Send Lesson Notification via Sockets

When Email notification is sent out about an upcoming lesson, send
the lesson to a Node server (which would be responsible for forwarding
the lesson to mobile devices).

Gemfile

@@ -62,6 +62,9 @@ gem 'modular-scale', '1.0.6'
 gem 'jquery-rails'
 gem 'chronic'
 
+# Allow use of sockets for mobile support
+gem 'socket.io-client-simple'
+
 group :test do
   gem "factory_girl_rails"
   gem "timecop"

Gemfile.lock

@@ -87,6 +87,7 @@ GEM
       mail (~> 2.2)
     equalizer (0.0.9)
     erubis (2.7.0)
+    event_emitter (0.2.5)
     execjs (2.3.0)
     factory_girl (4.5.0)
       activesupport (>= 3.0.0)
@@ -265,6 +266,11 @@ GEM
       rack-protection (~> 1.4)
       tilt (~> 1.3, >= 1.3.4)
     slop (3.6.0)
+    socket.io-client-simple (1.1.3)
+      event_emitter
+      httparty
+      json
+      websocket-client-simple (>= 0.2.1)
     sprockets (2.12.3)
       hike (~> 1.2)
       multi_json (~> 1.0)
@@ -305,6 +311,10 @@ GEM
     webmock (1.20.4)
       addressable (>= 2.3.6)
       crack (>= 0.3.2)
+    websocket (1.2.2)
+    websocket-client-simple (0.2.2)
+      event_emitter
+      websocket
     websocket-driver (0.5.1)
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.1)
@@ -356,6 +366,7 @@ DEPENDENCIES
   sidekiq
   simplecov
   sinatra
+  socket.io-client-simple
   sqlite3
   timecop
   twitter

app/controllers/users_controller.rb

@@ -39,6 +39,8 @@ def notify_subscribers
         flash[:notice] = "Subscribers notified but error sending tweet, \
 perhaps it was too long?"
       end
+
+      emit_lesson_notification_on_socket lesson
       lesson.update_attribute(:notification_sent_at, Time.now)
     else
       flash[:error] =
@@ -91,4 +93,18 @@ def authenticate_sendgrid_webhook
       return head status: 401
     end
   end
+
+  # Send the lesson (for which a notification is being sent) to a Node
+  # server with socket.io; the Node server will then send the lesson to
+  # all mobile devices subscribed to a channel
+  def emit_lesson_notification_on_socket lesson
+    server_addr = 'https://rs-socketio.herokuapp.com'
+    socket = SocketIO::Client::Simple.connect server_addr
+    message = lesson.as_json
+
+    socket.emit 'lessonNotification', message
+    socket.on :connect do
+      socket.emit 'lessonNotification', message
+    end
+  end
 end