Module: ActiveModel::MassAssignmentSecurity::ClassMethods

Defined in:
activemodel/lib/active_model/mass_assignment_security.rb

Overview

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

def self.admin_accessible_attributes
  accessible_attributes + [ :plan_id ]
end

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

protected

def account_params
  sanitize_for_mass_assignment(params[:account])
end

def mass_assignment_authorizer
  admin ? admin_accessible_attributes : super
end

end

Instance Method Summary (collapse)

Instance Method Details

- (Object) accessible_attributes 



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# File 'activemodel/lib/active_model/mass_assignment_security.rb', line 137

def accessible_attributes
  self._accessible_attributes ||= WhiteList.new.tap { |w| w.logger = self.logger if self.respond_to?(:logger) }
end

- (Object) active_authorizer 



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# File 'activemodel/lib/active_model/mass_assignment_security.rb', line 141

def active_authorizer
  self._active_authorizer ||= protected_attributes
end

- (Object) attr_accessible(*names)

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

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

  def attributes=(values)
    sanitize_for_mass_assignment(values).each do |k, v|
      send("#{k}=", v)
    end
  end
end

customer = Customer.new
customer.attributes = { :name => "David", :credit_rating => "Excellent" }
customer.name          # => "David"
customer.credit_rating # => nil

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

Note that using Hash#except or Hash#slice in place of attr_accessible to sanitize attributes won't provide sufficient protection.



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# File 'activemodel/lib/active_model/mass_assignment_security.rb', line 126

def attr_accessible(*names)
  self._accessible_attributes = self.accessible_attributes + names
  self._active_authorizer = self._accessible_attributes
end

- (Object) attr_protected(*names)

Attributes named in this macro are protected from mass-assignment whenever attributes are sanitized before assignment.

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

  def attributes=(values)
    sanitize_for_mass_assignment(values).each do |k, v|
      send("#{k}=", v)
    end
  end
end

customer = Customer.new
customer.attributes = { "name" => "David", "credit_rating" => "Excellent" }
customer.name          # => "David"
customer.credit_rating # => nil

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

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.



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# File 'activemodel/lib/active_model/mass_assignment_security.rb', line 87

def attr_protected(*names)
  self._protected_attributes = self.protected_attributes + names
  self._active_authorizer = self._protected_attributes
end

- (Object) attributes_protected_by_default 



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# File 'activemodel/lib/active_model/mass_assignment_security.rb', line 145

def attributes_protected_by_default
  []
end

- (Object) protected_attributes 



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# File 'activemodel/lib/active_model/mass_assignment_security.rb', line 131

def protected_attributes
  self._protected_attributes ||= BlackList.new(attributes_protected_by_default).tap do |w|
    w.logger = self.logger if self.respond_to?(:logger)
  end
end