--- loncom/lonnet/perl/lonnet.pm	2000/10/28 19:26:07	1.53
+++ loncom/lonnet/perl/lonnet.pm	2000/12/29 19:28:19	1.83
@@ -24,6 +24,7 @@
 # revokerole (udom,uname,url,role) : Revoke a role for url
 # revokecustomrole (udom,uname,url,rdom,rnam,rolename) : Revoke a custom role
 # appenv(hash)       : adds hash to session environment
+# delenv(varname)    : deletes all environment entries starting with varname
 # store(hash)        : stores hash permanently for this url
 # cstore(hash)       : critical store
 # restore            : returns hash for this url
@@ -41,17 +42,28 @@
 # directcondval(index) : reading condition value of single condition from 
 #                        state string
 # condval(index)     : value of condition index based on state
-# varval(name)       : value of a variable
-# refreshstate()     : refresh the state information string
+# EXT(name)          : value of a variable
 # symblist(map,hash) : Updates symbolic storage links
 # symbread([filename]) : returns the data handle (filename optional)
-# rndseed()          : returns a random seed  
+# rndseed()          : returns a random seed 
+# receipt()          : returns a receipt to be given out to users 
 # getfile(filename)  : returns the contents of filename, or a -1 if it can't
 #                      be found, replicates and subscribes to the file
 # filelocation(dir,file) : returns a farily clean absolute reference to file 
 #                          from the directory dir
 # hreflocation(dir,file) : same as filelocation, but for hrefs
 # log(domain,user,home,msg) : write to permanent log for user
+# usection(domain,user,courseid) : output of section name/number or '' for
+#                                  "not in course" and '-1' for "no section"
+# userenvironment(domain,user,what) : puts out any environment parameter 
+#                                     for a user
+# idput(domain,hash) : writes IDs for users from hash (name=>id,name=>id)
+# idget(domain,array): returns hash with usernames (id=>name,id=>name) for
+#                      an array of IDs
+# idrget(domain,array): returns hash with IDs for usernames (name=>id,...) for
+#                       an array of names
+# metadata(file,entry): returns the metadata entry for a file. entry='keys'
+#                       returns a comma separated list of keys
 #
 # 6/1/99,6/2,6/10,6/11,6/12,6/14,6/26,6/28,6/29,6/30,
 # 7/1,7/2,7/9,7/10,7/12,7/14,7/15,7/19,
@@ -66,8 +78,10 @@
 # 08/22,08/28,08/31,09/01,09/02,09/04,09/05,09/25,09/28,09/30 Gerd Kortemeyer
 # 10/04 Gerd Kortemeyer
 # 10/04 Guy Albertelli
-# 10/06,10/09,10/10,10/11,10/14,10/20,10/23,10/25,10/26,10/27,10/28 
-# Gerd Kortemeyer
+# 10/06,10/09,10/10,10/11,10/14,10/20,10/23,10/25,10/26,10/27,10/28,10/29, 
+# 10/30,10/31,
+# 11/2,11/14,11/15,11/16,11/20,11/21,11/22,11/25,11/27,
+# 12/02,12/12,12/13,12/14,12/28,12/29 Gerd Kortemeyer
 
 package Apache::lonnet;
 
@@ -76,10 +90,11 @@ use Apache::File;
 use LWP::UserAgent();
 use HTTP::Headers;
 use vars 
-qw(%perlvar %hostname %homecache %spareid %hostdom %libserv %pr %prp %fe %fd $readit);
+qw(%perlvar %hostname %homecache %spareid %hostdom %libserv %pr %prp %fe %fd $readit %metacache);
 use IO::Socket;
 use GDBM_File;
 use Apache::Constants qw(:common :http);
+use HTML::TokeParser;
 
 # --------------------------------------------------------------------- Logging
 
@@ -122,8 +137,7 @@ sub reply {
     my ($cmd,$server)=@_;
     my $answer=subreply($cmd,$server);
     if ($answer eq 'con_lost') { $answer=subreply($cmd,$server); }
-    if (($answer=~/^error:/) || ($answer=~/^refused/) || 
-        ($answer=~/^rejected/)) {
+    if (($answer=~/^refused/) || ($answer=~/^rejected/)) {
        &logthis("<font color=blue>WARNING:".
                 " $cmd to $server returned $answer</font>");
     }
@@ -250,6 +264,35 @@ sub appenv {
     }
     return 'ok';
 }
+# ----------------------------------------------------- Delete from Environment
+
+sub delenv {
+    my $delthis=shift;
+    my %newenv=();
+    if (($delthis=~/user\.role/) || ($delthis=~/user\.priv/)) {
+        &logthis("<font color=blue>WARNING: ".
+                "Attempt to delete from environment ".$delthis);
+        return 'error';
+    }
+    my @oldenv;
+    {
+     my $fh;
+     unless ($fh=Apache::File->new("$ENV{'user.environment'}")) {
+	return 'error';
+     }
+     @oldenv=<$fh>;
+    }
+    {
+     my $fh;
+     unless ($fh=Apache::File->new(">$ENV{'user.environment'}")) {
+	return 'error';
+     }
+     map {
+	 unless ($_=~/^$delthis/) { print $fh $_; }
+     } @oldenv;
+    }
+    return 'ok';
+}
 
