class ActionController::Parameters
Action Controller Parameters¶ ↑
Allows you 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 # => <ActionController::Parameters {"name"=>"Francesco", "age"=>22} permitted: true> 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 {} permitted: true> 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.
You can fetch values of ActionController::Parameters
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.
Attributes
Public Class Methods
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 142 def initialize(parameters = {}) @parameters = parameters.with_indifferent_access @permitted = self.class.permit_all_parameters end
Public Instance Methods
Returns true if another Parameters
object contains the same
content and permitted flag.
# File lib/action_controller/metal/strong_parameters.rb, line 149 def ==(other) if other.respond_to?(:permitted?) self.permitted? == other.permitted? && self.parameters == other.parameters elsif other.is_a?(Hash) ActiveSupport::Deprecation.warn " Comparing equality between `ActionController::Parameters` and a `Hash` is deprecated and will be removed in Rails 5.1. Please only do comparisons between instances of `ActionController::Parameters`. If you need to compare to a hash, first convert it using `ActionController::Parameters#new`. ".squish @parameters == other.with_indifferent_access else @parameters == other end end
Returns a parameter for the given key
. If not found, returns
nil
.
params = ActionController::Parameters.new(person: { name: 'Francesco' }) params[:person] # => <ActionController::Parameters {"name"=>"Francesco"} permitted: false> params[:none] # => nil
# File lib/action_controller/metal/strong_parameters.rb, line 408 def [](key) convert_hashes_to_parameters(key, @parameters[key]) end
Assigns a value to a given key
. The given key may still get
filtered out when permit
is called.
# File lib/action_controller/metal/strong_parameters.rb, line 414 def []=(key, value) @parameters[key] = value 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 216 def converted_arrays @converted_arrays ||= Set.new end
Returns duplicate of object including all parameters
# File lib/action_controller/metal/strong_parameters.rb, line 651 def deep_dup self.class.new(@parameters.deep_dup).tap do |duplicate| duplicate.permitted = @permitted end 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 539 def delete(key) convert_value_to_parameters(@parameters.delete(key)) end
Extracts the nested parameter from the given keys
by calling
dig
at each step. Returns nil
if any intermediate
step is nil
.
params = ::new(foo: { bar: { baz: 1 } }) params.dig(:foo, :bar, :baz) # => 1 params.dig(:foo, :zot, :xyz) # => nil
params2 = ::new(foo: [10, 11, 12]) params2.dig(:foo, 1) # => 11
# File lib/action_controller/metal/strong_parameters.rb, line 451 def dig(*keys) convert_value_to_parameters(@parameters.dig(*keys)) end
Convert all hashes in values into parameters, then yield each pair in the
same way as Hash#each_pair
# File lib/action_controller/metal/strong_parameters.rb, line 202 def each_pair(&block) @parameters.each_pair do |key, value| yield key, convert_hashes_to_parameters(key, value) end end
Returns a new ActionController::Parameters
instance that
filters out the given keys
.
params = ActionController::Parameters.new(a: 1, b: 2, c: 3) params.except(:a, :b) # => <ActionController::Parameters {"c"=>3} permitted: false> params.except(:d) # => <ActionController::Parameters {"a"=>1, "b"=>2, "c"=>3} permitted: false>
# File lib/action_controller/metal/strong_parameters.rb, line 480 def except(*keys) new_instance_with_inherited_permitted_status(@parameters.except(*keys)) 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) # => <ActionController::Parameters {"a"=>1, "b"=>2} permitted: false> params # => <ActionController::Parameters {"c"=>3} permitted: false>
# File lib/action_controller/metal/strong_parameters.rb, line 489 def extract!(*keys) new_instance_with_inherited_permitted_status(@parameters.extract!(*keys)) 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) # => <ActionController::Parameters {"name"=>"Francesco"} permitted: false> params.fetch(:none) # => ActionController::ParameterMissing: param is missing or the value is empty: none params.fetch(:none, 'Francesco') # => "Francesco" params.fetch(:none) { 'Francesco' } # => "Francesco"
# File lib/action_controller/metal/strong_parameters.rb, line 429 def fetch(key, *args) convert_value_to_parameters( @parameters.fetch(key) { if block_given? yield else args.fetch(0) { raise ActionController::ParameterMissing.new(key) } end } ) end
# File lib/action_controller/metal/strong_parameters.rb, line 597 def inspect "<#{self.class} #{@parameters} permitted: #{@permitted}>" end
Returns a new ActionController::Parameters
with all keys from
other_hash
merges into current hash.
# File lib/action_controller/metal/strong_parameters.rb, line 577 def merge(other_hash) new_instance_with_inherited_permitted_status( @parameters.merge(other_hash.to_h) ) end
Returns current ActionController::Parameters
instance which
other_hash
merges into current hash.
