Class: ActionController::Parameters

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Instance Chain: self, `::ActiveSupport::DeepMergeable`
Inherits:	Object
Defined in:	actionpack/lib/action_controller/metal/strong_parameters.rb

Overview

Allows you to choose which attributes should be permitted for mass updating and thus prevent accidentally exposing that which shouldn't be exposed.

Provides methods for filtering and requiring params:

#expect to safely permit and require parameters in one step.
#permit to filter params for mass assignment.
#require to require a parameter or raise an error.

Examples:

params = ActionController::Parameters.new({
  person: {
    name: "Francesco",
    age:  22,
    role: "admin"
  }
})

permitted = params.expect(person: [:name, :age])
permitted # => #<ActionController::Parameters {"name"=>"Francesco", "age"=>22} permitted: true>

Person.first.update!(permitted)
# => #<Person id: 1, name: "Francesco", age: 22, role: "user">

Parameters provides two options that control the top-level behavior of new instances:

.permit_all_parameters - If it's true, all the parameters will be permitted by default. The default is false.
.action_on_unpermitted_parameters - Controls behavior when parameters that are not explicitly permitted are found. The default value is :log in test and development environments, false otherwise. The values can be:
- false to take no action.
- :log to emit an ActiveSupport::Notifications.instrument event on the unpermitted_parameters.action_controller topic and log at the DEBUG level.
- :raise to raise an ActionController::UnpermittedParameters exception.

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 Parameters using either :key or "key".

params = ActionController::Parameters.new(key: "value")
params[:key]  # => "value"
params["key"] # => "value"

Constant Summary

EMPTY_ARRAY = Internal use only
# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1436
```
[].freeze
```
EMPTY_HASH = Internal use only
# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1437
```
{}.freeze
```
PERMITTED_SCALAR_TYPES =

This is a 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 one in the #permit doc as well.

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1387
```
[
  String,
  Symbol,
  NilClass,
  Numeric,
  TrueClass,
  FalseClass,
  Date,
  Time,
  # DateTimes are Dates, we document the type but avoid the redundant check.
  StringIO,
  IO,
  ActionDispatch::Http::UploadedFile,
  Rack::Test::UploadedFile,
].freeze
```

Class Attribute Summary

.action_on_unpermitted_parameters rw
.action_on_unpermitted_parameters? ⇒ Boolean rw
.always_permitted_parameters (also: #always_permitted_parameters) rw

By default, never raise an UnpermittedParameters exception if these params are present.
.permit_all_parameters rw
.permit_all_parameters? ⇒ Boolean rw

Class Method Summary

.new(parameters = {}, logging_context = {}) ⇒ Parameters constructor

Returns a new Parameters instance.
.hook_into_yaml_loading Internal use only
.nested_attribute?(key, value) ⇒ Boolean Internal use only

Instance Attribute Summary

#always_permitted_parameters rw
#each_key(&block) readonly

Calls block once for each key in the parameters, passing the key.
#has_key? readonly

Alias for #include?.
#key? readonly

Alias for #include?.
#keys readonly

Returns a new array of the keys of the parameters.
#member? readonly

Alias for #include?.
#permitted? ⇒ Boolean rw

Returns true if the parameter is permitted, false otherwise.
#nested_attributes? ⇒ Boolean readonly protected
#parameters readonly protected
#permitted=(value) rw protected

Instance Method Summary

#==(other)

Returns true if another Parameters object contains the same content and permitted flag.
#[](key)

Returns a parameter for the given key.
#[]=(key, value)

Assigns a value to a given key.
#as_json(options = nil)

Returns a hash that can be used as the JSON representation for the parameters.
#compact

Returns a new Parameters instance with nil values removed.
#compact!

Removes all nil values in place and returns self, or nil if no changes were made.
#compact_blank

Returns a new Parameters instance without the blank values.
#compact_blank!

Removes all blank values in place and returns self.
#converted_arrays

Attribute that keeps track of converted arrays, if any, to avoid double looping in the common use case permit + mass-assignment.
#deconstruct_keys(keys)
#deep_dup

Returns a duplicate Parameters instance with the same permitted parameters.
#deep_merge(other_hash, &block)

Returns a new Parameters instance with self and other_hash merged recursively.
#deep_merge!(other_hash, &block)

Same as #deep_merge, but modifies self.
#deep_transform_keys(&block)

Returns a new Parameters instance with the results of running block once for every key.
#deep_transform_keys!(&block)

Returns the same Parameters instance with changed keys.
#deep_transform_values(&block)

Returns a new Parameters instance with the results of running block once for every value.
#deep_transform_values!(&block)

Returns the same Parameters instance with changed values.
#delete(key, &block)

Deletes a key-value pair from Parameters and returns the value.
#delete_if(&block)

Alias for #reject!.
#dig(*keys)

Extracts the nested parameter from the given #keys by calling #dig at each step.
#each(&block)

Alias for #each_pair.
#each_pair(&block) (also: #each)

Convert all hashes in values into parameters, then yield each pair in the same way as Hash#each_pair.
#each_value(&block)

Convert all hashes in values into parameters, then yield each value in the same way as Hash#each_value.
#empty? ⇒ Boolean

Returns true if the parameters have no key/value pairs.
#eql?(other) ⇒ Boolean
#except(*keys) (also: #without)

Returns a new Parameters instance that filters out the given #keys.
#exclude?(key) ⇒ Boolean

Returns true if the given key is not present in the parameters.
#expect(*filters)

#expect is the preferred way to require and permit parameters.
#expect!(*filters)

Same as #expect, but raises an ExpectedParameterMissing instead of ParameterMissing.
#extract!(*keys)

Removes and returns the key/value pairs matching the given keys.
#extract_value(key, delimiter: "_")

Returns parameter value for the given key separated by delimiter.
#fetch(key, *args, &block)

Returns a parameter for the given key.
#fetch_values(*keys)

Returns parameters for the given keys.
#has_value?(value) ⇒ Boolean (also: #value?)

Returns true if the given value is present for some key in the parameters.
#hash
#include?(key) ⇒ Boolean (also: #has_key?, #key?, #member?)

Returns true if the given key is present in the parameters.
#inspect
#keep_if(&block)

Alias for #select!.
#merge(*other_hashes, &block)

Returns a new Parameters instance with all keys from other_hashes merged into current hash.
#merge!(*other_hashes)

Returns the current Parameters instance with other_hashes merged into current hash.
#permit(*filters)

Returns a new Parameters instance that includes only the given filters and sets the permitted attribute for the object to true.
#permit!

Sets the permitted attribute to true.
#reject(&block)

Returns a new Parameters instance with items that the block evaluates to true removed.
#reject!(&block) (also: #delete_if)

Removes items that the block evaluates to true and returns self.
#require(key) (also: #required)

This method accepts both a single key and an array of keys.
#required(key)

Alias for #require.
#reverse_merge(other_hash) (also: #with_defaults)

Returns a new Parameters instance with all keys from current hash merged into other_hash.
#reverse_merge!(other_hash) (also: #with_defaults!)

