Rails attr_accessible does not work for :type?

ruby-on-rails single-table-inheritance
LMH picture LMH · Oct 21, 2009 · Viewed 7.1k times · Source

Im trying set the single table inheritance model type in a form. So i have a select menu for attribute :type and the values are the names of the STI subclasses. The problem is the error log keeps printing:

WARNING: Can't mass-assign these protected attributes: type

So i added "attr_accessible :type" to the model:

class ContentItem < ActiveRecord::Base
  # needed so we can set/update :type in mass
  attr_accessible :position, :description, :type, :url, :youtube_id, :start_time, :end_time
  validates_presence_of :position
  belongs_to :chapter
  has_many :user_content_items
end

Doesn't change anything, the ContentItem still has :type=nil after .update_attributes() is called in the controller. Any idea how to mass update the :type from a form?

Answer

user510319 picture user510319 · Nov 17, 2010

we can override attributes_protected_by_default

class Example < ActiveRecord::Base

  def self.attributes_protected_by_default
    # default is ["id","type"]
    ["id"]
  end
end

e = Example.new(:type=>"my_type")

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