module ActiveModel::Conversion
Active Model Conversion¶ ↑
Handles default conversions: #to_model, #to_key, #to_param, and to_partial_path.
Let's take for example this non-persisted object.
class ContactMessage include ActiveModel::Conversion # ContactMessage are never persisted in the DB def persisted? false end end cm = ContactMessage.new cm.to_model == cm # => true cm.to_key # => nil cm.to_param # => nil cm.to_partial_path # => "contact_messages/contact_message"
Public Instance Methods
Returns an Enumerable of all key attributes if any is set, regardless if
the object is persisted or not. Returns nil
if there are no
key attributes.
class Person < ActiveRecord::Base end person = Person.create person.to_key # => [1]
# File lib/active_model/conversion.rb, line 51 def to_key key = respond_to?(:id) && id key ? [key] : nil end
If your object is already designed to implement all of the Active Model you can use the default :to_model
implementation, which simply returns self
.
class Person include ActiveModel::Conversion end person = Person.new person.to_model == person # => true
If your model does not act like an Active Model
object, then you should define :to_model
yourself returning a
proxy object that wraps your object with Active Model compliant methods.
# File lib/active_model/conversion.rb, line 39 def to_model self end
Returns a string
representing the object's key suitable
for use in URLs, or nil
if persisted?
is
false
.
class Person < ActiveRecord::Base end person = Person.create person.to_param # => "1"
# File lib/active_model/conversion.rb, line 64 def to_param (persisted? && key = to_key) ? key.join('-') : nil end
Returns a string
identifying the path associated with the
object. ActionPack uses this to find a suitable partial to represent the
object.
class Person include ActiveModel::Conversion end person = Person.new person.to_partial_path # => "people/person"
# File lib/active_model/conversion.rb, line 77 def to_partial_path self.class._to_partial_path end