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Class: ActiveModel::Type::ImmutableString

Overview

Active Model ImmutableString Type

::ActiveModel::Attribute type to represent immutable strings. It casts incoming values to frozen strings.

class Person
  include ActiveModel::Attributes

  attribute :name, :immutable_string
end

person = Person.new
person.name = 1

person.name # => "1"
person.name.frozen? # => true

Values are coerced to strings using their to_s method. Boolean values are treated differently, however: true will be cast to "t" and false will be cast to "f". These strings can be customized when declaring an attribute:

class Person
  include ActiveModel::Attributes

  attribute :active, :immutable_string, true: "aye", false: "nay"
end

person = Person.new
person.active = true

person.active # => "aye"

Class Method Summary

Value - Inherited

.new

Initializes a type with three basic configuration settings: precision, limit, and scale.

Instance Attribute Summary

Value - Inherited

#limit, #precision, #scale,
#binary?

These predicates are not documented, as I need to look further into their use, and see if they can be removed entirely.
#mutable?, #serialized?

Instance Method Summary

Value - Inherited

#==, #as_json, #assert_valid_value,
#cast

::ActiveModel::Type casts a value from user input (e.g. from a setter).
#changed?

Determines whether a value has changed for dirty checking.
#changed_in_place?

Determines whether the mutable value has been modified since it was read.
#deserialize

Converts a value from database input to the appropriate ruby type.
#eql?

Alias for Value#==.
#hash,
#serializable?

Returns true if this type can convert value to a type that is usable by the database.
#serialize

Casts a value from the ruby type to a type that the database knows how to understand.
#type

Returns the unique type name as a ::Symbol.
#cast_value

Convenience method for types which do not need separate type casting behavior for user and database inputs.
#force_equality?, #map,
#type_cast_for_schema

::ActiveModel::Type casts a value for schema dumping.
#value_constructed_by_mass_assignment?

SerializeCastValue - Included

#initialize, #itself_if_serialize_cast_value_compatible

Constructor Details

.new(**args) ⇒ ImmutableString

[ GitHub ] 

  


# File 'activemodel/lib/active_model/type/immutable_string.rb', line 38



def initialize(**args)
  @true  = -(args.delete(:true)&.to_s  || "t")
  @false = -(args.delete(:false)&.to_s || "f")
  super
end


  







Instance Method Details



  

    #cast_value(value)   (private)
  

  [ GitHub ]


  

  


# File 'activemodel/lib/active_model/type/immutable_string.rb', line 62



def cast_value(value)
  case value
  when true then @true
  when false then @false
  else value.to_s.freeze
  end
end


  








  

    #serialize(value)  
  

  [ GitHub ]


  

  


# File 'activemodel/lib/active_model/type/immutable_string.rb', line 48



def serialize(value)
  case value
  when ::Numeric, ::Symbol, ActiveSupport::Duration then value.to_s
  when true then @true
  when false then @false
  else super
  end
end


  








  

    #serialize_cast_value(value)  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'activemodel/lib/active_model/type/immutable_string.rb', line 57



def serialize_cast_value(value) # :nodoc:
  value
end


  








  

    #type  
  

  [ GitHub ]


  

  


# File 'activemodel/lib/active_model/type/immutable_string.rb', line 44



def type
  :string
end