DEPRECATED SINCE >= Rails 4.x

Tested on Rubies: 1.9.3, 2.0.0, 2.1.1 thanks to Travis!

If you need same functionallity for the Rails 2.3 or Rails 3.0, then use v0.2.2, it's fully tested and ready for this oldies. New version is total rewrite of the previous plugin, but API is the same, so it's easy to migrate if needed.

Latest version of the gem is only available for the Rails 3.2.x

This is an ActiveModel plugin with possibility to define block inside the attr_accessible class method. attr_protected not supported.

Because of block, it's possible to define accessibles for instances, not just for the class level.

It's also still possible to define class level accessibles, so an old attr_accessible :name will work.

Main features:

• Add an accessible attributes based on current record state (eg. record.new_record?)
• Add additional variables and use it in the block (eg. current user) ActiveModel::MassAssignmentSecurity::WhiteListBlock.add_variable(:user) { User.current || User.new }
• Add permanently full accessibility on defined condition (eg.user.admin?) ActiveModel::MassAssignmentSecurity::WhiteListBlock.always_accessible { user.admin? }
• Check is attribute mass-assignable or no using attr_accessible? instance method, that returns boolean value.

See an examples to understand the conception or specs.

gem install attr_accessible_block

How many times you had code like that:

class User < ActiveRecord::Base
  attr_accessible :password, :password_confirmation

  # ...
end

And in controller:

def create
  user = User.new(params[:user])
  user.email = params[:user][:email]
  user.save

  # ...
end

Now it's possible to do it easier:

class User < ActiveRecord::Base
  attr_accessible do
    add [:password, :password_confirmation]
    add :email if record.new_record?
  end
end

And creation of the user now can be written more DRYer

user = User.create(params[:user])

And on user update changing of email will be rejected because of new_record? method.

Sometimes you may need to check is attribute of model assignable or no (this method mostly interesting when doing form inputs). You can do it with using attr_accessible? method:

user.attr_accessible?(:email) # returns false
user.attr_accessible?(:password) # returns true

How do I add something similar to record, for example I want to check current users role?

Easy, with sentient_user gem and add the code to the config/initializers/plugins.rb file:

ActiveModel::MassAssignmentSecurity::WhiteListBlock.add_variable(:user) { User.current || User.new }

Now user method available, you can check:

attr_accessible do
  add [:password, :password_confirmation]
  add :email if record.new_record? || user.manager?
  add [:some_secret_fields, :another] if user.manager?
end

What if I want to provide an total accessibility for the admin user?

Just add this code to the config/initializers/plugins.rb file:

ActiveModel::MassAssignmentSecurity::WhiteListBlock.always_accessible { user.admin? }

It works even with standard attr_accessible, look into specs to see behaviour.

NOTE: if you are getting stack level too deep then you have recursive call of the model object in always_accessible or add_variable blocks. Try to avoid it.

Should be STI compatible, but haven't tested yet. Need's feedback on this feature. Feel free to contact with me if something goes wrong.

And there is more, you always still can use old implementation of the attr_accessible, just use old_attr_accessible method in your models.

For more answers on your questions you can look into tests and source code.

Used on http://tenerife.by

Copyright (c) 2010-2012 Dmitry Polushkin, released under the MIT license