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Diffstat (limited to 'actionpack/lib/action_controller/metal/strong_parameters.rb')
| -rw-r--r-- | actionpack/lib/action_controller/metal/strong_parameters.rb | 335 |
1 files changed, 335 insertions, 0 deletions
diff --git a/actionpack/lib/action_controller/metal/strong_parameters.rb b/actionpack/lib/action_controller/metal/strong_parameters.rb new file mode 100644 index 0000000000..24768b23a8 --- /dev/null +++ b/actionpack/lib/action_controller/metal/strong_parameters.rb @@ -0,0 +1,335 @@ +require 'active_support/concern' +require 'active_support/core_ext/hash/indifferent_access' +require 'active_support/rescuable' + +module ActionController + # Raised when a required parameter is missing. + # + # params = ActionController::Parameters.new(a: {}) + # params.fetch(:b) + # # => ActionController::ParameterMissing: key not found: b + # params.require(:a) + # # => ActionController::ParameterMissing: key not found: a + class ParameterMissing < KeyError + attr_reader :param # :nodoc: + + def initialize(param) # :nodoc: + @param = param + super("key not found: #{param}") + end + end + + # == Action Controller Parameters + # + # Allows to choose which attributes should be whitelisted for mass updating + # and thus prevent accidentally exposing that which shouldn’t be exposed. + # Provides two methods for this purpose: #require and #permit. The former is + # used to mark parameters as required. The latter is used to set the parameter + # as permitted and limit which attributes should be allowed for mass updating. + # + # params = ActionController::Parameters.new({ + # person: { + # name: 'Francesco', + # age: 22, + # role: 'admin' + # } + # }) + # + # permitted = params.require(:person).permit(:name, :age) + # permitted # => {"name"=>"Francesco", "age"=>22} + # permitted.class # => ActionController::Parameters + # permitted.permitted? # => true + # + # Person.first.update_attributes!(permitted) + # # => #<Person id: 1, name: "Francesco", age: 22, role: "user"> + # + # It provides a +permit_all_parameters+ option that controls the top-level + # behaviour of new instances. If it's +true+, all the parameters will be + # permitted by default. The default value for +permit_all_parameters+ + # option is +false+. + # + # params = ActionController::Parameters.new + # params.permitted? # => false + # + # ActionController::Parameters.permit_all_parameters = true + # + # params = ActionController::Parameters.new + # params.permitted? # => true + # + # <tt>ActionController::Parameters</tt> is inherited from + # <tt>ActiveSupport::HashWithIndifferentAccess</tt>, this means + # that you can fetch values using either <tt>:key</tt> or <tt>"key"</tt>. + # + # params = ActionController::Parameters.new(key: 'value') + # params[:key] # => "value" + # params["key"] # => "value" + class Parameters < ActiveSupport::HashWithIndifferentAccess + cattr_accessor :permit_all_parameters, instance_accessor: false + attr_accessor :permitted # :nodoc: + + # Returns a new instance of <tt>ActionController::Parameters</tt>. + # Also, sets the +permitted+ attribute to the default value of + # <tt>ActionController::Parameters.permit_all_parameters</tt>. + # + # class Person + # include ActiveRecord::Base + # end + # + # params = ActionController::Parameters.new(name: 'Francesco') + # params.permitted? # => false + # Person.new(params) # => ActiveModel::ForbiddenAttributesError + # + # ActionController::Parameters.permit_all_parameters = true + # + # params = ActionController::Parameters.new(name: 'Francesco') + # params.permitted? # => true + # Person.new(params) # => #<Person id: nil, name: "Francesco"> + def initialize(attributes = nil) + super(attributes) + @permitted = self.class.permit_all_parameters + end + + # Returns +true+ if the parameter is permitted, +false+ otherwise. + # + # params = ActionController::Parameters.new + # params.permitted? # => false + # params.permit! + # params.permitted? # => true + def permitted? + @permitted + end + + # Sets the +permitted+ attribute to +true+. This can be used to pass + # mass assignment. Returns +self+. + # + # class Person < ActiveRecord::Base + # end + # + # params = ActionController::Parameters.new(name: 'Francesco') + # params.permitted? # => false + # Person.new(params) # => ActiveModel::ForbiddenAttributesError + # params.permit! + # params.permitted? # => true + # Person.new(params) # => #<Person id: nil, name: "Francesco"> + def permit! + @permitted = true + self + end + + # Ensures that a parameter is present. If it's present, returns + # the parameter at the given +key+, otherwise raises an + # <tt>ActionController::ParameterMissing</tt> error. + # + # ActionController::Parameters.new(person: { name: 'Francesco' }).require(:person) + # # => {"name"=>"Francesco"} + # + # ActionController::Parameters.new(person: nil).require(:person) + # # => ActionController::ParameterMissing: key not found: person + # + # ActionController::Parameters.new(person: {}).require(:person) + # # => ActionController::ParameterMissing: key not found: person + def require(key) + self[key].presence || raise(ParameterMissing.new(key)) + end + + # Alias of #require. + alias :required :require + + # Returns a new <tt>ActionController::Parameters</tt> instance that + # includes only the given +filters+ and sets the +permitted+ for the + # object to +true+. This is useful for limiting which attributes + # should be allowed for mass updating. + # + # params = ActionController::Parameters.new(user: { name: 'Francesco', age: 22, role: 'admin' }) + # permitted = params.require(:user).permit(:name, :age) + # permitted.permitted? # => true + # permitted.has_key?