--- loncom/lonnet/perl/lonnet.pm	2002/09/05 19:37:00	1.278
+++ loncom/lonnet/perl/lonnet.pm	2003/03/06 21:08:21	1.333
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # TCP networking package
 #
-# $Id: lonnet.pm,v 1.278 2002/09/05 19:37:00 www Exp $
+# $Id: lonnet.pm,v 1.333 2003/03/06 21:08:21 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -47,23 +47,18 @@
 # 09/01 Guy Albertelli
 # 09/01,10/01,11/01 Gerd Kortemeyer
 # YEAR=2001
-# 02/27/01 Scott Harrison
 # 3/2 Gerd Kortemeyer
-# 3/15,3/19 Scott Harrison
 # 3/19,3/20 Gerd Kortemeyer
-# 3/22,3/27,4/2,4/16,4/17 Scott Harrison
 # 5/26,5/28 Gerd Kortemeyer
 # 5/30 H. K. Ng
 # 6/1 Gerd Kortemeyer
 # July Guy Albertelli
 # 8/4,8/7,8/8,8/9,8/11,8/16,8/17,8/18,8/20,8/23,9/20,9/21,9/26,
 # 10/2 Gerd Kortemeyer
-# 10/5,10/10,11/13,11/15 Scott Harrison
 # 11/17,11/20,11/22,11/29 Gerd Kortemeyer
 # 12/5 Matthew Hall
 # 12/5 Guy Albertelli
 # 12/6,12/7,12/12 Gerd Kortemeyer
-# 12/18 Scott Harrison
 # 12/21,12/22,12/27,12/28 Gerd Kortemeyer
 # YEAR=2002
 # 1/4,2/4,2/7 Gerd Kortemeyer
@@ -77,15 +72,18 @@ use Apache::File;
 use LWP::UserAgent();
 use HTTP::Headers;
 use vars 
-qw(%perlvar %hostname %homecache %badServerCache %hostip %spareid %hostdom 
-   %libserv %pr %prp %metacache %packagetab 
+qw(%perlvar %hostname %homecache %badServerCache %hostip %iphost %spareid %hostdom 
+   %libserv %pr %prp %metacache %packagetab %titlecache 
    %courselogs %accesshash $processmarker $dumpcount 
-   %coursedombuf %coursehombuf %courseresdatacache %domaindescription);
+   %coursedombuf %coursehombuf %courseresdatacache 
+   %domaindescription %domain_auth_def %domain_auth_arg_def $tmpdir);
 use IO::Socket;
 use GDBM_File;
 use Apache::Constants qw(:common :http);
 use HTML::LCParser;
 use Fcntl qw(:flock);
+use Apache::loncoursedata;
+
 my $readit;
 
 # --------------------------------------------------------------------- Logging
@@ -140,9 +138,9 @@ sub reply {
     unless (defined($hostname{$server})) { return 'no_such_host'; }
     my $answer=subreply($cmd,$server);
     if ($answer eq 'con_lost') {
-       #sleep 5; 
-       #$answer=subreply($cmd,$server);
-       #if ($answer eq 'con_lost') {
+        #sleep 5; 
+        #$answer=subreply($cmd,$server);
+        #if ($answer eq 'con_lost') {
 	#   &logthis("Second attempt con_lost on $server");
         #   my $peerfile="$perlvar{'lonSockDir'}/$server";
         #   my $client=IO::Socket::UNIX->new(Peer    =>"$peerfile",
@@ -213,7 +211,8 @@ sub critical {
             $middlename=substr($middlename,0,16);
             $middlename=~s/\W//g;
             my $dfilename=
-             "$perlvar{'lonSockDir'}/delayed/$now.$middlename.$server";
+      "$perlvar{'lonSockDir'}/delayed/$now.$dumpcount.$$.$middlename.$server";
+            $dumpcount++;
             {
              my $dfh;
              if ($dfh=Apache::File->new(">$dfilename")) {
@@ -348,12 +347,36 @@ 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)) {
@@ -567,6 +590,59 @@ sub idput {
 
