--- loncom/lonnet/perl/lonnet.pm	2002/08/30 18:36:03	1.276
+++ loncom/lonnet/perl/lonnet.pm	2002/09/24 18:25:45	1.286
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # TCP networking package
 #
-# $Id: lonnet.pm,v 1.276 2002/08/30 18:36:03 albertel Exp $
+# $Id: lonnet.pm,v 1.286 2002/09/24 18:25:45 matthew Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -348,12 +348,36 @@ sub delenv {
     return 'ok';
 }
 
+# ------------------------------------------ Fight off request when overloaded
+
+sub overloaderror {
+    my ($r,$checkserver)=@_;
+    unless ($checkserver) { $checkserver=$perlvar{'lonHostID'}; }
+    my $loadavg;
+    if ($checkserver eq $perlvar{'lonHostID'}) {
+       my $loadfile=Apache::File->new('/proc/loadavg');
+       $loadavg=<$loadfile>;
+       $loadavg =~ s/\s.*//g;
+       $loadavg = 100*$loadavg/$perlvar{'lonLoadLim'};
+    } else {
+       $loadavg=&reply('load',$checkserver);
+    }
+    my $overload=$loadavg-100;
+    if ($overload>0) {
+	$r->err_headers_out->{'Retry-After'}=$overload;
+        $r->log_error('Overload of '.$overload.' on '.$checkserver);
+        return 413;
+    }    
+    return '';
+}
+
 # ------------------------------ Find server with least workload from spare.tab
 
 sub spareserver {
+    my $loadpercent = shift;
     my $tryserver;
     my $spareserver='';
-    my $lowestserver=100;
+    my $lowestserver=$loadpercent; 
     foreach $tryserver (keys %spareid) {
        my $answer=reply('load',$tryserver);
        if (($answer =~ /\d/) && ($answer<$lowestserver)) {
@@ -871,7 +895,7 @@ sub countacc {
     my $url=&declutter(shift);
     unless ($ENV{'request.course.id'}) { return ''; }
     $accesshash{$ENV{'request.course.id'}.'___'.$url.'___course'}=1;
-    my $key=$processmarker.'_'.$dumpcount.'___'.$url.'___count';
+    my $key=$$.$processmarker.'_'.$dumpcount.'___'.$url.'___count';
     if (defined($accesshash{$key})) {
 	$accesshash{$key}++;
     } else {
@@ -2341,6 +2365,7 @@ sub createcourse {
     unless ($nonstandard) {
 # ------------------------------------------ For standard courses, make top url
         my $mapurl=&clutter($url);
+        if ($mapurl eq '/res/') { $mapurl=''; }
         $ENV{'form.initmap'}=(<<ENDINITMAP);
 <map>
 <resource id="1" type="start"></resource>
@@ -2534,6 +2559,14 @@ sub condval {
     return $result;
 }
 
+# ---------------------------------------------------- Devalidate courseresdata
+
+sub devalidatecourseresdata {
+    my ($coursenum,$coursedomain)=@_;
+    my $hashid=$coursenum.':'.$coursedomain;
+    delete $courseresdatacache{$hashid.'.time'};
+}
+
 # --------------------------------------------------- Course Resourcedata Query
 
 sub courseresdata {
@@ -2565,7 +2598,7 @@ sub courseresdata {
 # --------------------------------------------------------- Value of a Variable
 
 sub EXT {
-    my ($varname,$symbparm,$udom,$uname)=@_;
+    my ($varname,$symbparm,$udom,$uname,)=@_;
 
     unless ($varname) { return ''; }
 
@@ -2722,10 +2755,16 @@ sub EXT {
 # --------------------------------------------- last, look in resource metadata
 
 	$spacequalifierrest=~s/\./\_/;
-	my $metadata=&metadata($ENV{'request.filename'},$spacequalifierrest);
+	my $filename;
+	if (!$symbparm) { $symbparm=&symbread(); }
+	if ($symbparm) {
+	    $filename=(split(/\_\_\_/,$symbparm))[2];
+	} else {
+	    $filename=$ENV{'request.filename'};
+	}
+	my $metadata=&metadata($filename,$spacequalifierrest);
 	if ($metadata) { return $metadata; }
-	$metadata=&metadata($ENV{'request.filename'},
-			    'parameter_'.$spacequalifierrest);
+	$metadata=&metadata($filename,'parameter_'.$spacequalifierrest);
 	if ($metadata) { return $metadata; }
 
 # ------------------------------------------------------------------ Cascade up
@@ -2774,7 +2813,7 @@ sub metadata {
 # Look at timestamp of caching
 # Everything is cached by the main uri, libraries are never directly cached
 #
-    unless (abs($metacache{$uri.':cachedtimestamp'}-time)<600) {
+    unless (abs($metacache{$uri.':cachedtimestamp'}-time)<600 && !defined($liburi)) {
 #
 # Is this a recursive call for a library?
 #
@@ -2961,7 +3000,7 @@ sub symbverify {
     my $okay=0;
     if (tie(%bighash,'GDBM_File',$ENV{'request.course.fn'}.'.db',
                             &GDBM_READER(),0640)) {
-        my $ids=$bighash{'ids_/res/'.$thisfn};
+        my $ids=$bighash{'ids_'.&clutter($thisfn)};
         unless ($ids) { 
            $ids=$bighash{'ids_/'.$thisfn};
         }
@@ -3032,7 +3071,7 @@ sub symbread {
            if (tie(%bighash,'GDBM_File',$ENV{'request.course.fn'}.'.db',
                             &GDBM_READER(),0640)) {
 # ---------------------------------------------- Get ID(s) for current resource
-              my $ids=$bighash{'ids_/res/'.$thisfn};
+              my $ids=$bighash{'ids_'.&clutter($thisfn)};
               unless ($ids) { 
                  $ids=$bighash{'ids_/'.$thisfn};
               }
@@ -3292,7 +3331,7 @@ BEGIN {
 
     while (my $configline=<$config>) {
        chomp($configline);
-       if (($configline) && ($configline ne $perlvar{'lonHostID'})) {
+       if ($configline) {
           $spareid{$configline}=1;
        }
     }
@@ -3340,7 +3379,7 @@ BEGIN {
 
 %metacache=();
 
-$processmarker=$$.'_'.time.'_'.$perlvar{'lonHostID'};
+$processmarker='_'.time.'_'.$perlvar{'lonHostID'};
 $dumpcount=0;
 
 &logtouch();
@@ -3556,7 +3595,48 @@ modify user
 
 =item *
 
-modifystudent($udom,$uname,$uid,$umode,$upass,$first,$middle,$last,$gene,$usec,$end,$start) : modify student
+modifystudent
+
+modify a students enrollment and identification information.
+The course id is resolved based on the current users environment.  
+This means the envoking user must be a course coordinator or otherwise
+associated with a course.
+
+This call is essentially a wrapper for lonnet::modifyuser
+
+Inputs: 
+
+=over 4
+
+=item B<$udom> Students loncapa domain
+
+=item B<$uname> Students loncapa login name
+
+=item B<$uid> Students id/student number
+
+=item B<$umode> Students authentication mode
+
+=item B<$upass> Students password
+
+=item B<$first> Students first name
+
+=item B<$middle> Students middle name
+
+=item B<$last> Students last name
+
+=item B<$gene> Students generation
+
+=item B<$usec> Students section in course
+
+=item B<$end> Unix time of the roles expiration
+
+=item B<$start> Unix time of the roles start date
+
+=item B<$forceid> If defined, allow $uid to be changed
+
+=item B<$desiredhome> server to use as home server for student
+
+=back
 
 =item *