Action Controller Parameters

Allows you to choose which attributes should be permitted 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’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 ActionController::Parameters using either :key or "key".

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

Methods

Constants

PERMITTED_SCALAR_TYPES = [ 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, ]
 

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.

Attributes

[R] parameters
[W] permitted

Class Public methods

new(parameters = {}, logging_context = {})

Returns a new ActionController::Parameters instance. 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">
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 269
    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
🔎 See on GitHub

Instance Public methods

==(other)

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

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 283
    def ==(other)
      if other.respond_to?(:permitted?)
        permitted? == other.permitted? && parameters == other.parameters
      else
        if self.class.allow_deprecated_parameters_hash_equality && Hash === other
          ActionController.deprecator.warn <<-WARNING.squish
            Comparing equality between `ActionController::Parameters` and a
            `Hash` is deprecated and will be removed in Rails 7.2. Please only do
            comparisons between instances of `ActionController::Parameters`. If
            you need to compare to a hash, first convert it using
            `ActionController::Parameters#new`.
            To disable the deprecated behavior set
            `Rails.application.config.action_controller.allow_deprecated_parameters_hash_equality = false`.
          WARNING
          @parameters == other
        else
          super
        end
      end
    end
🔎 See on GitHub

[](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
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 665
    def [](key)
      convert_hashes_to_parameters(key, @parameters[key])
    end
🔎 See on GitHub

[]=(key, value)

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

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 671
    def []=(key, value)
      @parameters[key] = value
    end
🔎 See on GitHub

as_json(options=nil)

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

🔎 See on GitHub

compact()

Returns a new ActionController::Parameters instance with nil values removed.

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 842
    def compact
      new_instance_with_inherited_permitted_status(@parameters.compact)
    end
🔎 See on GitHub

compact!()

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

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 847
    def compact!
      self if @parameters.compact!
    end
🔎 See on GitHub

compact_blank()

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

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 853
    def compact_blank
      reject { |_k, v| v.blank? }
    end
🔎 See on GitHub

compact_blank!()

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

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 859
    def compact_blank!
      reject! { |_k, v| v.blank? }
    end
🔎 See on GitHub

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.

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 430
    def converted_arrays
      @converted_arrays ||= Set.new
    end
🔎 See on GitHub

deep_dup()

Returns a duplicate ActionController::Parameters instance with the same permitted parameters.

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 958
    def deep_dup
      self.class.new(@parameters.deep_dup, @logging_context).tap do |duplicate|
        duplicate.permitted = @permitted
      end
    end
🔎 See on GitHub

deep_merge(other_hash, &block)

Returns a new ActionController::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.

🔎 See on GitHub

deep_merge!(other_hash, &block)

Same as #deep_merge, but modifies self.

🔎 See on GitHub

deep_transform_keys(&block)

Returns a new ActionController::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.

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 793
    def deep_transform_keys(&block)
      new_instance_with_inherited_permitted_status(
        @parameters.deep_transform_keys(&block)
      )
    end
🔎 See on GitHub

deep_transform_keys!(&block)

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

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 802
    def deep_transform_keys!(&block)
      @parameters.deep_transform_keys!(&block)
      self
    end
🔎 See on GitHub

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 ActionController::Parameters object.

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 811
    def delete(key, &block)
      convert_value_to_parameters(@parameters.delete(key, &block))
    end
🔎 See on GitHub

delete_if(&block)

Alias for: 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
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 709
    def dig(*keys)
      convert_hashes_to_parameters(keys.first, @parameters[keys.first])
      @parameters.dig(*keys)
    end
🔎 See on GitHub

each(&block)

Alias for: each_pair

each_key(&block)

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

🔎 See on GitHub

each_pair(&block)

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

Also aliased as: each
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 397
    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
🔎 See on GitHub

each_value(&block)

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

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 409
    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
🔎 See on GitHub

empty?()

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

🔎 See on GitHub

eql?(other)