# File lib/action_controller/metal/strong_parameters.rb, line 585 def merge!(other_hash) @parameters.merge!(other_hash.to_h) self end
# File lib/action_controller/metal/strong_parameters.rb, line 632 def method_missing(method_sym, *args, &block) if @parameters.respond_to?(method_sym) message = " Method #{method_sym} is deprecated and will be removed in Rails 5.1, as `ActionController::Parameters` no longer inherits from hash. Using this deprecated behavior exposes potential security problems. If you continue to use this method you may be creating a security vulnerability in your app that can be exploited. Instead, consider using one of these documented methods which are not deprecated: http://api.rubyonrails.org/v#{ActionPack.version}/classes/ActionController/Parameters.html ".squish ActiveSupport::Deprecation.warn(message) @parameters.public_send(method_sym, *args, &block) else super end 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 if 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) # => <ActionController::Parameters {} permitted: true> params.require(:person).permit(contact: :phone) # => <ActionController::Parameters {"contact"=><ActionController::Parameters {"phone"=>"555-1234"} permitted: true>} permitted: true> params.require(:person).permit(contact: [ :email, :phone ]) # => <ActionController::Parameters {"contact"=><ActionController::Parameters {"email"=>"none@test.com", "phone"=>"555-1234"} permitted: true>} permitted: true>
# File lib/action_controller/metal/strong_parameters.rb, line 385 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 242 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 226 def permitted? @permitted end
Returns a new instance of ActionController::Parameters
with
items that the block evaluates to true removed.
# File lib/action_controller/metal/strong_parameters.rb, line 558 def reject(&block) new_instance_with_inherited_permitted_status(@parameters.reject(&block)) end
Removes items that the block evaluates to true and returns self.
# File lib/action_controller/metal/strong_parameters.rb, line 563 def reject!(&block) @parameters.reject!(&block) self end
This method accepts both a single key and an array of keys.
When passed a single key, if it exists and its associated value is either
present or the singleton false
, returns said value:
ActionController::Parameters.new(person: { name: 'Francesco' }).require(:person) # => <ActionController::Parameters {"name"=>"Francesco"} permitted: false>
Otherwise raises ActionController::ParameterMissing
:
ActionController::Parameters.new.require(:person) # ActionController::ParameterMissing: param is missing or the value is empty: person ActionController::Parameters.new(person: nil).require(:person) # ActionController::ParameterMissing: param is missing or the value is empty: person ActionController::Parameters.new(person: "\t").require(:person) # ActionController::ParameterMissing: param is missing or the value is empty: person ActionController::Parameters.new(person: {}).require(:person) # ActionController::ParameterMissing: param is missing or the value is empty: person
When given an array of keys, the method tries to require each one of them in order. If it succeeds, an array with the respective return values is returned:
params = ActionController::Parameters.new(user: { ... }, profile: { ... }) user_params, profile_params = params.require([:user, :profile])
Otherwise, the method re-raises the first exception found:
params = ActionController::Parameters.new(user: {}, profile: {}) user_params, profile_params = params.require([:user, :profile]) # ActionController::ParameterMissing: param is missing or the value is empty: user
Technically this method can be used to fetch terminal values:
# CAREFUL params = ActionController::Parameters.new(person: { name: 'Finn' }) name = params.require(:person).require(:name) # CAREFUL
but take into account that at some point those ones have to be permitted:
def person_params params.require(:person).permit(:name).tap do |person_params| person_params.require(:name) # SAFER end end
for example.
# File lib/action_controller/metal/strong_parameters.rb, line 303 def require(key) return key.map { |k| require(k) } if key.is_a?(Array) value = self[key] if value.present? || value == false value else raise ParameterMissing.new(key) end end
Returns a new instance of ActionController::Parameters
with
only items that the block evaluates to true.
# File lib/action_controller/metal/strong_parameters.rb, line 545 def select(&block) new_instance_with_inherited_permitted_status(@parameters.select(&block)) end
Equivalent to Hash#keep_if, but returns nil if no changes were made.
# File lib/action_controller/metal/strong_parameters.rb, line 550 def select!(&block) @parameters.select!(&block) self 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) # => <ActionController::Parameters {"a"=>1, "b"=>2} permitted: false> params.slice(:d) # => <ActionController::Parameters {} permitted: false>
# File lib/action_controller/metal/strong_parameters.rb, line 463 def slice(*keys) new_instance_with_inherited_permitted_status(@parameters.slice(*keys)) end
Returns current ActionController::Parameters
instance which
contains only the given keys
.
