diff --git a/actionpack/lib/action_dispatch/http/url.rb b/actionpack/lib/action_dispatch/http/url.rb
index 2e39d0dbc2..3e5cd6a2f9 100644
--- a/actionpack/lib/action_dispatch/http/url.rb
+++ b/actionpack/lib/action_dispatch/http/url.rb
@@ -15,12 +15,12 @@ module ActionDispatch
 
       # Returns 'https://' if this is an SSL request and 'http://' otherwise.
       def protocol
-        ssl? ? 'https://' : 'http://'
+        @protocol ||= ssl? ? 'https://' : 'http://'
       end
 
       # Is this an SSL request?
       def ssl?
-        @env['HTTPS'] == 'on' || @env['HTTP_X_FORWARDED_PROTO'] == 'https'
+        @ssl ||= @env['HTTPS'] == 'on' || @env['HTTP_X_FORWARDED_PROTO'] == 'https'
       end
 
       # Returns the \host for this request, such as "example.com".