Reform

Decouple your models from forms. Reform gives you a form object with validations and nested setup of models. It is completely framework-agnostic and doesn't care about your database.

Installation

Add this line to your Gemfile:

gem 'reform'

Defining Forms

Say you need a form for song requests on a radio station. Internally, this would imply associating songs table and the artists table. You don't wanna reflect that in your web form, do you?

class SongRequestForm < Reform::Form
  include DSL

  property :title,  on: :song
  property :name,   on: :artist

  validates :name, :title, presence: true
end

The ::property method allows defining the fields of the form. Using :on delegates this field to a nested object in your form.

Note: There is a convenience method ::properties that allows you to pass an array of fields at one time.

Using Forms

In your controller you'd create a form instance and pass in the models you wanna work on.

def new
  @form = SongRequestForm.new(song: Song.new, artist: Artist.new)
end

You can also setup the form for editing existing items.

def edit
  @form = SongRequestForm.new(song: Song.find(1), artist: Artist.find(2))
end

Rendering Forms

Your @form is now ready to be rendered, either do it yourself or use something like simple_form.

= simple_form_for @form do |f|

  = f.input :name
  = f.input :title

Validating Forms

After a form submission, you wanna validate the input.

def create
  @form = SongRequestForm.new(song: Song.new, artist: Artist.new)

  #=> params: {song_request: {title: "Rio", name: "Duran Duran"}}

  if @form.validate(params[:song_request])

Reform uses the validations you provided in the form - and nothing else.

Saving Forms

We provide a bullet-proof way to save your form data: by letting you do it!

  if @form.validate(params[:song_request])

    @form.save do |data, nested|
      #=> data:   <title: "Rio", name: "Duran Duran">
      #
      #   nested: {song:   {title: "Rio"},
      #            artist: {name: "Duran Duran"}}

      SongRequest.new(nested[:song][:title])
    end

While data gives you an object exposing the form property readers, nested already reflects the nesting you defined in your form earlier.

To push the incoming data to the models directly, call #save without the block.

    @form.save  #=> populates song and artist with incoming data
                #   by calling @form.song.name= and @form.artist.title=.

Coercion

Often you want incoming form data to be converted to a type, like timestamps. Reform uses virtus for coercion, the DSL is seamlessly integrated into Reform with the :type option.

Be sure to add virtus to your Gemfile.

require 'reform/form/coercion'

class SongRequestForm < Reform::Form
  include DSL
  include Reform::Form::Coercion

  property :written_at,  on: :song, type: DateTime
end

@form.save do |data, nested|
  data.written_at #=> <DateTime XXX>

Rails Integration

A sample Rails app using Reform.

Reform offers ActiveRecord support to easily make this accessible in Rails based projects. You simply include Reform::Form::ActiveRecord in your form object and the Rails specific code will be handled for you. This happens by adding behaviour to make the form ActiveModel-compliant. Note that this module will also work with other ORMs like Datamapper.

Simple Integration

Form Class

You have to include a call to model to specify which is the main object of the form.

require 'reform/rails'

class UserProfileForm < Reform::Form
  include DSL
  include Reform::Form::ActiveRecord

  property :email,        on: :user
  properties [:gender, :age],   on: :profile

  model :user

  validates :email, :gender, presence: true
  validates :age, numericality: true
  validates_uniqueness_of :email
end

Basically, model :user tells Reform to use the :user object in the composition as the form main object while using "user" as the form name (needed for URL computation). If you want to change the form name let Reform know.

  model :singer, :on => :user # form name is "singer" whereas main object is `:user` in composition.

View Form

The form becomes very dumb as it knows nothing about the backend assocations or data binding to the database layer. This simply takes input and passes it along to the controller as it should.

<%= form_for @form do |f| %>
  <%= f.email_field :email %>
  <%= f.input :gender %>
  <%= f.number_field :age %>
  <%= f.submit %>
<% end %>

Controller

In the controller you can easily create helpers to build these form objects for you. In the create and update actions Reform allows you total control of what to do with the data being passed via the form. How you interact with the data is entirely up to you.

class UsersController < ApplicationController

  def create
    @form = create_new_form
    if @form.validate(params[:user])
      @form.save do |data, map|
        new_user = User.new(map[:user])
        new_user.build_user_profile(map[:profile])
        new_user.save!
      end
    end
  end


  private
  def create_new_form
    UserProfileForm.new(user: User.new, profile: UserProfile.new)
  end
end

Note: this can also be used for the update action as well.

Using Your Models In Validations

Sometimes you want to access your database in a validation. You can access the models using the #model accessor in the form.

class ArtistForm < Reform::Form
  property :name

  validate "name_correct?"

  def name_correct?
    errors.add :name, "#{name} is stupid!" if model.artist.stupid_name?(name)
  end
end

Security

By explicitely defining the form layout using ::property there is no more need for protecting from unwanted input. strong_parameter or attr_accessible become obsolete. Reform will simply ignore undefined incoming parameters.

Maintainers

Nick Sutterer

Garrett Heinlen

Attributions!!!

Great thanks to Blake Education for giving us the freedom and time to develop this project while working on their project.

halorgium/reform