 # ------------------------------------- Find the section of student in a course
 
+sub getsection {
+    my ($udom,$unam,$courseid)=@_;
+    $courseid=~s/\_/\//g;
+    $courseid=~s/^(\w)/\/$1/;
+    my %Pending; 
+    my %Expired;
+    #
+    # Each role can either have not started yet (pending), be active, 
+    #    or have expired.
+    #
+    # If there is an active role, we are done.
+    #
+    # If there is more than one role which has not started yet, 
+    #     choose the one which will start sooner
+    # If there is one role which has not started yet, return it.
+    #
+    # If there is more than one expired role, choose the one which ended last.
+    # If there is a role which has expired, return it.
+    #
+    foreach (split(/\&/,&reply('dump:'.$udom.':'.$unam.':roles',
+                        &homeserver($unam,$udom)))) {
+        my ($key,$value)=split(/\=/,$_);
+        $key=&unescape($key);
+        next if ($key !~/^$courseid(?:\/)*(\w+)*\_st$/);
+        my $section=$1;
+        if ($key eq $courseid.'_st') { $section=''; }
+        my ($dummy,$end,$start)=split(/\_/,&unescape($value));
+        my $now=time;
+        if (defined($end) && ($now > $end)) {
+            $Expired{$end}=$section;
+            next;
+        }
+        if (defined($start) && ($now < $start)) {
+            $Pending{$start}=$section;
+            next;
+        }
+        return $section;
+    }
+    #
+    # Presumedly there will be few matching roles from the above
+    # loop and the sorting time will be negligible.
+    if (scalar(keys(%Pending))) {
+        my ($time) = sort {$a <=> $b} keys(%Pending);
+        return $Pending{$time};
+    } 
+    if (scalar(keys(%Expired))) {
+        my @sorted = sort {$a <=> $b} keys(%Expired);
+        my $time = pop(@sorted);
+        return $Expired{$time};
+    }
+    return '-1';
+}
+
 sub usection {
     my ($udom,$unam,$courseid)=@_;
     $courseid=~s/\_/\//g;
@@ -620,15 +696,40 @@ sub chatsend {
 		   &escape($newentry)),$chome);
 }
 
+# ------------------------------------------ Find current version of a resource
+
+sub getversion {
+    my $fname=&clutter(shift);
+    unless ($fname=~/^\/res\//) { return -1; }
+    return &currentversion(&filelocation('',$fname));
+}
+
+sub currentversion {
+    my $fname=shift;
+    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') { 
+        return -1; 
+    }
+    my $answer=reply("currentversion:$fname",$home);
+    if (($answer eq 'con_lost') || ($answer eq 'rejected')) {
+	return -1;
+    }
+    return $answer;
+}
+
 # ----------------------------- Subscribe to a resource, return URL if possible
 
 sub subscribe {
     my $fname=shift;
+    if ($fname=~/\/(aboutme|syllabus|bulletinboard|smppg)$/) { return ''; }
     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') || ($home eq $perlvar{'lonHostID'})) { 
+    if ($home eq 'no_host') { 
         return 'not_found'; 
     }
     my $answer=reply("sub:$fname",$home);
@@ -659,6 +760,11 @@ sub repcopy {
     } elsif ($remoteurl eq 'directory') {
            return OK;
     } else {
+        my $author=$filename;
+        $author=~s/\/home\/httpd\/html\/res\/([^\/]*)\/([^\/]*).*/$1\/$2/;
+        my ($udom,$uname)=split(/\//,$author);
+        my $home=homeserver($uname,$udom);
+        unless ($home eq $perlvar{'lonHostID'}) {
            my @parts=split(/\//,$filename);
            my $path="/$parts[1]/$parts[2]/$parts[3]/$parts[4]";
            if ($path ne "$perlvar{'lonDocRoot'}/res") {
@@ -694,9 +800,22 @@ sub repcopy {
                rename($transname,$filename);
                return OK;
            }
+       }
     }
 }
 
+# ------------------------------------------------ Get server side include body
+sub ssi_body {
+    my $filelink=shift;
+    my $output=($filelink=~/^http\:/?&externalssi($filelink):
+                                     &ssi($filelink));
+    $output=~s/^.*\<body[^\>]*\>//si;
+    $output=~s/\<\/body\s*\>.*$//si;
+    $output=~
+            s/\/\/ BEGIN LON\-CAPA Internal.+\/\/ END LON\-CAPA Internal\s//gs;
+    return $output;
+}
+
 # --------------------------------------------------------- Server Side Include
 
 sub ssi {
@@ -720,6 +839,14 @@ sub ssi {
     return $response->content;
 }
 
+sub externalssi {
+    my ($url)=@_;
+    my $ua=new LWP::UserAgent;
+    my $request=new HTTP::Request('GET',$url);
+    my $response=$ua->request($request);
+    return $response->content;
+}
+
 # ------- Add a token to a remote URI's query string to vouch for access rights
 
