--- loncom/interface/domainprefs.pm	2011/08/09 01:35:18	1.150
+++ loncom/interface/domainprefs.pm	2011/09/14 02:59:33	1.155
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Handler to set domain-wide configuration settings
 #
-# $Id: domainprefs.pm,v 1.150 2011/08/09 01:35:18 raeburn Exp $
+# $Id: domainprefs.pm,v 1.155 2011/09/14 02:59:33 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -171,6 +171,9 @@ use Locale::Language;
 use DateTime::TimeZone;
 use DateTime::Locale;
 
+my $registered_cleanup;
+my $modified_urls;
+
 sub handler {
     my $r=shift;
     if ($r->header_only) {
@@ -190,6 +193,10 @@ sub handler {
         "/adm/domainprefs:mau:0:0:Cannot modify domain settings";
         return HTTP_NOT_ACCEPTABLE;
     }
+
+    $registered_cleanup=0;
+    @{$modified_urls}=();
+
     &Apache::lonhtmlcommon::clear_breadcrumbs();
     &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},
                                             ['phase','actions']);
@@ -375,7 +382,6 @@ sub handler {
                             ],
                  },
     );
-    my $js;
     if (keys(%servers) > 1) {
         $prefs{'login'}  = { text   => 'Log-in page options',
                              help   => 'Domain_Configuration_Login_Page',
@@ -384,10 +390,6 @@ sub handler {
                                        {col1 => 'Log-in Page Items',
                                         col2 => ''}],
                            };
-        my ($othertitle,$usertypes,$types) =
-            &Apache::loncommon::sorted_inst_types($dom);
-
-        $js = &lonbalance_targets_js($dom,$types,\%servers); 
     }
     my @roles = ('student','coordinator','author','admin');
     my @actions = &Apache::loncommon::get_env_multiple('form.actions');
@@ -398,6 +400,15 @@ sub handler {
     if ($phase eq 'process') {
         &Apache::lonconfigsettings::make_changes($r,$dom,$phase,$context,\@prefs_order,\%prefs,\%domconfig,$confname,\@roles);
     } elsif ($phase eq 'display') {
+        my $js;
+        if (keys(%servers) > 1) {
+            my ($othertitle,$usertypes,$types) =
+                &Apache::loncommon::sorted_inst_types($dom);
+            $js = &lonbalance_targets_js($dom,$types,\%servers).
+                  &new_spares_js().
+                  &common_domprefs_js().
+                  &Apache::loncommon::javascript_array_indexof();
+        }
         &Apache::lonconfigsettings::display_settings($r,$dom,$phase,$context,\@prefs_order,\%prefs,\%domconfig,$confname,$js);
     } else {
         if (keys(%domconfig) == 0) {
@@ -2336,13 +2347,14 @@ sub print_usersessions {
     &build_location_hashes(\@intdoms,\%by_ip,\%by_location);
 
     my @alldoms = &Apache::lonnet::all_domains();
-    my %uniques = &Apache::lonnet::get_unique_servers(\@alldoms);
+    my %serverhomes = %Apache::lonnet::serverhomeIDs;
     my %servers = &Apache::lonnet::internet_dom_servers($dom);
+    my %altids = &id_for_thisdom(%servers);
     my $itemcount = 1;
     if ($position eq 'top') {
-        if (keys(%uniques) > 1) {
+        if (keys(%serverhomes) > 1) {
             my %spareid = &current_offloads_to($dom,$settings,\%servers);
-            $datatable .= &spares_row(\%servers,\%spareid,\%uniques,$rowtotal);
+            $datatable .= &spares_row($dom,\%servers,\%spareid,\%serverhomes,\%altids,$rowtotal);
         } else {
             $datatable .= '<tr'.$css_class.'><td colspan="2">'.
                           &mt('Nothing to set here, as the cluster to which this domain belongs only contains one server.');
@@ -2515,14 +2527,16 @@ sub build_location_hashes {
 sub current_offloads_to {
     my ($dom,$settings,$servers) = @_;
     my (%spareid,%otherdomconfigs);
-    if ((ref($settings) eq 'HASH') && (ref($servers) eq 'HASH')) {
+    if (ref($servers) eq 'HASH') {
         foreach my $lonhost (sort(keys(%{$servers}))) {
             my $gotspares;
-            if (ref($settings->{'spares'}) eq 'HASH') {
-                if (ref($settings->{'spares'}{$lonhost}) eq 'HASH') {
-                    $spareid{$lonhost}{'primary'} = $settings->{'spares'}{$lonhost}{'primary'};
-                    $spareid{$lonhost}{'default'} = $settings->{'spares'}{$lonhost}{'default'};
-                    $gotspares = 1;
+            if (ref($settings) eq 'HASH') {
+                if (ref($settings->{'spares'}) eq 'HASH') {
+                    if (ref($settings->{'spares'}{$lonhost}) eq 'HASH') {
+                        $spareid{$lonhost}{'primary'} = $settings->{'spares'}{$lonhost}{'primary'};
+                        $spareid{$lonhost}{'default'} = $settings->{'spares'}{$lonhost}{'default'};
+                        $gotspares = 1;
+                    }
                 }
             }
             unless ($gotspares) {
@@ -2590,63 +2604,101 @@ sub current_offloads_to {
 }
 