 # ------------------------------ Find server with least workload from spare.tab
 
@@ -328,6 +371,111 @@ sub homeserver {
     return 'no_host';
 }
 
+# ------------------------------------- Find the usernames behind a list of IDs
+
+sub idget {
+    my ($udom,@ids)=@_;
+    my %returnhash=();
+    
+    my $tryserver;
+    foreach $tryserver (keys %libserv) {
+       if ($hostdom{$tryserver} eq $udom) {
+	  my $idlist=join('&',@ids);
+          $idlist=~tr/A-Z/a-z/; 
+	  my $reply=&reply("idget:$udom:".$idlist,$tryserver);
+          my @answer=();
+          if (($reply ne 'con_lost') && ($reply!~/^error\:/)) {
+	      @answer=split(/\&/,$reply);
+          }                    ;
+          my $i;
+          for ($i=0;$i<=$#ids;$i++) {
+              if ($answer[$i]) {
+		  $returnhash{$ids[$i]}=$answer[$i];
+              } 
+          }
+       }
+    }    
+    return %returnhash;
+}
+
+# ------------------------------------- Find the IDs behind a list of usernames
+
+sub idrget {
+    my ($udom,@unames)=@_;
+    my %returnhash=();
+    map {
+        $returnhash{$_}=(&userenvironment($udom,$_,'id'))[1];
+    } @unames;
+    return %returnhash;
+}
+
+# ------------------------------- Store away a list of names and associated IDs
+
+sub idput {
+    my ($udom,%ids)=@_;
+    my %servers=();
+    map {
+        my $uhom=&homeserver($_,$udom);
+        if ($uhom ne 'no_host') {
+            my $id=&escape($ids{$_});
+            $id=~tr/A-Z/a-z/;
+            my $unam=&escape($_);
+	    if ($servers{$uhom}) {
+		$servers{$uhom}.='&'.$id.'='.$unam;
+            } else {
+                $servers{$uhom}=$id.'='.$unam;
+            }
+            &critical('put:'.$udom.':'.$unam.':environment:id='.$id,$uhom);
+        }
+    } keys %ids;
+    map {
+        &critical('idput:'.$udom.':'.$servers{$_},$_);
+    } keys %servers;
+}
+
+# ------------------------------------- Find the section of student in a course
+
+sub usection {
+    my ($udom,$unam,$courseid)=@_;
+    $courseid=~s/\_/\//g;
+    $courseid=~s/^(\w)/\/$1/;
+    map {
+        my ($key,$value)=split(/\=/,$_);
+        $key=&unescape($key);
+        if ($key=~/^$courseid(?:\/)*(\w+)*\_st$/) {
+            my $section=$1;
+            if ($key eq $courseid.'_st') { $section=''; }
+	    my ($dummy,$end,$start)=split(/\_/,&unescape($value));
+            my $now=time;
+            my $notactive=0;
+            if ($start) {
+		if ($now<$start) { $notactive=1; }
+            }
+            if ($end) {
+                if ($now>$end) { $notactive=1; }
+            } 
+            unless ($notactive) { return $section; }
+        }
+    } split(/\&/,&reply('dump:'.$udom.':'.$unam.':roles',
+                        &homeserver($unam,$udom)));
+    return '-1';
+}
+
+# ------------------------------------- Read an entry from a user's environment
+
+sub userenvironment {
+    my ($udom,$unam,@what)=@_;
+    my %returnhash=();
+    my @answer=split(/\&/,
+                &reply('get:'.$udom.':'.$unam.':environment:'.join('&',@what),
+                      &homeserver($unam,$udom)));
+    my $i;
+    for ($i=0;$i<=$#what;$i++) {
+	$returnhash{$what[$i]}=&unescape($answer[$i]);
+    }
+    return %returnhash;
+}
+
 # ----------------------------- Subscribe to a resource, return URL if possible
 
 sub subscribe {
@@ -340,6 +488,9 @@ sub subscribe {
         return 'not_found'; 
     }
     my $answer=reply("sub:$fname",$home);
+    if (($answer eq 'con_lost') || ($answer eq 'rejected')) {
+	$answer.=' by '.$home;
+    }
     return $answer;
 }
     