 sub tokenwrapper {
@@ -731,7 +858,8 @@ sub tokenwrapper {
     if ($uri=~/^uploaded\/([^\/]+)\/([^\/]+)\/([^\/]+)(\?\.*)*$/) {
 	&appenv('userfile.'.$1.'/'.$2.'/'.$3 => $ENV{'request.course.id'});
         return 'http://'.$hostname{ &homeserver($2,$1)}.'/'.$uri.
-               (($uri=~/\?/)?'&':'?').'token='.$token;
+               (($uri=~/\?/)?'&':'?').'token='.$token.
+                               '&tokenissued='.$perlvar{'lonHostID'};
     } else {
 	return '/adm/notfound.html';
     }
@@ -744,8 +872,15 @@ sub tokenwrapper {
 sub userfileupload {
     my ($formname,$coursedoc)=@_;
     my $fname=$ENV{'form.'.$formname.'.filename'};
+# Replace Windows backslashes by forward slashes
     $fname=~s/\\/\//g;
+# Get rid of everything but the actual filename
     $fname=~s/^.*\/([^\/]+)$/$1/;
+# Replace spaces by underscores
+    $fname=~s/\s+/\_/g;
+# Replace all other weird characters by nothing
+    $fname=~s/[^\w\.\-]//g;
+# See if there is anything left
     unless ($fname) { return 'error: no uploaded file'; }
     chop($ENV{'form.'.$formname});
 # Create the directory if not present
@@ -784,13 +919,16 @@ sub finishuserfileupload {
     }
 # Notify homeserver to grep it
 #
-    if 
-(&reply('fetchuserfile:'.$docudom.'/'.$docuname.'/'.$fname,$docuhome) eq 'ok') 
-    {
+    
+    my $fetchresult= 
+ &reply('fetchuserfile:'.$docudom.'/'.$docuname.'/'.$fname,$docuhome);
+    if ($fetchresult eq 'ok') {
 #
 # Return the URL to it
         return '/uploaded/'.$path.$fname;
     } else {
+        &logthis('Failed to transfer '.$docudom.'/'.$docuname.'/'.$fname.
+         ' to host '.$docuhome.': '.$fetchresult);
         return '/adm/notfound.html';
     }    
 }
@@ -871,7 +1009,7 @@ 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 {
@@ -986,12 +1124,16 @@ sub expirespread {
 # ----------------------------------------------------- Devalidate Spreadsheets
 
 sub devalidate {
-    my $symb=shift;
+    my ($symb,$uname,$udom)=@_;
     my $cid=$ENV{'request.course.id'}; 
     if ($cid) {
-	my $key=$ENV{'user.name'}.':'.$ENV{'user.domain'}.':';
+# delete the stored spreadsheets for
+# - the student level sheet of this user in course's homespace
+# - the assessment level sheet for this resource 
+#   for this user in user's homespace
+	my $key=$uname.':'.$udom.':';
         my $status=
-	    &del('nohist_calculatedsheet',
+	    &del('nohist_calculatedsheets',
 		 [$key.'studentcalc'],
 		 $ENV{'course.'.$cid.'.domain'},
 		 $ENV{'course.'.$cid.'.num'})
@@ -1000,7 +1142,7 @@ sub devalidate {
 		 [$key.'assesscalc:'.$symb]);
         unless ($status eq 'ok ok') {
            &logthis('Could not devalidate spreadsheet '.
-                    $ENV{'user.name'}.' at '.$ENV{'user.domain'}.' for '.
+                    $uname.' at '.$udom.' for '.
 		    $symb.': '.$status);
         }
     }
@@ -1332,7 +1474,10 @@ sub store {
     $symb=&symbclean($symb);
     if (!$symb) { unless ($symb=&symbread()) { return ''; } }
 
-    &devalidate($symb);
+    if (!$domain) { $domain=$ENV{'user.domain'}; }
+    if (!$stuname) { $stuname=$ENV{'user.name'}; }
+
+    &devalidate($symb,$stuname,$domain);
 
     $symb=escape($symb);
     if (!$namespace) { 
@@ -1340,8 +1485,6 @@ sub store {
           return ''; 
        } 
     }
-    if (!$domain) { $domain=$ENV{'user.domain'}; }
-    if (!$stuname) { $stuname=$ENV{'user.name'}; }
     if (!$home) { $home=$ENV{'user.home'}; }
     my $namevalue='';
     foreach (keys %$storehash) {
@@ -1363,7 +1506,10 @@ sub cstore {
     $symb=&symbclean($symb);
     if (!$symb) { unless ($symb=&symbread()) { return ''; } }
 
-    &devalidate($symb);
+    if (!$domain) { $domain=$ENV{'user.domain'}; }
+    if (!$stuname) { $stuname=$ENV{'user.name'}; }
+
+    &devalidate($symb,$stuname,$domain);
 
     $symb=escape($symb);
     if (!$namespace) { 
@@ -1371,8 +1517,6 @@ sub cstore {
           return ''; 
        } 
     }
-    if (!$domain) { $domain=$ENV{'user.domain'}; }
-    if (!$stuname) { $stuname=$ENV{'user.name'}; }
     if (!$home) { $home=$ENV{'user.home'}; }
 