 sub spares_row {
-    my ($servers,$spareid,$uniques,$rowtotal) = @_;
+    my ($dom,$servers,$spareid,$serverhomes,$altids,$rowtotal) = @_;
     my $css_class;
     my $numinrow = 4;
     my $itemcount = 1;
     my $datatable;
-    if ((ref($servers) eq 'HASH') && (ref($spareid) eq 'HASH')) {
+    my %typetitles = &sparestype_titles();
+    if ((ref($servers) eq 'HASH') && (ref($spareid) eq 'HASH') && (ref($altids) eq 'HASH')) {
         foreach my $server (sort(keys(%{$servers}))) {
+            my $serverhome = &Apache::lonnet::get_server_homeID($servers->{$server});
+            my ($othercontrol,$serverdom);
+            if ($serverhome ne $server) {
+                $serverdom = &Apache::lonnet::host_domain($serverhome);
+                $othercontrol = &mt('Session offloading controlled by domain: [_1]','<b>'.$serverdom.'</b>');
+            } else {
+                $serverdom = &Apache::lonnet::host_domain($server);
+                if ($serverdom ne $dom) {
+                    $othercontrol = &mt('Session offloading controlled by domain: [_1]','<b>'.$serverdom.'</b>');
+                }
+            }
+            next unless (ref($spareid->{$server}) eq 'HASH');
             $css_class = $itemcount%2 ? ' class="LC_odd_row"' : '';
             $datatable .= '<tr'.$css_class.'>
                            <td rowspan="2">
-                            <span class="LC_nobreak"><b>'.$server.'</b> when busy, offloads to:</span></td>';
+                            <span class="LC_nobreak"><b>'.$server.'</b> when busy, offloads to:</span></td>'."\n";
             my (%current,%canselect);
-            if (ref($spareid->{$server}) eq 'HASH') {
-                foreach my $type ('primary','default') {
+            my @choices = 
+                &possible_newspares($server,$spareid->{$server},$serverhomes,$altids);
+            foreach my $type ('primary','default') {
+                if (ref($spareid->{$server}) eq 'HASH') {
                     if (ref($spareid->{$server}{$type}) eq 'ARRAY') {
                         my @spares = @{$spareid->{$server}{$type}};
                         if (@spares > 0) {
-                            $current{$type} .= '<table>';
-                            for (my $i=0;  $i<@spares; $i++) {
-                                my $rem = $i%($numinrow);
-                                if ($rem == 0) {
-                                    if ($i > 0) {
-                                        $current{$type} .= '</tr>';
+                            if ($othercontrol) {
+                                $current{$type} = join(', ',@spares);
+                            } else {
+                                $current{$type} .= '<table>';
+                                my $numspares = scalar(@spares);
+                                for (my $i=0;  $i<@spares; $i++) {
+                                    my $rem = $i%($numinrow);
+                                    if ($rem == 0) {
+                                        if ($i > 0) {
+                                            $current{$type} .= '</tr>';
+                                        }
+                                        $current{$type} .= '<tr>';
                                     }
-                                    $current{$type} .= '<tr>';
+                                    $current{$type} .= '<td><label><input type="checkbox" name="spare_'.$type.'_'.$server.'" id="spare_'.$type.'_'.$server.'_'.$i.'" checked="checked" value="'.$spareid->{$server}{$type}[$i].'" onclick="updateNewSpares(this.form,'."'$server'".');" />&nbsp;'.
+                                                       $spareid->{$server}{$type}[$i].
+                                                       '</label></td>'."\n";
                                 }
-                                $current{$type} .= '<td><label><input type="checkbox" name="spare_'.$type.'_'.$server.'" checked="checked" value="'.$spareid->{$server}{$type}[$i].'" />&nbsp;'.
-                                                   $spareid->{$server}{$type}[$i].
-                                                   '</label></td>';
-                            }
-                            my $rem = @spares%($numinrow);
-                            my $colsleft = $numinrow - $rem;
-                            if ($colsleft > 1 ) {
-                                $current{$type} .= '<td colspan="'.$colsleft.
-                                                   '" class="LC_left_item">'.
-                                                   '&nbsp;</td>';
-                            } elsif ($colsleft == 1) {
-                                $current{$type} .= '<td class="LC_left_item">&nbsp;</td>';
+                                my $rem = @spares%($numinrow);
+                                my $colsleft = $numinrow - $rem;
+                                if ($colsleft > 1 ) {
+                                    $current{$type} .= '<td colspan="'.$colsleft.
+                                                       '" class="LC_left_item">'.
+                                                       '&nbsp;</td>';
+                                } elsif ($colsleft == 1) {
+                                    $current{$type} .= '<td class="LC_left_item">&nbsp;</td>'."\n";
+                                }
+                                $current{$type} .= '</tr></table>';
                             }
                         }
-                        $current{$type} .= '</tr></table>';
                     }
                     if ($current{$type} eq '') {
                         $current{$type} = &mt('None specified');
                     }
-                    $canselect{$type} =
-                        &newspare_select($server,$type,$spareid->{$server}{$type},$uniques);
+                    if ($othercontrol) {
+                        if ($type eq 'primary') {
+                            $canselect{$type} = $othercontrol;
+                        }
+                    } else {
+                        $canselect{$type} = 
+                            &mt('Add new [_1]'.$type.'[_2]:','<i>','</i>').'&nbsp;'.
+                            '<select name="newspare_'.$type.'_'.$server.'" '.
+                            'id="newspare_'.$type.'_'.$server.'" onchange="checkNewSpares('."'$server','$type'".');">'."\n".
+                            '<option value="" selected ="selected">'.&mt('Select').'</option>'."\n";
+                        if (@choices > 0) {
+                            foreach my $lonhost (@choices) {
+                                $canselect{$type} .= '<option value="'.$lonhost.'">'.$lonhost.'</option>'."\n";
+                            }
+                        }
+                        $canselect{$type} .= '</select>'."\n";
+                    }
+                } else {
+                    $current{$type} = &mt('Could not be determined');
+                    if ($type eq 'primary') {
+                        $canselect{$type} =  $othercontrol;
+                    }
+                }
+                if ($type eq 'default') {
+                    $datatable .= '<tr'.$css_class.'>';
                 }
+                $datatable .= '<td><i>'.$typetitles{$type}.'</i></td>'."\n".
+                              '<td>'.$current{$type}.'</td>'."\n".
+                              '<td>'.$canselect{$type}.'</td></tr>'."\n";
             }
-            $datatable .= '<td><i>'.&mt('primary').'</i><td>'.$current{'primary'}.'</td>'.
-                          '<td>'.&mt('Add new [_1]primary[_2]:','<i>','</i>').'&nbsp;'.
-                          $canselect{'primary'}.'</td></tr>'.
-                          '<tr'.$css_class.'>'.
-                          '<td><i>'.&mt('default').'</i></td>'.
-                          '<td>'.$current{'default'}.'</td>'.
-                          '<td>'.&mt('Add new [_1]default[_2]:','<i>','</i>').'&nbsp;'.
-                          $canselect{'default'}.'</td></tr>';
             $itemcount ++;
         }
     }
@@ -2654,26 +2706,42 @@ sub spares_row {
     return $datatable;
 }
 
