2 files changed, 21 insertions, 6 deletions
diff --git a/railties/lib/rails/application.rb b/railties/lib/rails/application.rb
index 7c590b701e..c403863007 100644
--- a/railties/lib/rails/application.rb
+++ b/railties/lib/rails/application.rb
@@ -145,9 +145,25 @@ module Rails
 
   protected
 
+    def static_paths
+      @static_paths ||= begin
+        static_paths = ActiveSupport::OrderedHash.new
+        static_paths["/"] = paths.public.to_a.first
+
+        railties.all do |railtie|
+          if railtie.config.respond_to?(:asset_path) && railtie.config.asset_path
+            public_path = railtie.config.paths.public.to_a.first
+            static_paths[railtie.config.asset_path % ""] = public_path if File.exists?(public_path)
+          end
+        end
+
+        static_paths
+      end
+    end
+
     def default_middleware_stack
       ActionDispatch::MiddlewareStack.new.tap do |middleware|
-        middleware.use ::ActionDispatch::Static, paths.public.to_a.first if config.serve_static_assets
+        middleware.use ::ActionDispatch::Static, static_paths if config.serve_static_assets
         middleware.use ::Rack::Lock if !config.allow_concurrency
         middleware.use ::Rack::Runtime
         middleware.use ::Rails::Rack::Logger
diff --git a/railties/lib/rails/engine.rb b/railties/lib/rails/engine.rb
index 49553a57f3..85ff09d2af 100644
--- a/railties/lib/rails/engine.rb
+++ b/railties/lib/rails/engine.rb
@@ -256,11 +256,7 @@ module Rails
     end
 
     def config
-      @config ||= begin
-        config = Engine::Configuration.new(find_root_with_flag("lib"))
-        config.asset_path = "/#{engine_name}%s" if File.exists?(config.paths.public.to_a.first)
-        config
-      end
+      @config ||= Engine::Configuration.new(find_root_with_flag("lib"))
     end
 
     # Add configured load paths to ruby load paths and remove duplicates.
@@ -335,6 +331,9 @@ module Rails
       require environment if environment
     end
 
+    initializer :default_asset_path do
+      config.asset_path = "/#{engine_name}%s" unless config.asset_path
+    end
   protected
     def find_root_with_flag(flag, default=nil)
       root_path = self.class.called_from