Returns the current Parameters instance with current hash merged into other_hash.
#select(&block)

Returns a new Parameters instance with only items that the block evaluates to true.
#select!(&block) (also: #keep_if)

Equivalent to Hash#keep_if, but returns nil if no changes were made.
#slice(*keys)

Returns a new Parameters instance that includes only the given #keys.
#slice!(*keys)

Returns the current Parameters instance which contains only the given #keys.
#to_h(&block)

Returns a safe ::ActiveSupport::HashWithIndifferentAccess representation of the parameters with all unpermitted keys removed.
#to_hash

Returns a safe ::Hash representation of the parameters with all unpermitted keys removed.
#to_param(*args)

Alias for #to_query.
#to_query(*args) (also: #to_param)

Returns a string representation of the receiver suitable for use as a URL query string:
#to_s ⇒ ?

Returns the content of the parameters as a string.
#to_unsafe_h (also: #to_unsafe_hash)

Returns an unsafe, unfiltered ::ActiveSupport::HashWithIndifferentAccess representation of the parameters.
#to_unsafe_hash

Alias for #to_unsafe_h.
#transform_keys(&block)

Returns a new Parameters instance with the results of running block once for every key.
#transform_keys!(&block)

Performs keys transformation and returns the altered Parameters instance.
#transform_values(&block)

Returns a new Parameters instance with the results of running block once for every value.
#transform_values!(&block)

Performs values transformation and returns the altered Parameters instance.
#value?(value)

Alias for #has_value?.
#values

Returns a new array of the values of the parameters.
#values_at(*keys)

Returns values that were assigned to the given #keys.
#with_defaults(other_hash)

Alias for #reverse_merge.
#with_defaults!(other_hash)

Alias for #reverse_merge!.
#without(*keys)

Alias for #except.
#each_nested_attribute(&block) protected
#permit_filters(filters, on_unpermitted: nil, explicit_arrays: true) protected

Filters self and optionally checks for unpermitted keys.
#_deep_transform_keys_in_object(object, &block) private
#_deep_transform_keys_in_object!(object, &block) private
#_deep_transform_values_in_object(object, &block) private
#_deep_transform_values_in_object!(object, &block) private
#array_filter?(filter) ⇒ Boolean private

When an array is expected, you must specify an array explicitly using the following format:
#convert_hashes_to_parameters(key, value) private
#convert_parameters_to_hashes(value, using, &block) private
#convert_value_to_parameters(value) private
#each_array_element(object, filter, &block) private

Called when an explicit array filter is encountered.
#hash_filter(params, filter, on_unpermitted: self.class.action_on_unpermitted_parameters, explicit_arrays: false) private
#initialize_copy(source) private
#new_instance_with_inherited_permitted_status(hash) private
#non_scalar?(value) ⇒ Boolean private
#permit_any_in_array(array) private
#permit_any_in_parameters(params) private
#permit_array_of_hashes(value, filter, on_unpermitted:, explicit_arrays:) private
#permit_array_of_scalars(value) private
#permit_hash(value, filter, on_unpermitted:, explicit_arrays:) private
#permit_hash_or_array(value, filter, on_unpermitted:, explicit_arrays:) private
#permit_value(value, filter, on_unpermitted:, explicit_arrays:) private
#permitted_scalar?(value) ⇒ Boolean private
#permitted_scalar_filter(params, permitted_key) private

Adds existing keys to the params if their values are scalar.
#specify_numeric_keys?(filter) ⇒ Boolean private
#unpermitted_keys(params) private
#unpermitted_parameters!(params, on_unpermitted: self.class.action_on_unpermitted_parameters) private
#deep_merge?(other_hash) ⇒ Boolean Internal use only
#encode_with(coder) Internal use only
#init_with(coder) Internal use only
#stringify_keys Internal use only

This is required by ::ActiveModel attribute assignment, so that user can pass Parameters to a mass assignment methods in a model.

`::ActiveSupport::DeepMergeable` - Included

#deep_merge	Returns a new instance with the values from `other` merged recursively.
#deep_merge!	Same as #deep_merge, but modifies `self`.
#deep_merge?	Returns true if `other` can be deep merged into `self`.

Constructor Details

.new(parameters = {}, logging_context = {}) ⇒ `Parameters`

Returns a new Parameters instance. Also, sets the permitted attribute to the default value of .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">

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 288


def initialize(parameters = {}, logging_context = {})
  parameters.each_key do |key|
    unless key.is_a?(String) || key.is_a?(Symbol)
      raise InvalidParameterKey, "all keys must be Strings or Symbols, got: #{key.class}"
    end
  end

  @parameters = parameters.with_indifferent_access
  @logging_context = logging_context
  @permitted = self.class.permit_all_parameters
end

Class Attribute Details

.action_on_unpermitted_parameters (rw)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 166


class_attribute :action_on_unpermitted_parameters, instance_accessor: false

.action_on_unpermitted_parameters? ⇒ `Boolean` (rw)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 166


class_attribute :action_on_unpermitted_parameters, instance_accessor: false

.always_permitted_parameters (rw) Also known as: #always_permitted_parameters

By default, never raise an UnpermittedParameters exception if these params are present. The default includes both 'controller' and 'action' because they are added by ::Rails and should be of no concern. One way to change these is to specify always_permitted_parameters in your config. For instance:

config.action_controller.always_permitted_parameters = %w( controller action format )

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 264


cattr_accessor :always_permitted_parameters, default: %w( controller action )

.permit_all_parameters (rw)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 164


class_attribute :permit_all_parameters, instance_accessor: false, default: false

.permit_all_parameters? ⇒ `Boolean` (rw)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 164


class_attribute :permit_all_parameters, instance_accessor: false, default: false

Class Method Details

.hook_into_yaml_loading

This method is for internal use only.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1114


def self.hook_into_yaml_loading # :nodoc:
  # Wire up YAML format compatibility with Rails 4.2 and Psych 2.0.8 and 2.0.9+.
  # Makes the YAML parser call `init_with` when it encounters the keys below
  # instead of trying its own parsing routines.
  YAML.load_tags["!ruby/hash-with-ivars:ActionController::Parameters"] = name
  YAML.load_tags["!ruby/hash:ActionController::Parameters"] = name
end

.nested_attribute?(key, value) ⇒ `Boolean`

This method is for internal use only.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 267


def nested_attribute?(key, value) # :nodoc:
  /\A-?\d+\z/.match?(key) && (value.is_a?(Hash) || value.is_a?(Parameters))
end

Instance Attribute Details

#always_permitted_parameters (rw)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 264


cattr_accessor :always_permitted_parameters, default: %w( controller action )

#each_key(&block) (readonly)

Calls block once for each key in the parameters, passing the key. If no block is given, an enumerator is returned instead.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 251


delegate :keys, :empty?, :exclude?, :include?,
  :as_json, :to_s, :each_key, to: :@parameters

#has_key? (readonly)

Alias for #include?.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 254


alias_method :has_key?, :include?

#key? (readonly)

Alias for #include?.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 255


alias_method :key?, :include?

#keys (readonly)

Returns a new array of the keys of the parameters.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 251


delegate :keys, :empty?, :exclude?, :include?,
  :as_json, :to_s, :each_key, to: :@parameters

#member? (readonly)

Alias for #include?.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 256


alias_method :member?, :include?

