# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 233
def initialize(parameters = {})
  @parameters = parameters.with_indifferent_access
  @permitted = self.class.permit_all_parameters
end

Returns a new instance of ActionController::Parameters. Also, sets the permitted attribute to the default value of ActionController::Parameters.permit_all_parameters.

class Person < ActiveRecord::Base
end

params = ActionController::Parameters.new(name: "Francesco")
params.permitted?  # => false
Person.new(params) # => ActiveModel::ForbiddenAttributesError

ActionController::Parameters.permit_all_parameters = true

params = ActionController::Parameters.new(name: "Francesco")
params.permitted?  # => true
Person.new(params) # => #<Person id: nil, name: "Francesco">

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 240
    def ==(other)
      if other.respond_to?(:permitted?)
        self.permitted? == other.permitted? && self.parameters == other.parameters
      elsif other.is_a?(Hash)
        ActiveSupport::Deprecation.warn "          Comparing equality between `ActionController::Parameters` and a
          `Hash` is deprecated and will be removed in Rails 5.1. Please only do
          comparisons between instances of `ActionController::Parameters`. If
          you need to compare to a hash, first convert it using
          `ActionController::Parameters#new`.
".squish
        @parameters == other.with_indifferent_access
      else
        @parameters == other
      end
    end

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 561
def [](key)
  convert_hashes_to_parameters(key, @parameters[key])
end

Returns a parameter for the given key. If not found, returns nil.

params = ActionController::Parameters.new(person: { name: "Francesco" })
params[:person] # => <ActionController::Parameters {"name"=>"Francesco"} permitted: false>
params[:none]   # => nil

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 567
def []=(key, value)
  @parameters[key] = value
end

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 134
    

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 369
def converted_arrays
  @converted_arrays ||= Set.new
end

Attribute that keeps track of converted arrays, if any, to avoid double looping in the common use case permit + mass-assignment. Defined in a method to instantiate it only if needed.

Testing membership still loops, but it's going to be faster than our own loop that converts values. Also, we are not going to build a new array object per fetch.

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 804
def deep_dup
  self.class.new(@parameters.deep_dup).tap do |duplicate|
    duplicate.permitted = @permitted
  end
end

Returns duplicate of object including all parameters.

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 692
def delete(key, &block)
  convert_value_to_parameters(@parameters.delete(key, &block))
end

Deletes and returns a key-value pair from Parameters whose key is equal to key. If the key is not found, returns the default value. If the optional code block is given and the key is not found, pass in the key and return the result of block.

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 604
def dig(*keys)
  convert_value_to_parameters(@parameters.dig(*keys))
end

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

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

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 355
def each_pair(&block)
  @parameters.each_pair do |key, value|
    yield key, convert_hashes_to_parameters(key, value)
  end
end

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 142
    

Returns true if the object has no key/value pairs.

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 633
def except(*keys)
  new_instance_with_inherited_permitted_status(@parameters.except(*keys))
end

Returns a new ActionController::Parameters instance that filters out the given keys.

params = ActionController::Parameters.new(a: 1, b: 2, c: 3)
params.except(:a, :b) # => <ActionController::Parameters {"c"=>3} permitted: false>
params.except(:d)     # => <ActionController::Parameters {"a"=>1, "b"=>2, "c"=>3} permitted: false>

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 642
def extract!(*keys)
  new_instance_with_inherited_permitted_status(@parameters.extract!(*keys))
end

Removes and returns the key/value pairs matching the given keys.

params = ActionController::Parameters.new(a: 1, b: 2, c: 3)
params.extract!(:a, :b) # => <ActionController::Parameters {"a"=>1, "b"=>2} permitted: false>
params                  # => <ActionController::Parameters {"c"=>3} permitted: false>

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 582
def fetch(key, *args)
  convert_value_to_parameters(
    @parameters.fetch(key) {
      if block_given?
        yield
      else
        args.fetch(0) { raise ActionController::ParameterMissing.new(key) }
      end
    }
  )
end

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

params = ActionController::Parameters.new(person: { name: "Francesco" })
params.fetch(:person)               # => <ActionController::Parameters {"name"=>"Francesco"} permitted: false>
params.fetch(:none)                 # => ActionController::ParameterMissing: param is missing or the value is empty: none
params.fetch(:none, "Francesco")    # => "Francesco"
params.fetch(:none) { "Francesco" } # => "Francesco"

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 150
    

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 158
    

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

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

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 174
    

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 182
    

Returns a new array of the keys of the parameters.

