1 files changed, 117 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..ed6a1f82d3
--- /dev/null
+++ b/railties/lib/rails/application/default_middleware_stack.rb
@@ -0,0 +1,117 @@
+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 config.force_ssl
+            middleware.use ::ActionDispatch::SSL, config.ssl_options
+          end
+
+          middleware.use ::Rack::Sendfile, config.action_dispatch.x_sendfile_header
+
+          if config.public_file_server.enabled
+            headers = config.public_file_server.headers || {}
+            headers['Cache-Control'.freeze] = config.static_cache_control if config.static_cache_control
+
+            middleware.use ::ActionDispatch::Static, paths["public"].first, index: config.public_file_server.index_name, headers: headers
+          end
+
+          if rack_cache = load_rack_cache
+            require "action_dispatch/http/rack_cache"
+            middleware.use ::Rack::Cache, rack_cache
+          end
+
+          if config.allow_concurrency == false
+            # User has explicitly opted out of concurrent request
+            # handling: presumably their code is not threadsafe
+
+            middleware.use ::Rack::Lock
+
+          elsif config.allow_concurrency == :unsafe
+            # Do nothing, even if we know this is dangerous. This is the
+            # historical behaviour for true.
+
+          else
+            # Default concurrency setting: enabled, but safe
+
+            unless config.cache_classes && config.eager_load
+              # Without cache_classes + eager_load, the load interlock
+              # is required for proper operation
+
+              middleware.use ::ActionDispatch::LoadInterlock
+            end
+          end
+
+          middleware.use ::Rack::Runtime
+          middleware.use ::Rack::MethodOverride unless config.api_only
+          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, config.debug_exception_response_format
+          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 unless config.api_only
+
+          if !config.api_only && 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 ::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 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