#nested_attributes? ⇒ `Boolean` (readonly, protected)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1174


def nested_attributes?
  @parameters.any? { |k, v| Parameters.nested_attribute?(k, v) }
end

#parameters (readonly, protected)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1170


attr_reader :parameters

#permitted=(value) (rw, protected)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1172


attr_writer :permitted

#permitted? ⇒ `Boolean` (rw)

Returns true if the parameter is permitted, false otherwise.

params = ActionController::Parameters.new
params.permitted? # => false
params.permit!
params.permitted? # => true

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 450


def permitted?
  @permitted
end

Instance Method Details

#==(other)

Returns true if another Parameters object contains the same content and permitted flag.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 302


def ==(other)
  if other.respond_to?(:permitted?)
    permitted? == other.permitted? && parameters == other.parameters
  else
    super
  end
end

#[](key)

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

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 802


def [](key)
  convert_hashes_to_parameters(key, @parameters[key])
end

#[]=(key, value)

Assigns a value to a given key. The given key may still get filtered out when #permit is called.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 808


def []=(key, value)
  @parameters[key] = value
end

#_deep_transform_keys_in_object(object, &block) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1247


def _deep_transform_keys_in_object(object, &block)
  case object
  when Hash
    object.each_with_object(self.class.new) do |(key, value), result|
      result[yield(key)] = _deep_transform_keys_in_object(value, &block)
    end
  when Parameters
    if object.permitted?
      object.to_h.deep_transform_keys(&block)
    else
      object.to_unsafe_h.deep_transform_keys(&block)
    end
  when Array
    object.map { |e| _deep_transform_keys_in_object(e, &block) }
  else
    object
  end
end

#_deep_transform_keys_in_object!(object, &block) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1266


def _deep_transform_keys_in_object!(object, &block)
  case object
  when Hash
    object.keys.each do |key|
      value = object.delete(key)
      object[yield(key)] = _deep_transform_keys_in_object!(value, &block)
    end
    object
  when Parameters
    if object.permitted?
      object.to_h.deep_transform_keys!(&block)
    else
      object.to_unsafe_h.deep_transform_keys!(&block)
    end
  when Array
    object.map! { |e| _deep_transform_keys_in_object!(e, &block) }
  else
    object
  end
end

#_deep_transform_values_in_object(object, &block) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1287


def _deep_transform_values_in_object(object, &block)
  case object
  when Hash
    object.transform_values { |value| _deep_transform_values_in_object(value, &block) }
  when Parameters
    if object.permitted?
      object.to_h.deep_transform_values(&block)
    else
      object.to_unsafe_h.deep_transform_values(&block)
    end
  when Array
    object.map { |e| _deep_transform_values_in_object(e, &block) }
  else
    yield(object)
  end
end

#_deep_transform_values_in_object!(object, &block) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1304


def _deep_transform_values_in_object!(object, &block)
  case object
  when Hash
    object.transform_values! { |value| _deep_transform_values_in_object!(value, &block) }
  when Parameters
    if object.permitted?
      object.to_h.deep_transform_values!(&block)
    else
      object.to_unsafe_h.deep_transform_values!(&block)
    end
  when Array
    object.map! { |e| _deep_transform_values_in_object!(e, &block) }
  else
    yield(object)
  end
end

#array_filter?(filter) ⇒ `Boolean` (private)

When an array is expected, you must specify an array explicitly using the following format:

params.expect(comments: [[:flavor]])

Which will match only the following array formats:

{ pies: [{ flavor: "rhubarb" }, { flavor: "apple" }] }
{ pies: { "0" => { flavor: "key lime" }, "1" =>  { flavor: "mince" } } }

When using #permit, arrays are specified the same way as hashes:

params.expect(pies: [:flavor])

In this case, #permit would also allow matching with a hash (or vice versa):

{ pies: { flavor: "cherry" } }

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1345


def array_filter?(filter)
  filter.is_a?(Array) && filter.size == 1 && filter.first.is_a?(Array)
end

#as_json(options = nil)

Returns a hash that can be used as the JSON representation for the parameters.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 251


delegate :keys, :empty?, :exclude?, :include?,
  :as_json, :to_s, :each_key, to: :@parameters

#compact

Returns a new Parameters instance with nil values removed.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1029


def compact
  new_instance_with_inherited_permitted_status(@parameters.compact)
end

#compact!

Removes all nil values in place and returns self, or nil if no changes were made.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1035


def compact!
  self if @parameters.compact!
end

#compact_blank

Returns a new Parameters instance without the blank values. Uses Object#blank? for determining if a value is blank.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1041


def compact_blank
  reject { |_k, v| v.blank? }
end

#compact_blank!

Removes all blank values in place and returns self. Uses Object#blank? for determining if a value is blank.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1047


def compact_blank!
  reject! { |_k, v| v.blank? }
end

#convert_hashes_to_parameters(key, value) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1227


def convert_hashes_to_parameters(key, value)
  converted = convert_value_to_parameters(value)
  @parameters[key] = converted unless converted.equal?(value)
  converted
end

#convert_parameters_to_hashes(value, using, &block) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1211


def convert_parameters_to_hashes(value, using, &block)
  case value
  when Array
    value.map { |v| convert_parameters_to_hashes(v, using) }
  when Hash
    transformed = value.transform_values do |v|
      convert_parameters_to_hashes(v, using)
    end
    (block_given? ? transformed.to_h(&block) : transformed).with_indifferent_access
  when Parameters
    value.send(using)
  else
    value
  end
end

#convert_value_to_parameters(value) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1233


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.dup
    converted
  when Hash
    self.class.new(value, @logging_context)
  else
    value
  end
end

#converted_arrays

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.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 440


def converted_arrays
  @converted_arrays ||= Set.new
end

#deconstruct_keys(keys)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 320


def deconstruct_keys(keys)
  slice(*keys).each.with_object({}) { |(key, value), hash| hash.merge!(key.to_sym => value) }
end

#deep_dup

Returns a duplicate Parameters instance with the same permitted parameters.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1147


def deep_dup
  self.class.new(@parameters.deep_dup, @logging_context).tap do |duplicate|
    duplicate.permitted = @permitted
  end
end

#deep_merge(other_hash, &block)

Returns a new Parameters instance with self and other_hash merged recursively.

Like with Hash#merge in the standard library, a block can be provided to merge values.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 169


rdoc_method :method: deep_merge

#deep_merge!(other_hash, &block)

Same as #deep_merge, but modifies self.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 184


rdoc_method :method: deep_merge!

#deep_merge?(other_hash) ⇒ `Boolean`

This method is for internal use only.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1082


def deep_merge?(other_hash) # :nodoc:
  other_hash.is_a?(ActiveSupport::DeepMergeable)
end

#deep_transform_keys(&block)

Returns a new Parameters instance with the results of running block once for every key. This includes the keys from the root hash and from all nested hashes and arrays. The values are unchanged.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 951


def deep_transform_keys(&block)
  new_instance_with_inherited_permitted_status(
    _deep_transform_keys_in_object(@parameters, &block).to_unsafe_h
  )
end

#deep_transform_keys!(&block)

Returns the same Parameters instance with changed keys. This includes the keys from the root hash and from all nested hashes and arrays. The values are unchanged.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 960


def deep_transform_keys!(&block)
  @parameters = _deep_transform_keys_in_object(@parameters, &block).to_unsafe_h
  self
end

#deep_transform_values(&block)

Returns a new Parameters instance with the results of running block once for every value. This includes the values from the root hash and from all nested hashes and arrays. The keys are unchanged.