@@ -351,14 +502,14 @@ sub repcopy {
     my $transname="$filename.in.transfer";
     if ((-e $filename) || (-e $transname)) { return OK; }
     my $remoteurl=subscribe($filename);
-    if ($remoteurl eq 'con_lost') {
-	   &logthis("Subscribe returned con_lost: $filename");
+    if ($remoteurl =~ /^con_lost by/) {
+	   &logthis("Subscribe returned $remoteurl: $filename");
            return HTTP_SERVICE_UNAVAILABLE;
     } elsif ($remoteurl eq 'not_found') {
 	   &logthis("Subscribe returned not_found: $filename");
 	   return HTTP_NOT_FOUND;
-    } elsif ($remoteurl eq 'rejected') {
-	   &logthis("Subscribe returned rejected: $filename");
+    } elsif ($remoteurl =~ /^rejected by/) {
+	   &logthis("Subscribe returned $remoteurl: $filename");
            return FORBIDDEN;
     } elsif ($remoteurl eq 'directory') {
            return OK;
@@ -482,9 +633,12 @@ sub restore {
 	my ($name,$value)=split(/\=/,$_);
         $returnhash{&unescape($name)}=&unescape($value);
     } split(/\&/,$answer);
-    map {
-        $returnhash{$_}=$returnhash{$returnhash{'version'}.':'.$_};
-    } split(/\:/,$returnhash{$returnhash{'version'}.':keys'});
+    my $version;
+    for ($version=1;$version<=$returnhash{'version'};$version++) {
+       map {
+          $returnhash{$_}=$returnhash{$version.':'.$_};
+       } split(/\:/,$returnhash{$version.':keys'});
+    }
     return %returnhash;
 }
 
@@ -499,6 +653,8 @@ sub coursedescription {
     if ($chome ne 'no_host') {
        my $rep=reply("dump:$cdomain:$cnum:environment",$chome);
        if ($rep ne 'con_lost') {
+           my $normalid=$courseid;
+           $normalid=~s/\//\_/g;
            my %envhash=();
            my %returnhash=('home'   => $chome, 
                            'domain' => $cdomain,
@@ -508,13 +664,15 @@ sub coursedescription {
                $name=&unescape($name);
                $value=&unescape($value);
                $returnhash{$name}=$value;
-               my $normalid=$courseid;
-               $normalid=~s/\//\_/g;
                $envhash{'course.'.$normalid.'.'.$name}=$value;
            } split(/\&/,$rep);
            $returnhash{'url'}='/res/'.declutter($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'}=$cnum;
            &appenv(%envhash);
            return %returnhash;
        }
@@ -717,9 +875,9 @@ sub allowed {
     my ($priv,$uri)=@_;
     $uri=&declutter($uri);
 
-# Free bre access to adm resources
+# Free bre access to adm and meta resources
 
-    if (($uri=~/^adm\//) && ($priv eq 'bre')) {
+    if ((($uri=~/^adm\//) || ($uri=~/\.meta$/)) && ($priv eq 'bre')) {
 	return 'F';
     }
 
@@ -741,8 +899,11 @@ sub allowed {
     }
 
 # Course: uri itself is a course
+    my $courseuri=$uri;
+    $courseuri=~s/\_(\d)/\/$1/;
+    $courseuri=~s/^([^\/])/\/$1/;
 
-    if ($ENV{'user.priv.'.$ENV{'request.role'}.'./'.$uri}
+    if ($ENV{'user.priv.'.$ENV{'request.role'}.'.'.$courseuri}
        =~/$priv\&([^\:]*)/) {
        $thisallowed.=$1;
     }
@@ -776,7 +937,7 @@ sub allowed {
        my $pathname=$uri;
        $pathname=~s/\/$filename$//;
        if ($ENV{'acc.res.'.$ENV{'request.course.id'}.'.'.$pathname}=~
-           /\&$filename\:(\d+)\&/) {
+           /\&$filename\:([\d\|]+)\&/) {
            $statecond=$1;
            if ($ENV{'user.priv.'.$ENV{'request.role'}.'./'.$courseprivid}
                =~/$priv\&([^\:]*)/) {
@@ -784,16 +945,19 @@ sub allowed {
                $checkreferer=0;
            }
        }
+       
        if (($ENV{'HTTP_REFERER'}) && ($checkreferer)) {
-	  my $refuri=&declutter($ENV{'HTTP_REFERER'});
+	  my $refuri=$ENV{'HTTP_REFERER'};
+          $refuri=~s/^http\:\/\/$ENV{'request.host'}//i;
+          $refuri=&declutter($refuri);
           my @uriparts=split(/\//,$refuri);
           my $filename=$uriparts[$#uriparts];
           my $pathname=$refuri;
           $pathname=~s/\/$filename$//;
-          my @filenameparts=split(/\./,$filename);
+          my @filenameparts=split(/\./,$uri);
           if (&fileembstyle($filenameparts[$#filenameparts]) ne 'ssi') {
             if ($ENV{'acc.res.'.$ENV{'request.course.id'}.'.'.$pathname}=~
-              /\&$filename\:(\d+)\&/) {
+              /\&$filename\:([\d\|]+)\&/) {
               my $refstatecond=$1;
               if ($ENV{'user.priv.'.$ENV{'request.role'}.'./'.$courseprivid}
                   =~/$priv\&([^\:]*)/) {
@@ -830,37 +994,43 @@ sub allowed {
 #
 
