1 files changed, 21 insertions, 3 deletions
diff --git a/actioncable/lib/action_cable/server/configuration.rb b/actioncable/lib/action_cable/server/configuration.rb
index 935133cbba..ebbf60c6e2 100644
--- a/actioncable/lib/action_cable/server/configuration.rb
+++ b/actioncable/lib/action_cable/server/configuration.rb
@@ -5,9 +5,9 @@ module ActionCable
     class Configuration
       attr_accessor :logger, :log_tags
       attr_accessor :connection_class, :worker_pool_size
-      attr_accessor :redis, :channels_path
+      attr_accessor :channels_path
       attr_accessor :disable_request_forgery_protection, :allowed_request_origins
-      attr_accessor :url
+      attr_accessor :cable, :url
 
       def initialize
         @log_tags = []
@@ -29,7 +29,25 @@ module ActionCable
           Pathname.new(channel_path).basename.to_s.split('.').first.camelize
         end
       end
+
+      # Returns constant of subscription adapter specified in config/cable.yml.
+      # If the adapter cannot be found, this will default to the Redis adapter.
+      # Also makes sure proper dependencies are required.
+      def pubsub_adapter
+        adapter = (cable.fetch('adapter') { 'redis' })
+        path_to_adapter = "action_cable/subscription_adapter/#{adapter}"
+        begin
+          require path_to_adapter
+        rescue Gem::LoadError => e
+          raise Gem::LoadError, "Specified '#{adapter}' for Action Cable pubsub adapter, but the gem is not loaded. Add `gem '#{e.name}'` to your Gemfile (and ensure its version is at the minimum required by Action Cable)."
+        rescue LoadError => e
+          raise LoadError, "Could not load '#{path_to_adapter}'. Make sure that the adapter in config/cable.yml is valid. If you use an adapter other than 'postgresql' or 'redis' add the necessary adapter gem to the Gemfile.", e.backtrace
+        end
+
+        adapter = adapter.camelize
+        adapter = 'PostgreSQL' if adapter == 'Postgresql'
+        "ActionCable::SubscriptionAdapter::#{adapter}".constantize
+      end
     end
   end
 end
-