     my $namevalue='';
@@ -1430,11 +1574,15 @@ sub coursedescription {
     $courseid=~s/\_/\//g;
     my ($cdomain,$cnum)=split(/\//,$courseid);
     my $chome=&homeserver($cnum,$cdomain);
+    my $normalid=$cdomain.'_'.$cnum;
+    # need to always cache even if we get errors otherwise we keep 
+    # trying and trying and trying to get the course description.
+    my %envhash=();
+    my %returnhash=();
+    $envhash{'course.'.$normalid.'.last_cache'}=time;
     if ($chome ne 'no_host') {
-       my %returnhash=&dump('environment',$cdomain,$cnum);
+       %returnhash=&dump('environment',$cdomain,$cnum);
        if (!exists($returnhash{'con_lost'})) {
-           my $normalid=$cdomain.'_'.$cnum;
-           my %envhash=();
            $returnhash{'home'}= $chome;
 	   $returnhash{'domain'} = $cdomain;
 	   $returnhash{'num'} = $cnum;
@@ -1444,15 +1592,13 @@ sub coursedescription {
            $returnhash{'url'}=&clutter($returnhash{'url'});
            $returnhash{'fn'}=$perlvar{'lonDaemons'}.'/tmp/'.
 	       $ENV{'user.name'}.'_'.$cdomain.'_'.$cnum;
-           $envhash{'course.'.$normalid.'.last_cache'}=time;
            $envhash{'course.'.$normalid.'.home'}=$chome;
            $envhash{'course.'.$normalid.'.domain'}=$cdomain;
            $envhash{'course.'.$normalid.'.num'}=$cnum;
-           &appenv(%envhash);
-           return %returnhash;
        }
     }
-    return ();
+    &appenv(%envhash);
+    return %returnhash;
 }
 
 # -------------------------------------------------------- Get user privileges
@@ -1619,6 +1765,58 @@ sub dump {
    return %returnhash;
 }
 
+# --------------------------------------------------------------- currentdump
+sub currentdump {
+   my ($courseid,$sdom,$sname)=@_;
+   $courseid = $ENV{'request.course.id'} if (! defined($courseid));
+   $sdom     = $ENV{'user.domain'}       if (! defined($sdom));
+   $sname    = $ENV{'user.name'}         if (! defined($sname));
+   my $uhome = &homeserver($sname,$sdom);
+   my $rep=reply('currentdump:'.$sdom.':'.$sname.':'.$courseid,$uhome);
+   return if ($rep =~ /^(error:|no_such_host)/);
+   #
+   my %returnhash=();
+   #
+   if ($rep eq "unknown_cmd") { 
+       # an old lond will not know currentdump
+       # Do a dump and make it look like a currentdump
+       my @tmp = &dump($courseid,$sdom,$sname,'.');
+       return if ($tmp[0] =~ /^(error:|no_such_host)/);
+       my %hash = @tmp;
+       @tmp=();
+       # Code ripped from lond, essentially.  The only difference
+       # here is the unescaping done by lonnet::dump().  Conceivably
+       # we might run in to problems with parameter names =~ /^v\./
+       while (my ($key,$value) = each(%hash)) {
+           my ($v,$symb,$param) = split(/:/,$key);
+           next if ($v eq 'version' || $symb eq 'keys');
+           next if (exists($returnhash{$symb}) &&
+                    exists($returnhash{$symb}->{$param}) &&
+                    $returnhash{$symb}->{'v.'.$param} > $v);
+           $returnhash{$symb}->{$param}=$value;
+           $returnhash{$symb}->{'v.'.$param}=$v;
+       }
+       #
+       # Remove all of the keys in the hashes which keep track of
+       # the version of the parameter.
+       while (my ($symb,$param_hash) = each(%returnhash)) {
+           # use a foreach because we are going to delete from the hash.
+           foreach my $key (keys(%$param_hash)) {
+               delete($param_hash->{$key}) if ($key =~ /^v\./);
+           }
+       }
+   } else {
+       my @pairs=split(/\&/,$rep);
+       foreach (@pairs) {
+           my ($key,$value)=split(/=/,$_);
+           my ($symb,$param) = split(/:/,$key);
+           $returnhash{&unescape($symb)}->{&unescape($param)} = 
+                                                          &unescape($value);
+       }
+   }
+   return %returnhash;
+}
+
 # --------------------------------------------------------------- put interface
 
 sub put {
@@ -1690,7 +1888,9 @@ sub allowed {
 
     if ($priv eq 'bre') {
         my $copyright=&metadata($uri,'copyright');
-	if ($copyright eq 'public') { return 'F'; }
+	if (($copyright eq 'public') && (!$ENV{'request.course.id'})) { 
+           return 'F'; 
+        }
         if ($copyright eq 'priv') {
             $uri=~/([^\/]+)\/([^\/]+)\//;
 	    unless (($ENV{'user.name'} eq $2) && ($ENV{'user.domain'} eq $1)) {
@@ -1744,6 +1944,12 @@ sub allowed {
        $thisallowed.=$1;
     }
 
+# URI is an uploaded document for this course
+
+    if (($priv eq 'bre') && 
+        ($uri=~/^uploaded\/$ENV{'course.'.$ENV{'request.course.id'}.'.domain'}\/$ENV{'course.'.$ENV{'request.course.id'}.'.num'}/)) {
+        return 'F';
+    }
 # Full access at system, domain or course-wide level? Exit.
 