-sub newspare_select {
-    my ($server,$type,$currspares,$uniques) = @_;
-    my $output;
-    if (ref($uniques) eq 'HASH') {
-        if (keys(%{$uniques}) > 1) {
-            $output = '<select name="newspare_'.$type.'_'.$server.'">'."\n".
-                      '<option value="" selected ="selected">'.&mt('Select').'</option>'."\n";
-            foreach my $lonhost (sort(keys(%{$uniques}))) {
-                next if ($lonhost eq $server);
-                if (ref($currspares) eq 'ARRAY') {
-                    if (@{$currspares} > 0) {
-                        next if (grep(/^\Q$lonhost\E$/,@{$currspares}));
+sub possible_newspares {
+    my ($server,$currspares,$serverhomes,$altids) = @_;
+    my $serverhostname = &Apache::lonnet::hostname($server);
+    my %excluded;
+    if ($serverhostname ne '') {
+        %excluded = (
+                       $serverhostname => 1,
+                    );
+    }
+    if (ref($currspares) eq 'HASH') {
+        foreach my $type (keys(%{$currspares})) {
+            if (ref($currspares->{$type}) eq 'ARRAY') {
+                if (@{$currspares->{$type}} > 0) {
+                    foreach my $curr (@{$currspares->{$type}}) {
+                        my $hostname = &Apache::lonnet::hostname($curr);
+                        $excluded{$hostname} = 1;
                     }
                 }
-                $output .= '<option value="'.$lonhost.'">'.$lonhost.'</option>'."\n";
             }
-            $output .= '<select>';
         }
     }
-    return $output;
+    my @choices;
+    if ((ref($serverhomes) eq 'HASH') && (ref($altids) eq 'HASH')) {
+        if (keys(%{$serverhomes}) > 1) {
+            foreach my $name (sort(keys(%{$serverhomes}))) {
+                unless ($excluded{$name}) {
+                    if (exists($altids->{$serverhomes->{$name}})) {
+                        push(@choices,$altids->{$serverhomes->{$name}});
+                    } else {
+                        push(@choices,$serverhomes->{$name});
+                    }
+                }
+            }
+        }
+    }
+    return sort(@choices);
 }
 
