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 false to just filter them out, :log to additionally 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 234

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

Class Method Details

.hook_into_yaml_loading ⇒ Object

:nodoc:



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# File 'lib/action_controller/metal/strong_parameters.rb', line 753

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 241

def ==(other)
  if other.respond_to?(:permitted?)
    permitted? == other.permitted? && parameters == other.parameters
  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 545

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 551

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

#converted_arrays ⇒ Object

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 344

def converted_arrays
  @converted_arrays ||= Set.new
end

#deep_dup ⇒ Object

Returns duplicate of object including all parameters.



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

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 676

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 588

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 330

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 617

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 626

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 566

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 762

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

#inspect ⇒ Object 



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# File 'lib/action_controller/metal/strong_parameters.rb', line 749

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

#keys ⇒ Object

: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 205

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 merged into current hash.



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# File 'lib/action_controller/metal/strong_parameters.rb', line 714

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 with other_hash merged into current hash.



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# File 'lib/action_controller/metal/strong_parameters.rb', line 722

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: [])

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 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 522

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

#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 370

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 354

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 695

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 700

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 431

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

#reverse_merge(other_hash) ⇒ Object

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



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# File 'lib/action_controller/metal/strong_parameters.rb', line 729

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

#reverse_merge!(other_hash) ⇒ Object

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



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# File 'lib/action_controller/metal/strong_parameters.rb', line 737

def reverse_merge!(other_hash)
  @parameters.merge!(other_hash.to_h) { |key, left, right| left }
  self
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 682

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 687

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 600

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 606

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

#stringify_keys ⇒ Object

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 745

def stringify_keys # :nodoc:
  dup
end

#to_h ⇒ Object

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 261

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

#to_hash ⇒ Object

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 281

def to_hash
  to_h.to_hash
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 308

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

#to_unsafe_h ⇒ Object 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 323

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 655

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 667

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 636

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 648

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 708

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