     if ($thisallowed=~/F/) {
@@ -1962,14 +2168,16 @@ sub is_on_map {
     my @uriparts=split(/\//,$uri);
     my $filename=$uriparts[$#uriparts];
     my $pathname=$uri;
-    $pathname=~s/\/$filename$//;
+    $pathname=~s|/\Q$filename\E$||;
+    $pathname=~s/^adm\/wrapper\///;    
+    #Trying to find the conditional for the file
     my $match=($ENV{'acc.res.'.$ENV{'request.course.id'}.'.'.$pathname}=~
-	       /\&$filename\:([\d\|]+)\&/);
+	       /\&\Q$filename\E\:([\d\|]+)\&/);
     if ($match) {
-       return (1,$1);
-   } else {
-       return (0,0);
-   }
+	return (1,$1);
+    } else {
+	return (0,0);
+    }
 }
 
 # ----------------------------------------------------------------- Define Role
@@ -2229,10 +2437,15 @@ sub modifyuser {
        }
     }
 # -------------------------------------------------------------- Add names, etc
-    my %names=&get('environment',
+    my @tmp=&get('environment',
 		   ['firstname','middlename','lastname','generation'],
 		   $udom,$uname);
-    if ($names{'firstname'} =~ m/^error:.*/) { %names=(); }
+    my %names;
+    if ($tmp[0] =~ m/^error:.*/) { 
+        %names=(); 
+    } else {
+        %names = @tmp;
+    }
     if ($first)  { $names{'firstname'}  = $first; }
     if ($middle) { $names{'middlename'} = $middle; }
     if ($last)   { $names{'lastname'}   = $last; }
@@ -2260,20 +2473,59 @@ sub modifystudent {
 	($udom,$uname,$uid,$umode,$upass,$first,$middle,$last,$gene,$forceid,
          $desiredhome);
     unless ($reply eq 'ok') { return $reply; }
+    # This will cause &modify_student_enrollment to get the uid from the
+    # students environment
+    $uid = undef if (!$forceid);
+    $reply = &modify_student_enrollment($udom,$uname,$uid,$first,$middle,
+                                        $last,$gene,$usec,$end,$start);
+    return $reply;
+}
+
+sub modify_student_enrollment {
+    my ($udom,$uname,$uid,$first,$middle,$last,$gene,$usec,$end,$start) = @_;
+    # Get the course id from the environment
+    my $cid='';
+    unless ($cid=$ENV{'request.course.id'}) {
+	return 'not_in_class';
+    }
+    # Make sure the user exists
     my $uhome=&homeserver($uname,$udom);
     if (($uhome eq '') || ($uhome eq 'no_host')) { 
 	return 'error: no such user';
     }
-# -------------------------------------------------- Add student to course list
-    $reply=critical('put:'.$ENV{'course.'.$cid.'.domain'}.':'.
+    #
+    # Get student data if we were not given enough information
+    if (!defined($first)  || $first  eq '' || 
+        !defined($last)   || $last   eq '' || 
+        !defined($uid)    || $uid    eq '' || 
+        !defined($middle) || $middle eq '' || 
+        !defined($gene)   || $gene   eq '') {
+        # They did not supply us with enough data to enroll the student, so
+        # we need to pick up more information.
+        my %tmp = &get('environment',
+                       ['firstname','middlename','lastname', 'generation','id']
+                       ,$udom,$uname);
+
+        foreach (keys(%tmp)) {
+            &logthis("key $_ = ".$tmp{$_});
+        }
+        $first  = $tmp{'firstname'}  if (!defined($first)  || $first  eq '');
+        $middle = $tmp{'middlename'} if (!defined($middle) || $middle eq '');
+        $last   = $tmp{'lastname'}   if (!defined($last)   || $last eq '');
+        $gene   = $tmp{'generation'} if (!defined($gene)   || $gene eq '');
+        $uid    = $tmp{'id'}         if (!defined($uid)    || $uid  eq '');
+    }
+    my $fullname = &Apache::loncoursedata::ProcessFullName($last,$gene,
+                                                           $first,$middle);
+    my $reply=critical('put:'.$ENV{'course.'.$cid.'.domain'}.':'.
 	              $ENV{'course.'.$cid.'.num'}.':classlist:'.
                       &escape($uname.':'.$udom).'='.
-                      &escape($end.':'.$start),
+                      &escape(join(':',$end,$start,$uid,$usec,$fullname)),
 	              $ENV{'course.'.$cid.'.home'});
     unless (($reply eq 'ok') || ($reply eq 'delayed')) {
 	return 'error: '.$reply;
     }
-# ---------------------------------------------------- Add student role to user
+    # Add student role to user
     my $uurl='/'.$cid;
     $uurl=~s/\_/\//g;
     if ($usec) {
@@ -2535,6 +2787,14 @@ sub condval {
     return $result;
 }
 
