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Diff for /loncom/lonnet/perl/lonnet.pm between versions 1.370 and 1.394

version 1.370, 2003/05/08 21:50:54 version 1.394, 2003/07/25 01:18:04
Line 243  sub critical { Line 243  sub critical {
     }      }
     return $answer;      return $answer;
 }  }
    
   # ------------------------------------------- Transfer profile into environment
   
   sub transfer_profile_to_env {
       my ($lonidsdir,$handle)=@_;
       my @profile;
       {
    my $idf=Apache::File->new("$lonidsdir/$handle.id");
    flock($idf,LOCK_SH);
    @profile=<$idf>;
    $idf->close();
       }
       my $envi;
       for ($envi=0;$envi<=$#profile;$envi++) {
    chomp($profile[$envi]);
    my ($envname,$envvalue)=split(/=/,$profile[$envi]);
    $ENV{$envname} = $envvalue;
       }
       $ENV{'user.environment'} = "$lonidsdir/$handle.id";
   }
   
 # ---------------------------------------------------------- Append Environment  # ---------------------------------------------------------- Append Environment
   
Line 358  sub userload { Line 378  sub userload {
  while ($filename=readdir(LONIDS)) {   while ($filename=readdir(LONIDS)) {
     if ($filename eq '.' || $filename eq '..') {next;}      if ($filename eq '.' || $filename eq '..') {next;}
     my ($atime)=(stat($perlvar{'lonIDsDir'}.'/'.$filename))[8];      my ($atime)=(stat($perlvar{'lonIDsDir'}.'/'.$filename))[8];
     if ($curtime-$atime < 3600) { $num_users++; }      if ($curtime-$atime < 3600) { $numusers++; }
  }   }
  closedir(LONIDS);   closedir(LONIDS);
     }      }
     my $userloadpercent=0;      my $userloadpercent=0;
     my $maxuserload=$perlvar{'lonUserLoadLim'};      my $maxuserload=$perlvar{'lonUserLoadLim'};
     if ($maxuserload) {      if ($maxuserload) {
  $userloadpercent=100*$num_users/$maxuserload;   $userloadpercent=100*$numusers/$maxuserload;
     }      }
       $userloadpercent=sprintf("%.2f",$userloadpercent);
     return $userloadpercent;      return $userloadpercent;
 }  }
   
Line 961  sub repcopy { Line 982  sub repcopy {
   
 # ------------------------------------------------ Get server side include body  # ------------------------------------------------ Get server side include body
 sub ssi_body {  sub ssi_body {
     my $filelink=shift;      my ($filelink,%form)=@_;
     my $output=($filelink=~/^http\:/?&externalssi($filelink):      my $output=($filelink=~/^http\:/?&externalssi($filelink):
                                      &ssi($filelink));                                       &ssi($filelink,%form));
     $output=~s/^.*\<body[^\>]*\>//si;      $output=~s/^.*\<body[^\>]*\>//si;
     $output=~s/\<\/body\s*\>.*$//si;      $output=~s/\<\/body\s*\>.*$//si;
     $output=~      $output=~
Line 1259  sub get_course_adv_roles { Line 1280  sub get_course_adv_roles {
         } else {          } else {
             $returnhash{$key}=$username.':'.$domain;              $returnhash{$key}=$username.':'.$domain;
         }          }
     }       }
     return sort %returnhash;      return %returnhash;
 }  }
   
