Module ActiveModel::MassAssignmentSecurity::ClassMethods
In: lib/active_model/mass_assignment_security.rb

Mass assignment security provides an interface for protecting attributes from end-user assignment. For more complex permissions, mass assignment security may be handled outside the model by extending a non-ActiveRecord class, such as a controller, with this behavior.

For example, a logged in user may need to assign additional attributes depending on their role:

  class AccountsController < ApplicationController
    include ActiveModel::MassAssignmentSecurity

    attr_accessible :first_name, :last_name
    attr_accessible :first_name, :last_name, :plan_id, :as => :admin

    def update
      ...
      @account.update_attributes(account_params)
      ...
    end

    protected

    def account_params
      role = admin ? :admin : :default
      sanitize_for_mass_assignment(params[:account], role)
    end

  end

Configuration options

  • mass_assignment_sanitizer - Defines sanitize method. Possible values are:

You can specify your own sanitizer object eg. MySanitizer.new. See ActiveModel::MassAssignmentSecurity::LoggerSanitizer for example implementation.

Methods

Public Instance methods

active_authorizer()

Alias for active_authorizers

Specifies a white list of model attributes that can be set via mass-assignment.

Like attr_protected, a role for the attributes is optional, if no role is provided then :default is used. A role can be defined by using the :as option.

This is the opposite of the attr_protected macro: Mass-assignment will only set attributes in this list, to assign to the rest of attributes you can use direct writer methods. This is meant to protect sensitive attributes from being overwritten by malicious users tampering with URLs or forms. If you‘d rather start from an all-open default and restrict attributes as needed, have a look at attr_protected.

  class Customer
    include ActiveModel::MassAssignmentSecurity

    attr_accessor :name, :credit_rating

    attr_accessible :name
    attr_accessible :name, :credit_rating, :as => :admin

    def assign_attributes(values, options = {})
      sanitize_for_mass_assignment(values, options[:as]).each do |k, v|
        send("#{k}=", v)
      end
    end
  end

When using the :default role :

  customer = Customer.new
  customer.assign_attributes({ "name" => "David", "credit_rating" => "Excellent", :last_login => 1.day.ago }, :as => :default)
  customer.name          # => "David"
  customer.credit_rating # => nil

  customer.credit_rating = "Average"
  customer.credit_rating # => "Average"

And using the :admin role :

  customer = Customer.new
  customer.assign_attributes({ "name" => "David", "credit_rating" => "Excellent", :last_login => 1.day.ago }, :as => :admin)
  customer.name          # => "David"
  customer.credit_rating # => "Excellent"

Note that using Hash#except or Hash#slice in place of attr_accessible to sanitize attributes won‘t provide sufficient protection.

Attributes named in this macro are protected from mass-assignment whenever attributes are sanitized before assignment. A role for the attributes is optional, if no role is provided then :default is used. A role can be defined by using the :as option.

Mass-assignment to these attributes will simply be ignored, to assign to them you can use direct writer methods. This is meant to protect sensitive attributes from being overwritten by malicious users tampering with URLs or forms. Example:

  class Customer
    include ActiveModel::MassAssignmentSecurity

    attr_accessor :name, :credit_rating

    attr_protected :credit_rating, :last_login
    attr_protected :last_login, :as => :admin

    def assign_attributes(values, options = {})
      sanitize_for_mass_assignment(values, options[:as]).each do |k, v|
        send("#{k}=", v)
      end
    end
  end

When using the :default role :

  customer = Customer.new
  customer.assign_attributes({ "name" => "David", "credit_rating" => "Excellent", :last_login => 1.day.ago }, :as => :default)
  customer.name          # => "David"
  customer.credit_rating # => nil
  customer.last_login    # => nil

  customer.credit_rating = "Average"
  customer.credit_rating # => "Average"

And using the :admin role :

  customer = Customer.new
  customer.assign_attributes({ "name" => "David", "credit_rating" => "Excellent", :last_login => 1.day.ago }, :as => :admin)
  customer.name          # => "David"
  customer.credit_rating # => "Excellent"
  customer.last_login    # => nil

To start from an all-closed default and enable attributes as needed, have a look at attr_accessible.

Note that using Hash#except or Hash#slice in place of attr_protected to sanitize attributes won‘t provide sufficient protection.

[Validate]