Module: ActiveModel::Dirty
- Extended by:
- ActiveSupport::Concern
- Includes:
- AttributeMethods
- Included in:
- ActiveRecord::AttributeMethods::Dirty
- Defined in:
- activemodel/lib/active_model/dirty.rb
Overview
Active Model Dirty
Provides a way to track changes in your object in the same way as Active Record does.
The requirements for implementing ActiveModel::Dirty are:
-
include ActiveModel::Dirty
in your object. -
Call
define_attribute_methods
passing each method you want to track. -
Call
attr_name_will_change!
before each change to the tracked attribute.
If you wish to also track previous changes on save or update, you need to add:
@previously_changed = changes
inside of your save or update method.
A minimal implementation could be:
class Person
include ActiveModel::Dirty
define_attribute_methods :name
def name
@name
end
def name=(val)
name_will_change! unless val == @name
@name = val
end
def save
@previously_changed = changes
@changed_attributes.clear
end
end
A newly instantiated object is unchanged:
person = Person.find_by(name: 'Uncle Bob')
person.changed? # => false
Change the name:
person.name = 'Bob'
person.changed? # => true
person.name_changed? # => true
person.name_was # => "Uncle Bob"
person.name_change # => ["Uncle Bob", "Bob"]
person.name = 'Bill'
person.name_change # => ["Uncle Bob", "Bill"]
Save the changes:
person.save
person.changed? # => false
person.name_changed? # => false
Assigning the same value leaves the attribute unchanged:
person.name = 'Bill'
person.name_changed? # => false
person.name_change # => nil
Which attributes have changed?
person.name = 'Bob'
person.changed # => ["name"]
person.changes # => {"name" => ["Bill", "Bob"]}
If an attribute is modified in-place then make use of [attribute_name]_will_change!
to mark that the attribute is changing. Otherwise ActiveModel can’t track changes to in-place attributes.
person.name_will_change!
person.name_change # => ["Bill", "Bill"]
person.name << 'y'
person.name_change # => ["Bill", "Billy"]
Constant Summary
Constants included from AttributeMethods
AttributeMethods::CALL_COMPILABLE_REGEXP, AttributeMethods::NAME_COMPILABLE_REGEXP
Instance Method Summary collapse
-
#attribute_changed?(attr) ⇒ Boolean
Handle
*_changed?
formethod_missing
. -
#attribute_was(attr) ⇒ Object
Handle
*_was
formethod_missing
. -
#changed ⇒ Object
Returns an array with the name of the attributes with unsaved changes.
-
#changed? ⇒ Boolean
Returns
true
if any attribute have unsaved changes,false
otherwise. -
#changed_attributes ⇒ Object
Returns a hash of the attributes with unsaved changes indicating their original values like
attr => original value
. -
#changes ⇒ Object
Returns a hash of changed attributes indicating their original and new values like
attr => [original value, new value]
. -
#previous_changes ⇒ Object
Returns a hash of attributes that were changed before the model was saved.
Methods included from ActiveSupport::Concern
append_features, extended, included
Methods included from AttributeMethods
#attribute_missing, #method_missing, #respond_to?, #respond_to_without_attributes?
Dynamic Method Handling
This class handles dynamic methods through the method_missing method in the class ActiveModel::AttributeMethods
Instance Method Details
#attribute_changed?(attr) ⇒ Boolean
Handle *_changed?
for method_missing
.
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# File 'activemodel/lib/active_model/dirty.rb', line 146 def attribute_changed?(attr) changed_attributes.include?(attr) end |
#attribute_was(attr) ⇒ Object
Handle *_was
for method_missing
.
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# File 'activemodel/lib/active_model/dirty.rb', line 151 def attribute_was(attr) attribute_changed?(attr) ? changed_attributes[attr] : __send__(attr) end |
#changed ⇒ Object
Returns an array with the name of the attributes with unsaved changes.
person.changed # => []
person.name = 'bob'
person.changed # => ["name"]
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# File 'activemodel/lib/active_model/dirty.rb', line 111 def changed changed_attributes.keys end |
#changed? ⇒ Boolean
Returns true
if any attribute have unsaved changes, false
otherwise.
person.changed? # => false
person.name = 'bob'
person.changed? # => true
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# File 'activemodel/lib/active_model/dirty.rb', line 102 def changed? changed_attributes.present? end |
#changed_attributes ⇒ Object
Returns a hash of the attributes with unsaved changes indicating their original values like attr => original value
.
person.name # => "bob"
person.name = 'robert'
person.changed_attributes # => {"name" => "bob"}
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# File 'activemodel/lib/active_model/dirty.rb', line 141 def changed_attributes @changed_attributes ||= {} end |
#changes ⇒ Object
Returns a hash of changed attributes indicating their original and new values like attr => [original value, new value]
.
person.changes # => {}
person.name = 'bob'
person.changes # => { "name" => ["bill", "bob"] }
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# File 'activemodel/lib/active_model/dirty.rb', line 121 def changes ActiveSupport::HashWithIndifferentAccess[changed.map { |attr| [attr, attribute_change(attr)] }] end |
#previous_changes ⇒ Object
Returns a hash of attributes that were changed before the model was saved.
person.name # => "bob"
person.name = 'robert'
person.save
person.previous_changes # => {"name" => ["bob", "robert"]}
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# File 'activemodel/lib/active_model/dirty.rb', line 131 def previous_changes @previously_changed end |