Module: ActiveModel::Dirty
- Extended by:
- ActiveSupport::Concern
- Includes:
- AttributeMethods
- Defined in:
- 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. -
Call
changes_applied
after the changes are persisted. -
Call
clear_changes_information
when you want to reset the changes information. -
Call
restore_attributes
when you want to restore previous data.
A minimal implementation could be:
class Person
include ActiveModel::Dirty
define_attribute_methods :name
def initialize(name)
@name = name
end
def name
@name
end
def name=(val)
name_will_change! unless val == @name
@name = val
end
def save
# do persistence work
changes_applied
end
def reload!
# get the values from the persistence layer
clear_changes_information
end
def rollback!
restore_attributes
end
end
A newly instantiated Person
object is unchanged:
person = Person.new("Uncle Bob")
person.changed? # => false
Change the name:
person.name = 'Bob'
person.changed? # => true
person.name_changed? # => true
person.name_changed?(from: "Uncle Bob", to: "Bob") # => 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
Reset the changes:
person.previous_changes # => {"name" => ["Uncle Bob", "Bill"]}
person.reload!
person.previous_changes # => {}
Rollback the changes:
person.name = "Uncle Bob"
person.rollback!
person.name # => "Bill"
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 Active Model can’t track changes to in-place attributes. Note that Active Record can detect in-place modifications automatically. You do not need to call [attribute_name]_will_change!
on Active Record models.
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, options = {}) ⇒ 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
(also: #attributes_changed_by_setter)
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.
-
#restore_attributes(attributes = changed) ⇒ Object
Restore all previous data of the provided attributes.
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, options = {}) ⇒ Boolean
Handle *_changed?
for method_missing
.
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# File 'lib/active_model/dirty.rb', line 176 def attribute_changed?(attr, = {}) #:nodoc: result = changes_include?(attr) result &&= [:to] == __send__(attr) if .key?(:to) result &&= [:from] == changed_attributes[attr] if .key?(:from) result end |
#attribute_was(attr) ⇒ Object
Handle *_was
for method_missing
.
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# File 'lib/active_model/dirty.rb', line 184 def attribute_was(attr) # :nodoc: 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 'lib/active_model/dirty.rb', line 141 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 'lib/active_model/dirty.rb', line 132 def changed? changed_attributes.present? end |
#changed_attributes ⇒ Object Also known as: attributes_changed_by_setter
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 'lib/active_model/dirty.rb', line 171 def changed_attributes @changed_attributes ||= ActiveSupport::HashWithIndifferentAccess.new 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 'lib/active_model/dirty.rb', line 151 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 'lib/active_model/dirty.rb', line 161 def previous_changes @previously_changed ||= ActiveSupport::HashWithIndifferentAccess.new end |
#restore_attributes(attributes = changed) ⇒ Object
Restore all previous data of the provided attributes.
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# File 'lib/active_model/dirty.rb', line 189 def restore_attributes(attributes = changed) attributes.each { |attr| restore_attribute! attr } end |