I recently started building a Rails 4 app and ran into some hangups when using strong parameters with nested models and forms. It seems to be lacking documentation for this specific scenario, so I wanted to share my findings.
In a scenario where you have an album that
has_many songs, and you want to be able to edit both with the same form, you need to add every nested attribute that you plan to pass through to the
params.permit(). This is the setup that ended up working for me:
= form_for @album do |f| = f.text_field :title = f.fields_for :songs do |s| = s.text_field :name ...
class Album < ActiveRecord::Base has_many :songs accepts_nested_attributes_for :songs, allow_destroy: true ... end
class AlbumsController < ApplicationController ... private def album_params params.require(:album).permit(:title, songs_attributes: [:id, :_destroy, :name]) end end
class Song < ActiveRecord::Base belongs_to :album ... end
Do you know of a better or easier way? Let me know!