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 304
    def eql?(other)
      self.class == other.class &&
        permitted? == other.permitted? &&
        parameters.eql?(other.parameters)
    end
🔎 See on GitHub

except(*keys)

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>
Also aliased as: without
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 738
    def except(*keys)
      new_instance_with_inherited_permitted_status(@parameters.except(*keys))
    end
🔎 See on GitHub

exclude?(key)

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

🔎 See on GitHub

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>
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 748
    def extract!(*keys)
      new_instance_with_inherited_permitted_status(@parameters.extract!(*keys))
    end
🔎 See on GitHub

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) # => ["ruby", "rails", "", "web"]
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 976
    def extract_value(key, delimiter: "_")
      @parameters[key]&.split(delimiter, -1)
    end
🔎 See on GitHub

fetch(key, *args)

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 a second argument is given, then that is returned (converted to an instance of ActionController::Parameters if possible); 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, {})             # => #<ActionController::Parameters {} permitted: false>
params.fetch(:none, "Francesco")    # => "Francesco"
params.fetch(:none) { "Francesco" } # => "Francesco"
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 688
    def fetch(key, *args)
      convert_value_to_parameters(
        @parameters.fetch(key) {
          if block_given?
            yield
          else
            args.fetch(0) { raise ActionController::ParameterMissing.new(key, @parameters.keys) }
          end
        }
      )
    end
🔎 See on GitHub

has_key?

Alias for: include?

has_value?(value)

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

Also aliased as: value?
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 864
    def has_value?(value)
      each_value.include?(convert_value_to_parameters(value))
    end
🔎 See on GitHub

hash()

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 310
    def hash
      [self.class, @parameters, @permitted].hash
    end
🔎 See on GitHub

include?(key)

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

Also aliased as: has_key?, key?, member?
🔎 See on GitHub

inspect()

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 922
    def inspect
      "#<#{self.class} #{@parameters} permitted: #{@permitted}>"
    end
🔎 See on GitHub

keep_if(&block)

Alias for: select!

key?

Alias for: include?

keys()

Returns a new array of the keys of the parameters.

🔎 See on GitHub

member?

Alias for: include?

merge(other_hash)

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

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 878
    def merge(other_hash)
      new_instance_with_inherited_permitted_status(
        @parameters.merge(other_hash.to_h)
      )
    end
🔎 See on GitHub

merge!(other_hash)

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

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 889
    def merge!(other_hash, &block)
      @parameters.merge!(other_hash.to_h, &block)
      self
    end
🔎 See on GitHub

permit(*filters)

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: [])

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, 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 permitted.

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>

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"}}}
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 642
    def permit(*filters)
      params = self.class.new

      filters.flatten.each do |filter|
        case filter
        when Symbol, String
          permitted_scalar_filter(params, filter)
        when Hash
          hash_filter(params, filter)
        end
      end

      unpermitted_parameters!(params) if self.class.action_on_unpermitted_parameters

      params.permit!
    end
🔎 See on GitHub

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">
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 456
    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
🔎 See on GitHub

permitted?()

Returns true if the parameter is permitted, false otherwise.

params = ActionController::Parameters.new
params.permitted? # => false
params.permit!
params.permitted? # => true
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 440
    def permitted?
      @permitted
    end
🔎 See on GitHub

reject(&block)

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

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 830
    def reject(&block)
      new_instance_with_inherited_permitted_status(@parameters.reject(&block))
    end
🔎 See on GitHub

reject!(&block)

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

Also aliased as: delete_if
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 835
    def reject!(&block)
      @parameters.reject!(&block)
      self
    end
🔎 See on GitHub

require(key)

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.

