Strong Parameters¶ ↑
With this plugin Action Controller parameters are forbidden to be used in Active Model mass assignments until they have been whitelisted. This means you’ll have to make a conscious choice about which attributes to allow for mass updating and thus prevent accidentally exposing that which shouldn’t be exposed.
In addition, parameters can be marked as required and flow through a predefined raise/rescue flow to end up as a 400 Bad Request with no effort.
class PeopleController < ActionController::Base # This will raise an ActiveModel::ForbiddenAttributes exception because it's using mass assignment # without an explicit permit step. def create Person.create(params[:person]) end # This will pass with flying colors as long as there's a person key in the parameters, otherwise # it'll raise a ActionController::MissingParameter exception, which will get caught by # ActionController::Base and turned into that 400 Bad Request reply. def update redirect_to current_account.people.find(params[:id]).tap { |person| person.update_attributes!(person_params) } end private # Using a private method to encapsulate the permissible parameters is just a good pattern # since you'll be able to reuse the same permit list between create and update. Also, you # can specialize this method with per-user checking of permissible attributes. def person_params params.require(:person).permit(:name, :age) end end
You can also use permit on nested parameters, like:
params.permit(:name, friends: [ :name, { family: [ :name ] }])
Thanks to Nick Kallen for the permit idea!
Installation¶ ↑
In Gemfile:
gem 'strong_parameters'
and then run ‘bundle`. To activate the strong parameters, you need to include this module in every model you want protected.
class Post < ActiveRecord::Base include ActiveModel::ForbiddenAttributesProtection end
If you want to now disable the default whitelisting that occurs in later versions of Rails, change the config.active_record.whitelist_attributes
property in your config/application.rb
:
config.active_record.whitelist_attributes = false
This will allow you to remove / not have to use attr_accessible
and do mass assignment inside your code and tests.
Compatibility¶ ↑
This plugin is only fully compatible with Rails versions 3.1 and 3.2 but not 4.0+, as it is part of Rails Core in 4.0.