Sanatio

Sanatio is a gem that does validation. It has no external dependencies.

Installation

Add this line to your application's Gemfile:

gem 'sanatio'

And then execute:

$ bundle

Or install it yourself as:

$ gem install sanatio

Usage

One-time validation

If you only need a validation in a single place. You can use a block.

If your block evaluates to a falsey value, then the validation fails with the reason that is given.

With field level validation:

class Person
  include Sanatio

  def initialize(name)
    @name = name
  end

  attr_reader :name

  ensure_that(:name).is { !nil? }.reason = :not_nil
end

person = Person.new(nil)
error = person.errors.first
error.field # :name
error.reason # :not_nil
person.valid? # false

Or, with a class level validation:

class Person
  include Sanatio

  def initialize(name)
    @name = name
  end

  attr_reader :name

  ensure_that(self).is { !name.nil? }.reason = :name_not_nil
end

person = Person.new(nil)
error = person.errors.first
error.reason # :name_not_nil
person.valid? # false

Skipping validations

You can skip validations if they are not needed or if they cannot run.

class Person
  include Sanatio

  def initialize(name)
    @name = name
  end

  attr_reader :name

  # NilClass#empty? does not exist, so the validation will fail when the name is nil.
  ensure_that(:name).is { !empty? }.skip_if { nil? }.reason = :not_empty
end

Person.new(nil).valid? # true
Person.new("").valid? # false

Built-in validations

Present

This validation fails when the value is not present. Or empty when appropriate.

class Person
  include Sanatio

  def initialize(name)
    @name = name
  end

  attr_reader :name

  ensure_that(:name).is Present
end

Person.new(nil).valid? #false
Person.new("").valid? #false
Person.new("Test Testington").valid? #true

GreaterThanOrEqualTo

This validation fails when the value is smaller than a given value.

class Person
  include Sanatio

  def initialize(age)
    @age = age
  end

  attr_reader :age

  ensure_that(:age).is GreaterThanOrEqualTo, 18
endO

Person.new(nil).valid? #true, validation is skipped
Person.new(15).valid? #false
Person.new(18).valid? #true

GreaterThan

This validation fails when the value is smaller than or equal a given value.

class Person
  include Sanatio

  def initialize(age)
    @age = age
  end

  attr_reader :age

  ensure_that(:age).is GreaterThan, 18
endO

Person.new(nil).valid? #true, validation is skipped
Person.new(15).valid? #false
Person.new(19).valid? #true

LessThanOrEqualTo

This validation fails when the value is greater than a given value.

class Person
  include Sanatio

  def initialize(age)
    @age = age
  end

  attr_reader :age

  ensure_that(:age).is LessThanOrEqualTo, 18
endO

Person.new(nil).valid? #true, validation is skipped
Person.new(15).valid? #true
Person.new(19).valid? #false

LessThan

This validation fails when the value is greater than or equal to a given value.

class Person
  include Sanatio

  def initialize(age)
    @age = age
  end

  attr_reader :age

  ensure_that(:age).is LessThan, 18
endO

Person.new(nil).valid? #true, validation is skipped
Person.new(15).valid? #true
Person.new(19).valid? #false

EqualTo

This validation fails when the field is not equal to the given value.

class Person
  include Sanatio

  def initialize(age)
    @age = age
  end

  attr_reader :age

  ensure_that(:age).is EqualTo, 18
endO

Person.new(nil).valid? #false
Person.new(15).valid? #false
Person.new(18).valid? #true

NotEqualTo

This validation fails when the field is equal to the given value.

class Person
  include Sanatio

  def initialize(age)
    @age = age
  end

  attr_reader :age

  ensure_that(:age).is NotEqualTo, 18
endO

Person.new(nil).valid? #true
Person.new(15).valid? #true
Person.new(18).valid? #false

OneOf

This validation fails when the value is not in the list given.

class Person
  include Sanatio

  def initialize(name)
    @name = name
  end

  attr_reader :name

  ensure_that(:name).is OneOf, 'Santa', 'Easter Bunny'
end

Person.new(nil).valid? #false
Person.new("Test Testington").valid? #false
Person.new("Easter Bunny").valid? #true
Person.new("Santa").valid? #true

Valid

This validation fails when the value is not valid.

class Address
  include Sanatio

  def initialize(street)
    @street = street
  end

  attr_reader :street

  ensure_that(:street).is Present
end

class Person
  include Sanatio

  def initialize(address)
    @address = address
  end

  attr_reader :address

  ensure_that(:address).is Valid
end

Person.new(Address.new('Alleystreet')).valid? #true
Person.new(Address.new(nil)).valid? #false
Person.new(Address.new(nil)).errors #[Error.new(:field => :address, :reason => :invalid)]

Matching

This validation fails when the value does not match the provided regex.

class Person
  include Sanatio

  def initialize(name)
    @name = name
  end

  attr_reader :name

  ensure_that(:name).is Matching, /Test/
end

Person.new(nil).valid? #false
Person.new("Test Testington").valid? #true
Person.new("DoesNotMatch").valid? #false
Person.new("DoesNotMatch").errors #[Error.new(:field => :name, :reason => :no_match)]

Either

This validation only passes when only one of the two fields matches the given validator.

The validation is skipped if either field contains a value that would be skipped.

class Person
  include Sanatio

  def initialize(first_name, last_name)
    @first_name = first_name
    @last_name = last_name
  end

  attr_reader :first_name, :last_name

  ensure_that(self).is Either, :first_name, :last_name, Present
end

Person.new('Test', 'Testington').valid? #false
Person.new('Test', nil).valid? #true
Person.new('', 'Testington).valid? #true
Person.new(nil, '').valid? #false
Person.new(nil, nil).errors #[Error.new(:reason => :neither, :params =>
                            #  [:first_name, :last_name])]
Person.new('Test', 'Testington').errors #[Error.new(:reason => :both,
                                        # :params =>
                                        #   [:first_name, :last_name])]

Development

After checking out the repo, run bin/setup to install dependencies. Then, run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release to create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Fork it ( https://github.com/ThijsWouters/sanatio/fork )
Create your feature branch (git checkout -b my-new-feature)
Commit your changes (git commit -am 'Add some feature')
Push to the branch (git push origin my-new-feature)
Create a new Pull Request