Created
March 31, 2010 13:46
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ActiveRecord::Dirty memoized
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# Extension of the ActiveRecord's Dirty module to enable | |
# tracking changes even after the record has been saved | |
# (as ActiveRecord's dirty changes are emptied on save). | |
# | |
# User.send :include, DirtyMemento | |
# | |
# user = User.find_by_name 'kares' | |
# | |
# assert ! user.name_changed? | |
# assert ! user.name_previously_changed? | |
# user.name = 'kares7' | |
# assert user.name_changed? | |
# assert ! user.name_previously_changed? | |
# user.save | |
# assert ! user.name_changed? | |
# assert user.name_previously_changed? | |
# | |
module DirtyMemento | |
def self.included(base) | |
base.attribute_method_suffix '_previously_changed?', '_was_previously' | |
base.alias_method_chain :save, :dirty_memento | |
base.alias_method_chain :save!, :dirty_memento | |
base.alias_method_chain :update, :dirty_memento | |
base.alias_method_chain :reload, :dirty_memento | |
end | |
# Do any attributes have unsaved changes? | |
# person.previously_changed? # => false | |
def previously_changed? | |
! previously_changed_attributes.empty? | |
end | |
# List of attributes with unsaved changes. | |
# person.previously_changed # => ['name'] | |
def previously_changed | |
previously_changed_attributes.keys | |
end | |
def save_with_dirty_memento(*args) #:nodoc: | |
set_previously_changed_attributes | |
save_without_dirty_memento(*args) | |
end | |
def save_with_dirty_memento!(*args) #:nodoc: | |
set_previously_changed_attributes | |
save_without_dirty_memento!(*args) | |
end | |
def update_with_dirty_memento(*args) #:nodoc: | |
set_previously_changed_attributes | |
update_without_dirty_memento(*args) | |
end | |
def reload_with_dirty_memento(*args) #:nodoc: | |
set_previously_changed_attributes | |
reload_without_dirty_memento(*args) | |
end | |
private | |
# Map of change attr => original value. | |
def previously_changed_attributes | |
@_previously_changed_attributes ||= {} | |
end | |
def set_previously_changed_attributes | |
@_previously_changed_attributes = changed_attributes.clone | |
end | |
# Handle *_previously_changed? for method_missing. | |
def attribute_previously_changed?(attr) | |
previously_changed_attributes.include?(attr) | |
end | |
# Handle *_was_previously for method_missing. | |
def attribute_was_previously(attr) | |
attribute_previously_changed?(attr) ? previously_changed_attributes[attr] : __send__(attr) | |
end | |
end |
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