File:  [LON-CAPA] / loncom / auth / lonroles.pm
Revision 1.128: download - view: text, annotated - select for diffs
Tue Aug 9 20:06:40 2005 UTC (18 years, 9 months ago) by albertel
Branches: MAIN
CVS tags: version_2_0_X, version_2_0_2, version_2_0_1, version_2_0_0, version_1_99_3, HEAD
- missed one bit for making sure the whatsnew page appears when it should with external nav screen

    1: # The LearningOnline Network with CAPA
    2: # User Roles Screen
    3: #
    4: # $Id: lonroles.pm,v 1.128 2005/08/09 20:06:40 albertel Exp $
    5: #
    6: # Copyright Michigan State University Board of Trustees
    7: #
    8: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
    9: #
   10: # LON-CAPA is free software; you can redistribute it and/or modify
   11: # it under the terms of the GNU General Public License as published by
   12: # the Free Software Foundation; either version 2 of the License, or
   13: # (at your option) any later version.
   14: #
   15: # LON-CAPA is distributed in the hope that it will be useful,
   16: # but WITHOUT ANY WARRANTY; without even the implied warranty of
   17: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   18: # GNU General Public License for more details.
   19: #
   20: # You should have received a copy of the GNU General Public License
   21: # along with LON-CAPA; if not, write to the Free Software
   22: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   23: #
   24: # /home/httpd/html/adm/gpl.txt
   25: #
   26: # http://www.lon-capa.org/
   27: #
   28: ###
   29: 
   30: package Apache::lonroles;
   31: 
   32: use strict;
   33: use Apache::lonnet;
   34: use Apache::lonuserstate();
   35: use Apache::Constants qw(:common);
   36: use Apache::File();
   37: use Apache::lonmenu;
   38: use Apache::loncommon;
   39: use Apache::lonhtmlcommon;
   40: use Apache::lonannounce;
   41: use Apache::lonlocal;
   42: use GDBM_File;
   43: 
   44: sub redirect_user {
   45:     my ($r,$title,$url,$msg,$launch_nav) = @_;
   46:     $msg = $title if (! defined($msg));
   47:     &Apache::loncommon::content_type($r,'text/html');
   48:     &Apache::loncommon::no_cache($r);
   49:     $r->send_http_header;
   50:     my $swinfo=&Apache::lonmenu::rawconfig();
   51:     my $navwindow;
   52:     if ($launch_nav eq 'on') {
   53: 	$navwindow.=&Apache::lonnavmaps::launch_win('now',undef,undef,
   54: 						    ($url eq '/adm/whatsnew'));
   55:     } else {
   56: 	$navwindow.=&Apache::lonnavmaps::close();
   57:     }
   58:     my $bodytag=&Apache::loncommon::bodytag('Switching Role');
   59: # Note to style police: 
   60: # This must only replace the spaces, nothing else, or it bombs elsewhere.
   61:     $url=~s/ /\%20/g;
   62:     $r->print(<<ENDREDIR);
   63: <head><title>$title</title>
   64: <meta HTTP-EQUIV="Refresh" CONTENT="1; url=$url">
   65: </head>
   66: <html>
   67: $bodytag
   68: <script type="text/javascript">
   69: $swinfo
   70: </script>
   71: $navwindow
   72: <h1>$msg</h1>
   73: <a href="$url">Continue</a>
   74: </body>
   75: </html>
   76: ENDREDIR
   77:     return;
   78: }
   79: 
   80: sub handler {
   81: 
   82:     my $r = shift;
   83: 
   84:     my $now=time;
   85:     my $then=$env{'user.login.time'};
   86:     my $envkey;
   87:     my %dcroles = ();
   88:     my $numdc = &check_fordc(\%dcroles,$then);
   89: 
   90: # ================================================================== Roles Init
   91:     if ($env{'form.selectrole'}) {
   92: 	if ($env{'request.course.id'}) {
   93: 	    my %temp=('logout_'.$env{'request.course.id'} => time);
   94: 	    &Apache::lonnet::put('email_status',\%temp);
   95: 	    &Apache::lonnet::delenv('user.state.'.$env{'request.course.id'});
   96: 	}
   97: 	&Apache::lonnet::appenv("request.course.id"   => '',
   98: 				"request.course.fn"   => '',
   99: 				"request.course.uri"  => '',
  100: 				"request.course.sec"  => '',
  101: 				"request.role"        => 'cm',
  102:                                 "request.role.adv"    => $env{'user.adv'},
  103: 				"request.role.domain" => $env{'user.domain'});
  104: 
  105: # Check if user is a DC trying to enter a course and needs privs to be created
  106:         if ($numdc > 0) {
  107:             foreach my $envkey (keys %env) {
  108:                 if ($envkey =~ m-^form\.cc\./(\w+)/(\w+)$-) {
  109:                     if ($dcroles{$1}) {
  110:                         my $cckey = 'user.role.cc./'.$1.'/'.$2;
  111:                         &check_privs($cckey,$then,$now);
  112:                     }
  113:                     last;
  114:                 }
  115:             }
  116:         }
  117: 
  118:         foreach $envkey (keys %env) {
  119:             next if ($envkey!~/^user\.role\./);
  120:             my ($where,$trolecode,$role,$tstatus,$tend,$tstart);
  121:             &role_status($envkey,$then,$now,\$role,\$where,\$trolecode,\$tstatus,\$tstart,\$tend);
  122:             if ($env{'form.'.$trolecode}) {
  123: 		if ($tstatus eq 'is') {
  124: 		    $where=~s/^\///;
  125: 		    my ($cdom,$cnum,$csec)=split(/\//,$where);
  126: # store role if recent_role list being kept
  127:                     if ($env{'environment.recentroles'}) {
  128: 			&Apache::lonhtmlcommon::store_recent('roles',
  129: 							     $trolecode,' ');
  130:                     }
  131: 
  132: 
  133: # check for keyed access
  134: 		    if (($role eq 'st') && 
  135:                        ($env{'course.'.$cdom.'_'.$cnum.'.keyaccess'} eq 'yes')) {
  136: # who is key authority?
