FIX: remove hardcoding from middleware stack so we can control it

app/controllers/static_controller.rb

@@ -76,7 +76,7 @@ class StaticController < ApplicationController
 
     # we must disable acceleration otherwise NGINX strips
     # access control headers
-    request.env['_disable_accl'] = true
+    request.env['sendfile.type'] = ''
     send_file(path, opts)
   end
 end

config/application.rb

@@ -122,13 +122,6 @@ module Discourse
     # supports etags (post 1.7)
     config.middleware.delete Rack::ETag
 
-    # We need to be able to disable for cdn assets
-    # x-accl-redirect strips headers we need to forward
-    # issue open since 2008
-    require 'middleware/optional_sendfile'
-    config.middleware.insert_after Rack::Sendfile, Middleware::OptionalSendfile, config.action_dispatch.x_sendfile_header
-    config.middleware.delete Rack::Sendfile
-
     # route all exceptions via our router
     config.exceptions_app = self.routes
 

config/environments/production.rb

@@ -21,9 +21,6 @@ Discourse::Application.configure do
   # Generate digests for assets URLs
   config.assets.digest = true
 
-  # Specifies the header that your server uses for sending files
-  config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' # for nginx
-
   # Enable locale fallbacks for I18n (makes lookups for any locale fall back to
   # the I18n.default_locale when a translation can not be found)
   config.i18n.fallbacks = true

lib/middleware/optional_sendfile.rb

@@ -1,11 +0,0 @@
-module Middleware
-  class OptionalSendfile < Rack::Sendfile
-    def call(env)
-      if env["_disable_accl"] == true
-        @app.call(env)
-      else
-        super(env)
-      end
-    end
-  end
-end