class ActionController::Parameters
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!(permitted) # => #<Person id: 1, name: "Francesco", age: 22, role: "user">
It provides two options that controls the top-level behavior of new instances:
-
permit_all_parameters
- If it'strue
, all the parameters will be permitted by default. The default isfalse
. -
action_on_unpermitted_parameters
- Allow to control the behavior when parameters that are not explicitly permitted are found. The values can be:log
to write a message on the logger or:raise
to raise ActionController::UnpermittedParameters exception. The default value is:log
in test and development environments,false
otherwise.
Examples:
params = ActionController::Parameters.new params.permitted? # => false ActionController::Parameters.permit_all_parameters = true params = ActionController::Parameters.new params.permitted? # => true params = ActionController::Parameters.new(a: "123", b: "456") params.permit(:c) # => {} ActionController::Parameters.action_on_unpermitted_parameters = :raise params = ActionController::Parameters.new(a: "123", b: "456") params.permit(:c) # => ActionController::UnpermittedParameters: found unpermitted keys: a, b
Please note that these options *are not thread-safe*. In a multi-threaded environment they should only be set once at boot-time and never mutated at runtime.
ActionController::Parameters
inherits from
ActiveSupport::HashWithIndifferentAccess
, this means that you
can fetch values using either :key
or
"key"
.
params = ActionController::Parameters.new(key: 'value') params[:key] # => "value" params["key"] # => "value"
Constants
- EMPTY_ARRAY
- PERMITTED_SCALAR_TYPES
This is a white list of permitted scalar types that includes the ones supported in XML and JSON requests.
This list is in particular used to filter ordinary requests, String goes as first element to quickly short-circuit the common case.
If you modify this collection please update the API of
permit
above.
Public Class Methods
# File lib/action_controller/metal/strong_parameters.rb, line 120 def self.const_missing(const_name) super unless const_name == :NEVER_UNPERMITTED_PARAMS ActiveSupport::Deprecation.warn(" `ActionController::Parameters::NEVER_UNPERMITTED_PARAMS` has been deprecated. Use `ActionController::Parameters.always_permitted_parameters` instead. ".squish) always_permitted_parameters end
Returns a new instance of ActionController::Parameters
. Also,
sets the permitted
attribute to the default value of
ActionController::Parameters.permit_all_parameters
.
class Person < 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">
# File lib/action_controller/metal/strong_parameters.rb, line 146 def initialize(attributes = nil) super(attributes) @permitted = self.class.permit_all_parameters end
Public Instance Methods
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
# File lib/action_controller/metal/strong_parameters.rb, line 348 def [](key) convert_hashes_to_parameters(key, super) end
Attribute that keeps track of converted arrays, if any, to avoid double looping in the common use case permit + mass-assignment. Defined in a method to instantiate it only if needed.
Testing membership still loops, but it's going to be faster than our own loop that converts values. Also, we are not going to build a new array object per fetch.
# File lib/action_controller/metal/strong_parameters.rb, line 195 def converted_arrays @converted_arrays ||= Set.new end
Deletes and returns a key-value pair from Parameters
whose key
is equal to key. If the key is not found, returns the default value. If the
optional code block is given and the key is not found, pass in the key and
return the result of block.
# File lib/action_controller/metal/strong_parameters.rb, line 418 def delete(key, &block) convert_hashes_to_parameters(key, super, false) end
Returns an exact copy of the ActionController::Parameters
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
# File lib/action_controller/metal/strong_parameters.rb, line 435 def dup super.tap do |duplicate| duplicate.permitted = @permitted end end
Convert all hashes in values into parameters, then yield each pair like the
same way as Hash#each_pair
# File lib/action_controller/metal/strong_parameters.rb, line 178 def each_pair(&block) super do |key, value| convert_hashes_to_parameters(key, value) end super end
Removes and returns the key/value pairs matching the given keys.
