--- loncom/lonnet/perl/lonnet.pm	2020/03/03 01:16:39	1.1419
+++ loncom/lonnet/perl/lonnet.pm	2020/05/13 17:44:10	1.1422
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # TCP networking package
 #
-# $Id: lonnet.pm,v 1.1419 2020/03/03 01:16:39 raeburn Exp $
+# $Id: lonnet.pm,v 1.1422 2020/05/13 17:44:10 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -1230,6 +1230,28 @@ sub choose_server {
     return ($login_host,$hostname,$portal_path,$isredirect,$lowest_load);
 }
 
+sub get_course_sessions {
+    my ($cnum,$cdom,$lastactivity) = @_;
+    my %servers = &internet_dom_servers($cdom);
+    my %returnhash;
+    foreach my $server (sort(keys(%servers))) {
+        my $rep = &reply("coursesessions:$cdom:$cnum:$lastactivity",$server);
+        my @pairs=split(/\&/,$rep);
+        unless (($rep eq 'unknown_cmd') || ($rep =~ /^error/)) {
+            foreach my $item (@pairs) {
+                my ($key,$value)=split(/=/,$item,2);
+                $key = &unescape($key);
+                next if ($key =~ /^error: 2 /);
+                if (exists($returnhash{$key})) {
+                    next if ($value < $returnhash{$key});
+                }
+                $returnhash{$key}=$value;
+            }
+        }
+    }
+    return %returnhash;
+}
+
 # --------------------------------------------- Try to change a user's password
 
 sub changepass {
@@ -3361,6 +3383,32 @@ sub repcopy {
     }
 }
 
+# ------------------------------------------------- Unsubscribe from a resource
+
+sub unsubscribe {
+    my ($fname) = @_;
+    my $answer;
+    if ($fname=~/\/(aboutme|syllabus|bulletinboard|smppg)$/) { return $answer; }
+    $fname=~s/[\n\r]//g;
+    my $author=$fname;
+    $author=~s/\/home\/httpd\/html\/res\/([^\/]*)\/([^\/]*).*/$1\/$2/;
+    my ($udom,$uname)=split(/\//,$author);
+    my $home=homeserver($uname,$udom);
+    if ($home eq 'no_host') {
+        $answer = 'no_host';
+    } elsif (grep { $_ eq $home } &current_machine_ids()) {
+        $answer = 'home';
+    } else {
+        my $defdom = $perlvar{'lonDefDomain'};
+        if (&will_trust('content',$defdom,$udom)) {
+            $answer = reply("unsub:$fname",$home);
+        } else {
+            $answer = 'untrusted';
+        }
+    }
+    return $answer;
+}
+
 # ------------------------------------------------ Get server side include body
 sub ssi_body {
     my ($filelink,%form)=@_;
@@ -3506,12 +3554,18 @@ sub remove_stale_resfile {
                                     $stale = 1;
                                 }
                                 if ($stale) {
-                                    unlink($fname);
-                                    if ($uri!~/\.meta$/) {
-                                        unlink($fname.'.meta');
+                                    if (unlink($fname)) {
+                                        if ($uri!~/\.meta$/) {
+                                            if (-e $fname.'.meta') {
+                                                unlink($fname.'.meta');
+                                            }
+                                        }
+                                        my $unsubresult = &unsubscribe($fname);
+                                        unless ($unsubresult eq 'ok') {
+                                            &logthis("no unsub of $fname from $homeserver, reason: $unsubresult");
+                                        }
+                                        $removed = 1;
                                     }
-                                    &reply("unsub:$fname",$homeserver);
-                                    $removed = 1;
                                 }
                             }
                         }