NestedStrongParameters

If in your Rails app you use strong_parameters with nested_attributes, and believe the old attr_accessible were easier to use. This gem is for you.

Installation

Add this line to your application's Gemfile:

  gem 'nested_strong_parameters'

And then execute:

$ bundle

Or install it yourself as:

$ gem install nested_strong_parameters

Usage

In your models use strong_fields to define the whitelist of fields that can be updated by params. If a model accepts nested attributes for some_model, add the field <some_model>_attributes. Also you can set a role with :as option, and works fine with STI. Yes, just like we used to do with protected_attributes. And an array parameter must be write in the same fashion at we do with strong_parameters.

And then use on permit this way: params.require(:<model>).permit(<Model>.whitelist)

An example:

  Class Project < ActiveRecord::Base
    has_many :tasks
    has_many :taggings
    has_many :tags, through: :taggings

    accepts_nested_attributes_for :tasks

    strong_fields :name, :description, :tasks_attributes, tag_ids: []
    strong_fields :budget, as: :admin
  end

  Class Task < ActiveRecord::Base
    belongs_to :project

    strong_fields :name, :start, :end
  end

Now call permit on params is really easy:

  # at console
  # with Project.whitelist, I got:
  ~/ (main) > Project.whitelist
  => [:name, :description, {:tasks_attributes=>[:name, :start, :end]},
  {tag_ids: []}]

  # or with admin role:
  ~/ (main) > Project.whitelist(:admin)
  => [:name, :description, {:tasks_attributes=>[:name, :start, :end]},
  {tag_ids: []}, :budget]

  # used to call permit
  @project.update_attributes(params.require(:project).permit(Project.whitelist))

Can I avoid error prone with whitelist? Take a look to this real life example:

  # irb:
  ~/rails/rfinan (main) > Dealing.whitelist
  [:due_date,
  :note,
  :status,
  {:items_attributes=>
    [:amount,
      :dealing_id,
      :product_selector,
      :price,
      :sign,
      :reference_value,
      :chk_item,
      :sequence,
      {:security_items_attributes=>
        [:commission,
        :commission_rate,
        :interest,
        :interest_rate,
        :net_value,
        :security_id,
        :item_id,
        :sequence,
        {:check_attributes=>
          [:amount,
            :note,
            :payment_day,
            :commodity_id,
            :owner,
            :branch,
            :number,
            :bank_lookup,
            :signer_lookup,
            :chk_refuse]},
        {:loan_attributes=>
          [:amount,
            :note,
            :payment_day,
            :commodity_id,
            :owner,
            :due_date,
            :params]}]},
      :payer_sequence,
      :paid_items_count]},
  {:person_attributes=>
    [:name,
      :phone,
      :mobile,
      :address,
      :city,
      :province,
      :estate,
      :postal_code,
      :email,
      :note]}]

  # controller code with nested_strong_parameters:
  Dealing.create(params.require(:dealing).permit(Dealing.whitelist))

  # without nested_strong_parameters:
  Dealing.create(params.require(:dealing).permit(
    [
      :due_date, :note, :status,
      {
        :items_attributes=>
          [
            :amount, :dealing_id, :product_selector, :price, :sign,
            :reference_value, :chk_item, :sequence,
            {
              :security_items_attributes=>
                [
                  :commission, :commission_rate, :interest, :interest_rate,
                  :net_value, :security_id, :item_id, :sequence,
                  {
                    :check_attributes=>
                      [
                        :amount, :note, :payment_day, :commodity_id, :owner,
                        :branch, :number, :bank_lookup, :signer_lookup,
                        :chk_refuse
                      ]
                  },
                  {
                    :loan_attributes=>
                      [
                        :amount, :note, :payment_day, :commodity_id, :owner,
                        :due_date, :params
                      ]
                  }
                ]
            },
            :payer_sequence, :paid_items_count
          ]
      },
      {
        :person_attributes=>
          [
            :name, :phone, :mobile, :address, :city, :province, :estate,
            :postal_code, :email, :note
          ]
      }
    ]
  )

Contributing

Fork it ( https://github.com/alejandrobabio/nested_strong_parameters/fork )
Create your feature branch (git checkout -b my-new-feature)
Commit your changes (git commit -am 'Add some feature')
Push to the branch (git push origin my-new-feature)
Create a new Pull Request