Handle files from ActionDispatch::Static with Rack::Sendfile (fixes #…

…5225)

This makes rails behave properly when you serve static assets
and you have X-Sendfile headers enabled. Nevertheless in most
cases you should not rely on that and serve static assets with
a webserver like Apache or Nginx (as you already have it in
place anyway if you use X-Sendfile)

railties/lib/rails/application.rb

@@ -229,6 +229,10 @@ def default_middleware_stack
           middleware.use ::Rack::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
@@ -242,10 +246,6 @@ def default_middleware_stack
         middleware.use ::ActionDispatch::DebugExceptions
         middleware.use ::ActionDispatch::RemoteIp, config.action_dispatch.ip_spoofing_check, config.action_dispatch.trusted_proxies
 
-        if config.action_dispatch.x_sendfile_header.present?
-          middleware.use ::Rack::Sendfile, config.action_dispatch.x_sendfile_header
-        end
-
         unless config.cache_classes
           app = self
           middleware.use ::ActionDispatch::Reloader, lambda { app.reload_dependencies? }

railties/test/application/middleware/sendfile_test.rb

@@ -57,5 +57,18 @@ def index
       get "/"
       assert_equal File.expand_path(__FILE__), last_response.headers["X-Lighttpd-Send-File"]
     end
+
+    test "files handled by ActionDispatch::Static are handled by Rack::Sendfile" do
+      make_basic_app do |app|
+        app.config.action_dispatch.x_sendfile_header = 'X-Sendfile'
+        app.config.serve_static_assets = true
+        app.paths["public"] = File.join(rails_root, "public")
+      end
+
+      app_file "public/foo.txt", "foo"
+
+      get "/foo.txt", "HTTP_X_SENDFILE_TYPE" => "X-Sendfile"
+      assert_equal File.join(rails_root, "public/foo.txt"), last_response.headers["X-Sendfile"]
+    end
   end
 end

railties/test/application/middleware_test.rb

@@ -26,6 +26,7 @@ def app
       boot!
 
       assert_equal [
+        "Rack::Sendfile",
         "ActionDispatch::Static",
         "Rack::Lock",
         "ActiveSupport::Cache::Strategy::LocalCache",
@@ -36,7 +37,6 @@ def app
         "ActionDispatch::ShowExceptions",
         "ActionDispatch::DebugExceptions",
         "ActionDispatch::RemoteIp",
-        "Rack::Sendfile",
         "ActionDispatch::Reloader",
         "ActionDispatch::Callbacks",
         "ActiveRecord::ConnectionAdapters::ConnectionManagement",