 # Possibly locked functionality, check all courses
+# Locks might take effect only after 10 minutes cache expiration for other
+# courses, and 2 minutes for current course
 
     my $envkey;
     if ($thisallowed=~/L/) {
         foreach $envkey (keys %ENV) {
-           if ($envkey=~/^user\.role\.st\.([^\.]*)/) {
-	       my ($cdom,$cnum,$csec)=split(/\//,$1);
-               my %locks=();
-               map {
-                   my ($name,$value)=split(/\=/,$_);
-                   $locks{&unescape($name)}=&unescape($value);
-               } split(/\&/,&reply('get:'.$cdom.':'.$cnum.
-                 ':environment:'.&escape('priv.'.$priv.'.lock.sections').
-                             ':'.&escape('priv.'.$priv.'.lock.expire').
-                             ':'.&escape('res.'.$uri.'.lock.sections').
-			     ':'.&escape('res.'.$uri.'.lock.expire'),
-                  &homeserver($cnum,$cdom)));
-               if (($locks{'res.'.$uri.'.lock.sections'}=~/\,$csec\,/) ||
-                   ($locks{'res.'.$uri.'.lock.sections'} eq 'all')) {
-		   if ($locks{'res.'.$uri.'.lock.expire'}>time) {
-                       &log('Locked by res: '.$priv.' for '.$uri.' due to '.
+           if ($envkey=~/^user\.role\.(st|ta)\.([^\.]*)/) {
+               my $courseid=$2;
+               my $roleid=$1.'.'.$2;
+               my $expiretime=600;
+               if ($ENV{'request.role'} eq $roleid) {
+		  $expiretime=120;
+               }
+	       my ($cdom,$cnum,$csec)=split(/\//,$courseid);
+               my $prefix='course.'.$cdom.'_'.$cnum.'.';
+               if ((time-$ENV{$prefix.'last_cache'})>$expiretime) {
+		   &coursedescription($courseid);
+               }
+               if (($ENV{$prefix.'res.'.$uri.'.lock.sections'}=~/\,$csec\,/)
+                || ($ENV{$prefix.'res.'.$uri.'.lock.sections'} eq 'all')) {
+		   if ($ENV{$prefix.'res.'.$uri.'.lock.expire'}>time) {
+                       &log($ENV{'user.domain'},$ENV{'user.name'},
+                            $ENV{'user.host'},
+                            'Locked by res: '.$priv.' for '.$uri.' due to '.
                             $cdom.'/'.$cnum.'/'.$csec.' expire '.
-                            $locks{'priv.'.$priv.'.lock.expire'});
+                            $ENV{$prefix.'priv.'.$priv.'.lock.expire'});
 		       return '';
                    }
                }
-               if (($locks{'priv.'.$priv.'.lock.sections'}=~/\,$csec\,/) ||
-                   ($locks{'priv.'.$priv.'.lock.sections'} eq 'all')) {
-		   if ($locks{'priv.'.$priv.'.lock.expire'}>time) {
-                       &log('Locked by priv: '.$priv.' for '.$uri.' due to '.
+               if (($ENV{$prefix.'priv.'.$priv.'.lock.sections'}=~/\,$csec\,/)
+                || ($ENV{$prefix.'priv.'.$priv.'.lock.sections'} eq 'all')) {
+		   if ($ENV{'priv.'.$priv.'.lock.expire'}>time) {
+                       &log($ENV{'user.domain'},$ENV{'user.name'},
+                            $ENV{'user.host'},
+                            'Locked by priv: '.$priv.' for '.$uri.' due to '.
                             $cdom.'/'.$cnum.'/'.$csec.' expire '.
-                            $locks{'priv.'.$priv.'.lock.expire'});
+                            $ENV{$prefix.'priv.'.$priv.'.lock.expire'});
 		       return '';
                    }
                }
@@ -884,17 +1054,35 @@ sub allowed {
 # Course preferences
 
    if ($thisallowed=~/C/) {
-#
-# Registered course preferences from environment
-#
+       my $rolecode=(split(/\./,$ENV{'request.role'}))[0];
+       if ($ENV{'course.'.$ENV{'request.course.id'}.'.'.$priv.'.roles.denied'}
+	   =~/\,$rolecode\,/) {
+           &log($ENV{'user.domain'},$ENV{'user.name'},$ENV{'user.host'},
+                'Denied by role: '.$priv.' for '.$uri.' as '.$rolecode.' in '.
+                $ENV{'request.course.id'});
+           return '';
+       }
    }
 
 # Resource preferences
 
    if ($thisallowed=~/R/) {
-#
-# Resource Metadata
-#
+       my $rolecode=(split(/\./,$ENV{'request.role'}))[0];
+       my $filename=$perlvar{'lonDocRoot'}.'/res/'.$uri.'.meta';
+       if (-e $filename) {
+           my @content;
+           {
+	     my $fh=Apache::File->new($filename);
+             @content=<$fh>;
+	   }
+           if (join('',@content)=~
+                    /\<roledeny[^\>]*\>[^\<]*$rolecode[^\<]*\<\/roledeny\>/) {
+	       &log($ENV{'user.domain'},$ENV{'user.name'},$ENV{'user.host'},
+                    'Denied by role: '.$priv.' for '.$uri.' as '.$rolecode);
+           return '';
+
+           }
+       }
    }
 