Also aliased as: required
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 517
    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
🔎 See on GitHub

required(key)

Alias for: require

reverse_merge(other_hash)

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

Also aliased as: with_defaults
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 900
    def reverse_merge(other_hash)
      new_instance_with_inherited_permitted_status(
        other_hash.to_h.merge(@parameters)
      )
    end
🔎 See on GitHub

reverse_merge!(other_hash)

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

Also aliased as: with_defaults!
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 909
    def reverse_merge!(other_hash)
      @parameters.merge!(other_hash.to_h) { |key, left, right| left }
      self
    end
🔎 See on GitHub

select(&block)

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

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 817
    def select(&block)
      new_instance_with_inherited_permitted_status(@parameters.select(&block))
    end
🔎 See on GitHub

select!(&block)

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

Also aliased as: keep_if
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 822
    def select!(&block)
      @parameters.select!(&block)
      self
    end
🔎 See on GitHub

slice(*keys)

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>
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 721
    def slice(*keys)
      new_instance_with_inherited_permitted_status(@parameters.slice(*keys))
    end
🔎 See on GitHub

slice!(*keys)

Returns the current ActionController::Parameters instance which contains only the given keys.

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 727
    def slice!(*keys)
      @parameters.slice!(*keys)
      self
    end
🔎 See on GitHub

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"}
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 326
    def to_h(&block)
      if permitted?
        convert_parameters_to_hashes(@parameters, :to_h, &block)
      else
        raise UnfilteredParameters
      end
    end
🔎 See on GitHub

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"}
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 346
    def to_hash
      to_h.to_hash
    end
🔎 See on GitHub

to_param(*args)

Alias for: to_query

to_query(*args)

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.

Also aliased as: to_param
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 376
    def to_query(*args)
      to_h.to_query(*args)
    end
🔎 See on GitHub

to_s()

Returns the content of the parameters as a string.

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 229
    delegate :keys, :empty?, :exclude?, :include?,
      :as_json, :to_s, :each_key, to: :@parameters
🔎 See on GitHub

to_unsafe_h()

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"}
Also aliased as: to_unsafe_hash
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 390
    def to_unsafe_h
      convert_parameters_to_hashes(@parameters, :to_unsafe_h)
    end
🔎 See on GitHub

to_unsafe_hash()

Alias for: to_unsafe_h

transform_keys(&block)

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

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 775
    def transform_keys(&block)
      return to_enum(:transform_keys) unless block_given?
      new_instance_with_inherited_permitted_status(
        @parameters.transform_keys(&block)
      )
    end
🔎 See on GitHub

transform_keys!(&block)

Performs keys transformation and returns the altered ActionController::Parameters instance.

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 784
    def transform_keys!(&block)
      return to_enum(:transform_keys!) unless block_given?
      @parameters.transform_keys!(&block)
      self
    end
🔎 See on GitHub

transform_values()

Returns a new ActionController::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>
📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 758
    def transform_values
      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
🔎 See on GitHub

transform_values!()

Performs values transformation and returns the altered ActionController::Parameters instance.

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 767
    def transform_values!
      return to_enum(:transform_values!) unless block_given?
      @parameters.transform_values! { |v| yield convert_value_to_parameters(v) }
      self
    end
🔎 See on GitHub

value?(value)

Alias for: has_value?

values()

Returns a new array of the values of the parameters.

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 419
    def values
      to_enum(:each_value).to_a
    end
🔎 See on GitHub

values_at(*keys)

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

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 872
    def values_at(*keys)
      convert_value_to_parameters(@parameters.values_at(*keys))
    end
🔎 See on GitHub

with_defaults(other_hash)

Alias for: reverse_merge

with_defaults!(other_hash)

Alias for: reverse_merge!

without(*keys)

Alias for: except

Instance Protected methods

each_nested_attribute()

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 989
      def each_nested_attribute
        hash = self.class.new
        self.each { |k, v| hash[k] = yield v if Parameters.nested_attribute?(k, v) }
        hash
      end
🔎 See on GitHub

nested_attributes?()

📝 Source code
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 985
      def nested_attributes?
        @parameters.any? { |k, v| Parameters.nested_attribute?(k, v) }
      end
🔎 See on GitHub