The returned instance carries the same permitted status as the receiver, so the result still has to be filtered through #permit / #expect before being mass-assigned. Prefer this to to_unsafe_h.deep_transform_values, which discards the permitted/unpermitted distinction.

params = ActionController::Parameters.new(
  user: { email: "  ALICE@EXAMPLE.COM  ", profile: { bio: "  Hello world  " } }
)
params.deep_transform_values { |v| v.is_a?(String) ? v.strip.downcase : v }
# => #<ActionController::Parameters {"user"=>#<ActionController::Parameters {"email"=>"alice@example.com", "profile"=>#<ActionController::Parameters {"bio"=>"hello world"} permitted: false>} permitted: false>} permitted: false>

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 979


def deep_transform_values(&block)
  new_instance_with_inherited_permitted_status(
    _deep_transform_values_in_object(@parameters, &block)
  )
end

#deep_transform_values!(&block)

Returns the same Parameters instance with changed values. This includes the values from the root hash and from all nested hashes and arrays. The keys are unchanged.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 988


def deep_transform_values!(&block)
  @parameters = _deep_transform_values_in_object!(@parameters, &block)
  self
end

#delete(key, &block)

Deletes a key-value pair from Parameters and returns the value. If key is not found, returns nil (or, with optional code block, yields key and returns the result). This method is similar to #extract!, which returns the corresponding Parameters object.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 997


def delete(key, &block)
  convert_value_to_parameters(@parameters.delete(key, &block))
end

#delete_if(&block)

Alias for #reject!.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1025


alias_method :delete_if, :reject!

#dig(*keys)

Extracts the nested parameter from the given #keys by calling dig at each step. Returns nil if any intermediate step is nil.

params = ActionController::Parameters.new(foo: { bar: { baz: 1 } })
params.dig(:foo, :bar, :baz) # => 1
params.dig(:foo, :zot, :xyz) # => nil

params2 = ActionController::Parameters.new(foo: [10, 11, 12])
params2.dig(:foo, 1) # => 11

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 868


def dig(*keys)
  convert_hashes_to_parameters(keys.first, @parameters[keys.first])
  @parameters.dig(*keys)
end

#each(&block)

Alias for #each_pair.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 415


alias_method :each, :each_pair

#each_array_element(object, filter, &block) (private)

Called when an explicit array filter is encountered.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1350


def each_array_element(object, filter, &block)
  case object
  when Array
    object.grep(Parameters).filter_map(&block)
  when Parameters
    if object.nested_attributes? && !specify_numeric_keys?(filter)
      object.each_nested_attribute(&block)
    end
  end
end

#each_nested_attribute(&block) (protected)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1178


def each_nested_attribute(&block)
  hash = self.class.new
  self.each { |k, v| hash[k] = yield v if Parameters.nested_attribute?(k, v) }
  hash
end

#each_pair(&block) Also known as: #each

Convert all hashes in values into parameters, then yield each pair in the same way as Hash#each_pair.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 407


def each_pair(&block)
  return to_enum(__callee__) unless block_given?
  @parameters.each_pair do |key, value|
    yield [key, convert_hashes_to_parameters(key, value)]
  end

  self
end

#each_value(&block)

Convert all hashes in values into parameters, then yield each value in the same way as Hash#each_value.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 419


def each_value(&block)
  return to_enum(:each_value) unless block_given?
  @parameters.each_pair do |key, value|
    yield convert_hashes_to_parameters(key, value)
  end

  self
end

#empty? ⇒ `Boolean`

Returns true if the parameters have no key/value pairs.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 251


delegate :keys, :empty?, :exclude?, :include?,
  :as_json, :to_s, :each_key, to: :@parameters

#encode_with(coder)

This method is for internal use only.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1141


def encode_with(coder) # :nodoc:
  coder.map = { "parameters" => @parameters, "permitted" => @permitted }
end

#eql?(other) ⇒ `Boolean`

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 310


def eql?(other)
  self.class == other.class &&
    permitted? == other.permitted? &&
    parameters.eql?(other.parameters)
end

#except(*keys) Also known as: #without

Returns a new 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>

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 896


def except(*keys)
  new_instance_with_inherited_permitted_status(@parameters.except(*keys))
end

#exclude?(key) ⇒ `Boolean`

Returns true if the given key is not present in the parameters.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 251


delegate :keys, :empty?, :exclude?, :include?,
  :as_json, :to_s, :each_key, to: :@parameters

#expect(*filters)

expect is the preferred way to require and permit parameters. It is safer than the previous recommendation to call #permit and #require in sequence, which could allow user triggered 500 errors.

expect is more strict with types to avoid a number of potential pitfalls that may be encountered with the .require.permit pattern.

For example:

params = ActionController::Parameters.new(comment: { text: "hello" })
params.expect(comment: [:text])
# => #<ActionController::Parameters { text: "hello" } permitted: true>

params = ActionController::Parameters.new(comment: [{ text: "hello" }, { text: "world" }])
params.expect(comment: [:text])
# => ActionController::ParameterMissing: param is missing or the value is empty or invalid: comment

In order to permit an array of parameters, the array must be defined explicitly. Use double array brackets, an array inside an array, to declare that an array of parameters is expected.

params = ActionController::Parameters.new(comments: [{ text: "hello" }, { text: "world" }])
params.expect(comments: [[:text]])
# => [#<ActionController::Parameters { "text" => "hello" } permitted: true>,
#     #<ActionController::Parameters { "text" => "world" } permitted: true>]

params = ActionController::Parameters.new(comments: { text: "hello" })
params.expect(comments: [[:text]])
# => ActionController::ParameterMissing: param is missing or the value is empty or invalid: comments

expect is intended to protect against array tampering.

params = ActionController::Parameters.new(user: "hack")
# The previous way of requiring and permitting parameters will error
params.require(:user).permit(:name, pets: [:name]) # wrong
# => NoMethodError: undefined method `permit' for an instance of String

# similarly with nested parameters
params = ActionController::Parameters.new(user: { name: "Martin", pets: { name: "hack" } })
user_params = params.require(:user).permit(:name, pets: [:name]) # wrong
# user_params[:pets] is expected to be an array but is a hash

expect solves this by being more strict with types.

params = ActionController::Parameters.new(user: "hack")
params.expect(user: [ :name, pets: [[:name]] ])
# => ActionController::ParameterMissing: param is missing or the value is empty or invalid: user

# with nested parameters
params = ActionController::Parameters.new(user: { name: "Martin", pets: { name: "hack" } })
user_params = params.expect(user: [:name, pets: [[:name]] ])
user_params[:pets] # => nil

As the examples show, expect requires the :user key, and any root keys similar to the .require.permit pattern. If multiple root keys are expected, they will all be required.

