--- loncom/auth/lonauth.pm	2010/05/27 22:05:47	1.101.8.1
+++ loncom/auth/lonauth.pm	2011/06/10 01:30:33	1.101.8.6
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # User Authentication Module
 #
-# $Id: lonauth.pm,v 1.101.8.1 2010/05/27 22:05:47 raeburn Exp $
+# $Id: lonauth.pm,v 1.101.8.6 2011/06/10 01:30:33 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -346,8 +346,10 @@ sub handler {
     if (grep(/^login$/,@cancreate)) {
         $defaultauth = 1;
     }
+    my $clientcancheckhost = 1;
     my $authhost=Apache::lonnet::authenticate($form{'uname'},$upass,
-                                              $form{'udom'},$defaultauth);
+                                              $form{'udom'},$defaultauth,
+                                              $clientcancheckhost);
     
 # --------------------------------------------------------------------- Failed?
 
@@ -359,10 +361,13 @@ sub handler {
         my %domconfig = 
             &Apache::lonnet::get_dom('configuration',['usercreation'],$form{'udom'});
         if (grep(/^login$/,@cancreate)) {
+            my $domdesc = &Apache::lonnet::domain($form{'udom'},'description');
+            unless (&check_can_host($r,\%form,'no_account_on_host',$domdesc)) {
+                return OK;     
+            }
             my $start_page = 
                 &Apache::loncommon::start_page('Create a user account in LON-CAPA',
                                                '',{'no_inline_link'   => 1,});
-            my $domdesc = &Apache::lonnet::domain($form{'udom'},'description');
             my $lonhost = $r->dir_config('lonHostID');
             my $origmail = $Apache::lonnet::perlvar{'lonSupportEMail'};
             my $contacts = 
@@ -412,15 +417,106 @@ sub handler {
 	}
     }
 
+    unless (&check_can_host($r,\%form,$authhost)) {
+        return OK;
+    }
+
     if ($r->dir_config("lonBalancer") eq 'yes') {
 	&success($r,$form{'uname'},$form{'udom'},$authhost,'noredirect',undef,
 		 \%form);
-	$r->internal_redirect('/adm/switchserver');
+        my $otherserver = &Apache::lonnet::spareserver(30000,undef,1,$form{'udom'});
+	$r->internal_redirect('/adm/switchserver?otherserver='.$otherserver.'&origurl='.$firsturl);
+        return OK;
     } else {
-	&success($r,$form{'uname'},$form{'udom'},$authhost,$firsturl,undef,
-		 \%form);
+# ------------------------------------------------------- Do the load balancing
+
+# ---------------------------------------------------------- Determine own load
+        my $loadlim = $r->dir_config('lonLoadLim');
+        my $loadavg;
+        {
+            my $loadfile=Apache::File->new('/proc/loadavg');
+            $loadavg=<$loadfile>;
+        }
+        $loadavg =~ s/\s.*//g;
+        my $loadpercent=sprintf("%.1f",100*$loadavg/$loadlim);
+        my $userloadpercent=&Apache::lonnet::userload();
+
+# ---------------------------------------------------------- Are we overloaded?
+        if ((($userloadpercent>100.0)||($loadpercent>100.0))) {
+            my $unloaded=Apache::lonnet::spareserver($loadpercent,$userloadpercent,1,$form{'udom'});
+            if ($unloaded) {
+                &success($r,$form{'uname'},$form{'udom'},$authhost,'noredirect',
+                         undef,\%form);
+                $r->internal_redirect('/adm/switchserver?otherserver='.$unloaded.'&origurl='.$firsturl);
+                return OK;
+            }
+        }
+        &success($r,$form{'uname'},$form{'udom'},$authhost,$firsturl,undef,
+                 \%form);
+        return OK;
+    }
+}
+
+sub check_can_host {
+    my ($r,$form,$authhost,$domdesc) = @_;
+    return unless (ref($form) eq 'HASH');
+    my $canhost = 1;
+    my $lonhost = $r->dir_config('lonHostID');
+    my $udom = $form->{'udom'};
+    my @intdoms;
+    my $internet_names = &Apache::lonnet::get_internet_names($lonhost);
+    if (ref($internet_names) eq 'ARRAY') {
+        @intdoms = @{$internet_names};
+    }
+    my $uprimary_id = &Apache::lonnet::domain($udom,'primary');
+    my $uint_dom = &Apache::lonnet::internet_dom($uprimary_id);
+    unless ($uint_dom ne '' && grep(/^\Q$uint_dom\E$/,@intdoms)) {
+        my $machine_dom = &Apache::lonnet::host_domain($lonhost);
+        my $hostname = &Apache::lonnet::hostname($lonhost);
+        my $serverhomeID = &Apache::lonnet::get_server_homeID($hostname);
+        my $serverhomedom = &Apache::lonnet::host_domain($serverhomeID);
+        my %defdomdefaults = &Apache::lonnet::get_domain_defaults($serverhomedom);
+        my %udomdefaults = &Apache::lonnet::get_domain_defaults($udom);
+        my $loncaparev;
+        if ($authhost eq 'no_account_on_host') {
+            $loncaparev = &Apache::lonnet::get_server_loncaparev($machine_dom);
+        } else {
+            $loncaparev = &Apache::lonnet::get_server_loncaparev($machine_dom,$lonhost);
+        }
+        $canhost = &Apache::lonnet::can_host_session($udom,$lonhost,$loncaparev,
+                                                     $udomdefaults{'remotesessions'},
+                                                     $defdomdefaults{'hostedsessions'});
+    }
+    unless ($canhost) {
+        if ($authhost eq 'no_account_on_host') {
+            my ($login_host,$hostname) = &Apache::lonnet::choose_server($udom);
+            &Apache::loncommon::content_type($r,'text/html');
+            $r->send_http_header;
+            if ($login_host ne '') {
+                my $protocol = $Apache::lonnet::protocol{$login_host};
+                $protocol = 'http' if ($protocol ne 'https');
+                my $newurl = $protocol.'://'.$hostname.'/adm/createaccount';
+                $r->print(&Apache::loncommon::start_page('Create a user account in LON-CAPA').
+                          '<h3>'.&mt('Account creation').'</h3>'.
+                          &mt('You do not currently have a LON-CAPA account at this institution.').'<br />'.
+                          '<p>'.&mt('You will be able to create one by logging into a LON-CAPA server within the [_1] domain.',$domdesc).'</p>'.
+                          '<p>'.&mt('[_1]Log in[_2]','<a href="'.$newurl.'">','</a>').
+                          &Apache::loncommon::end_page());
+            } else {
+                $r->print(&Apache::loncommon::start_page('Access to LON-CAPA unavailable').
+                          '<h3>'.&mt('Account creation unavailable').'</h3>'.
+                          &mt('You do not currently have a LON-CAPA account at this institution.').'<br />'.
+                          '<p>'.&mt('Currently a LON-CAPA server is not available within the [_1] domain for you to log-in to, to create an account.',$domdesc).'</p>'.
+                          &Apache::loncommon::end_page());
+            }
+        } else {
+            &success($r,$form->{'uname'},$udom,$authhost,'noredirect',undef,
+                     $form);
+            my ($otherserver) = &Apache::lonnet::choose_server($udom);
+            $r->internal_redirect('/adm/switchserver?otherserver='.$otherserver);
+        }
     }
-    return OK;
+    return $canhost;
 }
 
 1;