--- a/src/hdalab/settings.py	Tue Mar 13 16:52:47 2018 +0100
+++ b/src/hdalab/settings.py	Thu Mar 15 23:52:11 2018 +0100
@@ -225,3 +225,6 @@
     LOGIN_REDIRECT_URL = BASE_URL
 if 'LOGIN_URL' not in locals():
     LOGIN_URL = BASE_URL + "hdalab/hdabo/accounts/login"
+
+if 'FRONT_WEB_URL' not in locals():
+    FRONT_WEB_URL = WEB_URL #defined for preview calculation when internal url may be different than external url