 sub print_loadbalancing {
@@ -2702,7 +2770,7 @@ sub print_loadbalancing {
     if (ref($types) eq 'ARRAY') {
         $rownum += scalar(@{$types});
     }
-    my $css_class = 'class="LC_odd_row"';
+    my $css_class = ' class="LC_odd_row"';
     my $targets_div_style = 'display: none';
     my $disabled_div_style = 'display: block';
     my $homedom_div_style = 'display: none';
@@ -2775,14 +2843,14 @@ sub print_loadbalancing {
     $datatable .= '</div></td></tr>'.
                   &loadbalancing_rules($dom,$intdom,$currrules,$othertitle,
                                        $usertypes,$types,\%servers,$currbalancer,
-                                       $targets_div_style,$homedom_div_style);
+                                       $targets_div_style,$homedom_div_style,$css_class);
     $$rowtotal += $rownum;
     return $datatable;
 }
 
 sub loadbalancing_rules {
     my ($dom,$intdom,$currrules,$othertitle,$usertypes,$types,$servers,
-        $currbalancer,$targets_div_style,$homedom_div_style) = @_;
+        $currbalancer,$targets_div_style,$homedom_div_style,$css_class) = @_;
     my $output;
     my ($alltypes,$othertypes,$titles) = 
         &loadbalancing_titles($dom,$intdom,$usertypes,$types);
@@ -2799,7 +2867,7 @@ sub loadbalancing_rules {
             }
             $output .= &loadbalance_rule_row($type,$titles->{$type},$current,
                                              $servers,$currbalancer,$dom,
-                                             $targets_div_style,$homedom_div_style);
+                                             $targets_div_style,$homedom_div_style,$css_class);
         }
     }
     return $output;
@@ -2837,7 +2905,7 @@ sub loadbalancing_titles {
 