 # ---------------------------------------------------------- Course ID routines  # ---------------------------------------------------------- Course ID routines
Line 1404  sub devalidate { Line 1425  sub devalidate {
     my ($symb,$uname,$udom)=@_;      my ($symb,$uname,$udom)=@_;
     my $cid=$ENV{'request.course.id'};       my $cid=$ENV{'request.course.id'}; 
     if ($cid) {      if ($cid) {
 # delete the stored spreadsheets for          # delete the stored spreadsheets for
 # - the student level sheet of this user in course's homespace          # - the student level sheet of this user in course's homespace
 # - the assessment level sheet for this resource           # - the assessment level sheet for this resource 
 #   for this user in user's homespace          #   for this user in user's homespace
  my $key=$uname.':'.$udom.':';   my $key=$uname.':'.$udom.':';
         my $status=          my $status=
     &del('nohist_calculatedsheets',      &del('nohist_calculatedsheets',
  [$key.'studentcalc'],   [$key.'studentcalc:'],
  $ENV{'course.'.$cid.'.domain'},   $ENV{'course.'.$cid.'.domain'},
  $ENV{'course.'.$cid.'.num'})   $ENV{'course.'.$cid.'.num'})
  .' '.   .' '.
     &del('nohist_calculatedsheets_'.$cid,      &del('nohist_calculatedsheets_'.$cid,
  [$key.'assesscalc:'.$symb]);   [$key.'assesscalc:'.$symb],$udom,$uname);
         unless ($status eq 'ok ok') {          unless ($status eq 'ok ok') {
            &logthis('Could not devalidate spreadsheet '.             &logthis('Could not devalidate spreadsheet '.
                     $uname.' at '.$udom.' for '.                      $uname.' at '.$udom.' for '.
Line 1622  sub tmpreset { Line 1643  sub tmpreset {
   my ($symb,$namespace,$domain,$stuname) = @_;    my ($symb,$namespace,$domain,$stuname) = @_;
   if (!$symb) {    if (!$symb) {
     $symb=&symbread();      $symb=&symbread();
     if (!$symb) { $symb= $ENV{'REQUEST_URI'}; }      if (!$symb) { $symb= $ENV{'request.url'}; }
   }    }
   $symb=escape($symb);    $symb=escape($symb);
   
