Nested attributes unpermitted parameters

Question

I have a Bill object, which has many Due objects. The Due object also belongs to a Person. I want a form that can create the Bill and its children Dues all in one page. I am trying to create a form using nested attributes, similar to ones in this Railscast.

Relevant code is listed below:

due.rb

class Due < ActiveRecord::Base
    belongs_to :person
    belongs_to :bill
end

bill.rb

class Bill < ActiveRecord::Base
    has_many :dues, :dependent => :destroy 
    accepts_nested_attributes_for :dues, :allow_destroy => true
end

bills_controller.rb

  # GET /bills/new
  def new
      @bill = Bill.new
      3.times { @bill.dues.build }
  end

bills/_form.html.erb

  <%= form_for(@bill) do |f| %>
    <div class="field">
        <%= f.label :company %><br />
        <%= f.text_field :company %>
    </div>
    <div class="field">
        <%= f.label :month %><br />
        <%= f.text_field :month %>
    </div>
    <div class="field">
        <%= f.label :year %><br />
        <%= f.number_field :year %>
    </div>
    <div class="actions">
        <%= f.submit %>
    </div>
    <%= f.fields_for :dues do |builder| %>
        <%= render 'due_fields', :f => builder %>
    <% end %>
  <% end %>

bills/_due_fields.html.erb

<div>
    <%= f.label :amount, "Amount" %>        
    <%= f.text_field :amount %>
    <br>
    <%= f.label :person_id, "Renter" %>
    <%= f.text_field :person_id %>
</div>

UPDATE to bills_controller.rb This works!

def bill_params 
  params
  .require(:bill)
  .permit(:company, :month, :year, dues_attributes: [:amount, :person_id]) 
end

The proper fields are rendered on the page (albeit without a dropdown for Person yet) and submit is successful. However, none of the children dues are saved to the database, and an error is thrown in the server log:

Unpermitted parameters: dues_attributes

Just before the error, the log displays this:

Started POST "/bills" for 127.0.0.1 at 2013-04-10 00:16:37 -0700
Processing by BillsController#create as HTML<br>
Parameters: {"utf8"=>"✓", 
"authenticity_token"=>"ipxBOLOjx68fwvfmsMG3FecV/q/hPqUHsluBCPN2BeU=",
 "bill"=>{"company"=>"Comcast", "month"=>"April ", 
"year"=>"2013", "dues_attributes"=>{
"0"=>{"amount"=>"30", "person_id"=>"1"}, 
"1"=>{"amount"=>"30", "person_id"=>"2"},
 "2"=>{"amount"=>"30", "person_id"=>"3"}}}, "commit"=>"Create Bill"}

Has there been some change in Rails 4?

Answer 1

Seems there is a change in handling of attribute protection and now you must whitelist params in the controller (instead of attr_accessible in the model) because the former optional gem strong_parameters became part of the Rails Core.

This should look something like this:

class PeopleController < ActionController::Base
  def create
    Person.create(person_params)
  end

private
  def person_params
    params.require(:person).permit(:name, :age)
  end
end

So params.require(:model).permit(:fields) would be used

and for nested attributes something like

params.require(:person).permit(:name, :age, pets_attributes: [:id, :name, :category])

Some more details can be found in the Ruby edge API docs and strong_parameters on github or here

Answer 2

From the docs

To whitelist an entire hash of parameters, the permit! method can be used

params.require(:log_entry).permit!

Nested attributes are in the form of a hash. In my app, I have a Question.rb model accept nested attributes for an Answer.rb model (where the user creates answer choices for a question he creates). In the questions_controller, I do this

  def question_params

      params.require(:question).permit!

  end

Everything in the question hash is permitted, including the nested answer attributes. This also works if the nested attributes are in the form of an array.

Having said that, I wonder if there's a security concern with this approach because it basically permits anything that's inside the hash without specifying exactly what it is, which seems contrary to the purpose of strong parameters.

Answer 3

or you can simply use

def question_params

  params.require(:question).permit(team_ids: [])

end

Answer 4

Actually there is a way to just white-list all nested parameters.

params.require(:widget).permit(:name, :description).tap do |whitelisted|
  whitelisted[:position] = params[:widget][:position]
  whitelisted[:properties] = params[:widget][:properties]
end

This method has advantage over other solutions. It allows to permit deep-nested parameters.

While other solutions like:

params.require(:person).permit(:name, :age, pets_attributes: [:id, :name, :category])

Don't.

---

Source:

https://github.com/rails/rails/issues/9454#issuecomment-14167664

Answer 5

Today I came across this same issue, whilst working on rails 4, I was able to get it working by structuring my fields_for as:

<%= f.select :tag_ids, Tag.all.collect {|t| [t.name, t.id]}, {}, :multiple => true %>

Then in my controller I have my strong params as:

private
def post_params
    params.require(:post).permit(:id, :title, :content, :publish, tag_ids: [])
end

All works!

Answer 6

If you use a JSONB field, you must convert it to JSON with .to_json (ROR)