--- loncom/interface/lonnavmaps.pm	2016/11/26 01:47:04	1.526
+++ loncom/interface/lonnavmaps.pm	2017/02/18 23:39:16	1.527
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Navigate Maps Handler
 #
-# $Id: lonnavmaps.pm,v 1.526 2016/11/26 01:47:04 raeburn Exp $
+# $Id: lonnavmaps.pm,v 1.527 2017/02/18 23:39:16 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -1684,6 +1684,18 @@ END
 	undef($args->{'sort'});
     }
 
+    # Determine if page will be served with https in case
+    # it contains a syllabus which uses an external URL
+    # which points at an http site.
+
+    my ($is_ssl,$cdom,$cnum);
+    if ($ENV{'SERVER_PORT'} == 443) {
+        $is_ssl = 1;
+    }
+    if ($env{'request.course.id'}) {
+        $cdom = $env{'course.'.$env{'request.course.id'}.'.domain'};
+        $cnum = $env{'course.'.$env{'request.course.id'}.'.num'};
+    }
 
     while (1) {
 	if ($args->{'sort'}) {
@@ -1817,8 +1829,15 @@ END
 		$stack=$it->getStack();
 	    }
 	    ($src,$symb,$anchor)=getLinkForResource($stack);
+            my $srcHasQuestion = $src =~ /\?/;
+            if ($env{'request.course.id'}) {
+                if (($src =~ m{^\Q/public/$cdom/$cnum/syllabus\E($|\?)}) && ($is_ssl) &&
+                    ($env{'course.'.$env{'request.course.id'}.'.externalsyllabus'} =~ m{^http://})) {
+                    $src .= ($srcHasQuestion? '&' : '?') . 'usehttp=1';
+                    $srcHasQuestion = 1;
+                }
+            }
 	    if (defined($anchor)) { $anchor='#'.$anchor; }
-	    my $srcHasQuestion = $src =~ /\?/;
 	    $args->{"resourceLink"} = $src.
 		($srcHasQuestion?'&':'?') .
 		'symb=' . &escape($symb).$anchor;