rails3_acts_as_paranoid-bjones

ActsAsParanoid

A simple plugin which hides records instead of deleting them, being able to recover them.

This branch targets Rails 3.2. If you're working with another version, switch to the corresponding branch.

Credits

This plugin was inspired by acts_as_paranoid and acts_as_active.

While porting it to Rails 3, I decided to apply the ideas behind those plugins to an unified solution while removing a lot of the complexity found in them. I eventually ended up writing a new plugin from scratch.

Usage

You can enable ActsAsParanoid like this:

class Paranoiac < ActiveRecord::Base
  acts_as_paranoid
end

Options

You can also specify the name of the column to store it's deletion and the type of data it holds:

• :column => 'deleted_at'
• :column_type => 'time'

The values shown are the defaults. While column can be anything (as long as it exists in your database), type is restricted to:

• boolean
• time or
• string

If your column type is a string, you can also specify which value to use when marking an object as deleted by passing :deleted_value (default is "deleted").

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. if you want to access them, you have 2 choices:

Paranoiac.only_deleted # retrieves the deleted records
Paranoiac.with_deleted # retrieves all records, deleted or not

When using the default column_type of 'time', the following extra scopes are provided:

time = Time.now

Paranoiac.deleted_after_time(time)
Paranoiac.deleted_before_time(time)

# Or roll it all up and get a nice window:
Paranoiac.deleted_inside_time_window(time, 2.minutes)

Real deletion

In order to really delete a record, just use:

paranoiac.destroy!
Paranoiac.delete_all!(conditions)

You can also permanently delete a record by calling destroy or delete_all on it twice. If a record was already deleted (hidden by ActsAsParanoid) and you delete it again, it will be removed from the database. Take this example:

p = Paranoiac.first
p.destroy # does NOT delete the first record, just hides it
Paranoiac.only_deleted.where(:id => p.id).destroy # deletes the first record from the database

Recovery

Recovery is easy. Just invoke recover on it, like this:

Paranoiac.only_deleted.where("name = ?", "not dead yet").first.recover

All associations marked as :dependent => :destroy are also recursively recovered. If you would like to disable this behavior, you can call recover with the recursive option:

Paranoiac.only_deleted.where("name = ?", "not dead yet").first.recover(:recursive => false)

If you would like to change this default behavior for one model, you can use the recover_dependent_associations option

class Paranoiac < ActiveRecord::Base
    acts_as_paranoid :recover_dependent_associations => false
end

By default, dependent records will be recovered if they were deleted within 2 minutes of the object upon which they depend. This restores the objects to the state before the recursive deletion without restoring other objects that were deleted earlier. The behavior is only available when both parent and dependant are using timestamp fields to mark deletion, which is the default behavior. This window can be changed with the dependent_recovery_window option:

class Paranoiac < ActiveRecord::Base
    acts_as_paranoid
    has_many :paranoids, :dependent => :destroy
end

class Paranoid < ActiveRecord::Base
    belongs_to :paranoic

    # Paranoid objects will be recovered alongside Paranoic objects 
    # if they were deleted within 10 minutes of the Paranoic object
    acts_as_paranoid :dependent_recovery_window => 10.minutes
end

or in the recover statement

Paranoiac.only_deleted.where("name = ?", "not dead yet").first.recover(:recovery_window => 30.seconds)

Validation

ActiveRecord's built-in uniqueness validation does not account for records deleted by ActsAsParanoid. If you want to check for uniqueness among non-deleted records only, use the macro validates_as_paranoid in your model. Then, instead of using validates_uniqueness_of, use validates_uniqueness_of_without_deleted. This will keep deleted records from counting against the uniqueness check.

class Paranoiac < ActiveRecord::Base
    acts_as_paranoid
  	validates_as_paranoid
  	validates_uniqueness_of_without_deleted :name
end
  
p1 = Paranoiac.create(:name => 'foo')
p1.destroy
    
p2 = Paranoiac.new(:name => 'foo') 
p2.valid? #=> true
p2.save
 
p1.recover #=> fails validation!

Status

You can check the status of your paranoid objects with the deleted? helper

Paranoiac.create(:name => 'foo').destroy
Paranoiac.with_deleted.first.deleted? #=> true

Scopes

As you've probably guessed, with_deleted and only_deleted are scopes. You can, however, chain them freely with other scopes you might have. This

Paranoiac.pretty.with_deleted

is exactly the same as

Paranoiac.with_deleted.pretty

You can work freely with scopes and it will just work:

class Paranoiac < ActiveRecord::Base
	acts_as_paranoid
	scope :pretty, where(:pretty => true)
end
	
Paranoiac.create(:pretty => true)
	
Paranoiac.pretty.count #=> 1
Paranoiac.only_deleted.count #=> 0
Paranoiac.pretty.only_deleted.count #=> 0
	
Paranoiac.first.destroy
	
Paranoiac.pretty.count #=> 0
Paranoiac.only_deleted.count #=> 1
Paranoiac.pretty.only_deleted.count #=> 1

Associations

Associations are also supported. From the simplest behaviors you'd expect to more nifty things like the ones mentioned previously or the usage of the :with_deleted option with belongs_to

class ParanoiacParent < ActiveRecord::Base
	has_many :children, :class_name => "ParanoiacChild"
end
	
class ParanoiacChild < ActiveRecord::Base
	belongs_to :parent, :class_name => "ParanoiacParent"
	belongs_to :parent_with_deleted, :class_name => "ParanoiacParent", :with_deleted => true
end
	
parent = ParanoiacParent.first 	
child = parent.children.create
parent.destroy
     
child.parent #=> nil
child.parent_with_deleted #=> ParanoiacParent (it works!)

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
• unscoped will return all records, deleted or not

Support

This gem supports the most recent versions of Rails and Ruby.

Rails

For Rails 3.2 check the README at the rails3.2 branch and add this to your Gemfile:

gem "rails3_acts_as_paranoid", "~>0.2.0"

For Rails 3.1 check the README at the rails3.1 branch and add this to your Gemfile:

gem "rails3_acts_as_paranoid", "~>0.1.4"

For Rails 3.0 check the README at the rails3.0 branch and add this to your Gemfile:

gem "rails3_acts_as_paranoid", "~>0.0.9"

Ruby

This gem is tested on Ruby 1.9, JRuby and Rubinius (both in 1.9 mode). It might work fine in 1.8, but it's not officially supported.

Acknowledgements

• To cheerfulstoic for adding recursive recovery
• To Jonathan Vaught for adding paranoid validations
• To Geoffrey Hichborn for improving the overral code quality and adding support for after_commit
• To flah00 for adding support for STI-based associations (with :dependent)
• To vikramdhillon for the idea and initial implementation of support for string column type
• To Craig Walker for Rails 3.1 support and fixing various pending issues
• To Charles G. for Rails 3.2 support and for making a desperately needed global code refactoring

Copyright © 2010 Gonçalo Silva, released under the MIT license