params = ActionController::Parameters.new(a: 1, b: 2, c: 3) params.extract!(:a, :b) # => {"a"=>1, "b"=>2} params # => {"c"=>3}
# File lib/action_controller/metal/strong_parameters.rb, line 385 def extract!(*keys) new_instance_with_inherited_permitted_status(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 ActionController::ParameterMissing
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: param not found: none params.fetch(:none, 'Francesco') # => "Francesco" params.fetch(:none) { 'Francesco' } # => "Francesco"
# File lib/action_controller/metal/strong_parameters.rb, line 363 def fetch(key, *args) convert_hashes_to_parameters(key, super, false) rescue KeyError raise ActionController::ParameterMissing.new(key) end
Returns a new ActionController::Parameters
instance that
includes only the given filters
and sets the
permitted
attribute 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
Only permitted scalars pass the filter. For example, given
params.permit(:name)
:name
passes it is a key of params
whose
associated value is of type String
, Symbol
,
NilClass
, Numeric
, TrueClass
,
FalseClass
, Date
, Time
,
DateTime
, StringIO
, IO
,
ActionDispatch::Http::UploadedFile
or
Rack::Test::UploadedFile
. Otherwise, the key
:name
is filtered out.
You may declare that the parameter should be an array of permitted scalars by mapping it to an empty array:
params = ActionController::Parameters.new(tags: ['rails', 'parameters']) params.permit(tags: [])
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
Note that if you use permit
in a key that points to a hash, it
won't allow all the hash. You also need to specify which attributes
inside the hash should be whitelisted.
params = ActionController::Parameters.new({ person: { contact: { email: 'none@test.com', phone: '555-1234' } } }) params.require(:person).permit(:contact) # => {} params.require(:person).permit(contact: :phone) # => {"contact"=>{"phone"=>"555-1234"}} params.require(:person).permit(contact: [ :email, :phone ]) # => {"contact"=>{"email"=>"none@test.com", "phone"=>"555-1234"}}
# File lib/action_controller/metal/strong_parameters.rb, line 325 def permit(*filters) params = self.class.new filters.flatten.each do |filter| case filter when Symbol, String permitted_scalar_filter(params, filter) when Hash then hash_filter(params, filter) end end unpermitted_parameters!(params) if self.class.action_on_unpermitted_parameters params.permit! 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">
# File lib/action_controller/metal/strong_parameters.rb, line 221 def permit! each_pair do |key, value| Array.wrap(value).each do |v| v.permit! if v.respond_to? :permit! end end @permitted = true self end
Returns true
if the parameter is permitted, false
otherwise.
params = ActionController::Parameters.new params.permitted? # => false params.permit! params.permitted? # => true
# File lib/action_controller/metal/strong_parameters.rb, line 205 def permitted? @permitted end
Ensures that a parameter is present. If it's present, returns the
parameter at the given key
, otherwise raises an
ActionController::ParameterMissing
error.
ActionController::Parameters.new(person: { name: 'Francesco' }).require(:person) # => {"name"=>"Francesco"} ActionController::Parameters.new(person: nil).require(:person) # => ActionController::ParameterMissing: param not found: person ActionController::Parameters.new(person: {}).require(:person) # => ActionController::ParameterMissing: param not found: person
# File lib/action_controller/metal/strong_parameters.rb, line 244 def require(key) value = self[key] if value.present? || value == false value else raise ParameterMissing.new(key) end end
Equivalent to Hash#keep_if, but returns nil if no changes were made.
# File lib/action_controller/metal/strong_parameters.rb, line 423 def select!(&block) convert_value_to_parameters(super) end
Returns a new ActionController::Parameters
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) # => {}
# File lib/action_controller/metal/strong_parameters.rb, line 376 def slice(*keys) new_instance_with_inherited_permitted_status(super) end
Returns a safe Hash
representation of this parameter with all
unpermitted keys removed.
params = ActionController::Parameters.new({ name: 'Senjougahara Hitagi', oddity: 'Heavy stone crab' }) params.to_h # => {} safe_params = params.permit(:name) safe_params.to_h # => {"name"=>"Senjougahara Hitagi"}
# File lib/action_controller/metal/strong_parameters.rb, line 162 def to_h if permitted? to_hash else slice(*self.class.always_permitted_parameters).permit!.to_h end end
Returns an unsafe, unfiltered Hash
representation of this
parameter.