Line 1915  sub rolesinit { Line 1936  sub rolesinit {
  my ($tdummy,$tdomain,$trest)=split(/\//,$area);   my ($tdummy,$tdomain,$trest)=split(/\//,$area);
  if ($trole =~ /^cr\//) {   if ($trole =~ /^cr\//) {
     my ($rdummy,$rdomain,$rauthor,$rrole)=split(/\//,$trole);      my ($rdummy,$rdomain,$rauthor,$rrole)=split(/\//,$trole);
     my $homsvr=homeserver($rauthor,$rdomain);       my $homsvr=homeserver($rauthor,$rdomain);
     if ($hostname{$homsvr} ne '') {      if ($hostname{$homsvr} ne '') {
  my $roledef=   my ($rdummy,$roledef)=
     reply("get:$rdomain:$rauthor:roles:rolesdef_$rrole",     &get('roles',["rolesdef_$rrole"],$rdomain,$rauthor);
   $homsvr);  
  if (($roledef ne 'con_lost') && ($roledef ne '')) {   if (($rdummy ne 'con_lost') && ($roledef ne '')) {
     my ($syspriv,$dompriv,$coursepriv)=      my ($syspriv,$dompriv,$coursepriv)=
  split(/\_/,unescape($roledef));   split(/\_/,$roledef);
     if (defined($syspriv)) {      if (defined($syspriv)) {
  $allroles{'cm./'}.=':'.$syspriv;   $allroles{'cm./'}.=':'.$syspriv;
  $allroles{$spec.'./'}.=':'.$syspriv;   $allroles{$spec.'./'}.=':'.$syspriv;
Line 2500  sub is_on_map { Line 2521  sub is_on_map {
 sub definerole {  sub definerole {
   if (allowed('mcr','/')) {    if (allowed('mcr','/')) {
     my ($rolename,$sysrole,$domrole,$courole)=@_;      my ($rolename,$sysrole,$domrole,$courole)=@_;
     foreach (split('/',$sysrole)) {      foreach (split(':',$sysrole)) {
  my ($crole,$cqual)=split(/\&/,$_);   my ($crole,$cqual)=split(/\&/,$_);
         if ($pr{'cr:s'}!~/$crole/) { return "refused:s:$crole"; }          if ($pr{'cr:s'}!~/$crole/) { return "refused:s:$crole"; }
         if ($pr{'cr:s'}=~/$crole\&/) {          if ($pr{'cr:s'}=~/$crole\&/) {
Line 2509  sub definerole { Line 2530  sub definerole {
             }              }
         }          }
     }      }
     foreach (split('/',$domrole)) {      foreach (split(':',$domrole)) {
  my ($crole,$cqual)=split(/\&/,$_);   my ($crole,$cqual)=split(/\&/,$_);
         if ($pr{'cr:d'}!~/$crole/) { return "refused:d:$crole"; }          if ($pr{'cr:d'}!~/$crole/) { return "refused:d:$crole"; }
         if ($pr{'cr:d'}=~/$crole\&/) {          if ($pr{'cr:d'}=~/$crole\&/) {
Line 2518  sub definerole { Line 2539  sub definerole {
             }              }
         }          }
     }      }
     foreach (split('/',$courole)) {      foreach (split(':',$courole)) {
  my ($crole,$cqual)=split(/\&/,$_);   my ($crole,$cqual)=split(/\&/,$_);
         if ($pr{'cr:c'}!~/$crole/) { return "refused:c:$crole"; }          if ($pr{'cr:c'}!~/$crole/) { return "refused:c:$crole"; }
         if ($pr{'cr:c'}=~/$crole\&/) {          if ($pr{'cr:c'}=~/$crole\&/) {
Line 2630  sub assignrole { Line 2651  sub assignrole {
     my ($udom,$uname,$url,$role,$end,$start,$deleteflag)=@_;      my ($udom,$uname,$url,$role,$end,$start,$deleteflag)=@_;
     my $mrole;      my $mrole;
     if ($role =~ /^cr\//) {      if ($role =~ /^cr\//) {
  unless (&allowed('ccr',$url)) {          my $cwosec=$url;
           $cwosec=~s/^\/(\w+)\/(\w+)\/.*/$1\/$2/;
    unless (&allowed('ccr',$cwosec)) {
            &logthis('Refused custom assignrole: '.             &logthis('Refused custom assignrole: '.
              $udom.' '.$uname.' '.$url.' '.$role.' '.$end.' '.$start.' by '.               $udom.' '.$uname.' '.$url.' '.$role.' '.$end.' '.$start.' by '.
     $ENV{'user.name'}.' at '.$ENV{'user.domain'});      $ENV{'user.name'}.' at '.$ENV{'user.domain'});
Line 2640  sub assignrole { Line 2663  sub assignrole {
     } else {      } else {
         my $cwosec=$url;          my $cwosec=$url;
         $cwosec=~s/^\/(\w+)\/(\w+)\/.*/$1\/$2/;          $cwosec=~s/^\/(\w+)\/(\w+)\/.*/$1\/$2/;
         unless (&allowed('c'.$role,$cwosec)) {           unless ((&allowed('c'.$role,$cwosec)) || &allowed('c'.$role,$udom)) { 
            &logthis('Refused assignrole: '.             &logthis('Refused assignrole: '.