  137: 			my $authdom=$cdom;
  138: 			my $authnum=$cnum;
  139: 			if ($env{'course.'.$cdom.'_'.$cnum.'.keyauth'}) {
  140: 			    ($authnum,$authdom)=
  141: 				split(/\W/,$env{'course.'.$cdom.'_'.$cnum.'.keyauth'});
  142: 			}
  143: # check with key authority
  144: 			unless (&Apache::lonnet::validate_access_key(
  145: 				     $env{'environment.key.'.$cdom.'_'.$cnum},
  146: 					     $authdom,$authnum)) {
  147: # there is no valid key
  148: 			     if ($env{'form.newkey'}) {
  149: # student attempts to register a new key
  150: 				 &Apache::loncommon::content_type($r,'text/html');
  151: 				 &Apache::loncommon::no_cache($r);
  152: 				 $r->send_http_header;
  153: 				 my $swinfo=&Apache::lonmenu::rawconfig();
  154: 				 my $bodytag=&Apache::loncommon::bodytag
  155: 				    ('Verifying Access Key to Unlock this Course');
  156: 				 my $buttontext=&mt('Enter Course');
  157: 				 my $message=&mt('Successfully registered key');
  158: 				 my $assignresult=
  159: 				     &Apache::lonnet::assign_access_key(
  160: 						     $env{'form.newkey'},
  161: 						     $authdom,$authnum,
  162: 						     $cdom,$cnum,
  163:                                                      $env{'user.domain'},
  164: 						     $env{'user.name'},
  165: 	      'Assigned from '.$ENV{'REMOTE_ADDR'}.' at '.localtime().' for '.
  166:                                                      $trolecode);
  167: 				 unless ($assignresult eq 'ok') {
  168: 				     $assignresult=~s/^error\:\s*//;
  169: 				     $message=&mt($assignresult).
  170: 				     '<br /><a href="/adm/logout">'.
  171: 				     &mt('Logout').'</a>';
  172: 				     $buttontext=&mt('Re-Enter Key');
  173: 				 }
  174: 				 $r->print(<<ENDENTEREDKEY);
  175: <head><title>Verifying Course Access Key</title>
  176: </head>
  177: <html>
  178: $bodytag
  179: <script>
  180: $swinfo
  181: </script>
  182: <form method="post">
  183: <input type="hidden" name="selectrole" value="1" />
  184: <input type="hidden" name="$trolecode" value="1" />
  185: <font size="+2">$message</font><br />
  186: <input type="submit" value="$buttontext" />
  187: </form>
  188: </body></html>
  189: ENDENTEREDKEY
  190:                                  return OK;
  191: 			     } else {
  192: # print form to enter a new key
  193: 				 &Apache::loncommon::content_type($r,'text/html');
  194: 				 &Apache::loncommon::no_cache($r);
  195: 				 $r->send_http_header;
  196: 				 my $swinfo=&Apache::lonmenu::rawconfig();
  197: 				 my $bodytag=&Apache::loncommon::bodytag
  198: 				    ('Enter Access Key to Unlock this Course');
  199: 				 $r->print(<<ENDENTERKEY);
  200: <head><title>Entering Course Access Key</title>
  201: </head>
  202: <html>
  203: $bodytag
  204: <script>
  205: $swinfo
  206: </script>
  207: <form method="post">
  208: <input type="hidden" name="selectrole" value="1" />
  209: <input type="hidden" name="$trolecode" value="1" />
  210: <input type="text" size="20" name="newkey" value="$env{'form.newkey'}" />
  211: <input type="submit" value="Enter key" />
  212: </form>
  213: </body></html>
  214: ENDENTERKEY
  215: 				 return OK;
  216: 			     }
  217: 			 }
  218: 		     }
  219: 		    &Apache::lonnet::log($env{'user.domain'},
  220: 					 $env{'user.name'},
  221: 					 $env{'user.home'},
  222: 					 "Role ".$trolecode);
  223: 		    
  224: 		    &Apache::lonnet::appenv(
  225: 					   'request.role'        => $trolecode,
  226: 					   'request.role.domain' => $cdom,
  227: 					   'request.course.sec'  => $csec);
  228:                     my $tadv=0;
  229: 		    my $msg=&mt('Entering course ...');
  230: 
  231: 		    if (($cnum) && ($role ne 'ca') && ($role ne 'aa')) {
  232: 			my ($furl,$ferr)=
  233: 			    &Apache::lonuserstate::readmap($cdom.'/'.$cnum);
  234: 			if (($env{'form.orgurl'}) && 
  235: 			    ($env{'form.orgurl'}!~/^\/adm\/flip/)) {
  236: 			    my $dest=$env{'form.orgurl'};
  237: 			    if (&Apache::lonnet::allowed('adv') eq 'F') { $tadv=1; }
  238: 			    &Apache::lonnet::appenv('request.role.adv'=>$tadv);
  239: 			    $r->internal_redirect($dest);
  240: 			    return OK;
  241: 			} else {
  242: 			    unless ($env{'request.course.id'}) {
  243: 				&Apache::lonnet::appenv(
  244: 				      "request.course.id"  => $cdom.'_'.$cnum);
  245: 				$furl='/adm/roles?tryagain=1';
  246: 				$msg=
  247: 				    '<h1><font color=red>'.
  248: 			 &mt('Could not initialize course at this time.').
