FIX: attachment links in mail lacks protocol

lib/email/styles.rb

@@ -27,6 +27,7 @@ module Email
     def format_basic
       uri = URI(Discourse.base_url)
 
+      # images
       @fragment.css('img').each do |img|
 
         next if img['class'] == 'site-logo'
@@ -51,6 +52,20 @@ module Email
           img['src'] = "#{uri.scheme}:#{img['src']}"
         end
       end
+
+      # attachments
+      @fragment.css('a.attachment').each do |a|
+
+        # ensure all urls are absolute
+        if a['href'] =~ /^\/[^\/]/
+          a['href'] = "#{Discourse.base_url}#{a['href']}"
+        end
+
+        # ensure no schemaless urls
+        if a['href'] && a['href'].starts_with?("//")
+          a['href'] = "#{uri.scheme}:#{a['href']}"
+        end
+      end
     end
 
     def format_notification