(:name) # => true + # permitted.has_key?(:age) # => true + # permitted.has_key?(:role) # => false + # + # You can also use +permit+ on nested parameters, like: + # + # params = ActionController::Parameters.new({ + # person: { + # name: 'Francesco', + # age: 22, + # pets: [{ + # name: 'Purplish', + # category: 'dogs' + # }] + # } + # }) + # + # permitted = params.permit(person: [ :name, { pets: [ :name ] } ]) + # permitted.permitted? # => true + # permitted[:person][:name] # => "Francesco" + # permitted[:person][:age] # => nil + # permitted[:person][:pets][0][:name] # => "Purplish" + # permitted[:person][:pets][0][:category] # => nil + def permit(*filters) + params = self.class.new + + filters.each do |filter| + case filter + when Symbol, String then + params[filter] = self[filter] if has_key?(filter) + when Hash then + self.slice(*filter.keys).each do |key, values| + return unless values + + key = key.to_sym + + params[key] = each_element(values) do |value| + # filters are a Hash, so we expect value to be a Hash too + next if filter.is_a?(Hash) && !value.is_a?(Hash) + + value = self.class.new(value) if !value.respond_to?(:permit) + + value.permit(*Array.wrap(filter[key])) + end + end + end + end + + params.permit! + end + + # Returns a parameter for the given +key+. If not found, + # returns +nil+. + # + # params = ActionController::Parameters.new(person: { name: 'Francesco' }) + # params[:person] # => {"name"=>"Francesco"} + # params[:none] # => nil + def [](key) + convert_hashes_to_parameters(key, super) + end + + # Returns a parameter for the given +key+. If the +key+ + # can't be found, there are several options: With no other arguments, + # it will raise an <tt>ActionController::ParameterMissing</tt> error; + # if more arguments are given, then that will be returned; if a block + # is given, then that will be run and its result returned. + # + # params = ActionController::Parameters.new(person: { name: 'Francesco' }) + # params.fetch(:person) # => {"name"=>"Francesco"} + # params.fetch(:none) # => ActionController::ParameterMissing: key not found: none + # params.fetch(:none, 'Francesco') # => "Francesco" + # params.fetch(:none) { 'Francesco' } # => "Francesco" + def fetch(key, *args) + convert_hashes_to_parameters(key, super) + rescue KeyError + raise ActionController::ParameterMissing.new(key) + end + + # Returns a new <tt>ActionController::Parameters</tt> instance that + # includes only the given +keys+. If the given +keys+ + # don't exist, returns an empty hash. + # + # params = ActionController::Parameters.new(a: 1, b: 2, c: 3) + # params.slice(:a, :b) # => {"a"=>1, "b"=>2} + # params.slice(:d) # => {} + def slice(*keys) + self.class.new(super) + end + + # Returns an exact copy of the <tt>ActionController::Parameters</tt> + # instance. +permitted+ state is kept on the duped object. + # + # params = ActionController::Parameters.new(a: 1) + # params.permit! + # params.permitted? # => true + # copy_params = params.dup # => {"a"=>1} + # copy_params.permitted? # => true + def dup + super.tap do |duplicate| + duplicate.instance_variable_set :@permitted, @permitted + end + end + + private + def convert_hashes_to_parameters(key, value) + if value.is_a?(Parameters) || !value.is_a?(Hash) + value + else + # Convert to Parameters on first access + self[key] = self.class.new(value) + end + end + + def each_element(object) + if object.is_a?(Array) + object.map { |el| yield el }.compact + elsif object.is_a?(Hash) && object.keys.all? { |k| k =~ /\A-?\d+\z/ } + hash = object.class.new + object.each { |k,v| hash[k] = yield v } + hash + else + yield object + end + end + end + + # == Strong Parameters + # + # It provides an interface for proctecting attributes from end-user + # assignment. This makes Action Controller parameters are forbidden + # to be used in Active Model mass assignmets until they have been + # whitelisted. + # + # 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 + # + # See ActionController::Parameters.require and ActionController::Parameters.permit + # for more information. + module StrongParameters + extend ActiveSupport::Concern + include ActiveSupport::Rescuable + + included do + rescue_from(ActionController::ParameterMissing) do |parameter_missing_exception| + render text: "Required parameter missing: #{parameter_missing_exception.param}", status: :bad_request + end + end + + # Returns a new ActionController::Parameters object that + # has been instantiated with the <tt>request.parameters</tt>. + def params + @_params ||= Parameters.new(request.parameters) + end + + # Assigns the given +value+ to the +params+ hash. If +value+ + # is a Hash, this will create an ActionController::Parameters + # object that has been instantiated with the given +value+ hash. + def params=(value) + @_params = value.is_a?(Hash) ? Parameters.new(value) : value + end + end +end |