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 # => {"name"=>"Francesco", "age"=>22}
permitted.class # => ActionController::Parameters
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
- 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.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"
- #
- C
- D
- E
- F
- I
- K
- M
- N
- P
- R
- S
- T
- V
PERMITTED_SCALAR_TYPES | = | [ String, Symbol, NilClass, Numeric, TrueClass, FalseClass, Date, Time, # DateTimes are Dates, we document the type but avoid the redundant check. StringIO, IO, ActionDispatch::Http::UploadedFile, Rack::Test::UploadedFile, ] |
This is a white list of permitted scalar types that includes the ones supported in XML and JSON requests. This list is in particular used to filter ordinary requests, String goes as first element to quickly short-circuit the common case. If you modify this collection please update the API
of |
||
EMPTY_ARRAY | = | [] |
[R] | 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">
Returns true if another Parameters
object contains the same
content and permitted flag.
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 148 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 a parameter for the given key
. If not found, returns
nil
.
params = ActionController::Parameters.new(person: { name: 'Francesco' })
params[:person] # => {"name"=>"Francesco"}
params[:none] # => nil
Assigns a value to a given key
. The given key may still get
filtered out when permit
is called.
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.
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.
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
Returns an exact copy of the ActionController::Parameters
instance. permitted
state is kept on the duped object.
params = ActionController::Parameters.new(a: 1)
params.permit!
params.permitted? # => true
copy_params = params.dup # => {"a"=>1}
copy_params.permitted? # => true
Convert all hashes in values into parameters, then yield each pair in the
same way as Hash#each_pair
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) # => {"c"=>3}
params.except(:d) # => {"a"=>1,"b"=>2,"c"=>3}
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) # => {"a"=>1, "b"=>2}
params # => {"c"=>3}
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) # => {"name"=>"Francesco"}
params.fetch(:none) # => ActionController::ParameterMissing: param is missing or the value is empty: none
params.fetch(:none, 'Francesco') # => "Francesco"
params.fetch(:none) { 'Francesco' } # => "Francesco"
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 607 def method_missing(method_sym, *args, &block) if @parameters.respond_to?(method_sym) message = " 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 ".squish ActiveSupport::Deprecation.warn(message) @parameters.public_send(method_sym, *args, &block) else super end 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)
# => {}
params.require(:person).permit(contact: :phone)
# => {"contact"=>{"phone"=>"555-1234"}}
params.require(:person).permit(contact: [ :email, :phone ])
# => {"contact"=>{"email"=>"none@test.com", "phone"=>"555-1234"}}
# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 384 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
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">
Returns true
if the parameter is permitted, false
otherwise.
params = ActionController::Parameters.new
params.permitted? # => false
params.permit!
params.permitted? # => true
Returns a new instance of ActionController::Parameters
with
items that the block evaluates to true removed.
Removes items that the block evaluates to true and returns self.
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)
# => {"name"=>"Francesco"}
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.
Returns a new instance of ActionController::Parameters
with
only items that the block evaluates to true.
Equivalent to Hash#keep_if, but returns nil if no changes were made.
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) # => {"a"=>1, "b"=>2}
params.slice(:d) # => {}
Returns current ActionController::Parameters
instance which
contains only the given keys
.
Returns a safe ActiveSupport::HashWithIndifferentAccess
representation of this parameter with all unpermitted keys removed.
params = ActionController::Parameters.new({
name: 'Senjougahara Hitagi',
oddity: 'Heavy stone crab'
})
params.to_h # => {}
safe_params = params.permit(:name)
safe_params.to_h # => {"name"=>"Senjougahara Hitagi"}
Returns an unsafe, unfiltered
ActiveSupport::HashWithIndifferentAccess
representation of
this parameter.
params = ActionController::Parameters.new({
name: 'Senjougahara Hitagi',
oddity: 'Heavy stone crab'
})
params.to_unsafe_h
# => {"name"=>"Senjougahara Hitagi", "oddity" => "Heavy stone crab"}
Returns a new ActionController::Parameters
instance with the
results of running block
once for every key. The values are
unchanged.
Performs keys transformation and returns the altered
ActionController::Parameters
instance.
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 }
# => {"a"=>2, "b"=>4, "c"=>6}
Performs values transformation and returns the altered
ActionController::Parameters
instance.
Returns values that were assigned to the given keys
. Note that
all the Hash
objects will be converted to
ActionController::Parameters
.