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’strue
, all the parameters will be permitted by default. The default isfalse
. -
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 anActiveSupport::Notifications.instrument
event on theunpermitted_parameters.action_controller
topic and log at the DEBUG level. -
:raise
to raise anActionController::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"
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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, ] |
— Filtering ———————————————————- 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, If you modify this collection please update the one in the |
Attributes
[R] | parameters | |
[W] | permitted |
Class Public methods
allow_deprecated_parameters_hash_equality() Link
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 253 def allow_deprecated_parameters_hash_equality ActionController.deprecator.warn <<-WARNING.squish `Rails.application.config.action_controller.allow_deprecated_parameters_hash_equality` is deprecated and will be removed in Rails 8.0. WARNING end
allow_deprecated_parameters_hash_equality=(value) Link
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 260 def allow_deprecated_parameters_hash_equality=(value) ActionController.deprecator.warn <<-WARNING.squish `Rails.application.config.action_controller.allow_deprecated_parameters_hash_equality` is deprecated and will be removed in Rails 8.0. WARNING end
new(parameters = {}, logging_context = {}) Link
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">
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 288 def initialize(parameters = {}, logging_context = {}) parameters.each_key do |key| unless key.is_a?(String) || key.is_a?(Symbol) raise InvalidParameterKey, "all keys must be Strings or Symbols, got: #{key.class}" end end @parameters = parameters.with_indifferent_access @logging_context = logging_context @permitted = self.class.permit_all_parameters end
Instance Public methods
==(other) Link
Returns true if another Parameters
object contains the same content and permitted flag.
[](key) Link
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
[]=(key, value) Link
Assigns a value to a given key
. The given key may still get filtered out when permit
is called.
as_json(options=nil) Link
Returns a hash that can be used as the JSON representation for the parameters.
Source: on GitHub
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 181
compact() Link
Returns a new ActionController::Parameters
instance with nil
values removed.
compact!() Link
Removes all nil
values in place and returns self
, or nil
if no changes were made.
compact_blank() Link
Returns a new ActionController::Parameters
instance without the blank values. Uses Object#blank?
for determining if a value is blank.
compact_blank!() Link
Removes all blank values in place and returns self. Uses Object#blank?
for determining if a value is blank.
converted_arrays() Link
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.
deep_dup() Link
Returns a duplicate ActionController::Parameters
instance with the same permitted parameters.
deep_merge(other_hash, &block) Link
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.
Source: on GitHub
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 155
deep_merge!(other_hash, &block) Link
Same as #deep_merge
, but modifies self
.
Source: on GitHub
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 170
deep_transform_keys(&block) Link
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.
deep_transform_keys!(&block) Link
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.
delete(key, &block) Link
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.
dig(*keys) Link
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
each_key(&block) Link
Calls block once for each key in the parameters, passing the key. If no block is given, an enumerator is returned instead.
Source: on GitHub
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 189
each_pair(&block) Link
Convert all hashes in values into parameters, then yield each pair in the same way as Hash#each_pair
.
each_value(&block) Link
Convert all hashes in values into parameters, then yield each value in the same way as Hash#each_value
.
empty?() Link
Returns true if the parameters have no key/value pairs.
Source: on GitHub
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 198
eql?(other) Link
except(*keys) Link
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>
exclude?(key) Link
Returns true if the given key is not present in the parameters.
Source: on GitHub
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 206
extract!(*keys) Link
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>
extract_value(key, delimiter: "_") Link
Returns parameter value for the given key
separated by delimiter
.
params = ActionController::Parameters.new(id: "1_123", tags: "ruby,rails")
params.extract_value(:id) # => ["1", "123"]
params.extract_value(:tags, delimiter: ",") # => ["ruby", "rails"]
params.extract_value(:non_existent_key) # => nil
Note that if the given key
‘s value contains blank elements, then the returned array will include empty strings.
params = ActionController::Parameters.new(tags: "ruby,rails,,web")
params.extract_value(:tags, delimiter: ",") # => ["ruby", "rails", "", "web"]
fetch(key, *args) Link
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"
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 693 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
has_value?(value) Link
Returns true if the given value is present for some key in the parameters.
hash() Link
include?(key) Link
Returns true if the given key is present in the parameters.
Source: on GitHub
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 214
inspect() Link
keys() Link
Returns a new array of the keys of the parameters.
Source: on GitHub
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 222
merge(other_hash) Link
Returns a new ActionController::Parameters
instance with all keys from other_hash
merged into current hash.
merge!(other_hash) Link
Returns the current ActionController::Parameters
instance with other_hash
merged into current hash.
permit(*filters) Link
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"}}}
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 648 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!() Link
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">
permitted?() Link
Returns true
if the parameter is permitted, false
otherwise.
params = ActionController::Parameters.new
params.permitted? # => false
params.permit!
params.permitted? # => true
reject(&block) Link
Returns a new ActionController::Parameters
instance with items that the block evaluates to true removed.
reject!(&block) Link
Removes items that the block evaluates to true and returns self.
require(key) Link
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.
reverse_merge(other_hash) Link
Returns a new ActionController::Parameters
instance with all keys from current hash merged into other_hash
.
reverse_merge!(other_hash) Link
Returns the current ActionController::Parameters
instance with current hash merged into other_hash
.
select(&block) Link
Returns a new ActionController::Parameters
instance with only items that the block evaluates to true.
select!(&block) Link
Equivalent to Hash#keep_if, but returns nil
if no changes were made.
slice(*keys) Link
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>
slice!(*keys) Link
Returns the current ActionController::Parameters
instance which contains only the given keys
.
to_h(&block) Link
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"}
to_hash() Link
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"}
to_query(*args) Link
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.
to_s() Link
Returns the content of the parameters as a string.
to_unsafe_h() Link
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"}
transform_keys(&block) Link
Returns a new ActionController::Parameters
instance with the results of running block
once for every key. The values are unchanged.
transform_keys!(&block) Link
Performs keys transformation and returns the altered ActionController::Parameters
instance.
transform_values() Link
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>
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 762 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
transform_values!() Link
Performs values transformation and returns the altered ActionController::Parameters
instance.
values() Link
Returns a new array of the values of the parameters.
values_at(*keys) Link
Returns values that were assigned to the given keys
. Note that all the Hash
objects will be converted to ActionController::Parameters
.