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 730
def merge(other_hash)
  new_instance_with_inherited_permitted_status(
    @parameters.merge(other_hash.to_h)
  )
end

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 738
def merge!(other_hash)
  @parameters.merge!(other_hash.to_h)
  self
end

Returns current ActionController::Parameters instance which other_hash merges into current hash.

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 538
def permit(*filters)
  params = self.class.new

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

  unpermitted_parameters!(params) if self.class.action_on_unpermitted_parameters

  params.permit!
end

Returns a new ActionController::Parameters instance that includes only the given filters and sets the permitted attribute for the object to true. This is useful for limiting which attributes should be allowed for mass updating.

params = ActionController::Parameters.new(user: { name: "Francesco", age: 22, role: "admin" })
permitted = params.require(:user).permit(:name, :age)
permitted.permitted?      # => true
permitted.has_key?(:name) # => true
permitted.has_key?(:age)  # => true
permitted.has_key?(:role) # => false

Only permitted scalars pass the filter. For example, given

params.permit(:name)

:name passes if it is a key of params whose associated value is of type String, Symbol, NilClass, Numeric, TrueClass, FalseClass, Date, Time, DateTime, StringIO, IO, ActionDispatch::Http::UploadedFile or Rack::Test::UploadedFile. Otherwise, the key :name is filtered out.

You may declare that the parameter should be an array of permitted scalars by mapping it to an empty array:

params = ActionController::Parameters.new(tags: ["rails", "parameters"])
params.permit(tags: [])

You can also use permit on nested parameters, like:

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

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

Note that if you use permit in a key that points to a hash, it won't allow all the hash. You also need to specify which attributes inside the hash should be whitelisted.

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

params.require(:person).permit(:contact)
# => <ActionController::Parameters {} permitted: true>

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

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 395
def permit!
  each_pair do |key, value|
    Array.wrap(value).each do |v|
      v.permit! if v.respond_to? :permit!
    end
  end

  @permitted = true
  self
end

Sets the permitted attribute to true. This can be used to pass mass assignment. Returns self.

class Person < ActiveRecord::Base
end

params = ActionController::Parameters.new(name: "Francesco")
params.permitted?  # => false
Person.new(params) # => ActiveModel::ForbiddenAttributesError
params.permit!
params.permitted?  # => true
Person.new(params) # => #<Person id: nil, name: "Francesco">

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 379
def permitted?
  @permitted
end

Returns true if the parameter is permitted, false otherwise.

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 711
def reject(&block)
  new_instance_with_inherited_permitted_status(@parameters.reject(&block))
end

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 716
def reject!(&block)
  @parameters.reject!(&block)
  self
end

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 456
def require(key)
  return key.map { |k| require(k) } if key.is_a?(Array)
  value = self[key]
  if value.present? || value == false
    value
  else
    raise ParameterMissing.new(key)
  end
end

This method accepts both a single key and an array of keys.

