Creating a class to build the default middleware stack.

A lot of logic for building the default middleware stack is currently
kept in Application class, but this can be encapsulated and made more
modular by being moved to its own class. Also refactored a couple of the
helper methods.

1 files changed, 101 insertions, 0 deletions

diff --git a/railties/lib/rails/application/default_middleware_stack.rb b/railties/lib/rails/application/default_middleware_stack.rb
new file mode 100644
index 0000000000..370c906086
--- /dev/null
+++ b/railties/lib/rails/application/default_middleware_stack.rb
@@ -0,0 +1,101 @@
+module Rails
+  class Application
+    class DefaultMiddlewareStack
+      attr_reader :config, :paths, :app
+
+      def initialize(app, config, paths)
+        @app = app
+        @config = config
+        @paths = paths
+      end
+
+      def build_stack
+        ActionDispatch::MiddlewareStack.new.tap do |middleware|
+          if rack_cache = load_rack_cache
+            require "action_dispatch/http/rack_cache"
+            middleware.use ::Rack::Cache, rack_cache
+          end
+
+          if config.force_ssl
+            middleware.use ::ActionDispatch::SSL, config.ssl_options
+          end
+
+          if config.action_dispatch.x_sendfile_header.present?
+            middleware.use ::Rack::Sendfile, config.action_dispatch.x_sendfile_header
+          end
+
+          if config.serve_static_assets
+            middleware.use ::ActionDispatch::Static, paths["public"].first, config.static_cache_control
+          end
+
+          middleware.use ::Rack::Lock unless allow_concurrency?
+          middleware.use ::Rack::Runtime
+          middleware.use ::Rack::MethodOverride
+          middleware.use ::ActionDispatch::RequestId
+
+          # Must come after Rack::MethodOverride to properly log overridden methods
+          middleware.use ::Rails::Rack::Logger, config.log_tags
+          middleware.use ::ActionDispatch::ShowExceptions, show_exceptions_app
+          middleware.use ::ActionDispatch::DebugExceptions, app
+          middleware.use ::ActionDispatch::RemoteIp, config.action_dispatch.ip_spoofing_check, config.action_dispatch.trusted_proxies
+
+          unless config.cache_classes
+            middleware.use ::ActionDispatch::Reloader, lambda { reload_dependencies? }
+          end
+
+          middleware.use ::ActionDispatch::Callbacks
+          middleware.use ::ActionDispatch::Cookies
+
+          if config.session_store
+            if config.force_ssl && !config.session_options.key?(:secure)
+              config.session_options[:secure] = true
+            end
+            middleware.use config.session_store, config.session_options
+            middleware.use ::ActionDispatch::Flash
+          end
+
+          middleware.use ::ActionDispatch::ParamsParser
+          middleware.use ::Rack::Head
+          middleware.use ::Rack::ConditionalGet
+          middleware.use ::Rack::ETag, "no-cache"
+        end
+      end
+
+      private
+
+        def reload_dependencies?
+          config.reload_classes_only_on_change != true || app.reloaders.map(&:updated?).any?
+        end
+
+        def allow_concurrency?
+          config.allow_concurrency.nil? ? config.cache_classes : config.allow_concurrency
+        end
+
+        def load_rack_cache
+          rack_cache = config.action_dispatch.rack_cache
+          return unless rack_cache
+
+          begin
+            require 'rack/cache'
+          rescue LoadError => error
+            error.message << ' Be sure to add rack-cache to your Gemfile'
+            raise
+          end
+
+          if rack_cache == true
+            {
+              metastore: "rails:/",
+              entitystore: "rails:/",
+              verbose: false
+            }
+          else
+            rack_cache
+          end
+        end
+
+        def show_exceptions_app
+          config.exceptions_app || ActionDispatch::PublicExceptions.new(Rails.public_path)
+        end
+    end
+  end
+end