Activerecord mass assignment to virtual attribute

I'm posting the following datas:

{"commit"=&开发者_StackOverflow社区gt;"Create", "conversation"=>{... , "watchers_ids"=>["2", "3", "4", "5", ...]}}

To the following action

def create
  @conversation = @current_project.conversations.new(params[:conversation]) 
  ...
end

And the following class

class Conversation < RoleRecord
  include Watchable
end

With this module

module Watchable
  def self.included(model)
    model.attr_accessible :watchers_ids
  end

  def watchers_ids=(ids)
    add_watchers( ids )
  end

  def watchers_ids
    ...
  end


  ...
end

However, the mass assignment don't work with the virtual attribute. Any idea?

There's code that's missing there...

If you have a has_and_belongs_to_many :watchers you should be able to assign watcher_ids without having to do this custom module stuff.

Then if you can't do that then that attribute is protected by some attr_protected or, more likely, attr_accessible call in your model. You can set it manually:

@conversation.watcher_ids = params[:conversation][:watcher_ids]