Merge branch 'connection-management'

3 files changed, 228 insertions, 0 deletions

diff --git a/lib/action_cable/connection/base.rb b/lib/action_cable/connection/base.rb
new file mode 100644
index 0000000000..4ad1e7d065
--- /dev/null
+++ b/lib/action_cable/connection/base.rb
@@ -0,0 +1,145 @@
+module ActionCable
+  module Connection
+    class Base
+      include Registry
+
+      PING_INTERVAL = 3
+
+      attr_reader :env, :server
+      delegate :worker_pool, :pubsub, :logger, to: :server
+
+      def initialize(server, env)
+        @server = server
+        @env = env
+        @accept_messages = false
+        @pending_messages = []
+      end
+
+      def process
+        if Faye::WebSocket.websocket?(@env)
+          @subscriptions = {}
+
+          @websocket = Faye::WebSocket.new(@env)
+
+          @websocket.on(:open) do |event|
+            broadcast_ping_timestamp
+            @ping_timer = EventMachine.add_periodic_timer(PING_INTERVAL) { broadcast_ping_timestamp }
+            worker_pool.async.invoke(self, :initialize_client)
+          end
+
+          @websocket.on(:message) do |event|
+            message = event.data
+
+            if message.is_a?(String)
+              if @accept_messages
+                worker_pool.async.invoke(self, :received_data, message)
+              else
+                @pending_messages << message
+              end
+            end
+          end
+
+          @websocket.on(:close) do |event|
+            worker_pool.async.invoke(self, :cleanup_subscriptions)
+            worker_pool.async.invoke(self, :cleanup_internal_redis_subscriptions)
+            worker_pool.async.invoke(self, :disconnect) if respond_to?(:disconnect)
+
+            EventMachine.cancel_timer(@ping_timer) if @ping_timer
+          end
+
+          @websocket.rack_response
+        else
+          invalid_request
+        end
+      end
+
+      def received_data(data)
+        return unless websocket_alive?
+
+        data = ActiveSupport::JSON.decode data
+
+        case data['action']
+        when 'subscribe'
+          subscribe_channel(data)
+        when 'unsubscribe'
+          unsubscribe_channel(data)
+        when 'message'
+          process_message(data)
+        end
+      end
+
+      def cleanup_subscriptions
+        @subscriptions.each do |id, channel|
+          channel.unsubscribe
+        end
+      end
+
+      def broadcast(data)
+        logger.info "Sending data: #{data}"
+        @websocket.send data
+      end
+
+      def handle_exception
+        logger.error "[ActionCable] Closing connection"
+
+        @websocket.close
+      end
+
+      private
+        def initialize_client
+          connect if respond_to?(:connect)
+          register_connection
+
+          @accept_messages = true
+          worker_pool.async.invoke(self, :received_data, @pending_messages.shift) until @pending_messages.empty?
+        end
+
+        def broadcast_ping_timestamp
+          broadcast({ identifier: '_ping', message: Time.now.to_i }.to_json)
+        end
+
+        def subscribe_channel(data)
+          id_key = data['identifier']
+          id_options = ActiveSupport::JSON.decode(id_key).with_indifferent_access
+
+          subscription_klass = server.registered_channels.detect { |channel_klass| channel_klass.find_name == id_options[:channel] }
+
+          if subscription_klass
+            logger.info "[ActionCable] Subscribing to channel: #{id_key}"
+            @subscriptions[id_key] = subscription_klass.new(self, id_key, id_options)
+          else
+            logger.error "[ActionCable] Subscription class not found (#{data.inspect})"
+          end
+        rescue Exception => e
+          logger.error "[ActionCable] Could not subscribe to channel (#{data.inspect})"
+          logger.error e.backtrace.join("\n")
+        end
+
+        def process_message(message)
+          if @subscriptions[message['identifier']]
+            @subscriptions[message['identifier']].receive_data(ActiveSupport::JSON.decode message['data'])
+          else
+            logger.error "[ActionCable] Unable to process message because no subscription was found (#{message.inspect})"
+          end
+        rescue Exception => e
+          logger.error "[ActionCable] Could not process message (#{data.inspect})"
+          logger.error e.backtrace.join("\n")
+        end
+
+        def unsubscribe_channel(data)
+          logger.info "[ActionCable] Unsubscribing from channel: #{data['identifier']}"
+          @subscriptions[data['identifier']].unsubscribe
+          @subscriptions.delete(data['identifier'])
+        end
+
+        def invalid_request
+          [404, {'Content-Type' => 'text/plain'}, ['Page not found']]
+        end
+
+        def websocket_alive?
+          @websocket && @websocket.ready_state == Faye::WebSocket::API::OPEN
+        end
+
+    end
+  end
+end
diff --git a/lib/action_cable/connection/identifier.rb b/lib/action_cable/connection/identifier.rb
new file mode 100644
index 0000000000..9bfd773ab1
--- /dev/null
+++ b/lib/action_cable/connection/identifier.rb
@@ -0,0 +1,19 @@
+module ActionCable
+  module Connection
+    module Identifier
+
+      def internal_redis_channel
+        "action_cable/#{connection_identifier}"
+      end
+
+      def connection_identifier
+        @connection_identifier ||= connection_gid identifiers.map { |id| instance_variable_get("@#{id}")}
+      end
+
+      def connection_gid(ids)
+        ids.map {|o| o.to_global_id.to_s }.sort.join(":")
+      end
+
+    end
+  end
+end
diff --git a/lib/action_cable/connection/registry.rb b/lib/action_cable/connection/registry.rb
new file mode 100644
index 0000000000..03a0bf4fe9
--- /dev/null
+++ b/lib/action_cable/connection/registry.rb
@@ -0,0 +1,64 @@
+module ActionCable
+  module Connection
+    module Registry
+      extend ActiveSupport::Concern
+
+      included do
+        class_attribute :identifiers
+        self.identifiers = Set.new
+      end
+
+      module ClassMethods
+        def identified_by(*identifiers)
+          self.identifiers += identifiers
+        end
+      end
+
+      def register_connection
+        if connection_identifier.present?
+          callback = -> (message) { process_registry_message(message) }
+          @_internal_redis_subscriptions ||= []
+          @_internal_redis_subscriptions << [ internal_redis_channel, callback ]
+
+          pubsub.subscribe(internal_redis_channel, &callback)
+          logger.info "[ActionCable] Registered connection (#{connection_identifier})"
+        end
+      end
+
+      def internal_redis_channel
+        "action_cable/#{connection_identifier}"
+      end
+
+      def connection_identifier
+        @connection_identifier ||= connection_gid identifiers.map { |id| instance_variable_get("@#{id}")}
+      end
+
+      def connection_gid(ids)
+        ids.map {|o| o.to_global_id.to_s }.sort.join(":")
+      end
+
+      def cleanup_internal_redis_subscriptions
+        if @_internal_redis_subscriptions.present?
+          @_internal_redis_subscriptions.each { |channel, callback| pubsub.unsubscribe_proc(channel, callback) }
+        end
+      end
+
+      private
+        def process_registry_message(message)
+          message = ActiveSupport::JSON.decode(message)
+
+          case message['type']
+          when 'disconnect'
+            logger.info "[ActionCable] Removing connection (#{connection_identifier})"
+            @websocket.close
+          end
+        rescue Exception => e
+          logger.error "[ActionCable] There was an exception - #{e.class}(#{e.message})"
+          logger.error e.backtrace.join("\n")
+
+          handle_exception
+        end
+
+    end
+  end
+end