Repair Rails nested params

application_controller.rb

class ApplicationController < ActionController::Base
  before_action :repair_nested_params

  # -- your code here

  protected
  def repair_nested_params(obj = params)
    obj.each do |key, value|
      if value.is_a? Hash
        # If any non-integer keys
        if value.keys.find {|k, _| k =~ /\D/ }
          repair_nested_params(value)
        else
          obj[key] = value.values
          value.values.each {|h| repair_nested_params(h) }
        end
      end
    end
  end
end

For Rails 5, I replaced line 9 with:

if value.respond_to?('keys')