Added protocol negotiation

This is primarily for backwards compatibility for when
or if the protocol is changed in future versions.

If the server fails to respond with an acceptable
protocol, the client disconnects and disables
the monitor.

3 files changed, 50 insertions, 16 deletions

diff --git a/actioncable/app/assets/javascripts/action_cable/connection.coffee b/actioncable/app/assets/javascripts/action_cable/connection.coffee
index 92272cc5b8..af771f2d82 100644
--- a/actioncable/app/assets/javascripts/action_cable/connection.coffee
+++ b/actioncable/app/assets/javascripts/action_cable/connection.coffee
@@ -2,7 +2,8 @@
 
 # Encapsulate the cable connection held by the consumer. This is an internal class not intended for direct user manipulation.
 
-{message_types} = ActionCable.INTERNAL
+{message_types, protocols} = ActionCable.INTERNAL
+[supportedProtocols..., unsupportedProtocol] = protocols
 
 class ActionCable.Connection
   @reopenDelay: 500
@@ -10,6 +11,7 @@ class ActionCable.Connection
   constructor: (@consumer) ->
     {@subscriptions} = @consumer
     @monitor = new ActionCable.ConnectionMonitor this
+    @disconnected = true
 
   send: (data) ->
     if @isOpen()
@@ -23,15 +25,16 @@ class ActionCable.Connection
       ActionCable.log("Attemped to open WebSocket, but existing socket is #{@getState()}")
       throw new Error("Existing connection must be closed before opening")
     else
-      ActionCable.log("Opening WebSocket, current state is #{@getState()}")
+      ActionCable.log("Opening WebSocket, current state is #{@getState()}, subprotocols: #{protocols}")
       @uninstallEventHandlers() if @webSocket?
-      @webSocket = new WebSocket(@consumer.url)
+      @webSocket = new WebSocket(@consumer.url, protocols)
       @installEventHandlers()
       @monitor.start()
       true
 
-  close: ->
-    @webSocket?.close()
+  close: ({allowReconnect} = {allowReconnect: true}) ->
+    @monitor.stop() unless allowReconnect
+    @webSocket?.close() if @isActive()
 
   reopen: ->
     ActionCable.log("Reopening WebSocket, current state is #{@getState()}")
@@ -46,6 +49,9 @@ class ActionCable.Connection
     else
       @open()
 
+  getProtocol: ->
+    @webSocket?.protocol
+
   isOpen: ->
     @isState("open")
 
@@ -54,6 +60,9 @@ class ActionCable.Connection
 
   # Private
 
+  isProtocolSupported: ->
+    @getProtocol() in supportedProtocols
+
   isState: (states...) ->
     @getState() in states
 
@@ -74,10 +83,12 @@ class ActionCable.Connection
 
   events:
     message: (event) ->
+      return unless @isSupportedProtocol()
       {identifier, message, type} = JSON.parse(event.data)
       switch type
         when message_types.welcome
           @monitor.recordConnect()
+          @subscriptions.reload()
         when message_types.ping
           @monitor.recordPing()
         when message_types.confirmation
@@ -88,20 +99,18 @@ class ActionCable.Connection
           @subscriptions.notify(identifier, "received", message)
 
     open: ->
-      ActionCable.log("WebSocket onopen event")
+      ActionCable.log("WebSocket onopen event, using '#{@getProtocol()}' subprotocol")
       @disconnected = false
-      @subscriptions.reload()
+      if not @isProtocolSupported()
+        ActionCable.log("Protocol is unsupported. Stopping monitor and disconnecting.")
+        @close(allowReconnect: false)
 
-    close: ->
+    close: (event) ->
       ActionCable.log("WebSocket onclose event")
-      @disconnect()
+      return if @disconnected
+      @disconnected = true
+      @monitor.recordDisconnect()
+      @subscriptions.notifyAll("disconnected", {willAttemptReconnect: @monitor.isRunning()})
 
     error: ->
       ActionCable.log("WebSocket onerror event")
-      @disconnect()
-
-  disconnect: ->
-    return if @disconnected
-    @disconnected = true
-    @subscriptions.notifyAll("disconnected")
-    @monitor.recordDisconnect()
diff --git a/actioncable/app/assets/javascripts/action_cable/consumer.coffee b/actioncable/app/assets/javascripts/action_cable/consumer.coffee
index 7aae1ed8ed..3298be717f 100644
--- a/actioncable/app/assets/javascripts/action_cable/consumer.coffee
+++ b/actioncable/app/assets/javascripts/action_cable/consumer.coffee
@@ -14,6 +14,19 @@
 #   App.appearance = App.cable.subscriptions.create "AppearanceChannel"
 #
 # For more details on how you'd configure an actual channel subscription, see ActionCable.Subscription.
+#
+# When a consumer is created, it automatically connects with the server.
+#
+# To disconnect from the server, call
+#
+#   App.cable.disconnect()
+#
+# and to restart the connection:
+#
+#   App.cable.connect()
+#
+# Any channel subscriptions which existed prior to disconnecting will
+# automatically resubscribe.
 class ActionCable.Consumer
   constructor: (@url) ->
     @subscriptions = new ActionCable.Subscriptions this
@@ -22,6 +35,12 @@ class ActionCable.Consumer
   send: (data) ->
     @connection.send(data)
 
+  connect: ->
+    @connection.open()
+
+  disconnect: ->
+    @connection.close(allowReconnect: false)
+
   ensureActiveConnection: ->
     unless @connection.isActive()
       @connection.open()
diff --git a/actioncable/app/assets/javascripts/action_cable/subscription.coffee b/actioncable/app/assets/javascripts/action_cable/subscription.coffee
index 61a3fb1309..8e0805a174 100644
--- a/actioncable/app/assets/javascripts/action_cable/subscription.coffee
+++ b/actioncable/app/assets/javascripts/action_cable/subscription.coffee
@@ -8,6 +8,12 @@
 #     connected: ->
 #       # Called once the subscription has been successfully completed
 #
+#     disconnected: ({ willAttemptReconnect: boolean }) ->
+#       # Called when the client has disconnected with the server.
+#       # The object will have an `willAttemptReconnect` property which
+#       # says whether the client has the intention of attempting
+#       # to reconnect.
+#
 #     appear: ->
 #       @perform 'appear', appearing_on: @appearingOn()
 #