# File lib/action_controller/metal/strong_parameters.rb, line 171 def to_unsafe_h to_hash end
Returns a new ActionController::Parameters
with the results of
running block
once for every value. The keys are unchanged.
params = ActionController::Parameters.new(a: 1, b: 2, c: 3) params.transform_values { |x| x * 2 } # => {"a"=>2, "b"=>4, "c"=>6}
# File lib/action_controller/metal/strong_parameters.rb, line 395 def transform_values if block_given? new_instance_with_inherited_permitted_status(super) else super end end
Protected Instance Methods
# File lib/action_controller/metal/strong_parameters.rb, line 442 def permitted=(new_permitted) @permitted = new_permitted end
Private Instance Methods
# File lib/action_controller/metal/strong_parameters.rb, line 547 def array_of_permitted_scalars?(value) if value.is_a?(Array) value.all? {|element| permitted_scalar?(element)} end end
# File lib/action_controller/metal/strong_parameters.rb, line 553 def array_of_permitted_scalars_filter(params, key) if has_key?(key) && array_of_permitted_scalars?(self[key]) params[key] = self[key] end end
# File lib/action_controller/metal/strong_parameters.rb, line 453 def convert_hashes_to_parameters(key, value, assign_if_converted=true) converted = convert_value_to_parameters(value) self[key] = converted if assign_if_converted && !converted.equal?(value) converted end
# File lib/action_controller/metal/strong_parameters.rb, line 459 def convert_value_to_parameters(value) if value.is_a?(Array) && !converted_arrays.member?(value) converted = value.map { |_| convert_value_to_parameters(_) } converted_arrays << converted converted elsif value.is_a?(Parameters) || !value.is_a?(Hash) value else self.class.new(value) end end
# File lib/action_controller/metal/strong_parameters.rb, line 471 def each_element(object) if object.is_a?(Array) object.map { |el| yield el }.compact elsif fields_for_style?(object) hash = object.class.new object.each { |k,v| hash[k] = yield v } hash else yield object end end
# File lib/action_controller/metal/strong_parameters.rb, line 483 def fields_for_style?(object) object.is_a?(Hash) && object.all? { |k, v| k =~ /\A-?\d+\z/ && v.is_a?(Hash) } end
# File lib/action_controller/metal/strong_parameters.rb, line 560 def hash_filter(params, filter) filter = filter.with_indifferent_access # Slicing filters out non-declared keys. slice(*filter.keys).each do |key, value| next unless value if filter[key] == EMPTY_ARRAY # Declaration { comment_ids: [] }. array_of_permitted_scalars_filter(params, key) else # Declaration { user: :name } or { user: [:name, :age, { address: ... }] }. params[key] = each_element(value) do |element| if element.is_a?(Hash) element = self.class.new(element) unless element.respond_to?(:permit) element.permit(*Array.wrap(filter[key])) end end end end end
# File lib/action_controller/metal/strong_parameters.rb, line 447 def new_instance_with_inherited_permitted_status(hash) self.class.new(hash).tap do |new_instance| new_instance.permitted = @permitted end end
# File lib/action_controller/metal/strong_parameters.rb, line 531 def permitted_scalar?(value) PERMITTED_SCALAR_TYPES.any? {|type| value.is_a?(type)} end
# File lib/action_controller/metal/strong_parameters.rb, line 535 def permitted_scalar_filter(params, key) if has_key?(key) && permitted_scalar?(self[key]) params[key] = self[key] end keys.grep(/\A#{Regexp.escape(key)}\(\d+[if]?\)\z/) do |k| if permitted_scalar?(self[k]) params[k] = self[k] end end end
# File lib/action_controller/metal/strong_parameters.rb, line 500 def unpermitted_keys(params) self.keys - params.keys - self.always_permitted_parameters end
# File lib/action_controller/metal/strong_parameters.rb, line 487 def unpermitted_parameters!(params) unpermitted_keys = unpermitted_keys(params) if unpermitted_keys.any? case self.class.action_on_unpermitted_parameters when :log name = "unpermitted_parameters.action_controller" ActiveSupport::Notifications.instrument(name, keys: unpermitted_keys) when :raise raise ActionController::UnpermittedParameters.new(unpermitted_keys) end end end