From da7705b2746b36ccbe093d404d3f4c83a9b5e13e Mon Sep 17 00:00:00 2001
From: Eugen Rochko <eugen@zeonfederated.com>
Date: Wed, 10 Oct 2018 01:31:10 +0200
Subject: Add dns-prefetch if using different host for assets or uploads
 (#8942)

---
 app/helpers/application_helper.rb       | 16 ++++++++++++++++
 app/views/layouts/application.html.haml |  7 +++++++
 2 files changed, 23 insertions(+)

diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index f8e2c0e11..8533b398a 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -81,4 +81,20 @@ module ApplicationHelper
     output << 'rtl' if locale_direction == 'rtl'
     output.reject(&:blank?).join(' ')
   end
+
+  def cdn_host
+    ENV['CDN_HOST'].presence
+  end
+
+  def cdn_host?
+    cdn_host.present?
+  end
+
+  def storage_host
+    ENV['S3_ALIAS_HOST'].presence || ENV['S3_CLOUDFRONT_HOST'].presence
+  end
+
+  def storage_host?
+    storage_host.present?
+  end
 end
diff --git a/app/views/layouts/application.html.haml b/app/views/layouts/application.html.haml
index 436864237..3d63dc0f3 100755
--- a/app/views/layouts/application.html.haml
+++ b/app/views/layouts/application.html.haml
@@ -3,6 +3,13 @@
   %head
     %meta{ charset: 'utf-8' }/
     %meta{ name: 'viewport', content: 'width=device-width, initial-scale=1' }/
+
+    - if cdn_host?
+      %link{ rel: 'dns-prefetch', href: cdn_host }/
+
+    - if storage_host?
+      %link{ rel: 'dns-prefetch', href: storage_host }/
+
     %link{ rel: 'icon', href: favicon_path, type: 'image/x-icon' }/
     %link{ rel: 'apple-touch-icon', sizes: '180x180', href: '/apple-touch-icon.png' }/
     %link{ rel: 'mask-icon', href: '/mask-icon.svg', color: '#2B90D9' }/
-- 
cgit