[Awesome Ruby Gem] Use paranoia or acts_as_paranoid gem soft delete to hide and restore records without actually deleting them

Posted on 2020-09-05 Edited on 2023-09-02 In Programming Language , Ruby , Awesome Ruby Gem Views: Word count in article: 3k Reading time ≈ 3 mins.

paranoia or acts_as_paranoid

paranoia is a re-implementation of acts_as_paranoid for Rails 3/4/5, using much, much, much less code.

When your app is using Paranoia, calling destroy on an ActiveRecord object doesn’t actually destroy the database record, but just hides it. Paranoia does this by setting a deleted_at field to the current time when you destroy a record, and hides it by scoping all queries on your model to only include records which do not have a deleted_at field.

Use paranoia gem according to the RubyGem latest update:

	GitHub latest update	RubyGem latest update	Comments
paranoia	Now	2.4.3 - December 16, 2020	Paranoia will continue to accept bug fixes and support new versions of Rails but isn’t accepting new features.
acts_as_paranoid	Now	0.7.0 - August 29, 2020

Installation

You can install it as a gem:

1 2	$ gem install paranoia # OR gem install acts_as_paranoid

or add it into a Gemfile (Bundler):

# Gemfile

# rubysherpas/paranoia: acts_as_paranoid for Rails 3, 4 and 5
# https://github.com/rubysherpas/paranoia
gem 'paranoia', '2.4.3'

# Or use acts_as_paranoid
# ActsAsParanoid/acts_as_paranoid: ActiveRecord plugin allowing you to hide and restore records without actually deleting them.
# https://github.com/ActsAsParanoid/acts_as_paranoid
# gem 'acts_as_paranoid', '0.7.0'

Then, run bundle install.

1	$ bundle install

Migration

Create migration,

$ bin/rails generate migration AddDeletedAtToUsers deleted_at:datetime:index
Running via Spring preloader in process 2946
      invoke  active_record
      create    db/migrate/20200811215130_add_deleted_at_to_users.rb

Show the migration 20200811215130_add_deleted_at_to_users.rb.

class AddDeletedAtToUsers < ActiveRecord::Migration
  def change
    add_column :users, :deleted_at, :datetime
    add_index :users, :deleted_at
  end
end

Run db migrate.

1	$ bin/rails db:migrate

Usage

Enable ActsAsParanoid.

class User < ActiveRecord::Base
  acts_as_paranoid
end

# or inherit from ApplicationRecord
# class ApplicationRecord < ActiveRecord::Base
#   self.abstract_class = true
# 
#   acts_as_paranoid
# end

# class User < ApplicationRecord
# end

Magic Column

By default, ActsAsParanoid assumes a record’s deletion is stored in a datetime column called deleted_at.

Filtering

If a record is deleted by ActsAsParanoid, it won’t be retrieved when accessing the database.
So, Paranoiac.all will not include the deleted records.

When you want to access them, you have 2 choices:

1 2	User.only_deleted # retrieves only the deleted records User.with_deleted # retrieves all records, deleted or not

Caveats

Watch out for these caveats:

You cannot use scopes named with_deleted and only_deleted
You cannot use scopes named deleted_inside_time_window, deleted_before_time,
deleted_after_time if your paranoid column’s type is time
You cannot name association *_with_deleted
unscoped will return all records, deleted or not