Question

I have a model with two attr_accessible lines

attr_accessible ...., :as => :user
attr_accessible ...., :as => :admin 

Then in my controller I do this

if @user.update_attributes(params[:user],:as => :user)

And I get wrong number of parameters 2 for 1, however: @user.assign_atrributes(params[:user],:as => :user) works.

I am using mongoid. Any ideas?

Answer 1

I think you found something that has not been implemented yet in your version of Mongoid — but please check a later Mongoid version, where it seems to be implemented since 2.2.1!

The doc says that :as is a valid option in Mongoid::Document

http://mongoid.org/docs/documents/access.html (see bottom of page)

But it says: You can scope the mass assignment by role by providing the role as an option to the constructor or create methods.

It doesn’t speak of update_attributes in particular – update_attributes is not a constructor

Checking in the source code reveals that it’s not implemented in update_attributes() in Mongoid versions < 2.2.1 , but later versions have it implemented!

If you’re using a later version of Mongoid, and still experience problems,
I would recommend to post this on the Google Mongoid Group as a bug, mentioning your Mongoid version number.

See also:

http://groups.google.com/group/mongoid/

---

EDIT:

Looks like it’s a missing feature in Mongoid 2.1.7

in the mongoid source code, update_attributes() calles write_attributes(), which does not know about the option :as

but if you look at the source code of Mongoid 2.3.1 , you’ll see that it’s implemented there since 2.2.1!

write_attributes() calls assign_attributes , which honors the option :as

# Allows you to set all the attributes for a particular mass-assignment security role                                                                                                                                                                                                                                   
# by passing in a hash of attributes with keys matching the attribute names                                                                                                                                                                                                                                             
# (which again matches the column names)  and the role name using the :as option.                                                                                                                                                                                                                                       
# To bypass mass-assignment security you can use the :without_protection => true option.                                                                                                                                                                                                                                
#                                                                                                                                                                                                                                                                                                                       
# @example Assign the attributes.                                                                                                                                                                                                                                                                                       
#   person.assign_attributes(:title => "Mr.")                                                                                                                                                                                                                                                                           
#                                                                                                                                                                                                                                                                                                                       
# @example Assign the attributes (with a role).                                                                                                                                                                                                                                                                         
#   person.assign_attributes({ :title => "Mr." }, :as => :admin)                                                                                                                                                                                                                                                        
#                                                                                                                                                                                                                                                                                                                       
# @param [ Hash ] attrs The new attributes to set.                                                                                                                                                                                                                                                                      
# @param [ Hash ] options Supported options: :without_protection, :as                                                                                                                                                                                                                                                   
#                                                                                                                                                                                                                                                                                                                       
# @since 2.2.1                                                                                                                                                                                                                                                                                                          
def assign_attributes(attrs = nil, options = {})
  _assigning do
    process(attrs, options[:as] || :default, !options[:without_protection]) do |document|
      document.identify if new? && id.blank?
    end
  end
end

You can find the source code this way:

$ find   ~/.rvm/gems/ruby-1.9.2-p0/gems/mongoid-2.1.7/lib/ -type f -exec grep -l 'def write_attributes' {} \;
~/.rvm/gems/ruby-1.9.2-p0/gems/mongoid-2.1.7/lib/mongoid/attributes.rb
$ emacs ~/.rvm/gems/ruby-1.9.2-p0/gems/mongoid-2.1.7/lib/mongoid/attributes.rb