FIX: add ReadOnly hear to /srv/status

app/controllers/application_controller.rb

@@ -14,6 +14,7 @@ require_dependency 'global_path'
 require_dependency 'secure_session'
 require_dependency 'topic_query'
 require_dependency 'hijack'
+require_dependency 'read_only'
 
 class ApplicationController < ActionController::Base
   include CurrentUser
@@ -21,6 +22,7 @@ class ApplicationController < ActionController::Base
   include JsonError
   include GlobalPath
   include Hijack
+  include ReadOnly
 
   attr_reader :theme_ids
 
@@ -80,10 +82,6 @@ class ApplicationController < ActionController::Base
       (has_escaped_fragment? || CrawlerDetection.crawler?(request.user_agent) || params.key?("print"))
   end
 
-  def add_readonly_header
-    response.headers['Discourse-Readonly'] = 'true' if @readonly_mode
-  end
-
   def perform_refresh_session
     refresh_session(current_user) unless @readonly_mode
   end
@@ -508,10 +506,6 @@ class ApplicationController < ActionController::Base
 
   private
 
-  def check_readonly_mode
-    @readonly_mode = Discourse.readonly_mode?
-  end
-
   def locale_from_header
     begin
       # Rails I18n uses underscores between the locale and the region; the request

app/controllers/forums_controller.rb

@@ -1,6 +1,13 @@
 # frozen_string_literal: true
 
+require "read_only"
+
 class ForumsController < ActionController::Base
+  include ReadOnly
+
+  before_action :check_readonly_mode
+  after_action  :add_readonly_header
+
   def status
     if $shutdown
       render plain: 'shutting down', status: 500