  249: 		    '</font></h1><h3>'.&mt('Please try again.').'</h3>'.$ferr;
  250: 			    }
  251: 			    if (&Apache::lonnet::allowed('adv') eq 'F') { $tadv=1; }
  252: 			    &Apache::lonnet::appenv('request.role.adv'=>$tadv);
  253: 
  254: 			    # Check to see if the user is a CC entering a course 
  255: 			    # for the first time
  256: 			    my (undef, undef, $role, $courseid) = split(/\./, $envkey);
  257: 			    if (substr($courseid, 0, 1) eq '/') {
  258: 				$courseid = substr($courseid, 1);
  259: 			    }
  260: 			    $courseid =~ s/\//_/;
  261: 			    if ($role eq 'cc' && $env{'course.' . $courseid . 
  262: 							  '.course.helper.not.run'}) {
  263: 				$furl = "/adm/helper/course.initialization.helper";
  264: 				# Send the user to the course they selected
  265: 			    } elsif (($env{'request.course.fn'}) 
  266: 				     && ($role eq 'cc' && ($env{'environment.course_init_display'} ne 'firstres')))  {
  267: 				$msg = &mt('Entering course ....');
  268: 				&redirect_user($r,&mt('New in course'),
  269: 					       '/adm/whatsnew',$msg,
  270: 					       $env{'environment.remotenavmap'});
  271: 				return OK;
  272: 			    }
  273: 			    &redirect_user($r,&mt('Entering Course'),
  274:                                            $furl,$msg,
  275: 					   $env{'environment.remotenavmap'});
  276: 			    return OK;
  277: 			}
  278: 		    }
  279:                     #
  280:                     # Send the user to the construction space they selected
  281:                     if ($role =~ /^(au|ca|aa)$/) {
  282:                         my $redirect_url = '/priv/';
  283:                         if ($role eq 'au') {
  284:                             $redirect_url.=$env{'user.name'};
  285:                         } else {
  286:                             $where =~ /\/(.*)$/;
  287:                             $redirect_url .= $1;
  288:                         }
  289:                         $redirect_url .= '/';
  290:                         &redirect_user($r,&mt('Entering Construction Space'),
  291:                                        $redirect_url);
  292:                         return OK;
  293:                     }
  294:                     if ($role eq 'dc') {
  295:                         my $redirect_url = '/adm/menu/';
  296:                         &redirect_user($r,&mt('Loading Domain Coordinator Menu'),
  297:                                        $redirect_url);
  298:                         return OK;
  299:                     }
  300: 		}
  301:             }
  302:         }
  303:     }
  304: 
  305: 
  306: # =============================================================== No Roles Init
  307: 
  308:     &Apache::loncommon::content_type($r,'text/html');
  309:     &Apache::loncommon::no_cache($r);
  310:     $r->send_http_header;
  311:     return OK if $r->header_only;
  312: 
  313:     my $swinfo=&Apache::lonmenu::rawconfig();
  314:     my $bodytag=&Apache::loncommon::bodytag('User Roles');
  315:     my $helptag='<table><tr><td>'.&Apache::loncommon::help_open_menu('','General Intro','General_Intro','User Roles',1,undef,undef,undef,undef,,&mt("Click here for help")).'</td></td></tr></table>';
  316:     $r->print(<<ENDHEADER);
  317: <html>
  318: <head>
  319: <title>LON-CAPA User Roles</title>
  320: </head>
  321: $bodytag
  322: $helptag<br />
  323: <script>
  324: $swinfo
  325: window.focus();
  326: </script>
  327: ENDHEADER
  328: 
  329: # ------------------------------------------ Get Error Message from Environment
  330: 
  331:     my ($fn,$priv,$nochoose,$error,$msg)=split(/:/,$env{'user.error.msg'});
  332:     if ($env{'user.error.msg'}) {
  333: 	$r->log_reason(
  334:    "$msg for $env{'user.name'} domain $env{'user.domain'} access $priv",$fn);
  335:     }
  336: 
  337: # ------------------------------------------------- Can this user re-init, etc?
  338: 
  339:     my $advanced=$env{'user.adv'};
  340:     &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},['tryagain']);
  341:     my $tryagain=$env{'form.tryagain'};
  342: 
  343: # -------------------------------------------------------- Generate Page Output
  344: # --------------------------------------------------------------- Error Header?
  345:     if ($error) {
  346: 	$r->print("<h1>LON-CAPA Access Control</h1>");
  347:         $r->print("<!-- LONCAPAACCESSCONTROLERRORSCREEN --><hr /><pre>Access  : ".
  348:                   Apache::lonnet::plaintext($priv)."\n");
  349:         $r->print("Resource: ".&Apache::lonenc::check_encrypt($fn)."\n");
  350:         $r->print("Action  : $msg\n</pre><hr />");
  351: 	my $url=$fn;
  352: 	my $last;
  353: 	if (tie(my %hash,'GDBM_File',$env{'request.course.fn'}.'_symb.db',
  354: 		&GDBM_READER(),0640)) {
  355: 	    $last=$hash{'last_known'};
  356: 	    untie(%hash);
  357: 	}
  358: 	if ($last) { $fn.='?symb='.&Apache::lonnet::escape($last); }
  359: 
  360: 	&Apache::londocs::changewarning($r,undef,'You have modified your course recently, [_1] may fix this access problem.',
  361: 					&Apache::lonenc::check_encrypt($fn));
  362:     } else {
  363:         if ($env{'user.error.msg'}) {
  364: 	    $r->print(
  365:  '<h3><font color=red>'.
  366:  &mt('You need to choose another user role or enter a specific course for this function').'</font></h3>');
  367: 	}
  368:     }
  369: # -------------------------------------------------------- Choice or no choice?
  370:     if ($nochoose) {
  371:         if ($advanced) {
  372: 	    $r->print("<h2>".&mt('Assigned User Roles')."</h2>\n");
  373:         } else {
  374: 	    $r->print("<h2>".&mt('Sorry ...')."</h2>\n".
