--- loncom/lonnet/perl/lonnet.pm	2017/05/13 13:58:49	1.1172.2.93
+++ loncom/lonnet/perl/lonnet.pm	2018/09/02 02:13:59	1.1172.2.95
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # TCP networking package
 #
-# $Id: lonnet.pm,v 1.1172.2.93 2017/05/13 13:58:49 raeburn Exp $
+# $Id: lonnet.pm,v 1.1172.2.95 2018/09/02 02:13:59 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -8534,6 +8534,33 @@ sub auto_validate_class_sec {
     return $response;
 }
 
+sub auto_validate_instclasses {
+    my ($cdom,$cnum,$owners,$classesref) = @_;
+    my ($homeserver,%validations);
+    $homeserver = &homeserver($cnum,$cdom);
+    unless ($homeserver eq 'no_host') {
+        my $ownerlist;
+        if (ref($owners) eq 'ARRAY') {
+            $ownerlist = join(',',@{$owners});
+        } else {
+            $ownerlist = $owners;
+        }
+        if (ref($classesref) eq 'HASH') {
+            my $classes = &freeze_escape($classesref);
+            my $response=&reply('autovalidateinstclasses:'.&escape($ownerlist).
+                                ':'.$cdom.':'.$classes,$homeserver);
+            unless ($response =~ /(con_lost|error|no_such_host|refused)/) {
+                my @items = split(/&/,$response);
+                foreach my $item (@items) {
+                    my ($key,$value) = split('=',$item);
+                    $validations{&unescape($key)} = &thaw_unescape($value);
+                }
+            }
+        }
+    }
+    return %validations;
+}
+
 sub auto_crsreq_update {
     my ($cdom,$cnum,$crstype,$action,$ownername,$ownerdomain,$fullname,$title,
         $code,$accessstart,$accessend,$inbound) = @_;
@@ -9625,13 +9652,25 @@ sub generate_coursenum {
 sub is_course {
     my ($cdom, $cnum) = scalar(@_) == 1 ? 
          ($_[0] =~ /^($match_domain)_($match_courseid)$/)  :  @_;
-
-    return unless $cdom and $cnum;
-
-    my %courses = &courseiddump($cdom, '.', 1, '.', '.', $cnum, undef, undef,
-        '.');
-
-    return unless(exists($courses{$cdom.'_'.$cnum}));
+    return unless (($cdom =~ /^$match_domain$/) && ($cnum =~ /^$match_courseid$/));
+    my $uhome=&homeserver($cnum,$cdom);
+    my $iscourse;
+    if (grep { $_ eq $uhome } current_machine_ids()) {
+        $iscourse = &LONCAPA::Lond::is_course($cdom,$cnum);
+    } else {
+        my $hashid = $cdom.':'.$cnum;
+        ($iscourse,my $cached) = &is_cached_new('iscourse',$hashid);
+        unless (defined($cached)) {
+            my %courses = &courseiddump($cdom, '.', 1, '.', '.',
+                                        $cnum,undef,undef,'.');
+            $iscourse = 0;
+            if (exists($courses{$cdom.'_'.$cnum})) {
+                $iscourse = 1;
+            }
+            &do_cache_new('iscourse',$hashid,$iscourse,3600);
+        }
+    }
+    return unless($iscourse);
     return wantarray ? ($cdom, $cnum) : $cdom.'_'.$cnum;
 }