When passed a single key, if it exists and its associated value is either present or the singleton false, returns said value:

ActionController::Parameters.new(person: { name: "Francesco" }).require(:person)
# => <ActionController::Parameters {"name"=>"Francesco"} permitted: false>

Otherwise raises ActionController::ParameterMissing:

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

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

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

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

When given an array of keys, the method tries to require each one of them in order. If it succeeds, an array with the respective return values is returned:

params = ActionController::Parameters.new(user: { ... }, profile: { ... })
user_params, profile_params = params.require([:user, :profile])

Otherwise, the method re-raises the first exception found:

params = ActionController::Parameters.new(user: {}, profile: {})
user_params, profile_params = params.require([:user, :profile])
# ActionController::ParameterMissing: param is missing or the value is empty: user

Technically this method can be used to fetch terminal values:

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

but take into account that at some point those ones have to be permitted:

def person_params
  params.require(:person).permit(:name).tap do |person_params|
    person_params.require(:name) # SAFER
  end
end

for example.

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 698
def select(&block)
  new_instance_with_inherited_permitted_status(@parameters.select(&block))
end

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 703
def select!(&block)
  @parameters.select!(&block)
  self
end

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 616
def slice(*keys)
  new_instance_with_inherited_permitted_status(@parameters.slice(*keys))
end

Returns a new ActionController::Parameters instance that includes only the given keys. If the given keys don't exist, returns an empty hash.

params = ActionController::Parameters.new(a: 1, b: 2, c: 3)
params.slice(:a, :b) # => <ActionController::Parameters {"a"=>1, "b"=>2} permitted: false>
params.slice(:d)     # => <ActionController::Parameters {} permitted: false>

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 622
def slice!(*keys)
  @parameters.slice!(*keys)
  self
end

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 269
def to_h
  if permitted?
    convert_parameters_to_hashes(@parameters, :to_h)
  elsif self.class.raise_on_unfiltered_parameters
    raise UnfilteredParameters
  else
    slice(*self.class.always_permitted_parameters).permit!.to_h
  end
end

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 unfiltered parameters to hash

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 291
    def to_hash
      if self.class.raise_on_unfiltered_parameters || permitted?
        to_h.to_hash
      else
        message = "          #to_hash unexpectedly ignores parameter filtering, and will change to enforce it in Rails 5.1.
          Enable `raise_on_unfiltered_parameters` to respect parameter filtering, which is the default
          in new applications. For the existing deprecated behaviour, call #to_unsafe_h instead.
".squish
        ActiveSupport::Deprecation.warn(message)

        @parameters.to_hash
      end
    end

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 unfiltered parameters to hash

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 329
def to_query(*args)
  if self.class.raise_on_unfiltered_parameters
    to_h.to_query(*args)
  else
    @parameters.to_query(*args)
  end
end

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
# => "name=David&nationality=Danish"

An optional namespace can be passed to enclose key names:

params = ActionController::Parameters.new({
  name: "David",
  nationality: "Danish"
})
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.

This method is also aliased as to_param.

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 348
def to_unsafe_h
  convert_parameters_to_hashes(@parameters, :to_unsafe_h)
end

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"}

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 671
def transform_keys(&block)
  if block
    new_instance_with_inherited_permitted_status(
      @parameters.transform_keys(&block)
    )
  else
    @parameters.transform_keys
  end
end

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 683
def transform_keys!(&block)
  @parameters.transform_keys!(&block)
  self
end

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 652
def transform_values(&block)
  if block
    new_instance_with_inherited_permitted_status(
      @parameters.transform_values(&block)
    )
  else
    @parameters.transform_values
  end
end

Returns a new ActionController::Parameters with the results of running block once for every value. The keys are unchanged.

params = ActionController::Parameters.new(a: 1, b: 2, c: 3)
params.transform_values { |x| x * 2 }
# => <ActionController::Parameters {"a"=>2, "b"=>4, "c"=>6} permitted: false>

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 664
def transform_values!(&block)
  @parameters.transform_values!(&block)
  self
end

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 197
    

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

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 204
delegate :keys, :key?, :has_key?, :values, :has_value?, :value?, :empty?, :include?,
  :as_json, :to_s, to: :@parameters

Returns a new array of the values of the parameters.

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 724
def values_at(*keys)
  convert_value_to_parameters(@parameters.values_at(*keys))
end

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