  375: 		      &mt('This resource might be part of'));
  376: 	    if ($env{'request.course.id'}) {
  377: 		$r->print(&mt(' another'));
  378: 	    } else {
  379: 		$r->print(&mt(' a certain'));
  380: 	    } 
  381: 	    $r->print(&mt(' course.').'</body></html>');
  382: 	    return OK;
  383:         } 
  384:     } else {
  385:         if ($advanced) {
  386: 	    $r->print(&mt("Your home server is ").
  387: 		      $Apache::lonnet::hostname{&Apache::lonnet::homeserver
  388:                       ($env{'user.name'},$env{'user.domain'})}.
  389: 		      "<br />\n");
  390: 	    $r->print(&mt(
  391:       "Author and Co-Author roles are not available on servers other than their respective home servers."));
  392:         }
  393:         if (($ENV{'REDIRECT_QUERY_STRING'}) && ($fn)) {
  394:     	    $fn.='?'.$ENV{'REDIRECT_QUERY_STRING'};
  395:         }
  396:         $r->print('<form method="post" name="rolechoice" action="'.(($fn)?$fn:$r->uri).'">');
  397:         $r->print('<input type="hidden" name="orgurl" value="'.$fn.'" />');
  398:         $r->print('<input type="hidden" name="selectrole" value="1" />');
  399:     }
  400:     if ($env{'user.adv'}) {
  401: 	$r->print(
  402: 	      '<br /><label>'.&mt('Show all roles').': <input type="checkbox" name="showall"');
  403: 	if ($env{'form.showall'}) { $r->print(' checked="checked" '); }
  404: 	$r->print(' /></label><input type="submit" value="'.&mt('Display').'" />');
  405:     }
  406: 
  407:     my (%roletext,%sortrole,%roleclass);
  408:     my $countactive=0;
  409:     my $inrole=0;
  410:     my $possiblerole='';
  411:     foreach $envkey (sort keys %env) {
  412:         my $button = 1;
  413:         my $switchserver='';
  414: 	my $roletext;
  415: 	my $sortkey;
  416:         if ($envkey=~/^user\.role\./) {
  417:             my ($role,$where,$trolecode,$tstart,$tend,$tremark,$tstatus,$tpstart,$tpend,$tfont);
  418:             &role_status($envkey,$then,$now,\$role,\$where,\$trolecode,\$tstatus,\$tstart,\$tend);
  419:             next if (!defined($role) || $role eq '');
  420:             $tremark='';
  421:             $tpstart='&nbsp;';
  422:             $tpend='&nbsp;';
  423:             $tfont='#000000';
  424:             if ($tstart) {
  425:                 $tpstart=&Apache::lonlocal::locallocaltime($tstart);
  426:             }
  427:             if ($tend) {
  428:                 $tpend=&Apache::lonlocal::locallocaltime($tend);
  429:             }
  430:             if ($env{'request.role'} eq $trolecode) {
  431: 		$tstatus='selected';
  432:             }
  433:             my $tbg;
  434:             if (($tstatus eq 'is') || ($tstatus eq 'selected') ||
  435:                 ($env{'form.showall'})) {
  436:                 if ($tstatus eq 'is') {
  437:                     $tbg='#77FF77';
  438:                     $tfont='#003300';
  439: 		    $possiblerole=$trolecode;
  440: 		    $countactive++;
  441:                 } elsif ($tstatus eq 'future') {
  442:                     $tbg='#FFFF77';
  443:                     $button=0;
  444:                 } elsif ($tstatus eq 'will') {
  445:                     $tbg='#FFAA77';
  446:                     $tremark.=&mt('Active at next login. ');
  447:                 } elsif ($tstatus eq 'expired') {
  448:                     $tbg='#FF7777';
  449:                     $tfont='#330000';
  450:                     $button=0;
  451:                 } elsif ($tstatus eq 'will_not') {
  452:                     $tbg='#AAFF77';
  453:                     $tremark.=&mt('Expired after logout. ');
  454:                 } elsif ($tstatus eq 'selected') {
  455:                     $tbg='#11CC55';
  456:                     $tfont='#002200';
  457: 		    $inrole=1;
  458: 		    $countactive++;
  459:                     $tremark.=&mt('Currently selected. ');
  460:                 }
  461:                 my $trole;
  462:                 if ($role =~ /^cr\//) {
  463:                     my ($rdummy,$rdomain,$rauthor,$rrole)=split(/\//,$role);
  464:                     $tremark.='<br />'.&mt('Defined by ').$rauthor.
  465: 			&mt(' at ').$rdomain.'.';
  466:                     $trole=$rrole;
  467:                 } else {
  468:                     $trole=Apache::lonnet::plaintext($role);
  469:                 }
  470:                 my $ttype;
  471:                 my $twhere;
  472:                 my ($tdom,$trest,$tsection)=
  473:                     split(/\//,Apache::lonnet::declutter($where));
  474:                 # First, Co-Authorship roles
  475:                 if (($role eq 'ca') || ($role eq 'aa')) {
  476:                     my $home = &Apache::lonnet::homeserver($trest,$tdom);
  477: 		    my $allowed=0;
  478: 		    my @ids=&Apache::lonnet::current_machine_ids();
  479: 		    foreach my $id (@ids) { if ($id eq $home) { $allowed=1; } }
  480:                     if (!$allowed) {
  481: 			$button=0;
  482:                         $switchserver=&Apache::lonnet::escape('http://'.
  483:                          $Apache::lonnet::hostname{$home}.
  484:                          '/adm/login?domain='.$env{'user.domain'}.
  485: 			  '&username='.$env{'user.name'}.
  486:                           '&firsturl=/priv/'.$trest.'/');
  487:                     }
  488:                     #next if ($home eq 'no_host');
  489:                     $home = $Apache::lonnet::hostname{$home};
  490:                     $ttype='Construction Space';
  491:                     $twhere=&mt('User').': '.$trest.'<br />'.&mt('Domain').
