Form Objects for ActiveModel
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README.md

ActiveForm

Apply form objects to ActiveModel. Form objects have responsability to decouple the form logic from the model. It will help you to simplify your models.

Installation

Add this line to you Gemfile :

  gem 'activeform-rails'

Please make sure you are running a compatible version of Ruby, see below.

Quick example

In order to manage category and users, you can create an object like this :

class Form
  include ActiveForm::Form

  properties :name, on: :user
  properties :title, on: :category

  self.main_model = :user
end

Now, you can do this :

user = User.new
category = Category.new
form = Form.new(user: user, category: category)
form.user # return the user
form.user == user # return true

form.user.name # return nil
form.name # return nil
form.fill_attributes(name: 'GCorbel')
form.user.name # return 'GCorbel'
form.name # return 'GCorbel'

form.valid? # return true
form.save # save all models and return true

Example without backing by an ActiveModel

If you would like to use form objects to provide validations to simple objects, simply omit the on argument and main_model definition as follows :

class Form
  include ActiveForm::Form
  properties :name, :title
  validates_presence_of :title
end

form = Form.new(name: 'John')
form.name # return John
form.title # return nil
form.valid? # return false

Use validations

Validations works like a normal ActiveModel class. So, you can do this :

class Form
  include ActiveForm::Form

  properties :name, on: :user

  validates :name, presence: true

  self.main_model = :user
end

And use it like this :

user = User.new
form = Form.new(user: user)
form.valid? # return false
form.errors # return #<ActiveModel::Errors:0x007fe603816640 @messages={name:["can't be blank"]}>
form.fill_attributes(name: 'GCorbel')
form.valid? # return true

To validate the unicity or a property, you can do this :

class Form
  include ActiveForm::Form
  include ActiveForm::ValidateUniqueness
  properties :name, on: :user
  validates_uniqueness_of :name, :user
end

The validates_uniqueness_of take two parameters, the first is the property which should be unique and the second is the model for this property.

Saving forms

There is two methods to save forms, save and save!. save will return true or false if the model is valid or not. save! will return an error and will rollback all change mades.

You can customize those methods by adding a block like this :

class Form
  include ActiveForm::Form

  properties :name, on: :user

  self.main_model = :user
end

form = Form.new(user: User.new)
form.save do |f|
  f.user # return the user
end

You can also override the save method like this :

class Form
  include ActiveForm::Form

  properties :name, on: :user

  self.main_model = :user

  def save
    super do
      user.save
    end
  end
end

Take care : If your logic is too complex, it's probably better to use a service object.

has_many relationship

To manage a has_many relationship, you can do it like this :

class Form
  include ActiveForm::Form
  properties :name, on: :category
  self.main_model = :category

  attr_accessor :user_ids

  def save
    super do
      category.users = user_ids.map { |user_id| User.find(user_id) }
      category.save
    end
  end
end

Alias properties

Sometimes it's useful to create an alias for a method, you can do it like this :

class Form
  include ActiveForm::Form
  properties :name, on: :category
  alias_property :category_name, :name
  self.main_model = :category
end

form = Form.new(category: Category.new(name: 'bacon'))
form.category_name # return 'bacon'
form.category_name = 'beef'
form.category_name # return 'beef'

Complete Example

You can find an example of a working application in the spec/dummy directory.

Requirements

Ruby 2 or greater.

Contributing

  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request