              $udom.' '.$uname.' '.$url.' '.$role.' '.$end.' '.$start.' by '.               $udom.' '.$uname.' '.$url.' '.$role.' '.$end.' '.$start.' by '.
     $ENV{'user.name'}.' at '.$ENV{'user.domain'});      $ENV{'user.name'}.' at '.$ENV{'user.domain'});
Line 2660  sub assignrole { Line 2683  sub assignrole {
     }      }
 # actually delete  # actually delete
     if ($deleteflag) {      if ($deleteflag) {
  if (&allowed('dro',$udom)) {   if ((&allowed('dro',$udom)) || (&allowed('dro',$url))) {
 # modify command to delete the role  # modify command to delete the role
            $command="encrypt:rolesdel:$ENV{'user.domain'}:$ENV{'user.name'}:".             $command="encrypt:rolesdel:$ENV{'user.domain'}:$ENV{'user.name'}:".
                 "$udom:$uname:$url".'_'."$mrole";                  "$udom:$uname:$url".'_'."$mrole";
      &logthis("$ENV{'user.name'} at $ENV{'user.domain'} deletes $mrole in $url for $uname at $udom"); 
 # set start and finish to negative values for userrolelog  # set start and finish to negative values for userrolelog
            $start=-1;             $start=-1;
            $end=-1;             $end=-1;
Line 2710  sub modifyuser { Line 2734  sub modifyuser {
     my ($udom,    $uname, $uid,      my ($udom,    $uname, $uid,
         $umode,   $upass, $first,          $umode,   $upass, $first,
         $middle,  $last,  $gene,          $middle,  $last,  $gene,
         $forceid, $desiredhome)=@_;          $forceid, $desiredhome, $email)=@_;
     $udom=~s/\W//g;      $udom=~s/\W//g;
     $uname=~s/\W//g;      $uname=~s/\W//g;
     &logthis('Call to modify user '.$udom.', '.$uname.', '.$uid.', '.      &logthis('Call to modify user '.$udom.', '.$uname.', '.$uid.', '.
Line 2752  sub modifyuser { Line 2776  sub modifyuser {
         }             }   
         $uhome=&homeserver($uname,$udom,'true');          $uhome=&homeserver($uname,$udom,'true');
         if (($uhome eq '') || ($uhome eq 'no_host') || ($uhome ne $unhome)) {          if (($uhome eq '') || ($uhome eq 'no_host') || ($uhome ne $unhome)) {
     return 'error: verify home';      return 'error: unable verify users home machine.';
         }          }
     }   # End of creation of new user      }   # End of creation of new user
 # ---------------------------------------------------------------------- Add ID  # ---------------------------------------------------------------------- Add ID
Line 2762  sub modifyuser { Line 2786  sub modifyuser {
        if (($uidhash{$uname}) && ($uidhash{$uname}!~/error\:/)          if (($uidhash{$uname}) && ($uidhash{$uname}!~/error\:/) 
          && (!$forceid)) {           && (!$forceid)) {
   unless ($uid eq $uidhash{$uname}) {    unless ($uid eq $uidhash{$uname}) {
       return 'error: mismatch '.$uidhash{$uname}.' versus '.$uid;        return 'error: user id "'.$uid.'" does not match '.
                     'current user id "'.$uidhash{$uname}.'".';
           }            }
        } else {         } else {
   &idput($udom,($uname => $uid));    &idput($udom,($uname => $uid));
Line 2778  sub modifyuser { Line 2803  sub modifyuser {
     } else {      } else {
         %names = @tmp;          %names = @tmp;
     }      }
   #
   # Make sure to not trash student environment if instructor does not bother
   # to supply name and email information
   #
     if ($first)  { $names{'firstname'}  = $first; }      if ($first)  { $names{'firstname'}  = $first; }
     if ($middle) { $names{'middlename'} = $middle; }      if (defined($middle)) { $names{'middlename'} = $middle; }
     if ($last)   { $names{'lastname'}   = $last; }      if ($last)   { $names{'lastname'}   = $last; }
     if ($gene)   { $names{'generation'} = $gene; }      if (defined($gene))   { $names{'generation'} = $gene; }
       if ($email)  { $names{'notification'} = $email;
                      $names{'critnotification'} = $email; }
   