# File lib/action_controller/metal/strong_parameters.rb, line 469 def slice!(*keys) @parameters.slice!(*keys) self end
Returns a safe ActiveSupport::HashWithIndifferentAccess
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 177 def to_h if permitted? convert_parameters_to_hashes(@parameters, :to_h) else slice(*self.class.always_permitted_parameters).permit!.to_h end end
Returns an unsafe, unfiltered
ActiveSupport::HashWithIndifferentAccess
representation of
this parameter.
params = ActionController::Parameters.new({ name: 'Senjougahara Hitagi', oddity: 'Heavy stone crab' }) params.to_unsafe_h # => {"name"=>"Senjougahara Hitagi", "oddity" => "Heavy stone crab"}
# File lib/action_controller/metal/strong_parameters.rb, line 195 def to_unsafe_h convert_parameters_to_hashes(@parameters, :to_unsafe_h) end
Returns a new ActionController::Parameters
instance with the
results of running block
once for every key. The values are
unchanged.
# File lib/action_controller/metal/strong_parameters.rb, line 518 def transform_keys(&block) if block new_instance_with_inherited_permitted_status( @parameters.transform_keys(&block) ) else @parameters.transform_keys end end
Performs keys transformation and returns the altered
ActionController::Parameters
instance.
# File lib/action_controller/metal/strong_parameters.rb, line 530 def transform_keys!(&block) @parameters.transform_keys!(&block) self 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 } # => <ActionController::Parameters {"a"=>2, "b"=>4, "c"=>6} permitted: false>
# File lib/action_controller/metal/strong_parameters.rb, line 499 def transform_values(&block) if block new_instance_with_inherited_permitted_status( @parameters.transform_values(&block) ) else @parameters.transform_values end end
Performs values transformation and returns the altered
ActionController::Parameters
instance.
# File lib/action_controller/metal/strong_parameters.rb, line 511 def transform_values!(&block) @parameters.transform_values!(&block) self end
Returns values that were assigned to the given keys
. Note that
all the Hash
objects will be converted to
ActionController::Parameters
.
# File lib/action_controller/metal/strong_parameters.rb, line 571 def values_at(*keys) convert_value_to_parameters(@parameters.values_at(*keys)) end
Protected Instance Methods
# File lib/action_controller/metal/strong_parameters.rb, line 664 def fields_for_style? @parameters.all? { |k, v| k =~ /\A-?\d+\z/ && (v.is_a?(Hash) || v.is_a?(Parameters)) } end
# File lib/action_controller/metal/strong_parameters.rb, line 660 def permitted=(new_permitted) @permitted = new_permitted end
Private Instance Methods
# File lib/action_controller/metal/strong_parameters.rb, line 785 def array_of_permitted_scalars?(value) if value.is_a?(Array) && value.all? {|element| permitted_scalar?(element)} yield value end end
# File lib/action_controller/metal/strong_parameters.rb, line 690 def convert_hashes_to_parameters(key, value) converted = convert_value_to_parameters(value) @parameters[key] = converted unless converted.equal?(value) converted end
# File lib/action_controller/metal/strong_parameters.rb, line 675 def convert_parameters_to_hashes(value, using) case value when Array value.map { |v| convert_parameters_to_hashes(v, using) } when Hash value.transform_values do |v| convert_parameters_to_hashes(v, using) end.with_indifferent_access when Parameters value.send(using) else value end end
# File lib/action_controller/metal/strong_parameters.rb, line 696 def convert_value_to_parameters(value) case value when Array return value if converted_arrays.member?(value) converted = value.map { |_| convert_value_to_parameters(_) } converted_arrays << converted converted when Hash self.class.new(value) else value end end
# File lib/action_controller/metal/strong_parameters.rb, line 710 def each_element(object) case object when Array object.grep(Parameters).map { |el| yield el }.compact when Parameters if object.fields_for_style? hash = object.class.new object.each { |k,v| hash[k] = yield v } hash else yield object end end end
# File lib/action_controller/metal/strong_parameters.rb, line 796 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 next unless has_key? key if filter[key] == EMPTY_ARRAY # Declaration { comment_ids: [] }. array_of_permitted_scalars?(self[key]) do |val| params[key] = val end elsif non_scalar?(value) # Declaration { user: :name } or { user: [:name, :age, { address: ... }] }. params[key] = each_element(value) do |element| element.permit(*Array.wrap(filter[key])) end end end end
# File lib/action_controller/metal/strong_parameters.rb, line 818 def initialize_copy(source) super @parameters = @parameters.dup end
# File lib/action_controller/metal/strong_parameters.rb, line 669 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 791 def non_scalar?(value) value.is_a?(Array) || value.is_a?(Parameters) end
# File lib/action_controller/metal/strong_parameters.rb, line 769 def permitted_scalar?(value) PERMITTED_SCALAR_TYPES.any? {|type| value.is_a?(type)} end
# File lib/action_controller/metal/strong_parameters.rb, line 773 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 738 def unpermitted_keys(params) self.keys - params.keys - self.always_permitted_parameters end
# File lib/action_controller/metal/strong_parameters.rb, line 725 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