 sub loadbalance_rule_row {
     my ($type,$title,$current,$servers,$currbalancer,$dom,$targets_div_style,
-        $homedom_div_style) = @_;
+        $homedom_div_style,$css_class) = @_;
     my @rulenames = ('default','homeserver');
     my %ruletitles = &offloadtype_text();
     if ($type eq '_LC_external') {
@@ -2850,7 +2918,7 @@ sub loadbalance_rule_row {
         $style = $homedom_div_style;
     }
     my $output = 
-        '<tr><td valign="top"><div id="balanceruletitle_'.$type.'" style="'.$style.'">'.$title.'</div></td>'."\n".
+        '<tr'.$css_class.'><td valign="top"><div id="balanceruletitle_'.$type.'" style="'.$style.'">'.$title.'</div></td>'."\n".
         '<td><div id="balancerule_'.$type.'" style="'.$style.'">'."\n";
     for (my $i=0; $i<@rulenames; $i++) {
         my $rule = $rulenames[$i];
@@ -4944,8 +5012,15 @@ $env{'user.name'}.':'.$env{'user.domain'
             if (copy($source,$copyfile)) {
                 print $logfile "\nCopied original source to ".$copyfile."\n";
                 $output = 'ok';
-                &write_metadata($dom,$confname,$formname,$targetdir,$file,$logfile);
                 $logourl = '/res/'.$dom.'/'.$confname.'/'.$fname;
+                push(@{$modified_urls},[$copyfile,$source]);
+                my $metaoutput = 
+                    &write_metadata($dom,$confname,$formname,$targetdir,$file,$logfile);
+                unless ($registered_cleanup) {
+                    my $handlers = $r->get_handlers('PerlCleanupHandler');
+                    $r->set_handlers('PerlCleanupHandler' => [\&notifysubscribed,@{$handlers}]);
+                    $registered_cleanup=1;
+                }
             } else {
                 print $logfile "\nUnable to write ".$copyfile.':'.$!."\n";
                 $output = &mt('Failed to copy file to RES space').", $!";
@@ -4963,8 +5038,15 @@ $env{'user.name'}.':'.$env{'user.domain'
                             my $copyfile=$targetdir.'/tn-'.$file;
                             if (copy($outfile,$copyfile)) {
                                 print $logfile "\nCopied source to ".$copyfile."\n";
-                                &write_metadata($dom,$confname,$formname,
-                                                $targetdir,'tn-'.$file,$logfile);
+                                my $thumb_metaoutput = 
+                                    &write_metadata($dom,$confname,$formname,
+                                                    $targetdir,'tn-'.$file,$logfile);
+                                push(@{$modified_urls},[$copyfile,$outfile]);
+                                unless ($registered_cleanup) {
+                                    my $handlers = $r->get_handlers('PerlCleanupHandler');
+                                    $r->set_handlers('PerlCleanupHandler' => [\&notifysubscribed,@{$handlers}]);
+                                    $registered_cleanup=1;
+                                }
                             } else {
                                 print $logfile "\nUnable to write ".$copyfile.
                                                ':'.$!."\n";
@@ -5029,30 +5111,79 @@ sub write_metadata {
     {
         print $logfile "\nWrite metadata file for ".$targetdir.'/'.$file;
         my $mfh;
-        unless (open($mfh,'>'.$targetdir.'/'.$file.'.meta')) {
+        if (open($mfh,'>'.$targetdir.'/'.$file.'.meta')) {
+            foreach (sort keys %metadatafields) {
+                unless ($_=~/\./) {
+                    my $unikey=$_;
+                    $unikey=~/^([A-Za-z]+)/;
+                    my $tag=$1;
+                    $tag=~tr/A-Z/a-z/;
+                    print $mfh "\n\<$tag";
+                    foreach (split(/\,/,$metadatakeys{$unikey})) {
+                        my $value=$metadatafields{$unikey.'.'.$_};
+                        $value=~s/\"/\'\'/g;
+                        print $mfh ' '.$_.'="'.$value.'"';
+                    }
+                    print $mfh '>'.
+                        &HTML::Entities::encode($metadatafields{$unikey},'<>&"')
+                            .'</'.$tag.'>';
+                }
+            }
+            $output = 'ok';
+            print $logfile "\nWrote metadata";
+            close($mfh);
+        } else {
+            print $logfile "\nFailed to open metadata file";
             $output = &mt('Could not write metadata');
         }
-        foreach (sort keys %metadatafields) {
-            unless ($_=~/\./) {
-                my $unikey=$_;
-                $unikey=~/^([A-Za-z]+)/;
-                my $tag=$1;
-                $tag=~tr/A-Z/a-z/;
-                print $mfh "\n\<$tag";
-                foreach (split(/\,/,$metadatakeys{$unikey})) {
-                    my $value=$metadatafields{$unikey.'.'.$_};
-                    $value=~s/\"/\'\'/g;
-                    print $mfh ' '.$_.'="'.$value.'"';
-                }
-                print $mfh '>'.
-                    &HTML::Entities::encode($metadatafields{$unikey},'<>&"')
-                        .'</'.$tag.'>';
-            }
-        }
-        $output = 'ok';
-        print $logfile "\nWrote metadata";
-        close($mfh);
     }
+    return $output;
+}
+
+sub notifysubscribed {
+    foreach my $targetsource (@{$modified_urls}){
+        next unless (ref($targetsource) eq 'ARRAY');
+        my ($target,$source)=@{$targetsource};
+        if ($source ne '') {
+            if (open(my $logfh,'>>'.$source.'.log')) {
+                print $logfh "\nCleanup phase: Notifications\n";
+                my @subscribed=&subscribed_hosts($target);
+                foreach my $subhost (@subscribed) {
+                    print $logfh "\nNotifying host ".$subhost.':';
+                    my $reply=&Apache::lonnet::critical('update:'.$target,$subhost);
+                    print $logfh $reply;
+                }
+                my @subscribedmeta=&subscribed_hosts("$target.meta");
+                foreach my $subhost (@subscribedmeta) {
+                    print $logfh "\nNotifying host for metadata only ".$subhost.':';
+                    my $reply=&Apache::lonnet::critical('update:'.$target.'.meta',
+                                                        $subhost);
+                    print $logfh $reply;
+                }
+                print $logfh "\n============ Done ============\n";
+                close(logfh);
+            }
+        }
+    }
+    return OK;
+}
+
+sub subscribed_hosts {
+    my ($target) = @_;
+    my @subscribed;
+    if (open(my $fh,"<$target.subscription")) {
+        while (my $subline=<$fh>) {
+            if ($subline =~ /^($match_lonid):/) {
+                my $host = $1;
+                if ($host ne $Apache::lonnet::perlvar{'lonHostID'}) {
+                    unless (grep(/^\Q$host\E$/,@subscribed)) {
+                        push(@subscribed,$host);
+                    }
+                }
+            }
+        }
+    }
+    return @subscribed;
 }
 