params = ActionController::Parameters.new(name: "Martin", pies: [{ type: "dessert", flavor: "pumpkin"}])
name, pies = params.expect(:name, pies: [[:type, :flavor]])
name # => "Martin"
pies # => [#<ActionController::Parameters {"type"=>"dessert", "flavor"=>"pumpkin"} permitted: true>]

When called with a hash with multiple keys, expect will permit the parameters and require the keys in the order they are given in the hash, returning an array of the permitted parameters.

params = ActionController::Parameters.new(subject: { name: "Martin" }, object: { pie: "pumpkin" })
subject, object = params.expect(subject: [:name], object: [:pie])
subject # => #<ActionController::Parameters {"name"=>"Martin"} permitted: true>
object  # => #<ActionController::Parameters {"pie"=>"pumpkin"} permitted: true>

Besides being more strict about array vs hash params, expect uses permit internally, so it will behave similarly.

params = ActionController::Parameters.new({
  person: {
    name: "Francesco",
    age:  22,
    pets: [{
      name: "Purplish",
      category: "dogs"
    }]
  }
})

permitted = params.expect(person: [ :name, { pets: [[:name]] } ])
permitted.permitted?           # => true
permitted[:name]               # => "Francesco"
permitted[:age]                # => nil
permitted[:pets][0][:name]     # => "Purplish"
permitted[:pets][0][:category] # => nil

An array of permitted scalars may be expected with the following:

params = ActionController::Parameters.new(tags: ["rails", "parameters"])
permitted = params.expect(tags: [])
permitted                 # => ["rails", "parameters"]
permitted.is_a?(Array)    # => true
permitted.size            # => 2

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 777


def expect(*filters)
  params = permit_filters(filters)
  keys = filters.flatten.flat_map { |f| f.is_a?(Hash) ? f.keys : f }
  values = params.require(keys)
  values.size == 1 ? values.first : values
end

#expect!(*filters)

Same as #expect, but raises an ExpectedParameterMissing instead of ParameterMissing. Unlike #expect which will render a 400 response, expect! will raise an exception that is not handled. This is intended for debugging invalid params for an internal API where incorrectly formatted params would indicate a bug in a client library that should be fixed.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 791


def expect!(*filters)
  expect(*filters)
rescue ParameterMissing => e
  raise ExpectedParameterMissing.new(e.param, e.keys)
end

#extract!(*keys)

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>

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 906


def extract!(*keys)
  new_instance_with_inherited_permitted_status(@parameters.extract!(*keys))
end

#extract_value(key, delimiter: "_")

Returns parameter value for the given key separated by delimiter.

params = ActionController::Parameters.new(id: "1_123", tags: "ruby,rails")
params.extract_value(:id) # => ["1", "123"]
params.extract_value(:tags, delimiter: ",") # => ["ruby", "rails"]
params.extract_value(:non_existent_key) # => nil

Note that if the given key's value contains blank elements, then the returned array will include empty strings.

params = ActionController::Parameters.new(tags: "ruby,rails,,web")
params.extract_value(:tags, delimiter: ",") # => ["ruby", "rails", "", "web"]

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1165


def extract_value(key, delimiter: "_")
  @parameters[key]&.split(delimiter, -1)
end

#fetch(key, *args, &block)

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 ParameterMissing error; if a second argument is given, then that is returned (converted to an instance of Parameters if possible); if a block is given, the key is yielded to the block 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 or invalid: none
params.fetch(:none, {})             # => #<ActionController::Parameters {} permitted: false>
params.fetch(:none, "Francesco")    # => "Francesco"
params.fetch(:none) { |key| "Francesco" } # => "Francesco"

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 825


def fetch(key, *args, &block)
  convert_value_to_parameters(
    @parameters.fetch(key) {
      if block_given?
        yield key
      else
        args.fetch(0) { raise ActionController::ParameterMissing.new(key, @parameters.keys) }
      end
    }
  )
end

#fetch_values(*keys)

Returns parameters for the given keys. If a key can't be found, there are several options: With no other arguments, it will raise an ParameterMissing error; if a block is given, then that will be run and its result returned for the missing key.

params = ActionController::Parameters.new(name: "Francesco", age: 22)
params.fetch_values(:name, :age)                # => ["Francesco", 22]
params.fetch_values(:name, :none)               # => ActionController::ParameterMissing: param is missing or the value is empty or invalid: none
params.fetch_values(:name, :none) { |key| key } # => ["Francesco", :none]

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 846


def fetch_values(*keys)
  original_key_lookup = keys.index_by { |key| key.to_s }
  values = @parameters.fetch_values(*keys) do |missing_key|
    original_key = original_key_lookup[missing_key]
    if block_given?
      yield original_key
    else
      raise ActionController::ParameterMissing.new(original_key, @parameters.keys)
    end
  end
  values.map! { |value| convert_value_to_parameters(value) }
end

#has_value?(value) ⇒ `Boolean` Also known as: #value?

Returns true if the given value is present for some key in the parameters.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1052


def has_value?(value)
  each_value.include?(convert_value_to_parameters(value))
end

#hash

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 316


def hash
  [self.class, @parameters, @permitted].hash
end

#hash_filter(params, filter, on_unpermitted: self.class.action_on_unpermitted_parameters, explicit_arrays: false) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1438


def hash_filter(params, filter, on_unpermitted: self.class.action_on_unpermitted_parameters, explicit_arrays: false)
  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
    result = permit_value(value, filter[key], on_unpermitted:, explicit_arrays:)
    params[key] = result unless result.nil?
  end
end

#include?(key) ⇒ `Boolean` Also known as: #has_key?, #key?, #member?

Returns true if the given key is present in the parameters.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 251


delegate :keys, :empty?, :exclude?, :include?,
  :as_json, :to_s, :each_key, to: :@parameters

#init_with(coder)

This method is for internal use only.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1123


def init_with(coder) # :nodoc:
  case coder.tag
  when "!ruby/hash:ActionController::Parameters"
    # YAML 2.0.8's format where hash instance variables weren't stored.
    @parameters = coder.map.with_indifferent_access
    @permitted  = false
  when "!ruby/hash-with-ivars:ActionController::Parameters"
    # YAML 2.0.9's Hash subclass format where keys and values were stored under an
    # elements hash and `permitted` within an ivars hash.
    @parameters = coder.map["elements"].with_indifferent_access
    @permitted  = coder.map["ivars"][:@permitted]
  when "!ruby/object:ActionController::Parameters"
    # YAML's Object format. Only needed because of the format backwards
    # compatibility above, otherwise equivalent to YAML's initialization.
    @parameters, @permitted = coder.map["parameters"], coder.map["permitted"]
  end
end

#initialize_copy(source) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1523


def initialize_copy(source)
  super
  @parameters = @parameters.dup
end

#inspect

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1110


def inspect
  "#<#{self.class} #{@parameters} permitted: #{@permitted}>"
end

#keep_if(&block)

Alias for #select!.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1012


alias_method :keep_if, :select!

