Class: ActionController::Parameters

Inherits:
Object
  • Object
show all
Defined in:
lib/action_controller/metal/strong_parameters.rb

Overview

Action Controller Parameters

Allows you to choose which attributes should be whitelisted for mass updating and thus prevent accidentally exposing that which shouldn’t be exposed. Provides two methods for this purpose: #require and #permit. The former is used to mark parameters as required. The latter is used to set the parameter as permitted and limit which attributes should be allowed for mass updating.

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

permitted = params.require(:person).permit(:name, :age)
permitted            # => <ActionController::Parameters {"name"=>"Francesco", "age"=>22} permitted: true>
permitted.permitted? # => true

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

It provides two options that controls the top-level behavior of new instances:

  • permit_all_parameters - If it’s true, all the parameters will be permitted by default. The default is false.

  • action_on_unpermitted_parameters - Allow to control the behavior when parameters that are not explicitly permitted are found. The values can be :log to write a message on the logger or :raise to raise ActionController::UnpermittedParameters exception. The default value is :log in test and development environments, false otherwise.

Examples:

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

ActionController::Parameters.permit_all_parameters = true

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

params = ActionController::Parameters.new(a: "123", b: "456")
params.permit(:c)
# => <ActionController::Parameters {} permitted: true>

ActionController::Parameters.action_on_unpermitted_parameters = :raise

params = ActionController::Parameters.new(a: "123", b: "456")
params.permit(:c)
# => ActionController::UnpermittedParameters: found unpermitted keys: a, b

Please note that these options *are not thread-safe*. In a multi-threaded environment they should only be set once at boot-time and never mutated at runtime.

You can fetch values of ActionController::Parameters using either :key or "key".

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

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(parameters = {}) ⇒ Parameters

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">


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# File 'lib/action_controller/metal/strong_parameters.rb', line 233

def initialize(parameters = {})
  @parameters = parameters.with_indifferent_access
  @permitted = self.class.permit_all_parameters
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method_sym, *args, &block) ⇒ Object



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# File 'lib/action_controller/metal/strong_parameters.rb', line 781

def method_missing(method_sym, *args, &block)
  if @parameters.respond_to?(method_sym)
    message = <<-DEPRECATE.squish
      Method #{method_sym} is deprecated and will be removed in Rails 5.1,
      as `ActionController::Parameters` no longer inherits from
      hash. Using this deprecated behavior exposes potential security
      problems. If you continue to use this method you may be creating
      a security vulnerability in your app that can be exploited. Instead,
      consider using one of these documented methods which are not
      deprecated: http://api.rubyonrails.org/v#{ActionPack.version}/classes/ActionController/Parameters.html
    DEPRECATE
    ActiveSupport::Deprecation.warn(message)
    @parameters.public_send(method_sym, *args, &block)
  else
    super
  end
end

Class Method Details

.hook_into_yaml_loadingObject

:nodoc:



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# File 'lib/action_controller/metal/strong_parameters.rb', line 754

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

Instance Method Details

#==(other) ⇒ Object

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



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# File '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 <<-WARNING.squish
      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`.
    WARNING
    @parameters == other.with_indifferent_access
  else
    @parameters == other
  end
end

#[](key) ⇒ Object

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


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# File 'lib/action_controller/metal/strong_parameters.rb', line 561

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

#[]=(key, value) ⇒ Object

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



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# File 'lib/action_controller/metal/strong_parameters.rb', line 567

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

#converted_arraysObject

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.



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# File 'lib/action_controller/metal/strong_parameters.rb', line 369

def converted_arrays
  @converted_arrays ||= Set.new
end

#deep_dupObject

Returns duplicate of object including all parameters.



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# File '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

#delete(key, &block) ⇒ Object

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.



