Class: ActiveResource::Coder

Inherits:
Object
  • Object
show all
Defined in:
lib/active_resource/coder.rb

Overview

Integrates with Active Record’s serialize method as the :coder option.

Encodes Active Resource instances into a value to be stored in the database. Decodes values read from the database into Active Resource instances.

class User < ActiveRecord::Base
  serialize :person, coder: ActiveResource::Coder.new(Person)
end

class Person < ActiveResource::Base
  schema do
    attribute :name, :string
  end
end

user = User.new
user.person = Person.new name: "Matz"
user.person.name # => "Matz"

Values are loaded as persisted when decoded from data containing a primary key value, and new records when missing a primary key value:

user.person = Person.new
user.person.persisted? # => true

user.person = Person.find(1)
user.person.persisted? # => true

By default, #dump serializes the instance to a string value by calling Base#encode:

user.person_before_type_cast # => "{\"name\":\"Matz\"}"

To customize serialization, pass the method name or a block as the second argument:

person = Person.new name: "Matz"

coder = ActiveResource::Coder.new(Person, :serializable_hash)
coder.dump(person) # => { "name" => "Matz" }

coder = ActiveResource::Coder.new(Person) { |person| person.serializable_hash }
coder.dump(person) # => { "name" => "Matz" }

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(resource_class, encoder_method = :encode, &block) ⇒ Coder

Returns a new instance of Coder.



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# File 'lib/active_resource/coder.rb', line 53

def initialize(resource_class, encoder_method = :encode, &block)
  @resource_class = resource_class
  @encoder = block || encoder_method
end

Instance Attribute Details

#encoder ⇒ Object

Returns the value of attribute encoder.



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# File 'lib/active_resource/coder.rb', line 51

def encoder
  @encoder
end

#resource_class ⇒ Object

Returns the value of attribute resource_class.



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# File 'lib/active_resource/coder.rb', line 51

def resource_class
  @resource_class
end

Instance Method Details

#dump(value) ⇒ Object

Serializes a resource value to a value that will be stored in the database. Returns nil when passed nil

Raises:

  • (ArgumentError) 


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# File 'lib/active_resource/coder.rb', line 60

def dump(value)
  return if value.nil?
  raise ArgumentError.new("expected value to be #{resource_class}, but was #{value.class}") unless value.is_a?(resource_class)

  value.yield_self(&encoder)
end

#load(value) ⇒ Object

Deserializes a value from the database to a resource instance. Returns nil when passed nil

Raises:

  • (ArgumentError) 


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# File 'lib/active_resource/coder.rb', line 69

def load(value)
  return if value.nil?
  value = resource_class.format.decode(value) if value.is_a?(String)
  raise ArgumentError.new("expected value to be Hash, but was #{value.class}") unless value.is_a?(Hash)
  resource_class.new(value, value[resource_class.primary_key])
end