 # Restricted by state?
@@ -910,11 +1098,6 @@ sub allowed {
    return 'F';
 }
 
-# ---------------------------------------------------------- Refresh State Info
-
-sub refreshstate {
-}
-
 # ----------------------------------------------------------------- Define Role
 
 sub definerole {
@@ -973,7 +1156,7 @@ sub fileembstyle {
 
 # ------------------------------------------------------------ Description Text
 
-sub filedecription {
+sub filedescription {
     my $ending=shift;
     return $fd{$ending};
 }
@@ -983,29 +1166,140 @@ sub filedecription {
 sub assignrole {
     my ($udom,$uname,$url,$role,$end,$start)=@_;
     my $mrole;
-    $url=declutter($url);
     if ($role =~ /^cr\//) {
-        unless ($url=~/\.course$/) { return 'invalid'; }
-	unless (allowed('ccr',$url)) { return 'refused'; }
+	unless (&allowed('ccr',$url)) { return 'refused'; }
         $mrole='cr';
     } else {
-        unless (($url=~/\.course$/) || ($url=~/\/$/)) { return 'invalid'; }
-        unless (allowed('c'+$role)) { return 'refused'; }
+        my $cwosec=$url;
+        $cwosec=~s/^\/(\w+)\/(\w+)\/.*/$1\/$2/;
+        unless (&allowed('c'.$role,$cwosec)) { return 'refused'; }
         $mrole=$role;
     }
     my $command="encrypt:rolesput:$ENV{'user.domain'}:$ENV{'user.name'}:".
                 "$udom:$uname:$url".'_'."$mrole=$role";
-    if ($end) { $command.='_$end'; }
+    if ($end) { $command.='_'.$end; }
     if ($start) {
 	if ($end) { 
-           $command.='_$start'; 
+           $command.='_'.$start; 
         } else {
-           $command.='_0_$start';
+           $command.='_0_'.$start;
         }
     }
     return &reply($command,&homeserver($uname,$udom));
 }
 
+# --------------------------------------------------------------- Modify a user
+
+
+sub modifyuser {
+    my ($udom,$uname,$uid,$umode,$upass,$first,$middle,$last,$gene)=@_;
+    &logthis('Call to modify user '.$udom.', '.$uname.', '.$uid.', '.
+             $umode.', '.$first.', '.$middle.', '.
+	     $last.', '.$gene.' by '.
+             $ENV{'user.name'}.' at '.$ENV{'user.domain'});  
+    my $uhome=&homeserver($uname,$udom);
+# ----------------------------------------------------------------- Create User
+    if (($uhome eq 'no_host') && ($umode) && ($upass)) {
+        my $unhome='';
+	if ($ENV{'course.'.$ENV{'request.course.id'}.'.domain'} eq $udom) {
+	    $unhome=$ENV{'course.'.$ENV{'request.course.id'}.'.home'};
+        } else {
+            my $tryserver;
+            my $loadm=10000000;
+            foreach $tryserver (keys %libserv) {
+	       if ($hostdom{$tryserver} eq $udom) {
+                  my $answer=reply('load',$tryserver);
+                  if (($answer=~/\d+/) && ($answer<$loadm)) {
+		      $loadm=$answer;
+                      $unhome=$tryserver;
+                  }
+	       }
+	    }
+        }
+        if (($unhome eq '') || ($unhome eq 'no_host')) {
+	    return 'error: find home';
+        }
+        my $reply=&reply('encrypt:makeuser:'.$udom.':'.$uname.':'.$umode.':'.
+                         &escape($upass),$unhome);
+	unless ($reply eq 'ok') {
+            return 'error: '.$reply;
+        }   
+        $uhome=&homeserver($uname,$udom);
+        if (($uhome eq '') || ($uhome eq 'no_host') || ($uhome ne $unhome)) {
+	    return 'error: verify home';
+        }
+    }
+# ---------------------------------------------------------------------- Add ID
+    if ($uid) {
+       $uid=~tr/A-Z/a-z/;
+       my %uidhash=&idrget($udom,$uname);
+       if (($uidhash{$uname}) && ($uidhash{$uname}!~/error\:/)) {
+	  unless ($uid eq $uidhash{$uname}) {
+	      return 'error: mismatch '.$uidhash{$uname}.' versus '.$uid;
+          }
+       } else {
+	  &idput($udom,($uname => $uid));
+       }
+    }
+# -------------------------------------------------------------- Add names, etc
+    my $names=&reply('get:'.$udom.':'.$uname.
+                     ':environment:firstname&middlename&lastname&generation',
+                     $uhome);
+    my ($efirst,$emiddle,$elast,$egene)=split(/\&/,$names);
+    if ($first)  { $efirst  = &escape($first); }
+    if ($middle) { $emiddle = &escape($middle); }
+    if ($last)   { $elast   = &escape($last); }
+    if ($gene)   { $egene   = &escape($gene); }
+    my $reply=&reply('put:'.$udom.':'.$uname.
+           ':environment:firstname='.$efirst.
+                      '&middlename='.$emiddle.
+                        '&lastname='.$elast.
+                      '&generation='.$egene,$uhome);
+    if ($reply ne 'ok') {
+	return 'error: '.$reply;
+    }
+    &logthis('Success modifying user '.$udom.', '.$uname.', '.$uid.', '.
+             $umode.', '.$first.', '.$middle.', '.
+	     $last.', '.$gene.' by '.
+             $ENV{'user.name'}.' at '.$ENV{'user.domain'});
+    return 'ok'; 
+}
+
+# -------------------------------------------------------------- Modify student
+
+sub modifystudent {
+    my ($udom,$uname,$uid,$umode,$upass,$first,$middle,$last,$gene,$usec,
+        $end,$start)=@_;
+    my $cid='';
+    unless ($cid=$ENV{'request.course.id'}) {
+	return 'not_in_class';
+    }
+# --------------------------------------------------------------- Make the user
+    my $reply=&modifyuser
+	($udom,$uname,$uid,$umode,$upass,$first,$middle,$last,$gene);
+    unless ($reply eq 'ok') { return $reply; }
+    my $uhome=&homeserver($uname,$udom);
+    if (($uhome eq '') || ($uhome eq 'no_host')) { 
+	return 'error: no such user';
+    }
+# -------------------------------------------------- Add student to course list
+    my $reply=critical('put:'.$ENV{'course.'.$cid.'.domain'}.':'.
+	              $ENV{'course.'.$cid.'.num'}.':classlist:'.
+                      &escape($uname.':'.$udom).'='.
+                      &escape($end.':'.$start),
+	              $ENV{'course.'.$cid.'.home'});
+    unless (($reply eq 'ok') || ($reply eq 'delayed')) {
+	return 'error: '.$reply;
+    }
+# ---------------------------------------------------- Add student role to user
+    my $uurl='/'.$cid;
+    $uurl=~s/\_/\//g;
+    if ($usec) {
+	$uurl.='/'.$usec;
+    }
+    return &assignrole($udom,$uname,$uurl,'st',$end,$start);
+}
+
 # ---------------------------------------------------------- Assign Custom Role
 