 sub check_switchserver {
@@ -7342,7 +7473,6 @@ sub modify_usersessions {
     }
 
     my @alldoms = &Apache::lonnet::all_domains();
-    my %uniques = &Apache::lonnet::get_unique_servers(\@alldoms);
     my %servers = &Apache::lonnet::internet_dom_servers($dom);
     my %spareid = &current_offloads_to($dom,$domconfig{'usersessions'},\%servers);
     my $savespares;
@@ -7350,34 +7480,26 @@ sub modify_usersessions {
     foreach my $lonhost (sort(keys(%servers))) {
         my $serverhomeID =
             &Apache::lonnet::get_server_homeID($servers{$lonhost});
+        my $serverhostname = &Apache::lonnet::hostname($lonhost);
         $defaultshash{'usersessions'}{'spares'}{$lonhost} = {};
         my %spareschg;
         foreach my $type (@{$types{'spares'}}) {
             my @okspares;
             my @checked = &Apache::loncommon::get_env_multiple('form.spare_'.$type.'_'.$lonhost);
             foreach my $server (@checked) {
-                unless (($server eq $lonhost) || ($server eq $serverhomeID)) {
-                    if ($uniques{$server}) {
-                        push(@okspares,$server);
+                if (&Apache::lonnet::hostname($server) ne '') {
+                    unless (&Apache::lonnet::hostname($server) eq $serverhostname) {
+                        unless (grep(/^\Q$server\E$/,@okspares)) {
+                            push(@okspares,$server);
+                        }
                     }
                 }
             }
             my $new = $env{'form.newspare_'.$type.'_'.$lonhost};
             my $newspare;
-            if (($new ne '') && ($uniques{$new})) {
-                unless (($new eq $lonhost) || ($new eq $serverhomeID)) {
+            if (($new ne '') && (&Apache::lonnet::hostname($new))) {
+                unless (&Apache::lonnet::hostname($new) eq $serverhostname) {
                     $newspare = $new;
-                    $spareschg{$type} = 1;
-                }
-            }
-            if (ref($spareid{$lonhost}) eq 'HASH') {
-                if (ref($spareid{$lonhost}{$type}) eq 'ARRAY') {
-                    my @diffs = &Apache::loncommon::compare_arrays($domconfig{'usersessions'}{'spares'}{$lonhost}{$type},\@okspares);
-                    if (@diffs > 0) {
-                        $spareschg{$type} = 1;
-                    } elsif ($new ne '') {
-                        $spareschg{$type} = 1;
-                    }
                 }
             }
             my @spares;
@@ -7387,6 +7509,14 @@ sub modify_usersessions {
                 @spares = sort(@okspares);
             }
             $defaultshash{'usersessions'}{'spares'}{$lonhost}{$type} = \@spares;
+            if (ref($spareid{$lonhost}) eq 'HASH') {
+                if (ref($spareid{$lonhost}{$type}) eq 'ARRAY') {
+                    my @diffs = &Apache::loncommon::compare_arrays($spareid{$lonhost}{$type},\@spares);
+                    if (@diffs > 0) {
+                        $spareschg{$type} = 1;
+                    }
+                }
+            }
         }
         if (keys(%spareschg) > 0) {
             $changes{'spares'}{$lonhost} = \%spareschg;
@@ -7533,8 +7663,8 @@ sub modify_loadbalancing {
             }
             foreach my $sparetype (@sparestypes) {
                 my @targets = &Apache::loncommon::get_env_multiple('form.loadbalancing_target_'.$sparetype);
+                my @offloadto;
                 foreach my $target (@targets) {
-                    my @offloadto;
                     if (($servers{$target}) && ($target ne $balancer)) {
                         if ($sparetype eq 'default') {
                             if (ref($defaultshash{'loadbalancing'}{'targets'}{'primary'}) eq 'ARRAY') {
@@ -7802,17 +7932,28 @@ sub active_dc_picker {
 sub usersession_titles {
     return &Apache::lonlocal::texthash(
                hosted => 'Hosting of sessions for users from other domains on servers in this domain',
-
                remote => 'Hosting of sessions for users in this domain on servers in other domains',
                spares => 'Servers offloaded to, when busy',
                version => 'LON-CAPA version requirement',
                excludedomain => 'Allow all, but exclude specific domains',
                includedomain => 'Deny all, but include specific domains',
                primary => 'Primary (checked first)',
-               default => 'Default', 
+               default => 'Default',
            );
 }
 