+# ---------------------------------------------------- Devalidate courseresdata
+
+sub devalidatecourseresdata {
+    my ($coursenum,$coursedomain)=@_;
+    my $hashid=$coursenum.':'.$coursedomain;
+    delete $courseresdatacache{$hashid.'.time'};
+}
+
 # --------------------------------------------------- Course Resourcedata Query
 
 sub courseresdata {
@@ -2553,20 +2813,22 @@ sub courseresdata {
 	if ($tmp !~ /^(con_lost|error|no_such_host)/i) {
 	    $courseresdatacache{$hashid.'.time'}=time;
 	    $courseresdatacache{$hashid}=\%dumpreply;
+	} elsif ($tmp =~ /^(con_lost|no_such_host)/) {
+	    return $tmp;
 	}
     }
     foreach my $item (@which) {
-	if ($courseresdatacache{$hashid}->{$item}) {
+	if (defined($courseresdatacache{$hashid}->{$item})) {
 	    return $courseresdatacache{$hashid}->{$item};
 	}
     }
-    return '';
+    return undef;
 }
 
 # --------------------------------------------------------- Value of a Variable
 
 sub EXT {
-    my ($varname,$symbparm,$udom,$uname)=@_;
+    my ($varname,$symbparm,$udom,$uname,)=@_;
 
     unless ($varname) { return ''; }
 
@@ -2578,14 +2840,14 @@ sub EXT {
     } else {
 	$courseid=$ENV{'request.course.id'};
     }
-
     my ($realm,$space,$qualifier,@therest)=split(/\./,$varname);
     my $rest;
-    if ($therest[0]) {
+    if (defined($therest[0])) {
        $rest=join('.',@therest);
     } else {
        $rest='';
     }
+
     my $qualifierrest=$qualifier;
     if ($rest) { $qualifierrest.='.'.$rest; }
     my $spacequalifierrest=$space;
@@ -2679,24 +2941,35 @@ sub EXT {
 	    my $courselevelm=$courseid.'.'.$mapparm;
 
 # ----------------------------------------------------------- first, check user
-	    my %resourcedata=&get('resourcedata',
-				  [$courselevelr,$courselevelm,$courselevel],
-				 $udom,$uname);
-	    if (($resourcedata{$courselevelr}!~/^error\:/) &&
-		($resourcedata{$courselevelr}!~/^con_lost/)) {
-
-		if ($resourcedata{$courselevelr}) {
-		    return $resourcedata{$courselevelr}; }
-		if ($resourcedata{$courselevelm}) {
-		    return $resourcedata{$courselevelm}; }
-		if ($resourcedata{$courselevel}) {
-		    return $resourcedata{$courselevel}; }
-	    } else {
-		if ($resourcedata{$courselevelr}!~/No such file/) {
-		    &logthis("<font color=blue>WARNING:".
-			     " Trying to get resource data for ".
-			     $uname." at ".$udom.": ".
-			     $resourcedata{$courselevelr}."</font>");
+	    #most student don't have any data set, check if there is some data
+            #every thirty minutes
+	    if (!
+		(exists($ENV{'cache.studentresdata'})
+		    && (($ENV{'cache.studentresdata'}+1800) > time))) {
+		my %resourcedata=&get('resourcedata',
+				      [$courselevelr,$courselevelm,$courselevel],
+				      $udom,$uname);
+		my ($tmp)=keys(%resourcedata);
+		if (($tmp!~/^error\:/) && ($tmp!~/^con_lost/)) {
+		    if ($resourcedata{$courselevelr}) {
+			return $resourcedata{$courselevelr}; }
+		    if ($resourcedata{$courselevelm}) {
+			return $resourcedata{$courselevelm}; }
+		    if ($resourcedata{$courselevel}) {
+			return $resourcedata{$courselevel}; }
+		} else {
+		    if ($tmp!~/No such file/) {
+			&logthis("<font color=blue>WARNING:".
+				 " Trying to get resource data for ".
+				 $uname." at ".$udom.": ".
+				 $tmp."</font>");
+		    } elsif ($tmp=~/error:No such file/) {
+			$ENV{'cache.studentresdata'}=time;
+			&appenv(('cache.studentresdata'=>
+				 $ENV{'cache.studentresdata'}));
+		    } elsif ($tmp =~ /^(con_lost|no_such_host)/) {
+			return $tmp;
+		    }
 		}
 	    }
 
@@ -2707,7 +2980,7 @@ sub EXT {
 					  ($seclevelr,$seclevelm,$seclevel,
 					   $courselevelr,$courselevelm,
 					   $courselevel));
-	    if ($coursereply) { return $coursereply; }
+	    if (defined($coursereply)) { return $coursereply; }
 
 # ------------------------------------------------------ third, check map parms
 	    my %parmhash=();
@@ -2723,11 +2996,17 @@ sub EXT {
 # --------------------------------------------- last, look in resource metadata
 
