nested_form.md

##Вложенные формы с гемом cocoon https://github.com/nathanvda/cocoon

in Gamefile

# for nested form
gem "cocoon", '~> 1.2.0'

делаем bundle install

есть две модели:

class QaQuestion < ActiveRecord::Base

  # change table name
  self.table_name = "questions"
  # for nested form
  has_many :pictures, class_name: "QuestionPicture", foreign_key: 'question_id'
  accepts_nested_attributes_for :pictures, reject_if: :all_blank, allow_destroy: true
end

class QuestionPicture < ActiveRecord::Base

  belongs_to :question, class_name: "QaQuestion", foreign_key: 'question_id'
  # paperclip
  has_attached_file :picture, {
      url: "/question/picture/:attachment/:id_partition/:style/:hash.:extension",
      hash_secret: "asdf",
      :styles => {
          :thumb => ["100x100#",:png],
          :medium => ["200x200#",:jpg],
          :original => ["800x800", :jpg],
      },
      :convert_options => {:thumb => Proc.new{Gexcore::ImagesHelpers.convert_options}}
  }
  validates_attachment_content_type :picture, :content_type => /\Aimage\/.*\Z/
  
end

есть контроллер

class QaQuestionsController < ApplicationController
  ...
  any_methods_here
  ...
  
  private

  def question_params
    params.require(:qa_question).permit(:category_id, :title, :description, :status, :name, :picture,
                                        pictures_attributes: [:id, :description, :picture])
  end

end

pictures_attributes из-за того, что мы переименовали в связи между Qaquestion и QuestionPicture

в app/view/qa_question создаем файл с именем (ВАЖНО) _picture_fields.html.haml имя файла зависит от того как мы назвали не саму вложенную модель, а ее связь (has_many :pictures, class_name: "QuestionPicture", foreign_key: 'question_id', гдеforeign_key: 'question_id' указывает модели QuestionPicture с каким конкретно ключем ей обращаться к модели QaQuestion) и заполняем кодом (это наш частный случай):

app/view/qa_question/_picture_fields.html.haml

.nested-fields
  %hr
  = f.input :picture, as: :file
  = f.input :description, as: :text
  = link_to_remove_association "remove", f

в app/view/qa_question/_form.html.haml включаем вложенную форму

= horizontal_simple_form_for(@item, html: { class: 'form-horizontal', multipart: true }) do |f|
  = f.error_notification

  .input-group
    = f.input :title
    = f.input :description

    %h3 Pictures
    #pictures
      = f.simple_fields_for :pictures, html: { class: 'form-horizontal' } do |picture|
        = render 'picture_fields', f: picture
      .links
        = link_to_add_association 'add', f, :pictures, class: 'btn btn-primary btn-lg'
    
  %br
  = f.button :submit, :class => "btn btn-primary"