#merge(*other_hashes, &block)

Returns a new Parameters instance with all keys from other_hashes merged into current hash.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1066


def merge(*other_hashes, &block)
  new_instance_with_inherited_permitted_status(
    @parameters.merge(*other_hashes.map!(&:to_h), &block)
  )
end

#merge!(*other_hashes)

Returns the current Parameters instance with other_hashes merged into current hash.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1077


def merge!(*other_hashes, &block)
  @parameters.merge!(*other_hashes.map!(&:to_h), &block)
  self
end

#new_instance_with_inherited_permitted_status(hash) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1205


def new_instance_with_inherited_permitted_status(hash)
  self.class.new(hash, @logging_context).tap do |new_instance|
    new_instance.permitted = @permitted
  end
end

#non_scalar?(value) ⇒ `Boolean` (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1432


def non_scalar?(value)
  value.is_a?(Array) || value.is_a?(Parameters)
end

#permit(*filters)

Returns a new 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(name: "Francesco", age: 22, role: "admin")
permitted = params.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: [])

Sometimes it is not possible or convenient to declare the valid keys of a hash parameter or its internal structure. Just map to an empty hash:

params.permit(preferences: {})

Be careful because this opens the door to arbitrary input. In this case, permit ensures values in the returned structure are permitted scalars and filters out anything else.

You can also use permit on nested parameters:

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

This has the added benefit of rejecting user-modified inputs that send a string when a hash is expected.

When followed by #require, you can both filter and require parameters following the typical pattern of a ::Rails form. The #expect method was made specifically for this use case and is the recommended way to require and permit parameters.

permitted = params.expect(person: [:name, :age])

When using permit and #require separately, pay careful attention to the order of the method calls.

params = ActionController::Parameters.new(person: { name: "Martin", age: 40, role: "admin" })
permitted = params.permit(person: [:name, :age]).require(:person) # correct

When require is used first, it is possible for users of your application to trigger a NoMethodError when the user, for example, sends a string for :person.

params = ActionController::Parameters.new(person: "tampered")
permitted = params.require(:person).permit(:name, :age) # not recommended
# => NoMethodError: undefined method `permit' for an instance of String

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 permitted.

params = ActionController::Parameters.new({
  person: {
    contact: {
      email: "none@test.com",
      phone: "555-1234"
    }
  }
})

params.permit(person: :contact).require(:person)
# => ActionController::ParameterMissing: param is missing or the value is empty or invalid: person

params.permit(person: { contact: :phone }).require(:person)
# => #<ActionController::Parameters {"contact"=>#<ActionController::Parameters {"phone"=>"555-1234"} permitted: true>} permitted: true>

params.permit(person: { contact: [ :email, :phone ] }).require(:person)
# => #<ActionController::Parameters {"contact"=>#<ActionController::Parameters {"email"=>"none@test.com", "phone"=>"555-1234"} permitted: true>} permitted: true>

If your parameters specify multiple parameters indexed by a number, you can permit each set of parameters under the numeric key to be the same using the same syntax as permitting a single item.

params = ActionController::Parameters.new({
  person: {
    '0': {
      email: "none@test.com",
      phone: "555-1234"
    },
    '1': {
      email: "nothing@test.com",
      phone: "555-6789"
    },
  }
})
params.permit(person: [:email]).to_h
# => {"person"=>{"0"=>{"email"=>"none@test.com"}, "1"=>{"email"=>"nothing@test.com"}}}

If you want to specify what keys you want from each numeric key, you can instead specify each one individually

params = ActionController::Parameters.new({
  person: {
    '0': {
      email: "none@test.com",
      phone: "555-1234"
    },
    '1': {
      email: "nothing@test.com",
      phone: "555-6789"
    },
  }
})
params.permit(person: { '0': [:email], '1': [:phone]}).to_h
# => {"person"=>{"0"=>{"email"=>"none@test.com"}, "1"=>{"phone"=>"555-6789"}}}

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 673


def permit(*filters)
  permit_filters(filters, on_unpermitted: self.class.action_on_unpermitted_parameters, explicit_arrays: false)
end

#permit!

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">

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 466


def permit!
  each_pair do |key, value|
    Array.wrap(value).flatten.each do |v|
      v.permit! if v.respond_to? :permit!
    end
  end

  @permitted = true
  self
end

#permit_any_in_array(array) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1506


def permit_any_in_array(array)
  [].tap do |sanitized|
    array.each do |element|
      case element
      when ->(e) { permitted_scalar?(e) }
        sanitized << element
      when Array
        sanitized << permit_any_in_array(element)
      when Parameters
        sanitized << permit_any_in_parameters(element)
      else
        # Filter this one out.
      end
    end
  end
end

#permit_any_in_parameters(params) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1489


def permit_any_in_parameters(params)
  self.class.new.tap do |sanitized|
    params.each do |key, value|
      case value
      when ->(v) { permitted_scalar?(v) }
        sanitized[key] = value
      when Array
        sanitized[key] = permit_any_in_array(value)
      when Parameters
        sanitized[key] = permit_any_in_parameters(value)
      else
        # Filter this one out.
      end
    end
  end
end

#permit_array_of_hashes(value, filter, on_unpermitted:, explicit_arrays:) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1468


def permit_array_of_hashes(value, filter, on_unpermitted:, explicit_arrays:)
  each_array_element(value, filter) do |element|
    element.permit_filters(Array.wrap(filter), on_unpermitted:, explicit_arrays:)
  end
end

#permit_array_of_scalars(value) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1464


def permit_array_of_scalars(value)
  value if value.is_a?(Array) && value.all? { |element| permitted_scalar?(element) }
end

#permit_filters(filters, on_unpermitted: nil, explicit_arrays: true) (protected)

Filters self and optionally checks for unpermitted keys

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1185


def permit_filters(filters, on_unpermitted: nil, explicit_arrays: true)
  params = self.class.new

  filters.flatten.each do |filter|
    case filter
    when Symbol, String
      # Declaration [:name, "age"]
      permitted_scalar_filter(params, filter)
    when Hash
      # Declaration [{ person: ... }]
      hash_filter(params, filter, on_unpermitted:, explicit_arrays:)
    end
  end

  unpermitted_parameters!(params, on_unpermitted:)

  params.permit!
end

#permit_hash(value, filter, on_unpermitted:, explicit_arrays:) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1474


def permit_hash(value, filter, on_unpermitted:, explicit_arrays:)
  return unless value.is_a?(Parameters)

  if filter == EMPTY_HASH
    permit_any_in_parameters(value)
  else
    value.permit_filters(Array.wrap(filter), on_unpermitted:, explicit_arrays:)
  end
end

#permit_hash_or_array(value, filter, on_unpermitted:, explicit_arrays:) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1484


def permit_hash_or_array(value, filter, on_unpermitted:, explicit_arrays:)
  permit_array_of_hashes(value, filter, on_unpermitted:, explicit_arrays:) ||
    permit_hash(value, filter, on_unpermitted:, explicit_arrays:)
end

#permit_value(value, filter, on_unpermitted:, explicit_arrays:) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1450


def permit_value(value, filter, on_unpermitted:,  explicit_arrays:)
  if filter == EMPTY_ARRAY # Declaration { comment_ids: [] }.
    permit_array_of_scalars(value)
  elsif filter == EMPTY_HASH # Declaration { preferences: {} }.
    permit_hash(value, filter, on_unpermitted:, explicit_arrays:)
  elsif array_filter?(filter) # Declaration { comments: [[:text]] }
    permit_array_of_hashes(value, filter.first, on_unpermitted:, explicit_arrays:)
  elsif explicit_arrays # Declaration { user: { address: ... } } or { user: [:name, ...] } (only allows hash value)
    permit_hash(value, filter, on_unpermitted:, explicit_arrays:)
  elsif non_scalar?(value) # Declaration { user: { address: ... } } or { user: [:name, ...] }
    permit_hash_or_array(value, filter, on_unpermitted:, explicit_arrays:)
  end
end

#permitted_scalar?(value) ⇒ `Boolean` (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1403


def permitted_scalar?(value)
  PERMITTED_SCALAR_TYPES.any? { |type| value.is_a?(type) }
end

#permitted_scalar_filter(params, permitted_key) (private)

Adds existing keys to the params if their values are scalar.

