. Fork it
  2. Make it awesome (with passing tests)
  3. Create a new Pull Request.

Have Ideas?

Do you use a particular pattern on a regular basis that isn't here or you would like to contribute? For now, create a new issue in the issue tracker. I would be more than happy to consider adding it to the project.