Index: openacs-4/packages/acs-templating/acs-templating.info
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-templating/acs-templating.info,v
diff -u -N -r1.62 -r1.63
--- openacs-4/packages/acs-templating/acs-templating.info	29 Jan 2018 11:03:25 -0000	1.62
+++ openacs-4/packages/acs-templating/acs-templating.info	10 Mar 2018 18:59:33 -0000	1.63
@@ -9,7 +9,7 @@
     <implements-subsite-p>f</implements-subsite-p>
     <inherit-templates-p>t</inherit-templates-p>
     
-    <version name="5.10.0d4" url="http://openacs.org/repository/download/apm/acs-templating-5.10.0d4.apm">
+    <version name="5.10.0d5" url="http://openacs.org/repository/download/apm/acs-templating-5.10.0d5.apm">
         <owner url="http://openacs.org">OpenACS</owner>
         <summary>Templating library.</summary>
         <release-date>2017-08-06</release-date>
@@ -27,7 +27,7 @@
         <license>GPL version 2</license>
         <maturity>3</maturity>
 
-        <provides url="acs-templating" version="5.10.0d4"/>
+        <provides url="acs-templating" version="5.10.0d5"/>
         <requires url="acs-kernel" version="5.9.1"/>
         <requires url="acs-tcl" version="5.10.0d5"/>
 
Index: openacs-4/packages/acs-templating/tcl/head-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-templating/tcl/head-procs.tcl,v
diff -u -N -r1.24 -r1.25
--- openacs-4/packages/acs-templating/tcl/head-procs.tcl	9 Mar 2018 10:22:29 -0000	1.24
+++ openacs-4/packages/acs-templating/tcl/head-procs.tcl	10 Mar 2018 18:59:33 -0000	1.25
@@ -14,7 +14,7 @@
 namespace eval template::head {}
 
 ad_proc -private template::reset_request_vars {} {
-    Resets all global datastructures used to manage the head section of the
+    Resets all global data structures used to manage the head section of the
     returned document.  This should be called at the beginning of any request
     handled by the templating system.
 } {
@@ -28,6 +28,20 @@
     set ::template::footers [list]
 }
 
+ad_proc -public template::register_urn {
+    -urn:required
+    -resource:required
+} {
+
+    Register an urn for a resource. These urns provide a single place
+    for e.g updating references to external resources when switching
+    between a CDN and a local resource, or when a resource should be
+    updated.
+    
+} {
+   set ::template::head::urn($urn) $resource
+}
+
 ad_proc -public template::add_script {
     {-async:boolean}
     {-charset ""}
@@ -121,6 +135,14 @@
         set async ""
     }
 
+    #
+    # Replace potential urn in src with resolved value
+    #
+    set key ::template::head::urn($src)
+    if {[info exists $key]} {
+        set src [set $key]
+    }
+
     if {$src eq ""} {
         if {$script eq ""} {
             error "You must supply either -src or -script."
@@ -545,6 +567,8 @@
 
     if {$script ne ""} {
         #
+        # We have an inline script.
+        #
         # For the time being, not all browsers support
         # nonces. According to the specs the added 'unsafe-inline',
         # is ignored on browsers supporting nonces.
@@ -649,6 +673,19 @@
     }
 }
 
+ad_proc -private template::head::resolve_urn {
+    resource
+} {
+    Replace potential urn in provided resource name with resolved
+    value
+} {
+    set key ::template::head::urn($resource)
+    if {[info exists $key]} {
+        set resource [set $key]
+    }
+    return $resource
+}
+
 ad_proc template::head::prepare_multirows {} {
     Generate multirows for meta, css, scripts
     Called only from blank-master.tcl
@@ -693,7 +730,7 @@
                     template::multirow append link \
                         $rel \
                         $type \
-                        $href \
+                        [resolve_urn $href] \
                         $title \
                         $lang \
                         $media \
@@ -712,7 +749,7 @@
                     template::multirow append link \
                         $rel \
                         $type \
-                        $href \
+                        [resolve_urn $href] \
                         $title \
                         $lang \
                         $media \
@@ -754,9 +791,10 @@
             }
 
             foreach {type src charset defer async content order crossorigin integrity} $scripts($name) {
+                ns_log notice "ADD order $order src $src"
                 template::multirow append headscript \
                     $type \
-                    $src \
+                    [resolve_urn $src] \
                     $charset \
                     $defer \
                     $async \