diff --git a/config/environments/development.rb b/config/environments/development.rb
index 58967bb01de..585317584b8 100644
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@@ -38,15 +38,15 @@
 
     config.cache_store = :memory_store
     config.public_file_server.headers = {
-      'Cache-Control' => "public, max-age=#{2.days.to_i}",
+      Rack::CACHE_CONTROL => "public, max-age=#{2.days.to_i}",
     }
   else
     config.action_controller.perform_caching = false
 
     config.cache_store = :null_store
     config.public_file_server.headers = {
-      'Cache-Control' => 'public, no-cache, must-revalidate',
-      'Vary' => '*',
+      Rack::CACHE_CONTROL => 'public, no-cache, must-revalidate',
+      'vary' => '*',
     }
   end
 
diff --git a/config/environments/test.rb b/config/environments/test.rb
index 436f9eb4e52..57cb8880d9c 100644
--- a/config/environments/test.rb
+++ b/config/environments/test.rb
@@ -4,7 +4,7 @@
   config.action_view.cache_template_loading = true
   config.eager_load = false
   config.public_file_server.enabled = true
-  config.public_file_server.headers = { 'Cache-Control' => 'public, max-age=3600' }
+  config.public_file_server.headers = { Rack::CACHE_CONTROL => 'public, max-age=3600' }
   config.consider_all_requests_local = true
   config.action_controller.perform_caching = false
   config.cache_store = :memory_store