4 files changed, 140 insertions, 0 deletions

diff --git a/lib/action_cable.rb b/lib/action_cable.rb
index e7d8f4cbb1..0681b8bdde 100644
--- a/lib/action_cable.rb
+++ b/lib/action_cable.rb
@@ -12,6 +12,8 @@ require 'active_support/callbacks'
 require 'faye/websocket'
 require 'celluloid'
 
+require 'action_cable/engine' if defined?(Rails)
+
 module ActionCable
   VERSION = '0.0.1'
 
diff --git a/lib/action_cable/engine.rb b/lib/action_cable/engine.rb
new file mode 100644
index 0000000000..6c943c7971
--- /dev/null
+++ b/lib/action_cable/engine.rb
@@ -0,0 +1,4 @@
+module ActionCable
+  class Engine < ::Rails::Engine
+  end
+end
diff --git a/lib/assets/javascripts/cable.js.coffee b/lib/assets/javascripts/cable.js.coffee
new file mode 100644
index 0000000000..2a70693bf0
--- /dev/null
+++ b/lib/assets/javascripts/cable.js.coffee
@@ -0,0 +1,107 @@
+#= require_self
+#= require_tree .
+
+class @Cable
+  MAX_CONNECTION_ATTEMPTS: 10
+  MAX_CONNECTION_INTERVAL: 5 * 1000
+  MAX_PING_INTERVAL: 6
+
+  constructor: (@cableUrl) ->
+    @subscribers = {}
+    @resetPingTime()
+    @resetConnectionAttemptsCount()
+    @connect()
+
+  connect: ->
+    @connection = @createConnection()
+
+  createConnection: ->
+    connection = new WebSocket(@cableUrl)
+    connection.onmessage = @receiveData
+    connection.onopen    = @connected
+    connection.onclose   = @reconnect
+
+    connection.onerror   = @reconnect
+    connection
+
+  isConnected: =>
+    @connection?.readyState is 1
+
+  sendData: (identifier, data) =>
+    if @isConnected()
+      @connection.send JSON.stringify { action: 'message', identifier: identifier, data: data }
+
+  receiveData: (message) =>
+    data = JSON.parse message.data
+
+    if data.identifier is '_ping'
+      @pingReceived(data.message)
+    else
+      @subscribers[data.identifier]?.onReceiveData(data.message)
+
+  connected: =>
+    @resetConnectionAttemptsCount()
+
+    for identifier, callbacks of @subscribers
+      @subscribeOnServer(identifier)
+      callbacks['onConnect']?()
+
+  reconnect: =>
+    @resetPingTime()
+    @disconnected()
+
+    setTimeout =>
+      if @isMaxConnectionAttemptsReached()
+        @giveUp()
+      else
+        @incrementConnectionAttemptsCount()
+        @connect()
+    , @generateReconnectInterval()
+
+  resetConnectionAttemptsCount: =>
+    @connectionAttempts = 1
+
+  incrementConnectionAttemptsCount: =>
+    @connectionAttempts += 1
+
+  isMaxConnectionAttemptsReached: =>
+    @connectionAttempts > @MAX_CONNECTION_ATTEMPTS
+
+  generateReconnectInterval: () ->
+    interval = (Math.pow(2, @connectionAttempts) - 1) * 1000
+    if interval > @MAX_CONNECTION_INTERVAL then @MAX_CONNECTION_INTERVAL else interval
+
+  resetPingTime: () =>
+    @lastPingTime = null
+
+  disconnected: =>
+    callbacks['onDisconnect']?() for identifier, callbacks of @subscribers
+
+  giveUp: =>
+    # Show an error message
+
+  subscribe: (identifier, callbacks) =>
+    @subscribers[identifier] = callbacks
+
+    if @isConnected()
+      @subscribeOnServer(identifier)
+      @subscribers[identifier]['onConnect']?()
+
+  unsubscribe: (identifier) =>
+    @unsubscribeOnServer(identifier, 'unsubscribe')
+    delete @subscribers[identifier]
+
+  subscribeOnServer: (identifier) =>
+    if @isConnected()
+      @connection.send JSON.stringify { action: 'subscribe', identifier: identifier }
+
+  unsubscribeOnServer: (identifier) =>
+    if @isConnected()
+      @connection.send JSON.stringify { action: 'unsubscribe', identifier: identifier }
+
+  pingReceived: (timestamp) =>
+    if @lastPingTime? and (timestamp - @lastPingTime) > @MAX_PING_INTERVAL
+      console.log "Websocket connection is stale. Reconnecting.."
+      @connection.close()
+    else
+      @lastPingTime = timestamp
diff --git a/lib/assets/javascripts/channel.js.coffee b/lib/assets/javascripts/channel.js.coffee
new file mode 100644
index 0000000000..058bcc03aa
--- /dev/null
+++ b/lib/assets/javascripts/channel.js.coffee
@@ -0,0 +1,27 @@
+class @Cable.Channel
+  constructor: (params = {}) ->
+    @channelName ?= @underscore @constructor.name
+
+    params['channel'] = @channelName
+    @channelIdentifier = JSON.stringify params
+
+    cable.subscribe(@channelIdentifier, {
+      onConnect: @connected
+      onDisconnect: @disconnected
+      onReceiveData: @received
+    })
+
+  connected: =>
+    # Override in the subclass
+
+  disconnected: =>
+    # Override in the subclass
+
+  received: (data) =>
+    # Override in the subclass
+
+  send: (data) ->
+    cable.sendData @channelIdentifier, JSON.stringify data
+
+  underscore: (value) ->
+    value.replace(/[A-Z]/g, (match) => "_#{match.toLowerCase()}").substr(1)
\ No newline at end of file