Form Objects DSL

Form objects DSL

You can use schemas and fields on their own, or include the DSL module in your own classes to define form objects.

require "parametric/dsl"

class CreateUserForm
  include Paradocs::DSL

  schema(:test) do
    field(:name).type(:string).required
    field(:email).policy(:email).required
    field(:age).type(:integer)
    subschema_by(:age) { |age| age > 18 ? :allow : :deny }
  end

  subschema_for(:test, name: :allow) { field(:role).options(["sign_in"]) }
  subschema_for(:test, name: :deny) { field(:role).options([]) }

  attr_reader :params, :errors

  def initialize(input_data)
    results = self.class.schema.resolve(input_data)
    @params = results.output
    @errors = results.errors
  end

  def run!
    if !valid?
      raise InvalidFormError.new(errors)
    end

    run
  end

  def valid?
    !errors.any?
  end

  private

  def run
    User.create!(params)
  end
end

Form schemas can also be defined by passing another form or schema instance. This can be useful when building form classes in runtime.

UserSchema = Paradocs::Schema.new do
  field(:name).type(:string).present
  field(:age).type(:integer)
end

class CreateUserForm
  include Paradocs::DSL
  # copy from UserSchema
  schema UserSchema
end

Form object inheritance

Sub classes of classes using the DSL will inherit schemas defined on the parent class.

class UpdateUserForm < CreateUserForm
  # All field definitions in the parent are conserved.
  # New fields can be defined
  # or existing fields overriden
  schema do
    # make this field optional
    field(:name).declared.present
  end

  def initialize(user, input_data)
    super input_data
    @user = user
  end

  private
  def run
    @user.update params
  end
end