Notification/listener solution for ruby

Features

• any number of listners
• only one event of one kind can be fired per request (cache)
• disable/enable events (nice feature for tests)

Configuration for rails

In your Gemfile

gem 'notification_center'

Cache

To enable cache, in your:

config/initializers/notification_center.rb

NotificationCenter.enable_cache = true # only one event fired in one request scope, default is false

Dont forget to flush cache wach request, for this in your config/application.rb in config section:

config.middleware.use NotificationCenter::Cache

Use

In any class or multiple classes:

class SomeClass
  observe :some_event

  def some_event_handler # any number of args are possible
  end
end

Anywhere in code:

NotificationCenter.post_notification :some_event

Common practice

Create directory app/listeners and put listeners there, like user_listener.rb

class UserListener
  observe :user_did_some_action

  def user_did_some_action_handler
    # some complex logic
  end
end

Important

Make sure, that your classes are preloaded! So for app/listeners, put this code to your application.rb

Dir[Rails.root.join + 'app/listeners/*.rb'].map{|f| require f}

For rspec

In your spec_helper.rb

require 'notification_center/rspec_helpers'

Then you can use notifications: false in describe, context, it. Like:

describe User, notifications: false do

it "should do smth", notifications: false do