Dandy

Dandy is a minimalistic web API framework. Its main idea is to implement an approach from Clean Architecture principles - "web is just a delivery mechanism". Dandy is build on top of IoC container Hypo and forces to use dependency injection approach everywhere.

1. Dependency Injection is a heart of Dandy. Atomic actions can depend on request parameters, services, repositories, output of other actions and other stuff. You can easily inject such dependencies in your actions through a constructor. Dependency Injection significantly improves development experience: isolate your components, enjoy writing unit tests.

class LoadPost
  def initialize(id, post_storage)
    @id = id
    @storage = post_storage
  end
  
  def call
    @storage.find(@id)
  end
end

2. Instead of boring Ruby block-style routes definition like in Rails, Sinatra and others Dandy uses its own language for that. Small example:

:receive
    .->
        :before -> user@load_current_user          
        /posts ->
            $id ->
                :before -> load_post
                /comments ->
                    POST -> add_comment -> notify_author \
                         -> notify_subscribers -> :respond <- comment_test =201
:catch -> handle_errors

3. The combination of flexible router and dependency injection breaks existing dogmas. Dandy framework introduces Abstract Chain pattern as a replacement for Model-View-Controller and other ancient approaches. Every request handles by a set of atomic actions.

    # POST /posts/$id/comments
    ... -> load_post -> add_comment -> ... 

class LoadPost
  def initialize(id, post_storage)
    @id = id
    @storage = post_storage
  end
  
  def call
    @storage.find(@id)
  end
  
  def result_name
    'post'
  end 
end

class AddComment
  def initialize(post, dandy_data, user, comment_storage)
    @post = post
    @data = dandy_data
    @user = user
    @storage = comment_storage 
  end
  
  def call
    @storage.create(post: @post, message: @data[:message], user: @user)
  end  
end

4. Dandy is a micro-framework for micro-services. It's not intended to create monolithic giants! In terms of Domain Driven Design concepts one Dandy application should wrap only one Bounded Context.

1. Install Dandy:

    $ gem install dandy

2. At the command prompt, create a new Dandy application:

    $ dandy new dandy-app

3. Go to directory dandy-app and start the application using a server you prefer:

    $ puma -p 8000 config.ru

or just

    $ rackup -p 8000 config.ru

4. Run curl command curl http://localhost:8000 -H "Accept: application/json" and you'll see:

  {"message": "Welcome to dandy-app!"}

Please take attention - HTTP header "Accept: application/json" is a mandatory.

5. Investigate example application code, it explains most of Dandy aspects.
6. For more details visit our Wiki.

Usual, but always helpful steps:

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment. To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/cylon-v/dandy.

The gem is available as open source under the terms of the MIT License.