  492: 			': '.$tdom.'<br />'.
  493:                         ' '.&mt('Server').':&nbsp;'.$home;
  494:                     $env{'course.'.$tdom.'_'.$trest.'.description'}='ca';
  495: 		    $tremark.=&Apache::lonhtmlcommon::authorbombs('/res/'.$tdom.'/'.$trest.'/');
  496: 		    $sortkey=$role."$trest:$tdom";
  497:                 } elsif ($role eq 'au') {
  498:                     # Authors
  499:                     my $home = &Apache::lonnet::homeserver
  500:                         ($env{'user.name'},$env{'user.domain'});
  501: 		    my $allowed=0;
  502: 		    my @ids=&Apache::lonnet::current_machine_ids();
  503: 		    foreach my $id (@ids) { if ($id eq $home) { $allowed=1; } }
  504:                     if (!$allowed) {
  505: 			$button=0;
  506:                         $switchserver=&Apache::lonnet::escape('http://'.
  507:                          $Apache::lonnet::hostname{$home}.
  508:                           '/adm/login?domain='.$env{'user.domain'}.
  509: 			   '&username='.$env{'user.name'}.
  510:                            '&firsturl=/priv/'.$env{'user.name'}.'/');
  511:                     }
  512:                     #next if ($home eq 'no_host');
  513:                     $home = $Apache::lonnet::hostname{$home};
  514:                     $ttype='Construction Space';
  515:                     $twhere=&mt('Domain').': '.$tdom.'<br />'.&mt('Server').
  516: 			':&nbsp;'.$home;
  517:                     $env{'course.'.$tdom.'_'.$trest.'.description'}='ca';
  518: 		    $tremark.=&Apache::lonhtmlcommon::authorbombs('/res/'.$tdom.'/'.$env{'user.name'}.'/');
  519: 		    $sortkey=$role;
  520:                 } elsif ($trest) {
  521:                     $ttype='Course';
  522:                     my $tcourseid=$tdom.'_'.$trest;
  523:                     if ($env{'course.'.$tcourseid.'.description'}) {
  524:                         $twhere=$env{'course.'.$tcourseid.'.description'};
  525: 			$sortkey=$role."\0".$tdom."\0".$twhere."\0".$envkey;
  526:                         unless ($twhere eq &mt('Currently not available')) {
  527: 			    $twhere.=' <font size="-2">'.
  528:         &Apache::loncommon::syllabuswrapper(&mt('Syllabus'),$trest,$tdom,$tfont).
  529:                                     '</font>';
  530: 			}
  531:                     } else {
  532:                         my %newhash=&Apache::lonnet::coursedescription($tcourseid);
  533:                         if (%newhash) {
  534: 			    $sortkey=$role."\0".$tdom."\0".$newhash{'description'}.
  535: 				"\0".$envkey;
  536:                             $twhere=$newhash{'description'}.
  537:                               ' <font size="-2">'.
  538:         &Apache::loncommon::syllabuswrapper(&mt('Syllabus'),$trest,$tdom,$tfont).
  539:                               '</font>';
  540:                         } else {
  541:                             $twhere=&mt('Currently not available');
  542:                             $env{'course.'.$tcourseid.'.description'}=$twhere;
  543: 			    $sortkey=$role."\0".$tdom."\0".$twhere."\0".$envkey;
  544:                         }
  545:                     }
  546:                     if ($tsection) {
  547:                         $twhere.='<br />'.&mt('Section/Group').': '.$tsection;
  548: 		    }
  549: 
  550: 		    if ($role ne 'st') { $twhere.="<br />".&mt('Domain').":".$tdom; }
  551:                 } elsif ($tdom) {
  552:                     $ttype='Domain';
  553:                     $twhere=$tdom;
  554: 		    $sortkey=$role.$twhere;
  555:                 } else {
  556:                     $ttype='System';
  557:                     $twhere=&mt('system wide');
  558: 		    $sortkey=$role.$twhere;
  559:                 }
  560:  
  561:                 $roletext.=&build_roletext($trolecode,$tdom,$trest,$tstatus,$tryagain,$advanced,$tremark,$tbg,$tfont,$trole,$ttype,$twhere,$tpstart,$tpend,$nochoose,$button,$switchserver);
  562: 		$roletext{$envkey}=$roletext;
  563: 		if (!$sortkey) {$sortkey=$twhere."\0".$envkey;}
  564: 		$sortrole{$sortkey}=$envkey;
  565: 		$roleclass{$envkey}=$ttype;
  566: 	    }
  567:         }
  568:     }
  569: # No active roles
  570:     if ($countactive==0) {
  571: 	if ($inrole) {
  572: 	    $r->print('<h2>'.&mt('Currently no additional roles or courses').'</h2>');
  573: 	} else {
  574: 	    $r->print('<h2>'.&mt('Currently no active roles or courses').'</h2>');
  575: 	}
  576: 	$r->print('</form></body></html>');
  577: 	return OK;
  578: # Is there only one choice?
  579:     } elsif (($countactive==1) && ($env{'request.role'} eq 'cm')) {
  580: 	$r->print('<h3>'.&mt('Please stand by.').'</h3>'.
  581: 	    '<input type="hidden" name="'.$possiblerole.'" value="1" />');
  582: 	$r->print("</form>\n");
  583: 	$r->rflush();
  584: 	$r->print('<script>document.forms.rolechoice.submit();</script>');
  585: 	$r->print('</body></html>');
  586: 	return OK;
  587:     }
  588: # More than one possible role
  589: # ----------------------------------------------------------------------- Table
  590:     unless (($advanced) || ($nochoose)) {
  591: 	$r->print("<h2>".&mt('Select a Course to Enter')."</h2>\n");
  592:     }
  593:     $r->print('<br /><table><tr>');
  594:     unless ($nochoose) { $r->print('<th>&nbsp;</th>'); }
  595:     $r->print('<th>'.&mt('User Role').'</th><th>'.&mt('Extent').
