Undo

Undo last operation on object.
Undo gem allows to use custom adapters for storage (Redis, ActiveRecord, etc). And custom serializers when need (ActiveRecord, Virtus, etc)

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

Wrap object in Undo decorator:

Undo.wrap object

And use it as usual afterwards. Undo gem will store object state on each hit to mutator methods.
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

To restore previous version

Undo.restore uuid

uuid is provided by wrapped object:

Undo.wrap(object).uuid

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

Configuration options

storage option responsible for putting and fetching object state to or from some storage.
Implement put(uuid, object) and fetch(uuid) methods. See MemoryAdapter for example.
See also documentation on project repository for currently available storage adapters.
If provided storage cant handle objects (most of the storage works with own formats as json for example), pass serializer to it:

Undo.configure do |config|
  config.storage = AnotherStorage.new(serializer: config.serializer)
end

By default here is very basic Serializer::Simple.
There are no more serializers available now, but check documentation on project repository for currently available serializers.

Serializer is not used by Undo gem directly. It mean to be used in storage adopters to serialize and deserialize data to required format.
Storage adapter may use serializer this way:

json = serializer.to_json object # in put method
return serializer.load_from_json json # in fetch method

xml = serializer.to_xml object
object = serializer.load_from_xml xml

Usage of serializer is optional, some storages does not need them.
Serializer has the responsibility to write object to persistence (load_from_* methods) This seems a good candinate to extraction to own class (Deserializer or Loader) but due to to_* and load_from_* method are tightly coupled with data format it is in one class now. Let me know using the Github feedback (create an issue) if you have any idea on this topic.

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 set 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 only for given operation.
To restore object from another storage use storage option:

Undo.restore uuid, storage: AnotherStorage.new

To wrap an object using custom serializer use serializer option:

Undo.wrap object, serializer: AnotherSerializer.new

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
rbx-19mode
ruby-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