Rails 4 How to model a form with a collection of checkboxes with other text_field

Question

let me first start by saying this could also be a modeling problem and I am open to model suggestions.

Use Case: I have a form and I need to allow a user to select a checkbox on the category of their post. If there is no category that fits their post checking the other category will show a text field for the user to add a custom category. This should would for creating and updating nested modules

DB Modeling

class CreateCategories < ActiveRecord::Migration
  def change
    create_table :categories do |t|
      t.string :name, null: false
      t.timestamps null: false
    end

    reversible do |dir|
      dir.up {
        Category.create(name: 'Hats')
        Category.create(name: 'Shirts')
        Category.create(name: 'Pants')
        Category.create(name: 'Shoes')
        Category.create(name: 'Other')
      }
    end

    create_table :categorizations, id: false do |t|
      t.belongs_to :post, index: true, null: false
      t.belongs_to :category, index: true, null: false
      t.string :value
    end
  end
end

App Models

class Post < ActiveRecord::Base
  has_many :categorizations
  accepts_nested_attributes_for :categorizations, allow_destroy: true
  has_many :categories, through: :categorizations
  accepts_nested_attributes_for :categories
end

class Category < ActiveRecord::Base
  has_many :posts
end

Controller:

  def update

    if @post.update(post_params)
      flash.now[:success] = 'success'
    else
      flash.now[:alert] = @post.errors.full_messages.to_sentence
    end

    render :edit
  end

  private

  def set_post
    @post = Post.find(params[:id])
    (Category.all - @post.categories).each do |category|
      @post.categorizations.build(category: category)
    end
    @post.categorizations.to_a.sort_by! {|x| x.category.id }
  end

  def post_params
    params.require(:post).permit(:name, :description,
                                categorizations_attributes: [ :category_id, :value, :_destroy],
                                )
  end

View:

= f.fields_for :categorizations do |ff|
    = ff.check_box :_destroy, { checked: ff.object.persisted? }, '0', '1'
    = ff.label :_destroy, ff.object.category.name
    = ff.hidden_field :category_id
    = ff.text_field :value if ff.object.category.other?

However with the above solution i continue to run in to duplicate record errors when saving. Not sure why this is happening? Is there a better way to do this?

Answer 1

I would prefer something like this:

Models

post.rb

class Post < ActiveRecord::Base
  has_many :categorizations
  has_many :categories, through: :categorizations

  accepts_nested_attributes_for :categorizations, allow_destroy: true
  accepts_nested_attributes_for :categories
end

category.rb

class Category < ActiveRecord::Base
  has_many :categorizations
  has_many :posts, through: :categorizations
end

Controller

...
def update
  if @post.update(post_params)
    flash.now[:success] = 'success'
  else
    flash.now[:alert] = @post.errors.full_messages.to_sentence
  end
  render :edit
end

private

def set_post
  @post = Post.find(params[:id])
end

def post_params
  params.require(:post).permit(:name, :description, category_ids: [])
end
...

Views I always preferer plain .erb so, with help of simple_form.

<%= simple_form_for(@post) do |f| %>
  <%= f.error_notification %>

  <div class="form-inputs">
    <%= f.input :content -%>
    ...
  </div>

  <div class="form-inputs">
    <%= f.association :categories, as: :check_boxes -%>
  </div>

  <div class="form-actions">
    <%= f.button :submit %>
  </div>
<% end %>

You can have checked/unchecked states and destroy easily and cleanly by this way. In addition, you can add

<%= f.simple_fields_for :category do |category_fields| %>
  <%= category_fields.input :name -%>
<% end %>

to get nested fields for associations, but don't forget to add related params to strong_params when you do this.

...
def post_params
  params.require(:post).permit(:name, :description, category_attributes: [:name])
end
....

Answer 2

Don't store the other in your model, nor it's name! If you're using form_for for your posts, simply add an unrelated field.

ex: f.text_field :other_name to text_field_tag :other_name

Manually add your Other option to the dropdown collection.

You can add JS to hide and display a hidden text field if other is selected.

In your posts_controller do:

def create
  ...
  if params[:other_name]
    post.categories.create(name: param[:other_name])
  end
  ...
end