  596:          '</th><th>'.&mt('Start').'</th><th>'.&mt('End').'</th><th>'.
  597: 	      &mt('Remarks and Calendar Announcements').'</th></tr>'."\n");
  598:     my $doheaders=-1;
  599:     foreach my $type ('Construction Space','Course','Domain','System') {
  600: 	my $haverole=0;
  601: 	foreach my $which (sort {uc($a) cmp uc($b)} (keys(%sortrole))) {
  602: 	    if ($roleclass{$sortrole{$which}} =~ /^\Q$type\E/) { 
  603: 		$haverole=1;
  604: 	    }
  605: 	}
  606: 	if ($haverole) { $doheaders++; }
  607:     }
  608: 
  609:     if ($env{'environment.recentroles'}) {
  610:         my %recent_roles =
  611:                &Apache::lonhtmlcommon::get_recent('roles',$env{'environment.recentrolesn'});
  612: 	my $output='';
  613: 	foreach (sort(keys(%recent_roles))) {
  614: 	    if (defined($roletext{'user.role.'.$_})) {
  615: 		$output.=$roletext{'user.role.'.$_};
  616: 	    } elsif ($numdc > 0) {
  617:                 unless ($_ =~/^error\:/) {
  618:                     $output.=&display_cc_role('user.role.'.$_);
  619:                 }
  620:             } 
  621: 	}
  622: 	if ($output) {
  623: 	    $r->print("<tr><td align='center' colspan='6'><font face='arial'>".
  624: 		      &mt('Recent Roles')."</font></td>");
  625: 	    $r->print($output);
  626: 	    $r->print("</tr>");
  627:             $doheaders ++;
  628: 	}
  629:     }
  630: 
  631:     if ($numdc > 0) {
  632:         $r->print(&coursepick_jscript());
  633:         $r->print(&Apache::loncommon::coursebrowser_javascript());
  634:     }
  635:     foreach my $type ('Construction Space','Course','Domain','System') {
  636: 	my $output;
  637: 	foreach my $which (sort {uc($a) cmp uc($b)} (keys(%sortrole))) {
  638: 	    if ($roleclass{$sortrole{$which}} =~ /^\Q$type\E/) { 
  639: 		$output.=$roletext{$sortrole{$which}};
  640:                 if ($sortrole{$which} =~ m-dc\./(\w+)/-) {
  641:                     if ($dcroles{$1}) {
  642:                         $output .= &allcourses_row($1);
  643:                     }
  644:                 }
  645: 	    }
  646: 	}
  647: 	if ($output) {
  648: 	    if ($doheaders > 0) {
  649: 		$r->print("<tr>".
  650: 			  "<td align='center' colspan='6'><font face='arial'>".&mt($type)."</font></td></tr>");
  651: 	    }
  652: 	    $r->print($output);	
  653: 	}
  654:     }
  655:     my $tremark='';
  656:     my $tfont='#003300';
  657:     if ($env{'request.role'} eq 'cm') {
  658: 	$r->print('<tr bgcolor="#11CC55">');
  659:         $tremark=&mt('Currently selected. ');
  660:         $tfont='#002200';
  661:     } else {
  662:         $r->print('<tr bgcolor="#77FF77">');
  663:     }
  664:     unless ($nochoose) {
  665: 	if ($env{'request.role'} ne 'cm') {
  666: 	    $r->print('<td><input type=submit value="'.
  667: 		      &mt('Select').'" name="cm"></td>');
  668: 	} else {
  669: 	    $r->print('<td>&nbsp;</td>');
  670: 	}
  671:     }
  672:     $r->print('<td colspan="4"><font color="'.$tfont.'">'.&mt('No role specified').
  673:       '</font></td><td><font color="'.$tfont.'">'.$tremark.
  674:       '&nbsp;</font></td></tr>'."\n");
  675: 
  676:     $r->print('</table>');
  677:     unless ($nochoose) {
  678: 	$r->print("</form>\n");
  679:     }
  680: # ------------------------------------------------------------ Privileges Info
  681:     if (($advanced) && (($env{'user.error.msg'}) || ($error))) {
  682: 	$r->print('<hr /><h2>Current Privileges</h2>');
  683: 
  684: 	foreach $envkey (sort keys %env) {
  685: 	    if ($envkey=~/^user\.priv\.$env{'request.role'}\./) {
  686: 		my $where=$envkey;
  687: 		$where=~s/^user\.priv\.$env{'request.role'}\.//;
  688: 		my $ttype;
  689: 		my $twhere;
  690: 		my ($tdom,$trest,$tsec)=
  691: 		    split(/\//,Apache::lonnet::declutter($where));
  692: 		if ($trest) {
  693: 		    if ($env{'course.'.$tdom.'_'.$trest.'.description'} eq 'ca') {
  694: 			$ttype='Construction Space';
  695: 			$twhere='User: '.$trest.', Domain: '.$tdom;
  696: 		    } else {
  697: 			$ttype='Course';
  698: 			$twhere=$env{'course.'.$tdom.'_'.$trest.'.description'};
  699: 			if ($tsec) {
  700: 			    $twhere.=' (Section/Group: '.$tsec.')';
  701: 			}
  702: 		    }
  703: 		} elsif ($tdom) {
  704: 		    $ttype='Domain';
  705: 		    $twhere=$tdom;
  706: 		} else {
  707: 		    $ttype='System';
  708: 		    $twhere='/';
  709: 		}
  710: 		$r->print("\n<h3>".$ttype.': '.$twhere.'</h3><ul>');
  711: 		foreach (sort split(/:/,$env{$envkey})) {
  712: 		    if ($_) {
  713: 			my ($prv,$restr)=split(/\&/,$_);
  714: 			my $trestr='';
  715: 			if ($restr ne 'F') {
  716: 			    my $i;
  717: 			    $trestr.=' (';
  718: 			    for ($i=0;$i<length($restr);$i++) {
  719: 				$trestr.=
  720: 			       Apache::lonnet::plaintext(substr($restr,$i,1));
  721: 				if ($i<length($restr)-1) { $trestr.=', '; }
  722: 			    }
  723: 			    $trestr.=')';
  724: 			}
  725: 			$r->print('<li>'.