     my $reply = &put('environment', \%names, $udom,$uname);      my $reply = &put('environment', \%names, $udom,$uname);
     if ($reply ne 'ok') { return 'error: '.$reply; }      if ($reply ne 'ok') { return 'error: '.$reply; }
     &logthis('Success modifying user '.$udom.', '.$uname.', '.$uid.', '.      &logthis('Success modifying user '.$udom.', '.$uname.', '.$uid.', '.
Line 2795  sub modifyuser { Line 2827  sub modifyuser {
   
 sub modifystudent {  sub modifystudent {
     my ($udom,$uname,$uid,$umode,$upass,$first,$middle,$last,$gene,$usec,      my ($udom,$uname,$uid,$umode,$upass,$first,$middle,$last,$gene,$usec,
         $end,$start,$forceid,$desiredhome)=@_;          $end,$start,$forceid,$desiredhome,$email)=@_;
     my $cid='';      my $cid='';
     unless ($cid=$ENV{'request.course.id'}) {      unless ($cid=$ENV{'request.course.id'}) {
  return 'not_in_class';   return 'not_in_class';
Line 2803  sub modifystudent { Line 2835  sub modifystudent {
 # --------------------------------------------------------------- Make the user  # --------------------------------------------------------------- Make the user
     my $reply=&modifyuser      my $reply=&modifyuser
  ($udom,$uname,$uid,$umode,$upass,$first,$middle,$last,$gene,$forceid,   ($udom,$uname,$uid,$umode,$upass,$first,$middle,$last,$gene,$forceid,
          $desiredhome);           $desiredhome,$email);
     unless ($reply eq 'ok') { return $reply; }      unless ($reply eq 'ok') { return $reply; }
     # This will cause &modify_student_enrollment to get the uid from the      # This will cause &modify_student_enrollment to get the uid from the
     # students environment      # students environment
Line 3062  sub GetFileTimestamp { Line 3094  sub GetFileTimestamp {
     $subdir =~ s/(.)(.)(.).*/$1\/$2\/$3/;      $subdir =~ s/(.)(.)(.).*/$1\/$2\/$3/;
     my $proname="$studentDomain/$subdir/$studentName";      my $proname="$studentDomain/$subdir/$studentName";
     $proname .= '/'.$filename;      $proname .= '/'.$filename;
     my @dir = &Apache::lonnet::dirlist($proname, $studentDomain, $studentName,      my ($fileStat) = &Apache::lonnet::dirlist($proname, $studentDomain, 
                                        $root);                                                $studentName, $root);
     my $fileStat = $dir[0];  
     my @stats = split('&', $fileStat);      my @stats = split('&', $fileStat);
     if($stats[0] ne 'empty' && $stats[0] ne 'no_such_dir') {      if($stats[0] ne 'empty' && $stats[0] ne 'no_such_dir') {
         return $stats[9];          # @stats contains first the filename, then the stat output
           return $stats[10]; # so this is 10 instead of 9.
     } else {      } else {
         return -1;          return -1;
     }      }
Line 3163  sub courseresdata { Line 3195  sub courseresdata {
     return undef;      return undef;
 }  }
   
 # --------------------------------------------------------- Value of a Variable  #
   # EXT resource caching routines
   #
   
   sub clear_EXT_cache_status {
       &delenv('cache.EXT.');
   }
   
   sub EXT_cache_status {
       my ($target_domain,$target_user) = @_;
       my $cachename = 'cache.EXT.'.$target_user.'.'.$target_domain;
       if (exists($ENV{$cachename}) && ($ENV{$cachename}+600) > time) {
           # We know already the user has no data
           return 1;
       } else {
           return 0;
       }
   }
   
   sub EXT_cache_set {
       my ($target_domain,$target_user) = @_;
       my $cachename = 'cache.EXT.'.$target_user.'.'.$target_domain;
       &appenv($cachename => time);
   }
   
   # --------------------------------------------------------- Value of a Variable
 sub EXT {  sub EXT {
     my ($varname,$symbparm,$udom,$uname,)=@_;      my ($varname,$symbparm,$udom,$uname,$usection)=@_;
   
     unless ($varname) { return ''; }      unless ($varname) { return ''; }
     #get real user name/domain, courseid and symb      #get real user name/domain, courseid and symb
Line 3174  sub EXT { Line 3230  sub EXT {
     my $publicuser;      my $publicuser;
     if (!($uname && $udom)) {      if (!($uname && $udom)) {
       (my $cursymb,$courseid,$udom,$uname,$publicuser)=        (my $cursymb,$courseid,$udom,$uname,$publicuser)=
   &Apache::lonxml::whichuser();    &Apache::lonxml::whichuser($symbparm);
       if (!$symbparm) { $symbparm=$cursymb; }        if (!$symbparm) { $symbparm=$cursymb; }
     } else {      } else {
  $courseid=$ENV{'request.course.id'};   $courseid=$ENV{'request.course.id'};
Line 3251  sub EXT { Line 3307  sub EXT {
         }          }
     } elsif ($realm eq 'query') {      } elsif ($realm eq 'query') {
 # ---------------------------------------------- pull stuff out of query string  # ---------------------------------------------- pull stuff out of query string
         &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},[$space]);          &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},
  return $ENV{'form.'.$space};    [$spacequalifierrest]);
    return $ENV{'form.'.$spacequalifierrest}; 
    } elsif ($realm eq 'request') {     } elsif ($realm eq 'request') {
 # ------------------------------------------------------------- request.browser  # ------------------------------------------------------------- request.browser
         if ($space eq 'browser') {          if ($space eq 'browser') {
Line 3283  sub EXT { Line 3340  sub EXT {
  ($ENV{'user.domain'} eq $udom)) {   ($ENV{'user.domain'} eq $udom)) {
  $section=$ENV{'request.course.sec'};   $section=$ENV{'request.course.sec'};
     } else {      } else {
  $section=&usection($udom,$uname,$courseid);                  if (! defined($usection)) {
                       $section=&usection($udom,$uname,$courseid);
                   } else {
                       $section = $usection;
                   }
     }      }
   
