Live Chat & ActionCable

I want to publish a short note on how to integrate, recently released, ActionCable into your Ruby on Rails project using the example of a live chat. I will not go deep into how ActionCable works , I will just give a small example of use.

Training

First of all, add actioncable and puma to Gemfile :

gem 'actioncable', github: 'rails/actioncable' gem 'puma' 

ActionCable will be launched by a separate process from the main application. Therefore, we will use the multi-threaded Puma web server.
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Chat architecture

The user will enter his nickname on the main page, after which we will write it in the cookie and send it to the chat page.

Add a couple of routes in the config / routes.rb :

 resources :messages, only: [:index, :create] resources :sessions, only: [:new, :create] 

Create controllers with action games. Record nickname in cookies:

 # app/controllers/sessions_controller.rb class SessionsController < ApplicationController def create cookies.signed[:username] = params[:session][:username] redirect_to messages_path end end 

User authorization forms app / views / sessions / new.html.slim:

 = form_for :session, url: sessions_path do |f| p = f.label :username, '  ' p = f.text_field :username p = f.submit '' 

In the chat itself for the time being we will simply send 200 in response to the printed message:

 # app/controllers/messages_controller.rb class MessagesController < ApplicationController def create head :ok end end 

View app / views / messages / index.html.slim:

 p = cookies.signed[:username] p #messages p = form_for :message, url: messages_path, remote: true, id: 'messages-form' do |f| p = f.label :body, ' :' p = f.text_field :body p = f.submit '' 

The message will be sent by AJAX to the server.

Configuring ActionCalbe

Create three classes that will be responsible for integrating with ActionCable.

 # app/channels/application_cable/connection.rb module ApplicationCable class Connection < ActionCable::Connection::Base end end # app/channels/application_cable/channel.rb module ApplicationCable class Channel < ActionCable::Channel::Base end end # app/channels/messages_channel.rb class MessagesChannel < ApplicationCable::Channel def subscribed stream_from 'messages' end end 

Do not forget to add the created directories in autoload_paths . Now, everyone who subscribes to the MessagesChannel channel will be able to receive messages on the corresponding stream defined in the subscribed method, i.e. - messages .

ActionCable provides messaging through Redis. We assume that you have it already installed. We need to set up a connection with it in config / redis / cable.yml :

 development: &dev :url: redis://localhost:6379 :host: localhost :port: 6379 :timeout: 1 :inline: true test: *dev production: *dev 

Now configure Puma:

 # cable/config.ru require ::File.expand_path('../../config/environment', __FILE__) Rails.application.eager_load! require 'action_cable/process/logging' run ActionCable.server 

We will launch Puma on port 34523, why not ...

 # /bin/bash bundle exec puma -p 34523 cable/config.ru 

Now the cougar is launched by the command ./bin/cable .

Sending messages to the general chat

Few update app / controllers / messages_controller.rb :

 class MessagesController < ApplicationController def create ActionCable.server.broadcast 'messages', message: params[:message][:body], username: cookies.signed[:username] head :ok end end 

The most important thing is to subscribe to the channel. Create two coffee files (do not forget to recompile them):

 #app/assets/javascripts/channels/messages.coffee App.messages = App.cable.subscriptions.create 'MessagesChannel', received: (data) -> $('#messages').append("<p><b>[#{data.username}]:</b> #{data.message}</p>") #app/assets/javascripts/channels/index.coffee #= require cable #= require_self #= require_tree . @App = {} App.cable = Cable.createConsumer('ws://127.0.0.1:34523') 

That's all.
As always, a small project - https://github.com/lon10/live-chat