 	$spacequalifierrest=~s/\./\_/;
-	my $metadata=&metadata($ENV{'request.filename'},$spacequalifierrest);
-	if ($metadata) { return $metadata; }
-	$metadata=&metadata($ENV{'request.filename'},
-			    'parameter_'.$spacequalifierrest);
-	if ($metadata) { return $metadata; }
+	my $filename;
+	if (!$symbparm) { $symbparm=&symbread(); }
+	if ($symbparm) {
+	    $filename=(split(/\_\_\_/,$symbparm))[2];
+	} else {
+	    $filename=$ENV{'request.filename'};
+	}
+	my $metadata=&metadata($filename,$spacequalifierrest);
+	if (defined($metadata)) { return $metadata; }
+	$metadata=&metadata($filename,'parameter_'.$spacequalifierrest);
+	if (defined($metadata)) { return $metadata; }
 
 # ------------------------------------------------------------------ Cascade up
 	unless ($space eq '0') {
@@ -2735,11 +3014,11 @@ sub EXT {
 	    if ($id) {
 		my $partgeneral=&EXT('resource.'.$part.'.'.$qualifierrest,
 				     $symbparm,$udom,$uname);
-		if ($partgeneral) { return $partgeneral; }
+		if (defined($partgeneral)) { return $partgeneral; }
 	    } else {
 		my $resourcegeneral=&EXT('resource.0.'.$qualifierrest,
 					 $symbparm,$udom,$uname);
-		if ($resourcegeneral) { return $resourcegeneral; }
+		if (defined($resourcegeneral)) { return $resourcegeneral; }
 	    }
 	}
 
@@ -2768,6 +3047,11 @@ sub metadata {
     my ($uri,$what,$liburi,$prefix,$depthcount)=@_;
 
     $uri=&declutter($uri);
+    # if it is a non metadata possible uri return quickly
+    if (($uri eq '') || (($uri =~ m|^/*adm/|) && ($uri !~ m|^adm/includes|)) ||
+        ($uri =~ m|/$|) || ($uri =~ m|/.meta$|)) {
+	return '';
+    }
     my $filename=$uri;
     $uri=~s/\.meta$//;
 #
@@ -2797,12 +3081,19 @@ sub metadata {
 #
 	      my $package=$token->[2]->{'package'};
 	      my $keyroot='';
-              if ($prefix) {
-		  $keyroot.=$prefix;
-              } else {
-                if (defined($token->[2]->{'part'})) { 
-                   $keyroot.='_'.$token->[2]->{'part'}; 
-	        }
+              if (defined($prefix) && $prefix !~ /^__/) {
+		  # prefix that has a part already
+		  $keyroot=$prefix;
+              } elsif (defined($prefix)) {
+		  # prefix that is missing a part
+		  if (defined($token->[2]->{'part'})) {
+		      $keyroot='_'.$token->[2]->{'part'}.substr($prefix,1);
+		  }
+	      } else {
+		  # no prefix at all
+		  if (defined($token->[2]->{'part'})) {
+		      $keyroot='_'.$token->[2]->{'part'};
+		  }
 	      }
               if (defined($token->[2]->{'id'})) { 
                  $keyroot.='_'.$token->[2]->{'id'}; 
@@ -2824,9 +3115,12 @@ sub metadata {
                       my $unikey='parameter'.$keyroot.'_'.$name;
                       $metathesekeys{$unikey}=1;
                       $metacache{$uri.':'.$unikey.'.part'}=$part;
-                      unless 
-                       (defined($metacache{$uri.':'.$unikey.'.'.$subp})) {
-                         $metacache{$uri.':'.$unikey.'.'.$subp}=$value;
+                      unless (defined($metacache{$uri.':'.$unikey.'.'.$subp})) {
+			  $metacache{$uri.':'.$unikey.'.'.$subp}=$value;
+		      }
+		      if (defined($metacache{$uri.':'.$unikey.'.default'})) {
+			  $metacache{$uri.':'.$unikey}=
+			     $metacache{$uri.':'.$unikey.'.default'}
 		      }
                   }
               }
@@ -2876,11 +3170,17 @@ sub metadata {
               foreach (@{$token->[3]}) {
 		  $metacache{$uri.':'.$unikey.'.'.$_}=$token->[2]->{$_};
               }
-              unless (
-                 $metacache{$uri.':'.$unikey}=&HTML::Entities::decode($parser->get_text('/'.$entry))
-		      ) { $metacache{$uri.':'.$unikey}=
-			      $metacache{$uri.':'.$unikey.'.default'};
-		      }
+	      my $internaltext=&HTML::Entities::decode($parser->get_text('/'.$entry));
+	      my $default=$metacache{$uri.':'.$unikey.'.default'};
+	      if ( $internaltext =~ /^\s*$/ && $default !~ /^\s*$/) {
+		  # only ws inside the tag, and not in default, so use default
+                  # as value
+		  $metacache{$uri.':'.$unikey}=$default;
+	      } else {
+		  # either something interesting inside the tag or default
+                  # uninteresting
+		  $metacache{$uri.':'.$unikey}=$internaltext;
+	      }
 # end of not-a-package not-a-library import
 	   }
 # end of not-a-package start tag
@@ -2925,6 +3225,33 @@ sub metadata_generate_part0 {
     }
 }
 