 sub assigncustomrole {
@@ -1094,8 +1388,16 @@ sub directcondval {
 sub condval {
     my $condidx=shift;
     my $result=0;
+    my $allpathcond='';
+    map {
+       if (defined($ENV{'acc.cond.'.$ENV{'request.course.id'}.'.'.$_})) {
+	   $allpathcond.=
+               '('.$ENV{'acc.cond.'.$ENV{'request.course.id'}.'.'.$_}.')|';
+       }
+    } split(/\|/,$condidx);
+    $allpathcond=~s/\|$//;
     if ($ENV{'request.course.id'}) {
-       if (defined($ENV{'acc.cond.'.$ENV{'request.course.id'}.'.'.$condidx})) {
+       if ($allpathcond) {
           my $operand='|';
 	  my @stack;
           map {
@@ -1118,8 +1420,7 @@ sub condval {
                      $result=$result>$new?$result:$new;
                   }                  
               }
-          } ($ENV{'acc.cond.'.$ENV{'request.course.id'}.'.'.$condidx}=~
-             /(\d+|\(|\)|\&|\|)/g);
+          } ($allpathcond=~/(\d+|\(|\)|\&|\|)/g);
        }
     }
     return $result;
@@ -1127,8 +1428,9 @@ sub condval {
 
 # --------------------------------------------------------- Value of a Variable
 
-sub varval {
+sub EXT {
     my $varname=shift;
+    unless ($varname) { return ''; }
     my ($realm,$space,$qualifier,@therest)=split(/\./,$varname);
     my $rest;
     if ($therest[0]) {
@@ -1136,15 +1438,21 @@ sub varval {
     } else {
        $rest='';
     }
+    my $qualifierrest=$qualifier;
+    if ($rest) { $qualifierrest.='.'.$rest; }
+    my $spacequalifierrest=$space;
+    if ($qualifierrest) { $spacequalifierrest.='.'.$qualifierrest; }
     if ($realm eq 'user') {
 # --------------------------------------------------------------- user.resource
 	if ($space eq 'resource') {
+	    my %restored=&restore;
+            return $restored{$qualifierrest};
 # ----------------------------------------------------------------- user.access
         } elsif ($space eq 'access') {
             return &allowed($qualifier,$rest);
 # ------------------------------------------ user.preferences, user.environment
         } elsif (($space eq 'preferences') || ($space eq 'environment')) {
-            return $ENV{join('.',('environment',$qualifier,$rest))};
+            return $ENV{join('.',('environment',$qualifierrest))};
 # ----------------------------------------------------------------- user.course
         } elsif ($space eq 'course') {
             return $ENV{join('.',('request.course',$qualifier))};
@@ -1172,33 +1480,99 @@ sub varval {
 # ------------------------------------------------------------- request.browser
         if ($space eq 'browser') {
 	    return $ENV{'browser.'.$qualifier};
-        } elsif ($space eq 'filename') {
-            return $ENV{'request.filename'};
+# ------------------------------------------------------------ request.filename
+        } else {
+            return $ENV{'request.'.$spacequalifierrest};
         }
     } elsif ($realm eq 'course') {
 # ---------------------------------------------------------- course.description
-        if ($space eq 'description') {
-            my %reply=&coursedescription($ENV{'request.course.id'});
-            return $reply{'description'};
-# ------------------------------------------------------------------- course.id
-        } elsif ($space eq 'id') {
-            return $ENV{'request.course.id'};
-# -------------------------------------------------- Any other course namespace
-        } else {
-	    my ($cdom,$cnam)=split(/\_/,$ENV{'request.course.id'});
-	    my $chome=&homeserver($cnam,$cdom);
-            my $item=join('.',($qualifier,$rest));
-            return &unescape
-                   (&reply('get:'.$cdom.':'.$cnam.':'.&escape($space).':'.
-			   &escape($item),$chome));
-        }
