Paranoia

Paranoia is a re-implementation of acts_as_paranoid for Rails 3, using much, much, much less code.

You would use either plugin / gem if you wished that when you called destroy on an Active Record object that it didn't actually destroy it, but just hide the record. 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.

If you wish to actually destroy an object you may call really_destroy!. WARNING: This will also really destroy all dependent: destroy records, so please aim this method away from face when using.**

If a record has has_many associations defined AND those associations have dependent: :destroy set on them, then they will also be soft-deleted if acts_as_paranoid is set, otherwise the normal destroy will be called.

Installation & Usage

For Rails 3, please use version 1 of Paranoia:

gem "paranoia", "~> 1.0"

For Rails 4, please use version 2 of Paranoia:

gem "paranoia", "~> 2.0"

Of course you can install this from GitHub as well:

gem "paranoia", :github => "radar/paranoia", :branch => "master"
# or
gem "paranoia", :github => "radar/paranoia", :branch => "rails4"

Then run:

bundle install

Updating is as simple as bundle update paranoia.

Run your migrations for the desired models

Run:

rails generate migration AddDeletedAtToClients deleted_at:datetime:index

and now you have a migration

class AddDeletedAtToClients < ActiveRecord::Migration
  def change
    add_column :clients, :deleted_at, :datetime
    add_index :clients, :deleted_at
  end
end

Usage

In your model:

class Client < ActiveRecord::Base
  acts_as_paranoid

  # ...
end

Hey presto, it's there! Calling destroy will now set the deleted_at column:

>> client.deleted_at
# => nil
>> client.destroy
# => client
>> client.deleted_at
# => [current timestamp]

If you really want it gone gone, call really_destroy!:

>> client.deleted_at
# => nil
>> client.really_destroy!
# => client

If you want a method to be called on destroy, simply provide a before_destroy callback:

class Client < ActiveRecord::Base
  acts_as_paranoid

  before_destroy :some_method

  def some_method
    # do stuff
  end

  # ...
end

If you want to use a column other than deleted_at, you can pass it as an option:

class Client < ActiveRecord::Base
  acts_as_paranoid column: :destroyed_at

  ...
end

If you want to access soft-deleted associations, override the getter method:

def product
  Product.unscoped { super }
end

If you want to find all records, even those which are deleted:

Client.with_deleted

If you want to find only the deleted records:

Client.only_deleted

If you want to check if a record is soft-deleted:

client.destroyed?

If you want to restore a record:

Client.restore(id)

If you want to restore a whole bunch of records:

Client.restore([id1, id2, ..., idN])

If you want to restore a record and their dependently destroyed associated records:

Client.restore(id, :recursive => true)

If you want callbacks to trigger before a restore:

before_restore :callback_name_goes_here

For more information, please look at the tests.

Acts As Paranoid Migration

You can replace the older acts_as_paranoid methods as follows:

Old Syntax	New Syntax
find_with_deleted(:all)	Client.with_deleted
find_with_deleted(:first)	Client.with_deleted.first
find_with_deleted(id)	Client.with_deleted.find(id)

Support for Unique Keys with Null Values

With most databases, a unique key containing a null value will not be enforced because the null value is unique per row.

class AddDeletedAtToClients < ActiveRecord::Migration
  def change
    add_column :clients, :deleted_at, :datetime
    add_index :clients, [:username, :deleted_at], unique: true
  end
end

Given the migration above, you could have multiple users with username bob given the following inserts: ('bob', null), ('bob', null), ('bob', null). We can agree this is not the expected behavior.

To avoid this problem, we could use a flag column instead of a datetime, but the datetime value has intrinsic usefulness. Instead, we can add a second column for the unique key that always has a value, in this case 0 or 1:

class AddDeletedAtToClients < ActiveRecord::Migration
  def change
    add_column :clients, :deleted_at, :datetime
    add_column :clients, :is_deleted, :boolean, null: false, default: 0
    add_index :clients, [:username, :is_deleted], unique: true
  end
end

Support this new column by updating your model as such:

class Client < ActiveRecord::Base
  acts_as_paranoid :flag_column => :is_deleted
  ...
end

If you create an index on the flag column, and you want paranoia to use that index instead of deleted_at, you can add :index_column => :is_deleted to the acts_as_paranoid definition.

License

This gem is released under the MIT license.