What Is New in Rails 5


Similar to ApplicationController which is the common base class for all controllers that you get with new Rails apps, ApplicationRecord will provide a base class for your ActiveRecord models. This provides a common place to put any base model concerns. app/models/application_record.rb file will be automatically added to models in Rails 5 applications.

# app/models/application_record.rb
class ApplicationRecord < ActiveRecord::Base
    self.abstract_class = true


Action Cable can integrates websocket with rails application. Action Cable server can handle multiple connection instances. It has only one instance per websocket connection. The client websocker connection(consumer) can subscribe to multiple cable channels.For example Action Cable server can have a ChatChannel and an AppearancesChannel and a consumer(websocket) can subscribe to either one or both of channels.

#Publisher Streams
# app/channels/chat_channel.rb
class ChatChannel < ApplicationCable::Channel
    def subscribed
        stream_from "chat_#{params[:room]}"

// app/javascript/channels/chat_channel.js
import consumer from "./consumer"
consumer.subscriptions.create({ channel: "ChatChannel", room: "Best Room" })


Define an attribute on a model with type. It is not essential to have a database column with the custom model attribute. attribute can also be used to provide default values.

# db/schema.rb
create_table :profiles, force: true do |t|
    t.decimal :gpa
    t.string :name, default: "Full Name"

# app/models/profile.rb
class Profile < ActiveRecord::Base

profile = Profile.new(gpa: '4.1')

# before
profile.gpa # => BigDecimal.new(4.1)
profile.new.name # => "Full Name"

class Profile < ActiveRecord::Base
    attribute :gpa, :integer # custom type
    attribute :name, :string, default: "Your Name" # default value
    attribute :current_time, :datetime, default: -> { Time.now } # default value
    attribute :field_without_db_column, :integer, array: true

# after
profile.gpa # => 10
Profile.new.name # => "Your Name"
Profile.new.current_time # => 2015-05-30 11:04:48 -0600
model = Profile.new(field_without_db_column: ["1", "2", "3"])
model.attributes # => {field_without_db_column: [1, 2, 3]}

Rails API – ActionController::API

To avoid middlewares used for browser based web applications and server public facing json APIs, we can create API only rails application here after 5.0. rails new my_api --api can be used to generate application which will be API only and will not generate assets and views.

# app/controllers/application_controller.rb
class ApplicationController < ActionController::API

Ruby 2.2.2+ required version from Rails 5.0

Ruby 2.2.2+ required version from Rails 5.0