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# File 'lib/action_controller/metal/strong_parameters.rb', line 692

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

#dig(*keys) ⇒ Object

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



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# File 'lib/action_controller/metal/strong_parameters.rb', line 604

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

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

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



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# File '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

#except(*keys) ⇒ Object

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>


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# File 'lib/action_controller/metal/strong_parameters.rb', line 633

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

#extract!(*keys) ⇒ Object

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>


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# File 'lib/action_controller/metal/strong_parameters.rb', line 642

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

#fetch(key, *args) ⇒ Object

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"


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# File '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

#init_with(coder) ⇒ Object

:nodoc:



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# File 'lib/action_controller/metal/strong_parameters.rb', line 763

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
    # backwardscompability above, otherwise equivalent to YAML's initialization.
    @parameters, @permitted = coder.map['parameters'], coder.map['permitted']
  end
end

#inspectObject



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# File 'lib/action_controller/metal/strong_parameters.rb', line 750

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

#keysObject

:method: values

:call-seq:

values()

Returns a new array of the values of the parameters.



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# File '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

#merge(other_hash) ⇒ Object

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



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# File '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

#merge!(other_hash) ⇒ Object

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



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# File 'lib/action_controller/metal/strong_parameters.rb', line 738

def merge!(other_hash)
  @parameters.merge!(other_hash.to_h)
  self
end

#permit(*filters) ⇒ Object

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: "[email protected]",
      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"=>"[email protected]", "phone"=>"555-1234"} permitted: true>} permitted: true>


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# File '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

#permit!Object

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">


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# File '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

#permitted?Boolean

Returns true if the parameter is permitted, false otherwise.

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

Returns:

  • (Boolean)


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# File 'lib/action_controller/metal/strong_parameters.rb', line 379

def permitted?
  @permitted
end

#reject(&block) ⇒ Object

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



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# File 'lib/action_controller/metal/strong_parameters.rb', line 711

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

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

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



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# File 'lib/action_controller/metal/strong_parameters.rb', line 716

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

#require(key) ⇒ Object 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 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.



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# File '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

#respond_to?(name, include_all = false) ⇒ Boolean

:nodoc:

Returns:

  • (Boolean)


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# File 'lib/action_controller/metal/strong_parameters.rb', line 799

def respond_to?(name, include_all = false) # :nodoc:
  super || @parameters.respond_to?(name, include_all)
end

#select(&block) ⇒ Object

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



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# File 'lib/action_controller/metal/strong_parameters.rb', line 698

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

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

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



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# File 'lib/action_controller/metal/strong_parameters.rb', line 703

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

#slice(*keys) ⇒ Object

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>


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# File 'lib/action_controller/metal/strong_parameters.rb', line 616

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

#slice!(*keys) ⇒ Object

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



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# File 'lib/action_controller/metal/strong_parameters.rb', line 622

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

#stringify_keysObject

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.



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# File 'lib/action_controller/metal/strong_parameters.rb', line 746

def stringify_keys # :nodoc:
  dup
end

#to_hObject

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"}


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# File '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

#to_hashObject

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"}


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# File 'lib/action_controller/metal/strong_parameters.rb', line 291

def to_hash
  if self.class.raise_on_unfiltered_parameters
    to_h.to_hash
  else
    message = <<-DEPRECATE.squish
      #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.
    DEPRECATE
    ActiveSupport::Deprecation.warn(message)

    @parameters.to_hash
  end
end

#to_query(*args) ⇒ Object 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
# => "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.



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# File '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

#to_unsafe_hObject 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"}


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# File 'lib/action_controller/metal/strong_parameters.rb', line 348

def to_unsafe_h
  convert_parameters_to_hashes(@parameters, :to_unsafe_h)
end

#transform_keys(&block) ⇒ Object

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



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# File '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

#transform_keys!(&block) ⇒ Object

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



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# File 'lib/action_controller/metal/strong_parameters.rb', line 683

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

#transform_values(&block) ⇒ Object

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>


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# File '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

#transform_values!(&block) ⇒ Object

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



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# File 'lib/action_controller/metal/strong_parameters.rb', line 664

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

#values_at(*keys) ⇒ Object

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



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# File 'lib/action_controller/metal/strong_parameters.rb', line 724

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