  726: 				  Apache::lonnet::plaintext($prv).$trestr.
  727: 				  '</li>');
  728: 		    }
  729: 		}
  730: 		$r->print('</ul>');
  731: 	    }
  732: 	}
  733:     }
  734:     $r->print(&Apache::lonnet::getannounce());
  735:     if ($advanced) {
  736: 	$r->print('<p><small><i>This is LON-CAPA '.
  737: 		  $r->dir_config('lonVersion').'</i><br />'.
  738: 		  '<a href="/adm/logout">'.&mt('Logout').'</a></small></p>');
  739:     }
  740:     $r->print("</body></html>\n");
  741:     return OK;
  742: }
  743: 
  744: sub role_status {
  745:     my ($rolekey,$then,$now,$role,$where,$trolecode,$tstatus,$tstart,$tend) = @_;
  746:     my @pwhere = ();
  747:     if (exists($env{$rolekey}) && $env{$rolekey} ne '') {
  748:         (undef,undef,$$role,@pwhere)=split(/\./,$rolekey);
  749:         unless (!defined($$role) || $$role eq '') {
  750:             $$where=join('.',@pwhere);
  751:             $$trolecode=$$role.'.'.$$where;
  752:             ($$tstart,$$tend)=split(/\./,$env{$rolekey});
  753:             $$tstatus='is';
  754:             if ($$tstart && $$tstart>$then) {
  755: 		$$tstatus='future';
  756: 		if ($$tstart<$now) { $$tstatus='will'; }
  757:             }
  758:             if ($$tend) {
  759:                 if ($$tend<$then) {
  760:                     $$tstatus='expired';
  761:                 } elsif ($$tend<$now) {
  762:                     $$tstatus='will_not';
  763:                 }
  764:             }
  765:         }
  766:     }
  767: }
  768: 
  769: sub build_roletext {
  770:     my ($trolecode,$tdom,$trest,$tstatus,$tryagain,$advanced,$tremark,$tbg,$tfont,$trole,$ttype,$twhere,$tpstart,$tpend,$nochoose,$button,$switchserver) = @_;
  771:     my $roletext='<tr bgcolor="'.$tbg.'">';
  772:     unless ($nochoose) {
  773:         if (!$button) {
  774:             if ($switchserver) {
  775:                 $roletext.='<td><a href="/adm/logout?handover='.
  776:                 $switchserver.'">'.&mt('Switch Server').'</a></td>';
  777:             } else {
  778:                 $roletext.=('<td>&nbsp;</td>');
  779:             }
  780:         } elsif ($tstatus eq 'is') {
  781:             $roletext.=('<td><input type=submit value="'.
  782:                         &mt('Select').'" name="'.
  783:                         $trolecode.'"></td>');
  784:         } elsif ($tryagain) {
  785:             $roletext.=
  786:                 '<td><input type=submit value="'.
  787:                 &mt('Try Selecting Again').'" name="'.$trolecode.'"></td>';
  788:         } elsif ($advanced) {
  789:             $roletext.=
  790:                 '<td><input type=submit value="'.
  791:                 &mt('Re-Initialize').'" name="'.$trolecode.'"></td>';
  792:         } else {
  793:             $roletext.='<td>&nbsp;</td>';
  794:         }
  795:     }
  796:     $tremark.=&Apache::lonannounce::showday(time,1,
  797:                  &Apache::lonannounce::readcalendar($tdom.'_'.$trest));
  798: 
  799: 
  800:     $roletext.='<td><font color="'.$tfont.'">'.$trole.
  801: 	       '</font></td><td><font color="'.$tfont.'">'.$twhere.
  802:                '</font></td><td><font color="'.$tfont.'">'.$tpstart.
  803:                '</font></td><td><font color="'.$tfont.'">'.$tpend.
  804:                '</font></td><td><font color="'.$tfont.'">'.$tremark.
  805:                '&nbsp;</font></td></tr>'."\n";
  806:     return $roletext;
  807: }
  808: 
  809: sub check_privs {
  810:     my ($cckey,$then,$now) = @_;
  811:     if ($env{$cckey}) {
  812:         my ($role,$where,$trolecode,$tstart,$tend,$tremark,$tstatus,$tpstart,$tpend,$tfont);
  813:         &role_status($cckey,$then,$now,\$role,\$where,\$trolecode,\$tstatus,\$tstart,\$tend);
  814:         unless (($tstatus eq 'is') || ($tstatus eq 'will_not')) {
  815:             &set_privileges($1,$2);
  816:         }
  817:     } else {
  818:         &set_privileges($1,$2);
  819:     }
  820: }
  821: 
  822: sub check_fordc {
  823:     my ($dcroles,$then) = @_;
  824:     my $numdc = 0;
  825:     if ($env{'user.adv'}) {
  826:         foreach my $envkey (sort keys %env) {
  827:             if ($envkey=~/^user\.role\.dc\.\/(\w+)\/$/) {
  828:                 my $dcdom = $1;
  829:                 my $livedc = 1;
  830:                 my ($tstart,$tend)=split(/\./,$env{$envkey});
  831:                 if ($tstart && $tstart>$then) { $livedc = 0; }
  832:                 if ($tend   && $tend  <$then) { $livedc = 0; }
  833:                 if ($livedc) {
  834:                     $$dcroles{$dcdom} = $envkey;
  835:                     $numdc++;
  836:                 }
  837:             }
  838:         }
  839:     }
  840:     return $numdc;
  841: }
  842: 
  843: sub courselink {
  844:     my ($dcdom) = @_;
  845:     my $courseform=&Apache::loncommon::selectcourse_link
  846:                      ('rolechoice','dccourse_'.$dcdom,'dcdomain_'.$dcdom,'coursedesc_'.$dcdom,$dcdom);
  847:     my $hiddenitems = '<input type="hidden" name="dcdomain_'.$dcdom.'" value="'.$dcdom.'" />'.
