An implementation of the command pattern for Ruby

• Context validation

• Callbacks

  Context:

  • before_validation
  • after_validation

  Services:

  • before_perform
  • around_perform
  • after_perform

• Transations By default transactions are disabled, but you can include the following in your ApplicationService

  transactional true

  In case transactions are enabled after_commit will triger after after_peform

• Asynchronous execution Instead of calling perform you can use perform_later to execute a service asynchronously, this uses ActiveJob.

Add this line to your application's Gemfile:

gem 'servitium'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install servitium

You define a context for the service, which describes what goes in and out

class ExampleContext < ApplicationContext
  attribute :some, type: String, default: "new"

  validates :some, presence: true
end

You can be very explicit in what goes in our out:

class ExampleContext < ApplicationContext
  input do
    attribute :some, type: String, default: "new"
    validates :some, presence: true
  end
  output do
    attribute :some, type: String, default: "new"
  end
end

And you define the service itself:

class ExampleService < ApplicationService
  def perform
    context.some.reverse!
  end
end

You can also include the context in the service, for less complicated services:

class ExampleService < ApplicationService
  context do
    attribute :some, type: :string, default: "new"
  end
  def perform
    context.some.reverse!
  end
end

Next you use it as follows:

ExampleService.perform(some: 'test').some # => tset

A service always returns it context

Services can also run in the background:

ExampleService.perform_later(some: 'test') # => #<ExampleContext>

You can use the generator to generate service code:

❯ rails g servitium:service Example

      create  app/services/example_service.rb
      create  app/services/example_context.rb
      create  test/services/example_service_test.rb

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

Everyone interacting in the Servitium project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.