+# ------------------------------------------------- Get the title of a resource
+
+sub gettitle {
+    my $urlsymb=shift;
+    my $symb=&symbread($urlsymb);
+    unless ($symb) {
+	unless ($urlsymb) { $urlsymb=$ENV{'request.filename'}; }
+        return &metadata($urlsymb,'title'); 
+    }
+    if ($titlecache{$symb}) { return $titlecache{$symb}; }
+    my ($map,$resid,$url)=split(/\_\_\_/,$symb);
+    my $title='';
+    my %bighash;
+    if (tie(%bighash,'GDBM_File',$ENV{'request.course.fn'}.'.db',
+                            &GDBM_READER(),0640)) {
+        my $mapid=$bighash{'map_pc_'.&clutter($map)};
+        $title=$bighash{'title_'.$mapid.'.'.$resid};
+        untie %bighash;
+    }
+    if ($title) {
+        $titlecache{$symb}=$title;
+        return $title;
+    } else {
+	return &metadata($urlsymb,'title');
+    }
+}
+    
 # ------------------------------------------------- Update symbolic store links
 
 sub symblist {
@@ -2962,7 +3289,7 @@ 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_/'.$thisfn};
         }
@@ -3033,7 +3360,7 @@ sub symbread {
            if (tie(%bighash,'GDBM_File',$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};
               }
@@ -3266,18 +3593,42 @@ BEGIN {
     }
 }
 
+# ------------------------------------------------------------ Read domain file
+{
+    my $fh=Apache::File->new($Apache::lonnet::perlvar{'lonTabDir'}.
+                            '/domain.tab');
+    %domaindescription = ();
+    %domain_auth_def = ();
+    %domain_auth_arg_def = ();
+    if ($fh) {
+       while (<$fh>) {
+           next if /^\#/;
+           chomp;
+           my ($domain, $domain_description, $def_auth, $def_auth_arg)
+               = split(/:/,$_,4);
+           $domain_auth_def{$domain}=$def_auth;
+           $domain_auth_arg_def{$domain}=$def_auth_arg;
+           $domaindescription{$domain}=$domain_description;
+#          &logthis("Domain.tab: $domain, $domain_auth_def{$domain}, $domain_auth_arg_def{$domain},$domaindescription{$domain}");
+#          &logthis("Domain.tab: $domain ".$domaindescription{$domain} );
+       }
+    }
+}
+
+
 # ------------------------------------------------------------- Read hosts file
 {
     my $config=Apache::File->new("$perlvar{'lonTabDir'}/hosts.tab");
 
     while (my $configline=<$config>) {
+       next if ($configline =~ /^(\#|\s*$)/);
        chomp($configline);
        my ($id,$domain,$role,$name,$ip,$domdescr)=split(/:/,$configline);
        if ($id && $domain && $role && $name && $ip) {
 	 $hostname{$id}=$name;
 	 $hostdom{$id}=$domain;
 	 $hostip{$id}=$ip;
-	 if ($domdescr) { $domaindescription{$domain}=$domdescr; }
+	 $iphost{$ip}=$id;
 	 if ($role eq 'library') { $libserv{$id}=$name; }
        } else {
 	 if ($configline) {
@@ -3293,7 +3644,7 @@ BEGIN {
 
     while (my $configline=<$config>) {
        chomp($configline);
-       if (($configline) && ($configline ne $perlvar{'lonHostID'})) {
+       if ($configline) {
           $spareid{$configline}=1;
        }
     }
@@ -3339,9 +3690,15 @@ BEGIN {
     }
 }
 
+# ------------- set up temporary directory
+{
+    $tmpdir = $perlvar{'lonDaemons'}.'/tmp/';
+
+}
+
 %metacache=();
 
-$processmarker=$$.'_'.time.'_'.$perlvar{'lonHostID'};
+$processmarker='_'.time.'_'.$perlvar{'lonHostID'};
 $dumpcount=0;
 
 &logtouch();
@@ -3557,7 +3914,83 @@ 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 and
+lonnet::modify_student_enrollment
+
+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 *
+
+modify_student_enrollment
+
+Change a students enrollment status in a class.  The environment variable
+'role.request.course' must be defined for this function to proceed.
+
+Inputs:
+
+=over 4
+
+=item $udom, students domain
+
+=item $uname, students name
+
+=item $uid, students user id
+
+=item $first, students first name
+
+=item $middle
+
+=item $last
+
+=item $gene
+
+=item $usec
+
+=item $end
+
+=item $start
+
+=back
+
 
 =item *