     my $seclevel=$courseid.'.['.$section.'].'.$spacequalifierrest;      my $seclevel=$courseid.'.['.$section.'].'.$spacequalifierrest;
Line 3295  sub EXT { Line 3356  sub EXT {
     my $courselevelm=$courseid.'.'.$mapparm;      my $courselevelm=$courseid.'.'.$mapparm;
   
 # ----------------------------------------------------------- first, check user  # ----------------------------------------------------------- first, check user
     #most student don't have any data set, check if there is some data      #most student don\'t have any data set, check if there is some data
             #every thirty minutes              #every thirty minutes
     if (!      if (! &EXT_cache_status($udom,$uname)) {
  (exists($ENV{'cache.studentresdata'})  
     && (($ENV{'cache.studentresdata'}+1800) > time))) {  
  my %resourcedata=&get('resourcedata',   my %resourcedata=&get('resourcedata',
       [$courselevelr,$courselevelm,$courselevel],        [$courselevelr,$courselevelm,$courselevel],
       $udom,$uname);        $udom,$uname);
Line 3318  sub EXT { Line 3377  sub EXT {
  $uname." at ".$udom.": ".   $uname." at ".$udom.": ".
  $tmp."</font>");   $tmp."</font>");
     } elsif ($tmp=~/error:No such file/) {      } elsif ($tmp=~/error:No such file/) {
  $ENV{'cache.studentresdata'}=time;                          &EXT_cache_set($udom,$uname);
  &appenv(('cache.studentresdata'=>  
  $ENV{'cache.studentresdata'}));  
     } elsif ($tmp =~ /^(con_lost|no_such_host)/) {      } elsif ($tmp =~ /^(con_lost|no_such_host)/) {
  return $tmp;   return $tmp;
     }      }
Line 3606  sub gettitle { Line 3663  sub gettitle {
  unless ($urlsymb) { $urlsymb=$ENV{'request.filename'}; }   unless ($urlsymb) { $urlsymb=$ENV{'request.filename'}; }
         return &metadata($urlsymb,'title');           return &metadata($urlsymb,'title'); 
     }      }
     if ($titlecache{$symb}) { return $titlecache{$symb}; }      if ($titlecache{$symb}) {
    if (time < ($titlecache{$symb}[1] + 600)) {
       return $titlecache{$symb}[0];
    } else {
       delete($titlecache{$symb});
    }
       }
     my ($map,$resid,$url)=split(/\_\_\_/,$symb);      my ($map,$resid,$url)=split(/\_\_\_/,$symb);
     my $title='';      my $title='';
     my %bighash;      my %bighash;
Line 3618  sub gettitle { Line 3681  sub gettitle {
     }      }
     $title=~s/\&colon\;/\:/gs;      $title=~s/\&colon\;/\:/gs;
     if ($title) {      if ($title) {
         $titlecache{$symb}=$title;          $titlecache{$symb}=[$title,time];
         return $title;          return $title;
     } else {      } else {
  return &metadata($urlsymb,'title');   return &metadata($urlsymb,'title');
Line 4039  BEGIN { Line 4102  BEGIN {
     %domain_auth_arg_def = ();      %domain_auth_arg_def = ();
     if ($fh) {      if ($fh) {
        while (<$fh>) {         while (<$fh>) {
            next if /^\#/;             next if (/^(\#|\s*$)/);
   #           next if /^\#/;
            chomp;             chomp;
            my ($domain, $domain_description, $def_auth, $def_auth_arg)             my ($domain, $domain_description, $def_auth, $def_auth_arg)
                = split(/:/,$_,4);                 = split(/:/,$_,4);
Line 4182  being set. Line 4246  being set.
   
