Web... wait for it... sockets!

Gemfile

@@ -18,4 +18,5 @@ group :test do
   gem "connection_pool", "~> 2.0"
   gem "rbnacl"
   gem "domain_name"
+  gem "websocket-client-simple"
 end

lib/rage-rb.rb

@@ -7,27 +7,17 @@
 
 module Rage
   def self.application
-    app = Application.new(__router)
-
-    config.middleware.middlewares.reverse.inject(app) do |next_in_chain, (middleware, args, block)|
-      # in Rails compatibility mode we first check if the middleware is a part of the Rails middleware stack;
-      # if it is - it is expected to be built using `ActionDispatch::MiddlewareStack::Middleware#build`
-      if Rage.config.internal.rails_mode
-        rails_middleware = Rails.application.config.middleware.middlewares.find { |m| m.name == middleware.name }
-      end
-
-      if rails_middleware
-        rails_middleware.build(next_in_chain)
-      else
-        middleware.new(next_in_chain, *args, &block)
-      end
-    end
+    with_middlewares(Application.new(__router), config.middleware.middlewares)
   end
 
   def self.multi_application
     Rage::Router::Util::Cascade.new(application, Rails.application)
   end
 
+  def self.cable
+    Rage::Cable
+  end
+
   def self.routes
     Rage::Router::DSL.new(__router)
   end
@@ -90,6 +80,23 @@ def self.patch_active_record_connection_pool
     end
   end
 
+  # @private
+  def self.with_middlewares(app, middlewares)
+    middlewares.reverse.inject(app) do |next_in_chain, (middleware, args, block)|
+      # in Rails compatibility mode we first check if the middleware is a part of the Rails middleware stack;
+      # if it is - it is expected to be built using `ActionDispatch::MiddlewareStack::Middleware#build`
+      if Rage.config.internal.rails_mode
+        rails_middleware = Rails.application.config.middleware.middlewares.find { |m| m.name == middleware.name }
+      end
+
+      if rails_middleware
+        rails_middleware.build(next_in_chain)
+      else
+        middleware.new(next_in_chain, *args, &block)
+      end
+    end
+  end
+
   module Router
     module Strategies
     end
@@ -106,6 +113,7 @@ module ActiveRecord
 
   autoload :Cookies, "rage/cookies"
   autoload :Session, "rage/session"
+  autoload :Cable, "rage/cable/cable"
 end
 
 module RageController

lib/rage/all.rb

@@ -26,6 +26,7 @@
 require_relative "logger/json_formatter"
 require_relative "logger/logger"
 
+require_relative "middleware/origin_validator"
 require_relative "middleware/fiber_wrapper"
 require_relative "middleware/cors"
 require_relative "middleware/reloader"

lib/rage/cable/cable.rb

@@ -0,0 +1,130 @@
+# frozen_string_literal: true
+
+module Rage::Cable
+  # Create a new Cable application.
+  #
+  # @example
+  #   map "/cable" do
+  #     run Rage.cable.application
+  #   end
+  def self.application
+    protocol = Rage.config.cable.protocol
+    protocol.init(__router)
+
+    handler = __build_handler(protocol)
+    accept_response = [0, protocol.protocol_definition, []]
+
+    application = ->(env) do
+      if env["rack.upgrade?"] == :websocket
+        env["rack.upgrade"] = handler
+        accept_response
+      else
+        [426, { "Connection" => "Upgrade", "Upgrade" => "websocket" }, []]
+      end
+    end
+
+    Rage.with_middlewares(application, Rage.config.cable.middlewares)
+  end
+
+  # @private
+  def self.__router
+    @__router ||= Router.new
+  end
+
+  # @private
+  def self.__build_handler(protocol)
+    klass = Class.new do
+      def initialize(protocol)
+        Iodine.on_state(:on_start) do
+          unless Fiber.scheduler
+            Fiber.set_scheduler(Rage::FiberScheduler.new)
+          end
+        end
+
+        @protocol = protocol
+      end
+
+      def on_open(connection)
+        Fiber.schedule do
+          @protocol.on_open(connection)
+        rescue => e
+          log_error(e)
+        end
+      end
+
+      def on_message(connection, data)
+        Fiber.schedule do
+          @protocol.on_message(connection, data)
+        rescue => e
+          log_error(e)
+        end
+      end
+
+      if protocol.respond_to?(:on_close)
+        def on_close(connection)
+          return unless ::Iodine.running?
+
+          Fiber.schedule do
+            @protocol.on_close(connection)
+          rescue => e
+            log_error(e)
+          end
+        end
+      end
+
+      if protocol.respond_to?(:on_shutdown)
+        def on_shutdown(connection)
+          @protocol.on_shutdown(connection)
+        rescue => e
+          log_error(e)
+        end
+      end
+
+      private
+
+      def log_error(e)
+        Rage.logger.error("Unhandled exception has occured - #{e.class} (#{e.message}):\n#{e.backtrace.join("\n")}")
+      end
+    end
+
+    klass.new(protocol)
+  end
+
+  # Broadcast data directly to a named stream.
+  #
+  # @param stream [String] the name of the stream
+  # @param data [Object] the object to send to the clients. This will later be encoded according to the protocol used.
+  # @example
+  #   Rage.cable.broadcast("chat", { message: "A new member has joined!" })
+  def self.broadcast(stream, data)
+    Rage.config.cable.protocol.broadcast(stream, data)
+  end
+
+  # @!parse [ruby]
+  #   # @abstract
+  #   class WebSocketConnection
+  #     # Write data to the connection.
+  #     #
+  #     # @param data [String] the data to write
+  #     def write(data)
+  #     end
+  #
+  #     # Subscribe to a channel.
+  #     #
+  #     # @param name [String] the channel name
+  #     def subscribe(name)
+  #     end
+  #
+  #     # Close the connection.
+  #     def close
+  #     end
+  #   end
+
+  module Protocol
+  end
+end
+
+require_relative "protocol/actioncable_v1_json"
+require_relative "channel"
+require_relative "connection"
+require_relative "router"