--- loncom/lonnet/perl/lonnet.pm	2007/03/28 00:05:45	1.851
+++ loncom/lonnet/perl/lonnet.pm	2007/03/28 00:12:58	1.852
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # TCP networking package
 #
-# $Id: lonnet.pm,v 1.851 2007/03/28 00:05:45 albertel Exp $
+# $Id: lonnet.pm,v 1.852 2007/03/28 00:12:58 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -7587,17 +7587,33 @@ BEGIN {
     %perlvar = (%perlvar,%{$configvars});
 }
 
+sub get_dns {
+    my ($url,$func) = @_;
+    open(my $config,"<$perlvar{'lonTabDir'}/hosts.tab");
+    foreach my $dns (<$config>) {
+	next if ($dns !~ /^\^(\S*)/x);
+	$dns = $1;
+	my $ua=new LWP::UserAgent;
+	my $request=new HTTP::Request('GET',"http://$dns$url");
+	my $response=$ua->request($request);
+	next if ($response->is_error());
+	my @content = split("\n",$response->content);
+	&$func(\@content);
+    }
+    close($config);
+}
 # ------------------------------------------------------------ Read domain file
 {
+    my $loaded;
     my %domain;
 
-    my $fh;
-    if (open($fh,"<".$Apache::lonnet::perlvar{'lonTabDir'}.'/domain.tab')) {
-	while (my $line = <$fh>) {
-	    next if ($line =~ /^(\#|\s*$ )/);
+    sub parse_domain_tab {
+	my ($lines) = @_;
+	foreach my $line (@$lines) {
+	    next if ($line =~ /^(\#|\s*$ )/x);
 
 	    chomp($line);
-	    my ($name,@elements) =  split(/:/,$line,9);
+	    my ($name,@elements) = split(/:/,$line,9);
 	    my %this_domain;
 	    foreach my $field ('description', 'auth_def', 'auth_arg_def',
 			       'lang_def', 'city', 'longi', 'lati',
@@ -7605,12 +7621,24 @@ BEGIN {
 		$this_domain{$field} = shift(@elements);
 	    }
 	    $domain{$name} = \%this_domain;
-#          &logthis("Domain.tab: $domain ".$domaindescription{$domain} );
+	    &logthis("Domain.tab: $name ".$domain{$name}{'description'} );
 	}
     }
-    close ($fh);
+    
+    sub load_domain_tab {
+	&get_dns('/adm/dns/domain',\&parse_domain_tab);
+	my $fh;
+	if (open($fh,"<".$perlvar{'lonTabDir'}.'/domain.tab')) {
+	    my @lines = <$fh>;
+	    &parse_domain_tab(\@lines);
+	}
+	close($fh);
+	$loaded = 1;
+    }
 
     sub domain {
+	&load_domain_tab() if (!$loaded);
+
 	my ($name,$what) = @_;
 	return if ( !exists($domain{$name}) );
 
@@ -7627,41 +7655,65 @@ BEGIN {
     my %hostname;
     my %hostdom;
     my %libserv;
-    open(my $config,"<$perlvar{'lonTabDir'}/hosts.tab");
+    my $loaded;
 
-    while (my $configline=<$config>) {
-       next if ($configline =~ /^(\#|\s*$)/);
-       chomp($configline);
-       my ($id,$domain,$role,$name)=split(/:/,$configline);
-       $name=~s/\s//g;
-       if ($id && $domain && $role && $name) {
-	 $hostname{$id}=$name;
-	 $hostdom{$id}=$domain;
-	 if ($role eq 'library') { $libserv{$id}=$name; }
-       }
+    sub parse_hosts_tab {
+	my ($file) = @_;
+	foreach my $configline (@$file) {
+	    next if ($configline =~ /^(\#|\s*$ )/x);
+	    next if ($configline =~ /^\^/);
+	    chomp($configline);
+	    my ($id,$domain,$role,$name)=split(/:/,$configline);
+	    $name=~s/\s//g;
+	    if ($id && $domain && $role && $name) {
+		$hostname{$id}=$name;
+		$hostdom{$id}=$domain;
+		if ($role eq 'library') { $libserv{$id}=$name; }
+	    }
+	    &logthis("Hosts.tab: $name ".$id );
+	}
     }
-    close($config);
+
+    sub load_hosts_tab {
+	&get_dns('/adm/dns/hosts',\&parse_hosts_tab);
+	open(my $config,"<$perlvar{'lonTabDir'}/hosts.tab");
+	my @config = <$config>;
+	&parse_hosts_tab(\@config);
+	close($config);
+	$loaded=1;
+    }
+
     # FIXME: dev server don't want this, production servers _do_ want this
     #&get_iphost();
 
     sub hostname {
+	&load_hosts_tab() if (!$loaded);
+
 	my ($lonid) = @_;
 	return $hostname{$lonid};
     }
 
     sub all_hostnames {
+	&load_hosts_tab() if (!$loaded);
+
 	return %hostname;
     }
 
     sub is_library {
+	&load_hosts_tab() if (!$loaded);
+
 	return exists($libserv{$_[0]});
     }
 
     sub all_library {
+	&load_hosts_tab() if (!$loaded);
+
 	return %libserv;
     }
 
     sub get_servers {
+	&load_hosts_tab() if (!$loaded);
+
 	my ($domain,$type) = @_;
 	my %possible_hosts = ($type eq 'library') ? %libserv
 	                                          : %hostname;
@@ -7683,11 +7735,15 @@ BEGIN {
     }
 
     sub host_domain {
+	&load_hosts_tab() if (!$loaded);
+
 	my ($lonid) = @_;
 	return $hostdom{$lonid};
     }
 
     sub all_domains {
+	&load_hosts_tab() if (!$loaded);
+
 	my %seen;
 	my @uniq = grep(!$seen{$_}++, values(%hostdom));
 	return @uniq;