 =back  =back
   
 =head1 INTRODUCTION  =head1 OVERVIEW
   
 This module provides subroutines which interact with the  lonnet provides subroutines which interact with the
 lonc/lond (TCP) network layer of LON-CAPA. And Can be used to ask about   lonc/lond (TCP) network layer of LON-CAPA. They can be used to ask
 - classes  about classes, users, and resources.
 - users   
 - resources  
   
 For many of these objects you can also use this to store data about  For many of these objects you can also use this to store data about
 them or modify them in various ways.  them or modify them in various ways.
   
 This is part of the LearningOnline Network with CAPA project  =head2 Symbs
 described at http://www.lon-capa.org.  
   
 =head1 RETURN MESSAGES  To identify a specific instance of a resource, LON-CAPA uses symbols
   or "symbs"X<symb>. These identifiers are built from the URL of the
   map, the resource number of the resource in the map, and the URL of
   the resource itself. The latter is somewhat redundant, but might help
   if maps change.
   
 =over 4  An example is
   
 =item *   msu/korte/parts/part1.sequence___19___msu/korte/tests/part12.problem
   
 con_lost : unable to contact remote host  The respective map entry is
   
 =item *   <resource id="19" src="/res/msu/korte/tests/part12.problem"
     title="Problem 2">
    </resource>
   
 con_delayed : unable to contact remote host, message will be delivered  Symbs are used by the random number generator, as well as to store and
 when the connection is brought back up  restore data specific to a certain instance of for example a problem.
   
 =item *  =head2 Storing And Retrieving Data
   
 con_failed : unable to contact remote host and unable to save message  X<store()>X<cstore()>X<restore()>Three of the most important functions
 for later delivery  in C<lonnet.pm> are C<&Apache::lonnet::cstore()>,
   C<&Apache::lonnet:restore()>, and C<&Apache::lonnet::store()>, which
   is is the non-critical message twin of cstore. These functions are for
   handlers to store a perl hash to a user's permanent data space in an
   easy manner, and to retrieve it again on another call. It is expected
   that a handler would use this once at the beginning to retrieve data,
   and then again once at the end to send only the new data back.
   
 =item *  The data is stored in the user's data directory on the user's
   homeserver under the ID of the course.
   
 error: : an error a occured, a description of the error follows the :  The hash that is returned by restore will have all of the previous
   value for all of the elements of the hash.
   
 =item *  Example:
   
    #creating a hash
    my %hash;
    $hash{'foo'}='bar';
   
    #storing it
    &Apache::lonnet::cstore(\%hash);
   
    #changing a value
    $hash{'foo'}='notbar';
   
    #adding a new value
    $hash{'bar'}='foo';
    &Apache::lonnet::cstore(\%hash);
   
    #retrieving the hash
    my %history=&Apache::lonnet::restore();
   
    #print the hash
    foreach my $key (sort(keys(%history))) {
      print("\%history{$key} = $history{$key}");
    }
   
   Will print out:
   
    %history{1:foo} = bar
    %history{1:keys} = foo:timestamp
    %history{1:timestamp} = 990455579
    %history{2:bar} = foo
    %history{2:foo} = notbar
    %history{2:keys} = foo:bar:timestamp
    %history{2:timestamp} = 990455580
    %history{bar} = foo
    %history{foo} = notbar
    %history{timestamp} = 990455580
    %history{version} = 2
   
   Note that the special hash entries C<keys>, C<version> and
   C<timestamp> were added to the hash. C<version> will be equal to the
   total number of versions of the data that have been stored. The
   C<timestamp> attribute will be the UNIX time the hash was
   stored. C<keys> is available in every historical section to list which
   keys were added or changed at a specific historical revision of a
   hash.
   
   B<Warning>: do not store the hash that restore returns directly. This
   will cause a mess since it will restore the historical keys as if the
   were new keys. I.E. 1:foo will become 1:1:foo etc.
   
   Calling convention:
   
    my %record=&Apache::lonnet::restore($symb,$courseid,$domain,$uname,$home);
    &Apache::lonnet::cstore(\%newrecord,$symb,$courseid,$domain,$uname,$home);
   
   For more detailed information, see lonnet specific documentation.
   
