Undo

Undo reverts operation made upon object.
It stores the object state before the mutator operation and allows to restore this state later.

Undo uses adapters for storage (Redis, ActiveRecord, etc) and custom serializers (ActiveRecord, Virtus, etc). It is very lightweight solution that can be used as well with heavy ActiveRecord as with simple Hash or Virtus objects. No database required: store data as it suites you.

Installation
Requirements
Usage
1. Undo operation
2. Configuration options
3. In place configuration
Contacts
Compatibility
Contributing
Copyright

Installation

Add this line to your application's Gemfile:

gem 'undo'

And then execute:

$ bundle

Or install it yourself as:

$ gem install undo

Requirements

Ruby 1.9 or above
gem virtus ~> 1.0

Usage

Undo operation

uuid = Undo.store object
Undo.restore uuid

That is basically it :)

Additionally possible to wrap object in Undo decorator:

decorated_object = Undo.wrap object
Undo.restore decorated_object.uuid

Use decorated_object as usual afterwards. Undo gem will store object state on each hit to mutator methods. By default mutator_methods are update, delete, destroy. Those methods can be changed either in place or using global configuration (see below).

To use something more advanced rather plain memory storage and pass through serializer, configure the Undo:

Undo.configure do |config|
  config.storage = Undo::Storage::RailsCache.new
  config.serializer = Undo::Serializer::ActiveModel.new
end

gem undo-storage-rails_cache and gem undo-serializer-active_model are required for this.
There are a bunch of other Rails free adapters. Read about them in configuration chapter below.

UUID

By default uuids are generated by SecureRandom.uuid. The generator is managed by uuid_generator setting (see below in configuration chapter).

UUID can be provided to both #wrap and #store methods and it will be used instead of generated one:

uuid = "uniq identifier"

Undo.store object, uuid: uuid
Undo.restore uuid

If object respond to #uuid method then it value will be used instead:

object = OpenStruct.new uuid: "uniq identifier"
Undo.store object # => uniq identifier
Undo.restore "uniq identifier"

Configuration options

storage option responsible for putting and fetching object state to or from some storage.
Implement put(uuid, object) and fetch(uuid) methods.
Currently available storages:

Undo::Storage::Memory simple runtime storage (Hash)
gem "undo-storage-rails_cache" designed for Rails, but can be used with any ducktype cache store
gem "undo-storage-redis" designed to be used with gem "redis" from v0.1 to current

See also documentation on project repository for full list of currently available storage adapters.

To convert objects to data that can be processed by storage adapters and backward, use serializers:

Undo.configure do |config|
  config.serializer = CustomSerializer.new
end

Currently available serializers:

Undo::Serializer::Null pass though serializer. It do nothing and returns whatever passed to it.
gem undo-serializer-active_model depends on #attributes method so can be used with Virtus and PORO objects as well as with ActiveRecord objects.

Check documentation on project repository for currently available serializers.

uuid_generator option allows to setup custom uuid generator.

By default it is using SecureRandom.uuid.
To define custom uuid generator use uuid_generator option:

Undo.configure do |config|
  config.uuid_generator = ->(object) { "#{object.class.name}_#{object.id}" }
end

mutator methods option defines a list of methods that will trigger storage#put By default mutator_methods are update, delete, destroy.
To append custom mutator_methods use

Undo.configure do |config|
  config.mutator_methods += [:put, :push, :pop]
end

In place configuration

Any configuration option from previous chapter can be applied in place for given operation. To restore object from another storage use storage option:

Undo.restore uuid, storage: AnotherStorage.new

To wrap an object using custom mutator_methods use mutator_methods option:

Undo.wrap object, mutator_methods: [:save]

To use custom serializer or deserializer use serializer option:

Undo.wrap post, serializer: PostSerializer.new(post)
post.destroy
Undo.restore uuid, serializer: PostDeserializer.new(options)

Additionally when given serializer accepts additional options to #serialize or #deserialize, those options can be set in place as well:

Undo.store post, include: :comments

Contacts

Have questions or recommendations? Contact me via [email protected] Found a bug or have enhancement request? You are welcome at Github bugtracker

Compatibility

tested with Ruby

2.1
2.0
1.9.3
ruby-head
rbx
jruby-19mode
jruby-head

See build history

Contributing

Fork repository ( http://github.com/AlexParamonov/undo/fork )
Create your feature branch (git checkout -b my-new-feature)
Commit your changes (git commit -am 'Add some feature')
Push to the branch (git push origin my-new-feature)
Create new Pull Request