Soft Deletable Base

Provides mechanism for soft delete functionality when a model inherits from this class. Soft delete means that on delete, an object is flagged as deleted rather than being removed from the database. This makes it far easier to recover objects that have been deleted by mistake.

Requirements

This plugin is designed for Rails 3. The syntax of the scope options will not work with Rails 2.

The model object needs to have a 'deleted_at' datetime field, that on delete will be set to the current time.

Usage

Change the class definition so that the class inherits from SoftDeletableBase rather than ActiveRecord::Base. So

class Thing < ActiveRecord::Base

will become

class Thing < SoftDeletableBase

Functionality

Adds 'extant' and 'deleted' scopes to the model. For example, if added to a Thing model, would allow you to do the following:

 thing.soft_delete   ---- Soft deletes an instance of thing

 Thing.extant        ---- Finds all things that are not deleted
 Thing.deleted.count ---- Counts how many things have been deleted

 Thing.extant.find(
   :all,
   :conditions => ["colour = ?", 'red']
 )                   ---- Finds all extant things that have colour set as red

 Thing.extant.where(:colour => 'red')      ---- As above using where

Also if Box has_many things

 box.things.deleted ---- Finds all the deleted things in the box

Note that Thing's delete instance method is not effected by this functionality so:

thing.soft_delete  --- alters the thing instance to be flagged as deleted
thing.delete       --- deletes the thing from the database.

If you want delete actions to soft_delete, overwrite delete:

class Thing < SoftDeletableBase

def delete
  soft_delete
end

end

Copyright (c) 2010 Rob Nichols, released under the MIT license