   =head1 RETURN MESSAGES
   
   =over 4
   
 no_such_host : unable to fund a host associated with the user/domain  =item * B<con_lost>: unable to contact remote host
   
   =item * B<con_delayed>: unable to contact remote host, message will be delivered
   when the connection is brought back up
   
   =item * B<con_failed>: unable to contact remote host and unable to save message
   for later delivery
   
   =item * B<error:>: an error a occured, a description of the error follows the :
   
   =item * B<no_such_host>: unable to fund a host associated with the user/domain
 that was requested  that was requested
   
 =back  =back
Line 4231  that was requested Line 4375  that was requested
   
 =over 4  =over 4
   
 =item *  =item * 
   X<appenv()>
 appenv(%hash) : the value of %hash is written to the user envirnoment  B<appenv(%hash)>: the value of %hash is written to
 file, and will be restored for each access this user makes during this  the user envirnoment file, and will be restored for each access this
 session, also modifies the %ENV for the current process  user makes during this session, also modifies the %ENV for the current
   process
   
 =item *  =item *
   X<delenv()>
 delenv($regexp) : removes all items from the session environment file that matches the regular expression in $regexp. The values are also delted from the current processes %ENV.  B<delenv($regexp)>: removes all items from the session
   environment file that matches the regular expression in $regexp. The
   values are also delted from the current processes %ENV.
   
 =back  =back
   
Line 4248  delenv($regexp) : removes all items from Line 4395  delenv($regexp) : removes all items from
 =over 4  =over 4
   
 =item *  =item *
   X<queryauthenticate()>
 queryauthenticate($uname,$udom) : try to determine user's current  B<queryauthenticate($uname,$udom)>: try to determine user's current 
 authentication scheme  authentication scheme
   
 =item *  =item *
   X<authenticate()>
 authenticate($uname,$upass,$udom) : try to authenticate user from domain's lib  B<authenticate($uname,$upass,$udom)>: try to
 servers (first use the current one), $upass should be the users password  authenticate user from domain's lib servers (first use the current
   one). C<$upass> should be the users password.
   
 =item *  =item *
   X<homeserver()>
 homeserver($uname,$udom) : find the server which has the user's  B<homeserver($uname,$udom)>: find the server which has
 directory and files (there must be only one), this caches the answer,  the user's directory and files (there must be only one), this caches
 and also caches if there is a borken connection.  the answer, and also caches if there is a borken connection.
   
 =item *  =item *
   X<idget()>
 idget($udom,@ids) : find the usernames behind a list of IDs (IDs are a  B<idget($udom,@ids)>: find the usernames behind a list of IDs
 unique resource in a domain, there must be only 1 ID per username, and  (IDs are a unique resource in a domain, there must be only 1 ID per
 only 1 username per ID in a specific domain) (returns hash:  username, and only 1 username per ID in a specific domain) (returns
 id=>name,id=>name)  hash: id=>name,id=>name)
   
 =item *  =item *
   X<idrget()>
 idrget($udom,@unames) : find the IDs behind a list of usernames (returns hash:  B<idrget($udom,@unames)>: find the IDs behind a list of
 name=>id,name=>id)  usernames (returns hash: name=>id,name=>id)
   
 =item *  =item *
   X<idput()>
 idput($udom,%ids) : store away a list of names and associated IDs  B<idput($udom,%ids)>: store away a list of names and associated IDs
   
 =item *  =item *
   X<rolesinit()>
 rolesinit($udom,$username,$authhost) : get user privileges  B<rolesinit($udom,$username,$authhost)>: get user privileges
   
 =item *  =item *
   X<usection()>
 usection($udom,$uname,$cname) : finds the section of student in the  B<usection($udom,$uname,$cname)>: finds the section of student in the
 course $cname, return section name/number or '' for "not in course"  course $cname, return section name/number or '' for "not in course"
 and '-1' for "no section"  and '-1' for "no section"
   
 =item *  =item *
   X<userenvironment()>
 userenvironment($udom,$uname,@what) : gets the values of the keys  B<userenvironment($udom,$uname,@what)>: gets the values of the keys
 passed in @what from the requested user's environment, returns a hash  passed in @what from the requested user's environment, returns a hash
   
 =back  =back
Removed from v.1.370  
changed lines
  Added in v.1.394

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