For example:

puts self.keys #=> ["zipcode(90210i)"]
params = {}

permitted_scalar_filter(params, "zipcode")

puts params.keys # => ["zipcode"]

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1417


def permitted_scalar_filter(params, permitted_key)
  permitted_key = permitted_key.to_s

  if has_key?(permitted_key) && permitted_scalar?(self[permitted_key])
    params[permitted_key] = self[permitted_key]
  end

  each_key do |key|
    next unless key =~ /\(\d+[if]?\)\z/
    next unless $~.pre_match == permitted_key

    params[key] = self[key] if permitted_scalar?(self[key])
  end
end

#reject(&block)

Returns a new Parameters instance with items that the block evaluates to true removed.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1016


def reject(&block)
  new_instance_with_inherited_permitted_status(@parameters.reject(&block))
end

#reject!(&block) Also known as: #delete_if

Removes items that the block evaluates to true and returns self.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1021


def reject!(&block)
  @parameters.reject!(&block)
  self
end

#require(key) Also known as: #required

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 ParameterMissing:

ActionController::Parameters.new.require(:person)
# ActionController::ParameterMissing: param is missing or the value is empty or invalid: person

ActionController::Parameters.new(person: nil).require(:person)
# ActionController::ParameterMissing: param is missing or the value is empty or invalid: person

ActionController::Parameters.new(person: "\t").require(:person)
# ActionController::ParameterMissing: param is missing or the value is empty or invalid: person

ActionController::Parameters.new(person: {}).require(:person)
# ActionController::ParameterMissing: param is missing or the value is empty or invalid: 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 or invalid: user

This method is not recommended for fetching terminal values because it does not permit the values. For example, this can cause problems:

# CAREFUL
params = ActionController::Parameters.new(person: { name: "Finn" })
name = params.require(:person).require(:name) # CAREFUL

It is recommended to use #expect instead:

def person_params
  params.expect(person: :name).require(:name)
end

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 524


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, @parameters.keys)
  end
end

#required(key)

Alias for #require.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 534


alias :required :require

#reverse_merge(other_hash) Also known as: #with_defaults

Returns a new Parameters instance with all keys from current hash merged into other_hash.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1088


def reverse_merge(other_hash)
  new_instance_with_inherited_permitted_status(
    other_hash.to_h.merge(@parameters)
  )
end

#reverse_merge!(other_hash) Also known as: #with_defaults!

Returns the current Parameters instance with current hash merged into other_hash.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1097


def reverse_merge!(other_hash)
  @parameters.merge!(other_hash.to_h) { |key, left, right| left }
  self
end

#select(&block)

Returns a new Parameters instance with only items that the block evaluates to true.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1003


def select(&block)
  new_instance_with_inherited_permitted_status(@parameters.select(&block))
end

#select!(&block) Also known as: #keep_if

Equivalent to Hash#keep_if, but returns nil if no changes were made.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1008


def select!(&block)
  @parameters.select!(&block)
  self
end

#slice(*keys)

Returns a new 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>

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 879


def slice(*keys)
  new_instance_with_inherited_permitted_status(@parameters.slice(*keys))
end

#slice!(*keys)

Returns the current Parameters instance which contains only the given #keys.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 885


def slice!(*keys)
  @parameters.slice!(*keys)
  self
end

#specify_numeric_keys?(filter) ⇒ `Boolean` (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1321


def specify_numeric_keys?(filter)
  if filter.respond_to?(:keys)
    filter.keys.any? { |key| /\A-?\d+\z/.match?(key) }
  end
end

#stringify_keys

This method is for internal use only.

This is required by ::ActiveModel attribute assignment, so that user can pass Parameters to a mass assignment methods in a model. It should not matter as we are using HashWithIndifferentAccess internally.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1106


def stringify_keys # :nodoc:
  dup
end

#to_h(&block)

Returns a safe ::ActiveSupport::HashWithIndifferentAccess representation of the parameters with all unpermitted keys removed.

params = ActionController::Parameters.new({
  name: "Senjougahara Hitagi",
  oddity: "Heavy stone crab"
})
params.to_h
# => ActionController::UnfilteredParameters: unable to convert unpermitted parameters to hash

safe_params = params.permit(:name)
safe_params.to_h # => {"name"=>"Senjougahara Hitagi"}

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 336


def to_h(&block)
  if permitted?
    convert_parameters_to_hashes(@parameters, :to_h, &block)
  else
    raise UnfilteredParameters
  end
end

#to_hash

Returns a safe ::Hash representation of the parameters with all unpermitted keys removed.

params = ActionController::Parameters.new({
  name: "Senjougahara Hitagi",
  oddity: "Heavy stone crab"
})
params.to_hash
# => ActionController::UnfilteredParameters: unable to convert unpermitted parameters to hash

safe_params = params.permit(:name)
safe_params.to_hash # => {"name"=>"Senjougahara Hitagi"}

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 356


def to_hash
  to_h.to_hash
end

#to_param(*args)

Alias for #to_query.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 389


alias_method :to_param, :to_query

#to_query(*args) Also known as: #to_param

Returns a string representation of the receiver suitable for use as a URL query string:

params = ActionController::Parameters.new({
  name: "David",
  nationality: "Danish"
})
params.to_query
# => ActionController::UnfilteredParameters: unable to convert unpermitted parameters to hash

safe_params = params.permit(:name, :nationality)
safe_params.to_query
# => "name=David&nationality=Danish"

An optional namespace can be passed to enclose key names:

params = ActionController::Parameters.new({
  name: "David",
  nationality: "Danish"
})
safe_params = params.permit(:name, :nationality)
safe_params.to_query("user")
# => "user%5Bname%5D=David&user%5Bnationality%5D=Danish"

The string pairs "key=value" that conform the query string are sorted lexicographically in ascending order.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 386


def to_query(*args)
  to_h.to_query(*args)
end

#to_s ⇒ ?