-    } elsif ($realm eq 'userdata') {
-        my $uhome=&homeserver($qualifier,$space);
-# ----------------------------------------------- userdata.domain.name.resource
+        my $section='';
+        if ($ENV{'request.course.sec'}) {
+	    $section='_'.$ENV{'request.course.sec'};
+        }
+        return $ENV{'course.'.$ENV{'request.course.id'}.$section.'.'.
+                              $spacequalifierrest};
+    } elsif ($realm eq 'resource') {
+      if ($ENV{'request.course.id'}) {
+# ----------------------------------------------------- Cascading lookup scheme
+       my $symbp=&symbread();
+       my $mapp=(split(/\_\_\_/,$symbp))[0];
+
+       my $symbparm=$symbp.'.'.$spacequalifierrest;
+       my $mapparm=$mapp.'___(all).'.$spacequalifierrest;
+
+       my $seclevel=
+            $ENV{'request.course.id'}.'.['.
+		$ENV{'request.course.sec'}.'].'.$spacequalifierrest;
+       my $seclevelr=
+            $ENV{'request.course.id'}.'.['.
+		$ENV{'request.course.sec'}.'].'.$symbparm;
+       my $seclevelm=
+            $ENV{'request.course.id'}.'.['.
+		$ENV{'request.course.sec'}.'].'.$mapparm;
+
+       my $courselevel=
+            $ENV{'request.course.id'}.'.'.$spacequalifierrest;
+       my $courselevelr=
+            $ENV{'request.course.id'}.'.'.$symbparm;
+       my $courselevelm=
+            $ENV{'request.course.id'}.'.'.$mapparm;
+
+
+# ----------------------------------------------------------- first, check user
+      my %resourcedata=get('resourcedata',
+                           ($courselevelr,$courselevelm,$courselevel));
+      if ($resourcedata{$courselevelr}!~/^error\:/) {
+
+       if ($resourcedata{$courselevelr}) { 
+          return $resourcedata{$courselevelr}; }
+       if ($resourcedata{$courselevelm}) { 
+          return $resourcedata{$courselevelm}; }
+       if ($resourcedata{$courselevel}) { return $resourcedata{$courselevel}; }
+
+      }
+# -------------------------------------------------------- second, check course
+        my $section='';
+        if ($ENV{'request.course.sec'}) {
+	    $section='_'.$ENV{'request.course.sec'};
+        }
+        my $reply=&reply('get:'.
+              $ENV{'course.'.$ENV{'request.course.id'}.$section.'.domain'}.':'.
+              $ENV{'course.'.$ENV{'request.course.id'}.$section.'.num'}.
+	      ':resourcedata:'.
+   &escape($seclevelr).'&'.&escape($seclevelm).'&'.&escape($seclevel).'&'.
+   &escape($courselevelr).'&'.&escape($courselevelm).'&'.&escape($courselevel),
+		   $ENV{'course.'.$ENV{'request.course.id'}.$section.'.home'});
+      if ($reply!~/^error\:/) {
+	  map {
+	      if ($_) { return &unescape($_); }
+          } split(/\&/,$reply);
+      }
+
+# ------------------------------------------------------ third, check map parms
+       my %parmhash=();
+       my $thisparm='';       
+       if (tie(%parmhash,'GDBM_File',
+          $ENV{'request.course.fn'}.'_parms.db',&GDBM_READER,0640)) {
+           $thisparm=$parmhash{$symbparm};
+	   untie(%parmhash);
+       }
+       if ($thisparm) { return $thisparm; }
+     }
+     
+# --------------------------------------------- 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 $metadata; }
+
 # ---------------------------------------------------- Any other user namespace
     } elsif ($realm eq 'environment') {
 # ----------------------------------------------------------------- environment
-        return $ENV{join('.',($space,$qualifier,$rest))};
+        return $ENV{$spacequalifierrest};
     } elsif ($realm eq 'system') {
 # ----------------------------------------------------------------- system.time
 	if ($space eq 'time') {
@@ -1208,6 +1582,48 @@ sub varval {
     return '';
 }
 
