From c846f43d46908750020710b4e9437f9395fb9594 Mon Sep 17 00:00:00 2001
From: Javan Makhmali <javan@javan.us>
Date: Thu, 25 Jun 2015 13:52:47 -0400
Subject: Extract connection monitoring and rewrite as a subscriber

---
 lib/assets/javascripts/cable/connection.js.coffee  | 94 +++++-----------------
 .../javascripts/cable/connection_monitor.js.coffee | 41 ++++++++++
 .../javascripts/cable/subscriber_manager.js.coffee |  1 +
 3 files changed, 64 insertions(+), 72 deletions(-)
 create mode 100644 lib/assets/javascripts/cable/connection_monitor.js.coffee

(limited to 'lib/assets/javascripts/cable')

diff --git a/lib/assets/javascripts/cable/connection.js.coffee b/lib/assets/javascripts/cable/connection.js.coffee
index e987c227c6..096dd519f7 100644
--- a/lib/assets/javascripts/cable/connection.js.coffee
+++ b/lib/assets/javascripts/cable/connection.js.coffee
@@ -1,10 +1,8 @@
-class Cable.Connection
-  MAX_CONNECTION_INTERVAL: 5 * 1000
-  PING_STALE_INTERVAL: 8
+#= require cable/connection_monitor
 
+class Cable.Connection
   constructor: (@cable) ->
-    @resetPingTime()
-    @resetConnectionAttemptsCount()
+    new Cable.ConnectionMonitor @cable
     @connect()
 
   send: (data) ->
@@ -15,88 +13,40 @@ class Cable.Connection
       false
 
   connect: ->
-    @websocket = @createWebSocket()
+    @removeWebsocket()
+    @createWebSocket()
 
   createWebSocket: ->
-    ws = new WebSocket(@cable.url)
-    ws.onmessage = @onMessage
-    ws.onopen    = @onConnect
-    ws.onclose   = @onClose
-    ws.onerror   = @onError
-    ws
+    @websocket = new WebSocket(@cable.url)
+    @websocket.onmessage = @onMessage
+    @websocket.onopen    = @onConnect
+    @websocket.onclose   = @onClose
+    @websocket.onerror   = @onError
+    @websocket
+
+  removeWebsocket: ->
+    if @websocket?
+      @websocket.onclose = -> # no-op
+      @websocket.onerror = -> # no-op
+      @websocket.close()
+      @websocket = null
 
   onMessage: (message) =>
     data = JSON.parse message.data
-
-    if data.identifier is '_ping'
-      @pingReceived(data.message)
-    else
-      @cable.subscribers.notify(data.identifier, "received", data.message)
+    @cable.subscribers.notify(data.identifier, "received", data.message)
 
   onConnect: =>
-    @startWaitingForPing()
-    @resetConnectionAttemptsCount()
     @cable.subscribers.reload()
 
   onClose: =>
-    @reconnect()
+    @disconnect()
 
   onError: =>
-    @reconnect()
+    @disconnect()
 
   isConnected: ->
     @websocket?.readyState is 1
 
   disconnect: ->
-    @removeExistingConnection()
-    @resetPingTime()
     @cable.subscribers.notifyAll("disconnected")
-
-  reconnect: ->
-    @disconnect()
-
-    setTimeout =>
-      @incrementConnectionAttemptsCount()
-      @connect()
-    , @generateReconnectInterval()
-
-  removeExistingConnection: ->
-    if @websocket?
-      @clearPingWaitTimeout()
-
-      @websocket.onclose = -> # no-op
-      @websocket.onerror = -> # no-op
-      @websocket.close()
-      @websocket = null
-
-  resetConnectionAttemptsCount: ->
-    @connectionAttempts = 1
-
-  incrementConnectionAttemptsCount: ->
-    @connectionAttempts += 1
-
-  generateReconnectInterval: () ->
-    interval = (Math.pow(2, @connectionAttempts) - 1) * 1000
-    if interval > @MAX_CONNECTION_INTERVAL then @MAX_CONNECTION_INTERVAL else interval
-
-  startWaitingForPing: ->
-    @clearPingWaitTimeout()
-
-    @waitForPingTimeout = setTimeout =>
-      console.log "Ping took too long to arrive. Reconnecting.."
-      @reconnect()
-    , @PING_STALE_INTERVAL * 1000
-
-  clearPingWaitTimeout: ->
-    clearTimeout(@waitForPingTimeout)
-
-  resetPingTime: ->
-    @lastPingTime = null
-
-  pingReceived: (timestamp) ->
-    if @lastPingTime? and (timestamp - @lastPingTime) > @PING_STALE_INTERVAL
-      console.log "Websocket connection is stale. Reconnecting.."
-      @reconnect()
-    else
-      @startWaitingForPing()
-      @lastPingTime = timestamp
+    @removeWebsocket()
diff --git a/lib/assets/javascripts/cable/connection_monitor.js.coffee b/lib/assets/javascripts/cable/connection_monitor.js.coffee
new file mode 100644
index 0000000000..078e1d3b26
--- /dev/null
+++ b/lib/assets/javascripts/cable/connection_monitor.js.coffee
@@ -0,0 +1,41 @@
+class Cable.ConnectionMonitor
+  MAX_CONNECTION_INTERVAL: 5 * 1000
+  PING_STALE_INTERVAL: 8 * 1000
+
+  identifier: Cable.PING_IDENTIFIER
+
+  constructor: (@cable) ->
+    @reset()
+    @cable.subscribers.add(this)
+    @pollConnection()
+
+  connected: ->
+    @reset()
+    @pingedAt = now()
+
+  received: ->
+    @pingedAt = now()
+
+  reset: ->
+    @connectionAttempts = 1
+
+  pollConnection: ->
+    setTimeout =>
+      @reconnect() if @connectionIsStale()
+      @pollConnection()
+    , @getPollTimeout()
+
+  getPollTimeout: ->
+    interval = (Math.pow(2, @connectionAttempts) - 1) * 1000
+    if interval > @MAX_CONNECTION_INTERVAL then @MAX_CONNECTION_INTERVAL else interval
+
+  connectionIsStale: ->
+    @pingedAt? and (now() - @pingedAt) > @PING_STALE_INTERVAL
+
+  reconnect: ->
+    console.log "Ping took too long to arrive. Reconnecting.."
+    @connectionAttempts += 1
+    @cable.connection.connect()
+
+  now = ->
+    new Date().getTime()
diff --git a/lib/assets/javascripts/cable/subscriber_manager.js.coffee b/lib/assets/javascripts/cable/subscriber_manager.js.coffee
index e2e6c9e228..d76832a802 100644
--- a/lib/assets/javascripts/cable/subscriber_manager.js.coffee
+++ b/lib/assets/javascripts/cable/subscriber_manager.js.coffee
@@ -30,4 +30,5 @@ class Cable.SubscriberManager
       subscriber[event]?(args...)
 
   sendCommand: (command, identifier) ->
+    return true if identifier is Cable.PING_IDENTIFIER
     @cable.send({command, identifier})
-- 
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