Returns the content of the parameters as a string.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 251


delegate :keys, :empty?, :exclude?, :include?,
  :as_json, :to_s, :each_key, to: :@parameters

#to_unsafe_h Also known as: #to_unsafe_hash

Returns an unsafe, unfiltered ::ActiveSupport::HashWithIndifferentAccess representation of the parameters.

params = ActionController::Parameters.new({
  name: "Senjougahara Hitagi",
  oddity: "Heavy stone crab"
})
params.to_unsafe_h
# => {"name"=>"Senjougahara Hitagi", "oddity" => "Heavy stone crab"}

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 400


def to_unsafe_h
  convert_parameters_to_hashes(@parameters, :to_unsafe_h)
end

#to_unsafe_hash

Alias for #to_unsafe_h.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 403


alias_method :to_unsafe_hash, :to_unsafe_h

#transform_keys(&block)

Returns a new Parameters instance with the results of running block once for every key. The values are unchanged.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 933


def transform_keys(&block)
  return to_enum(:transform_keys) unless block_given?
  new_instance_with_inherited_permitted_status(
    @parameters.transform_keys(&block)
  )
end

#transform_keys!(&block)

Performs keys transformation and returns the altered Parameters instance.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 942


def transform_keys!(&block)
  return to_enum(:transform_keys!) unless block_given?
  @parameters.transform_keys!(&block)
  self
end

#transform_values(&block)

Returns a new Parameters instance 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>

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 916


def transform_values(&block)
  return to_enum(:transform_values) unless block_given?
  new_instance_with_inherited_permitted_status(
    @parameters.transform_values { |v| yield convert_value_to_parameters(v) }
  )
end

#transform_values!(&block)

Performs values transformation and returns the altered Parameters instance.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 925


def transform_values!(&block)
  return to_enum(:transform_values!) unless block_given?
  @parameters.transform_values! { |v| yield convert_value_to_parameters(v) }
  self
end

#unpermitted_keys(params) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1375


def unpermitted_keys(params)
  keys - params.keys - always_permitted_parameters
end

#unpermitted_parameters!(params, on_unpermitted: self.class.action_on_unpermitted_parameters) (private)

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1361


def unpermitted_parameters!(params, on_unpermitted: self.class.action_on_unpermitted_parameters)
  return unless on_unpermitted
  unpermitted_keys = unpermitted_keys(params)
  if unpermitted_keys.any?
    case on_unpermitted
    when :log
      name = "unpermitted_parameters.action_controller"
      ActiveSupport::Notifications.instrument(name, keys: unpermitted_keys, context: @logging_context)
    when :raise
      raise ActionController::UnpermittedParameters.new(unpermitted_keys)
    end
  end
end

#value?(value)

Alias for #has_value?.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1056


alias value? has_value?

#values

Returns a new array of the values of the parameters.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 429


def values
  to_enum(:each_value).to_a
end

#values_at(*keys)

Returns values that were assigned to the given #keys. Note that all the ::Hash objects will be converted to Parameters.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1060


def values_at(*keys)
  convert_value_to_parameters(@parameters.values_at(*keys))
end

#with_defaults(other_hash)

Alias for #reverse_merge.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1093


alias_method :with_defaults, :reverse_merge

#with_defaults!(other_hash)

Alias for #reverse_merge!.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 1101


alias_method :with_defaults!, :reverse_merge!

#without(*keys)

Alias for #except.

[ GitHub ]

# File 'actionpack/lib/action_controller/metal/strong_parameters.rb', line 899


alias_method :without, :except

Class: ActionController::Parameters

Overview

Constant Summary

Class Attribute Summary

Class Method Summary

Instance Attribute Summary

Instance Method Summary

::ActiveSupport::DeepMergeable - Included

Constructor Details

.new(parameters = {}, logging_context = {}) ⇒ Parameters

Class Attribute Details

.action_on_unpermitted_parameters (rw)

.action_on_unpermitted_parameters? ⇒ Boolean (rw)

.always_permitted_parameters (rw) Also known as: #always_permitted_parameters

.permit_all_parameters (rw)

.permit_all_parameters? ⇒ Boolean (rw)

Class Method Details

.hook_into_yaml_loading

.nested_attribute?(key, value) ⇒ Boolean

Instance Attribute Details

#always_permitted_parameters (rw)

#each_key(&block) (readonly)

#has_key? (readonly)

#key? (readonly)

#keys (readonly)

#member? (readonly)

#nested_attributes? ⇒ Boolean (readonly, protected)

#parameters (readonly, protected)

#permitted=(value) (rw, protected)

#permitted? ⇒ Boolean (rw)

Instance Method Details

#==(other)

#[](key)

#[]=(key, value)

#_deep_transform_keys_in_object(object, &block) (private)

#_deep_transform_keys_in_object!(object, &block) (private)

#_deep_transform_values_in_object(object, &block) (private)

#_deep_transform_values_in_object!(object, &block) (private)

#array_filter?(filter) ⇒ Boolean (private)

#as_json(options = nil)

#compact

#compact!

#compact_blank

#compact_blank!

#convert_hashes_to_parameters(key, value) (private)

#convert_parameters_to_hashes(value, using, &block) (private)

#convert_value_to_parameters(value) (private)

#converted_arrays

#deconstruct_keys(keys)

#deep_dup

#deep_merge(other_hash, &block)

#deep_merge!(other_hash, &block)

#deep_merge?(other_hash) ⇒ Boolean

#deep_transform_keys(&block)

#deep_transform_keys!(&block)

#deep_transform_values(&block)

#deep_transform_values!(&block)

#delete(key, &block)

#delete_if(&block)

#dig(*keys)

#each(&block)

#each_array_element(object, filter, &block) (private)

#each_nested_attribute(&block) (protected)

#each_pair(&block) Also known as: #each

#each_value(&block)

#empty? ⇒ Boolean

#encode_with(coder)

#eql?(other) ⇒ Boolean

#except(*keys) Also known as: #without

#exclude?(key) ⇒ Boolean

#expect(*filters)

#expect!(*filters)

#extract!(*keys)

#extract_value(key, delimiter: "_")

#fetch(key, *args, &block)

#fetch_values(*keys)

#has_value?(value) ⇒ Boolean Also known as: #value?

#hash

#hash_filter(params, filter, on_unpermitted: self.class.action_on_unpermitted_parameters, explicit_arrays: false) (private)

#include?(key) ⇒ Boolean Also known as: #has_key?, #key?, #member?

`::ActiveSupport::DeepMergeable` - Included

.new(parameters = {}, logging_context = {}) ⇒ `Parameters`

.action_on_unpermitted_parameters? ⇒ `Boolean` (rw)

.permit_all_parameters? ⇒ `Boolean` (rw)

.nested_attribute?(key, value) ⇒ `Boolean`

#nested_attributes? ⇒ `Boolean` (readonly, protected)

#permitted? ⇒ `Boolean` (rw)

#array_filter?(filter) ⇒ `Boolean` (private)

#deep_merge?(other_hash) ⇒ `Boolean`

#empty? ⇒ `Boolean`

#eql?(other) ⇒ `Boolean`

#exclude?(key) ⇒ `Boolean`

#has_value?(value) ⇒ `Boolean` Also known as: #value?

#include?(key) ⇒ `Boolean` Also known as: #has_key?, #key?, #member?

#non_scalar?(value) ⇒ `Boolean` (private)

#permitted_scalar?(value) ⇒ `Boolean` (private)

#specify_numeric_keys?(filter) ⇒ `Boolean` (private)