+sub id_for_thisdom {
+    my (%servers) = @_;
+    my %altids;
+    foreach my $server (keys(%servers)) {
+        my $serverhome = &Apache::lonnet::get_server_homeID($servers{$server});
+        if ($serverhome ne $server) {
+            $altids{$serverhome} = $server;
+        }
+    }
+    return %altids;
+}
+
 sub count_servers {
     my ($currbalancer,%servers) = @_;
     my (@spares,$numspares);
@@ -7871,42 +8012,45 @@ function toggleTargets() {
 function showSpares(balancer,ishomedom) {
     var alltargets = new Array('$alltargets');
     var insttypes = new Array('$allinsttypes');
+    var offloadtypes = new Array('primary','default');
+
     document.getElementById('loadbalancing_targets').style.display='block';
     document.getElementById('loadbalancing_disabled').style.display='none';
-    var count = 0;
-    for (var i=0; i<alltargets.length; i++) {
-        if (alltargets[i] != balancer) {
-
-            document.getElementById('loadbalancing_target_'+count).value = alltargets[i];
-            document.getElementById('loadbalancing_targettxt_'+count).style.textAlign='left';
-            document.getElementById('loadbalancing_targettxt_'+count).style.textFace='normal';
-            document.getElementById('loadbalancing_targettxt_'+count).innerHTML = alltargets[i];
-
-            count ++;
+ 
+    for (var i=0; i<offloadtypes.length; i++) {
+        var count = 0;
+        for (var j=0; j<alltargets.length; j++) {
+            if (alltargets[j] != balancer) {
+                document.getElementById('loadbalancing_target_'+offloadtypes[i]+'_'+count).value = alltargets[j];
+                document.getElementById('loadbalancing_targettxt_'+offloadtypes[i]+'_'+count).style.textAlign='left';
+                document.getElementById('loadbalancing_targettxt_'+offloadtypes[i]+'_'+count).style.textFace='normal';
+                document.getElementById('loadbalancing_targettxt_'+offloadtypes[i]+'_'+count).innerHTML = alltargets[j];
+                count ++;
+            }
         }
     }
-    for (var j=0; j<insttypes.length; j++) {
-        if ((insttypes[j] == '_LC_external') || (insttypes[j] == '_LC_internetdom')) {
+    for (var k=0; k<insttypes.length; k++) {
+        if ((insttypes[k] == '_LC_external') || (insttypes[k] == '_LC_internetdom')) {
             if (ishomedom == 1) {
-                document.getElementById('balanceruletitle_'+insttypes[j]).style.display='block';
-                document.getElementById('balancerule_'+insttypes[j]).style.display='block';
+                document.getElementById('balanceruletitle_'+insttypes[k]).style.display='block';
+                document.getElementById('balancerule_'+insttypes[k]).style.display='block';
             } else {
-                document.getElementById('balanceruletitle_'+insttypes[j]).style.display='none';
-                document.getElementById('balancerule_'+insttypes[j]).style.display='none';
+                document.getElementById('balanceruletitle_'+insttypes[k]).style.display='none';
+                document.getElementById('balancerule_'+insttypes[k]).style.display='none';
 
             }
         } else {
-            document.getElementById('balanceruletitle_'+insttypes[j]).style.display='block';
-            document.getElementById('balancerule_'+insttypes[j]).style.display='block';
+            document.getElementById('balanceruletitle_'+insttypes[k]).style.display='block';
+            document.getElementById('balancerule_'+insttypes[k]).style.display='block';
         }
-        if ((insttypes[j] != '_LC_external') && 
-            ((insttypes[j] != '_LC_internetdom') ||
-             ((insttypes[j] == '_LC_internetdom') && (homedom == 1)))) {
-            document.getElementById('loadbalancing_singleserver_'+insttypes[j]).options[0] = new Option("","",true,true);
-            for (var k=0; k<alltargets.length; k++) {
-                var idx = k+1;
-                if (alltargets[k] != balancer) {
-                    document.getElementById('loadbalancing_singleserver_'+insttypes[j]).options[idx] = new Option(alltargets[k],alltargets[k],false,false);
+        if ((insttypes[k] != '_LC_external') && 
+            ((insttypes[k] != '_LC_internetdom') ||
+             ((insttypes[k] == '_LC_internetdom') && (ishomedom == 1)))) {
+            document.getElementById('loadbalancing_singleserver_'+insttypes[k]).options[0] = new Option("","",true,true);
+            for (var m=0; m<alltargets.length; m++) {
+                var idx = m+1;
+                if (alltargets[m] != balancer) {
+                    document.getElementById('loadbalancing_singleserver_'+insttypes[k]).options[idx] = new Option(alltargets[m],alltargets[m],false,false);
                 }
             }
         }
@@ -7928,13 +8072,14 @@ function hideSpares() {
            document.getElementById('loadbalancing_target_'+offloadtypes[i]+'_'+j).checked = false;
            document.getElementById('loadbalancing_target_'+offloadtypes[i]+'_'+j).value = '';
            document.getElementById('loadbalancing_targettxt_'+offloadtypes[i]+'_'+j).innerHTML = '';
+        }
     }
     for (var k=0; k<insttypes.length; k++) {
-        document.getElementById('balanceruletitle_'+insttypes[j]).style.display='none';
-        document.getElementById('balancerule_'+insttypes[j]).style.display='none';
-        if (insttypes[j] != '_LC_external') {
-            document.getElementById('loadbalancing_singleserver_'+insttypes[j]).length = 0;
-            document.getElementById('loadbalancing_singleserver_'+insttypes[j]).options[0] = new Option("","",true,true);
+        document.getElementById('balanceruletitle_'+insttypes[k]).style.display='none';
+        document.getElementById('balancerule_'+insttypes[k]).style.display='none';
+        if (insttypes[k] != '_LC_external') {
+            document.getElementById('loadbalancing_singleserver_'+insttypes[k]).length = 0;
+            document.getElementById('loadbalancing_singleserver_'+insttypes[k]).options[0] = new Option("","",true,true);
         }
     }
     return;
@@ -7947,9 +8092,9 @@ function checkOffloads(item,type) {
         var total = alltargets.length - 1;
         var other;
         if (type == offloadtypes[0]) {
-            other = offoadtypes[1];
+            other = offloadtypes[1];
         } else {
-            other = offoadtypes[0];
+            other = offloadtypes[0];
         }
         for (var i=0; i<total; i++) {
             var server = document.getElementById('loadbalancing_target_'+other+'_'+i).value;
@@ -7994,20 +8139,129 @@ function balanceruleChange(formname,type
     return;
 }
 