+# ---------------------------------------------------------------- Get metadata
+
+sub metadata {
+    my ($uri,$what)=@_;
+
+    $uri=&declutter($uri);
+    my $filename=$uri;
+    $uri=~s/\.meta$//;
+    unless ($metacache{$uri.':keys'}) {
+        unless ($filename=~/\.meta$/) { $filename.='.meta'; }
+	my $metastring=&getfile($perlvar{'lonDocRoot'}.'/res/'.$filename);
+        my $parser=HTML::TokeParser->new(\$metastring);
+        my $token;
+        while ($token=$parser->get_token) {
+           if ($token->[0] eq 'S') {
+	      my $entry=$token->[1];
+              my $unikey=$entry;
+              if (defined($token->[2]->{'part'})) { 
+                 $unikey.='_'.$token->[2]->{'part'}; 
+	      }
+              if (defined($token->[2]->{'name'})) { 
+                 $unikey.='_'.$token->[2]->{'name'}; 
+	      }
+              if ($metacache{$uri.':keys'}) {
+                 $metacache{$uri.':keys'}.=','.$unikey;
+              } else {
+                 $metacache{$uri.':keys'}=$unikey;
+	      }
+              map {
+		  $metacache{$uri.':'.$unikey.'.'.$_}=$token->[2]->{$_};
+              } @{$token->[3]};
+              unless (
+                 $metacache{$uri.':'.$unikey}=$parser->get_text('/'.$entry)
+		      ) { $metacache{$uri.':'.$unikey}=
+			      $metacache{$uri.':'.$unikey.'.default'};
+		      }
+          }
+       }
+    }
+    return $metacache{$uri.':'.$what};
+}
+
 # ------------------------------------------------- Update symbolic store links
 
 sub symblist {
@@ -1260,6 +1676,9 @@ sub symbread {
                             &GDBM_READER,0640)) {
 # ---------------------------------------------- Get ID(s) for current resource
               my $ids=$bighash{'ids_/res/'.$thisfn};
+              unless ($ids) { 
+                 $ids=$bighash{'ids_/'.$thisfn};
+              }
               if ($ids) {
 # ------------------------------------------------------------------- Has ID(s)
                  my @possibilities=split(/\,/,$ids);
@@ -1287,7 +1706,9 @@ sub symbread {
               untie(%bighash)
            } 
         }
-        if ($syval) { return $syval.'___'.$thisfn; }
+        if ($syval) {
+           return $syval.'___'.$thisfn; 
+        }
     }
     &appenv('request.ambiguous' => $thisfn);
     return '';
@@ -1322,6 +1743,27 @@ sub rndseed {
                .$symbchck);
 }
 
+sub ireceipt {
+    my ($funame,$fudom,$fucourseid,$fusymb)=@_;
+    my $cuname=unpack("%32C*",$funame);
+    my $cudom=unpack("%32C*",$fudom);
+    my $cucourseid=unpack("%32C*",$fucourseid);
+    my $cusymb=unpack("%32C*",$fusymb);
+    my $cunique=unpack("%32C*",$perlvar{'lonReceipt'});
+    return unpack("%32C*",$perlvar{'lonHostID'}).'-'.
+           ($cunique%$cuname+
+            $cunique%$cudom+
+            $cusymb%$cuname+
+            $cusymb%$cudom+
+            $cucourseid%$cuname+
+            $cucourseid%$cudom);
+}
+
+sub receipt {
+    return &ireceipt($ENV{'user.name'},$ENV{'user.domain'},
+                     $ENV{'request.course.id'},&symbread());
+}
+  
 # ------------------------------------------------------------ Serves up a file
 # returns either the contents of the file or a -1
 sub getfile {
@@ -1338,12 +1780,17 @@ sub filelocation {
   my ($dir,$file) = @_;
   my $location;
   $file=~ s/^\s*(\S+)\s*$/$1/; ## strip off leading and trailing spaces
-  $file=~s/^$perlvar{'lonDocRoot'}//;
-  $file=~s:^/*res::;
-  if ( !( $file =~ m:^/:) ) {
-    $location = $dir. '/'.$file;
+  if ($file=~m:^/~:) { # is a contruction space reference
+    $location = $file;
+    $location =~ s:/~(.*?)/(.*):/home/$1/public_html/$2:;
   } else {
-    $location = '/home/httpd/html/res'.$file;
+    $file=~s/^$perlvar{'lonDocRoot'}//;
+    $file=~s:^/*res::;
+    if ( !( $file =~ m:^/:) ) {
+      $location = $dir. '/'.$file;
+    } else {
+      $location = '/home/httpd/html/res'.$file;
+    }
   }
   $location=~s://+:/:g; # remove duplicate /
   while ($location=~m:/\.\./:) {$location=~ s:/[^/]+/\.\./:/:g;} #remove dir/..
@@ -1463,6 +1910,7 @@ if ($readit ne 'done') {
     }
 }
 
+%metacache=();
 
 $readit='done';
 &logthis('<font color=yellow>INFO: Read configuration</font>');