A simple Ruby form library, intended for use with Rails

Largely inspired by Code Climate's 7 Patterns to Refactor Fat ActiveRecord Models as a method for encapsulating validation into an object with a single responsibility.


Cave::Form is a light glue layer around Rails' ActiveModel::Validations and Virtus' type coercion. You may want to consult their documentation for more options.

class FormClass < Cave::Form
  field :name, String,
    presence: true,
    format: { :with => /\A[a-zA-Z]+\z/, :message => "Only letters allowed" }
    # Takes any number of standard Rails validation helper options
  field :favorite_number, Integer,
    inclusion: { :in => 1..10 }

  def persist!
    # Define your persistence logic here.
    # This method will be called whenever a valid form is saved.
    "Form saved!"

form = FormClass.bind name: 'James Dabbs', favorite_number: 11
=> false
=> ["Name Only letters allowed", "Favorite number is not included in the list"]

form = FormClass.bind name: 'jamesdabbs', favorite_number: '7'
=> true
=> 7  // Note the type coercion!
=> "Form saved!"

Forms for Models

For the common use case of creating or updating a model with a form, Cave provides the Cave::ModelForm class.

class ProfileForm < Cave::ModelForm
  model Profile

  field :name, String, presence: true
  field :age,  Integer

ProfileForm.bind(name: 'James').save!  # Creates a new Profile named 'James'

instance = Profile.first
ProfileForm.bind(instance, name: 'Jim').save!  # Updates the Profile's name

Planned features

  • Add presenters for rendering forms into html (inc. a bootstrap template)
  • Improve handling of intial values (as for unbound ModelForms)
  • Write docs
  • Requests?