Real-time Recipe for Rails and Ember using Pusher

application.js

// app/routes/application.js
import Ember from 'ember';

export default Ember.Route.extend({
  currentUser: Ember.inject.service(),
  pusher: Ember.inject.service(),

  activate() {
    this._listenToPusherEvents();
  },

  _listenToPusherEvents() {
    const user = this.get('currentUser.user');

    if (user) {
      this.get('pusher').listenToUser(user);
    }
  }
});

comment.rb

# app/models/comment.rb
class Comment < ActiveRecord::Base
  include PublishesUpdatesToPusher
end

index.html

<script src="https://js.pusher.com/3.1/pusher.min.js"></script>

publishes_updates_to_pusher.rb

# app/models/concerns/publishes_updates_to_pusher.rb
require 'active_support/concern'

module PublishesUpdatesToPusher
  extend ActiveSupport::Concern

  included do
    after_commit :notify_via_pusher, on: [:create, :update]

    def notify_via_pusher
      if Sidekiq.server?
        PusherUpdateWorker.new.perform(self.class.name, id)
      else
        PusherUpdateWorker.perform_async(self.class.name, id)
      end
    end
  end
end

pusher.js

// app/services/pusher.js
import Ember from 'ember';
import ENV from 'my-app-name/config/environment';

/* global Pusher */

const { computed, run } = Ember;

export default Ember.Service.extend({
  store: Ember.inject.service(),

  listenToUser(user) {
    if (this.get('hasSubscribedToUser')) {
      return;
    }

    this.subscribe(`User-${user.get('id')}`, "objectUpdated", (data) => {
      run.scheduleOnce('afterRender', this, this._pushPayload, data);
    });

    this.set('hasSubscribedToUser', true);
  },

  subscribe(channelName, event, callback) {
    const channel = this.get('_client').subscribe(channelName);
    channel.bind(event, callback);
  },

  _pushPayload(data) {
    this.get('store').pushPayload(data);
  },

  _client: computed(function() {
    Pusher.logToConsole = ENV.environment !== "production";

    return new Pusher(ENV.pusher.key);
  })
});

pusher_update_worker.rb

# app/workers/pusher_update_worker.rb
class PusherUpdateWorker
  include Sidekiq::Worker

  def perform(klass, id)
    Pusher.encrypted = true
    pusher = Pusher::Client.from_env
    obj = Object.const_get(klass).find(id)
    channel_id = "User-#{obj.user_id}"

    resource_klass = Object.const_get("#{klass}Resource")

    serialized = JSONAPI::ResourceSerializer.new(resource_klass, {
      always_include_to_one_linkage_data: true,
      always_include_to_many_linkage_data: true
    }).serialize_to_hash(resource_klass.new(obj, nil))

    pusher.trigger(channel_id, "objectUpdated", serialized)
  end
end