How can I store random nested variables with strong params methods in Rails?

Question

I have the following class:

 class ArticlesController < ApplicationController
      def create
        article = Article.new(article_params) 
     
      end
      
      private
        def article_params
          params.permit(:name, :age, book: [])
        end  
    end

and I have a field called book that contains a collection followed by a hash [{...}], inside the hash object it can contain any random attribute, for example:

book_1 = 
    [
          {
            "id": "a1",
            "type": "Color",
            "title": "Live life cicle",
            "content": "image_intro.png"
           },
      ] 

book_2 =
      [
          {
            "id": "a2",
            "email": "[email protected]",
            "domain": "http://ddd.com"
           }
      ]
    ...

book_7
     [
          {
            "id": "a23",
            "width": "3px",
            "heigth": "5px",
            "exist": true
           }
      ]

What I would like is that every time I save a book, it can go through article_params no matter what attributes it contains within the hash, if you could help me please I would be grateful.

Answer 1

ActionController::Parameters does not have a "wildcard" syntax to allow any nested hash keys. But it does have #permit! which is an acknowledgement that strong parameters is not the solution for every possible problem.

permit! completely circumvents whitelisting by setting the permitted attribute on the ActionController::Parameters instance.

It will also set the permitted attribute on any nested instances of ActionController::Parameters - ie nested hashes in the parameters.

This is a very sharp tool which should be used with care.

In this case you might want to just use it on the nested attributes:

params.permit(:name, :age).merge(
  books: params.dup.permit!.fetch(:books, [])
)