+// ]]>
+</script>
+
+END
+}
+
+sub new_spares_js {
+    my @sparestypes = ('primary','default');
+    my $types = join("','",@sparestypes);
+    my $select = &mt('Select');
+    return <<"END";
+
+<script type="text/javascript">
+// <![CDATA[
+
+function updateNewSpares(formname,lonhost) {
+    var types = new Array('$types');
+    var include = new Array();
+    var exclude = new Array();
+    for (var i=0; i<types.length; i++) {
+        var spareboxes = getIndicesByName(formname,'spare_'+types[i]+'_'+lonhost);
+        for (var j=0; j<spareboxes.length; j++) {
+            if (formname.elements[spareboxes[j]].checked) {
+                exclude.push(formname.elements[spareboxes[j]].value);
+            } else {
+                include.push(formname.elements[spareboxes[j]].value);
+            }
+        }
+    }
+    for (var i=0; i<types.length; i++) {
+        var newSpare = document.getElementById('newspare_'+types[i]+'_'+lonhost);
+        var selIdx = newSpare.selectedIndex;
+        var currnew = newSpare.options[selIdx].value;
+        var okSpares = new Array();
+        for (var j=0; j<newSpare.options.length; j++) {
+            var possible = newSpare.options[j].value;
+            if (possible != '') {
+                if (exclude.indexOf(possible) == -1) {
+                    okSpares.push(possible);
+                } else {
+                    if (currnew == possible) {
+                        selIdx = 0;
+                    }
+                }
+            }
+        }
+        for (var k=0; k<include.length; k++) {
+            if (okSpares.indexOf(include[k]) == -1) {
+                okSpares.push(include[k]);
+            }
+        }
+        okSpares.sort();
+        newSpare.options.length = 0;
+        if (selIdx == 0) {
+            newSpare.options[0] = new Option("$select","",true,true);
+        } else {
+            newSpare.options[0] = new Option("$select","",false,false);
+        }
+        for (var m=0; m<okSpares.length; m++) {
+            var idx = m+1;
+            var selThis = 0;
+            if (selIdx != 0) {
+                if (okSpares[m] == currnew) {
+                    selThis = 1;
+                }
+            }
+            if (selThis == 1) {
+                newSpare.options[idx] = new Option(okSpares[m],okSpares[m],true,true);
+            } else {
+                newSpare.options[idx] = new Option(okSpares[m],okSpares[m],false,false);
+            }
+        }
+    }
+    return;
+}
+
+function checkNewSpares(lonhost,type) {
+    var newSpare = document.getElementById('newspare_'+type+'_'+lonhost);
+    var chosen =  newSpare.options[newSpare.selectedIndex].value;
+    if (chosen != '') { 
+        var othertype;
+        var othernewSpare;
+        if (type == 'primary') {
+            othernewSpare = document.getElementById('newspare_default_'+lonhost);
+        }
+        if (type == 'default') {
+            othernewSpare = document.getElementById('newspare_primary_'+lonhost);
+        }
+        if (othernewSpare.options[othernewSpare.selectedIndex].value == chosen) {
+            othernewSpare.selectedIndex = 0;
+        }
+    }
+    return;
+}
+
+// ]]>
+</script>
+
+END
+
+}
+
+sub common_domprefs_js {
+    return <<"END";
+
+<script type="text/javascript">
+// <![CDATA[
+
 function getIndicesByName(formname,item) {
-    var radiogroup = new Array(); 
+    var group = new Array();
     for (var i=0;i<formname.elements.length;i++) {
         if (formname.elements[i].name == item) {
-            radiogroup.push(formname.elements[i].id);
+            group.push(formname.elements[i].id);
         }
     }
-    return radiogroup; 
+    return group;
 }
 
 // ]]>
 </script>
 
 END
+
 }
 
 1;