  848:                       '<input type="hidden" name="origdom_'.$dcdom.'" value="'.$dcdom.'" />'.
  849:                       '<input type="hidden" name="dccourse_'.$dcdom.'" value="" />'.
  850:                       '<input type="hidden" name="coursedesc_'.$dcdom.'" value="" />';
  851:     return $courseform.$hiddenitems;
  852: }
  853: 
  854: sub coursepick_jscript {
  855:     my $verify_script = <<"END";
  856: <script>
  857: function verifyCoursePick(caller) {
  858:     var numbutton = getIndex(caller)
  859:     var pickedCourse = document.rolechoice.elements[numbutton+4].value
  860:     var pickedDomain = document.rolechoice.elements[numbutton+2].value
  861:     if (document.rolechoice.elements[numbutton+2].value == document.rolechoice.elements[numbutton+3].value) {
  862:         if (pickedCourse != '') {
  863:             if (numbutton != -1) {
  864:                 var courseTarget = "cc./"+pickedDomain+"/"+pickedCourse
  865:                 document.rolechoice.elements[numbutton+1].name = courseTarget
  866:                 document.rolechoice.submit()
  867:             }
  868:         }
  869:         else {
  870:             alert("Please use the 'Select Course' link to open a separate pick course window where you may select the course you wish to enter.");
  871:         }
  872:     }
  873:     else {
  874:         alert("You can only use this screen to select courses in the current domain")
  875:     }
  876: }
  877: function getIndex(caller) {
  878:     for (var i=0;i<document.rolechoice.elements.length;i++) {
  879:         if (document.rolechoice.elements[i] == caller) {
  880:             return i;
  881:         }
  882:     }
  883:     return -1;
  884: }
  885: </script>
  886: END
  887:     return $verify_script;
  888: }
  889: 
  890: sub processpick {
  891:     my $dcdom = shift;
  892:     my $process_pick = <<"END";
  893: <script>
  894: function process_pick(dom) {
  895:     var numbutton = getIndex(dom)
  896:     var pickedCourse = opener.document.rolechoice.dccourse_$dcdom.value
  897:     var pickedDomain = opener.document.rolechoice.dcdomain_$dcdom.value
  898:     if (opener.document.rolechoice.dcdomain_$dcdom.value == opener.document.rolechoice.origdom_$dcdom.value) {
  899:         if (pickedCourse != '') {
  900:             if (numbutton != -1) {
  901:                 var courseTarget = "cc./"+pickedDomain+"/"+pickedCourse
  902:                 opener.document.rolechoice.elements[numbutton+1].name = courseTarget
  903:                 opener.document.rolechoice.submit()
  904:             }
  905:         }
  906:     }
  907: }
  908:  
  909: function getIndex(dom) {
  910:     var callername = 'ccpick_'+dom
  911:     for (var i=0;i<opener.document.rolechoice.elements.length;i++) {
  912:         var elemname = opener.document.rolechoice.elements[i].name
  913:         if (elemname == callername) {
  914:             return i;
  915:         }
  916:     }
  917:     return -1;
  918: }
  919: </script>
  920: END
  921:     return $process_pick;
  922: }
  923: 
  924: sub display_cc_role {
  925:     my $rolekey = shift;
  926:     my $roletext;
  927:     my $advanced = $env{'user.adv'};
  928:     my $tryagain = $env{'form.tryagain'};
  929:     unless ($rolekey =~/^error\:/) {
  930:         if ($rolekey =~ m-^user\.role.cc\./(\w+)/(\w+)$-) {
  931:             my $tcourseid = $1.'_'.$2;
  932:             my $trolecode = 'cc./'.$1.'/'.$2;
  933:             my $trole = Apache::lonnet::plaintext('cc');
  934:             my $twhere;
  935:             my $tbg='#77FF77';
  936:             my $tfont='#003300';
  937:             my %newhash=&Apache::lonnet::coursedescription($tcourseid);
  938:             if (%newhash) {
  939:                 $twhere=$newhash{'description'}.
  940:                         ' <font size="-2">'.
  941:                         &Apache::loncommon::syllabuswrapper(&mt('Syllabus'),$2,$1,$tfont).
  942:                         '</font>';
  943:             } else {
  944:                 $twhere=&mt('Currently not available');
  945:                 $env{'course.'.$tcourseid.'.description'}=$twhere;
  946:             }
  947:             $twhere.="<br />".&mt('Domain').":".$1;
  948:             $roletext = &build_roletext($trolecode,$1,$2,'is',$tryagain,$advanced,'',$tbg,$tfont,$trole,&mt('Course'),$twhere,'','','',1,'');
  949:         }
  950:     }
  951:     return $roletext;
  952: }
  953: 
  954: sub allcourses_row {
  955:     my $dcdom = shift;
  956:     my $ccrole = Apache::lonnet::plaintext('cc');
  957:     my $selectlink = &courselink($dcdom);
  958:     my $output = '<tr bgcolor="#99FF99">'.
  959:               '<td><input type="button" value="'.
  960:               &mt('Select').'" name="ccpick_'.$dcdom.'"'.
  961:               'onClick="verifyCoursePick(this)">'.
  962:               '<input type="hidden" name="pick_'.$dcdom.'" value="1"></td>'.
  963:               '<td><font color="#002200">'.
  964:               $ccrole.'</font></td>'.
  965:               '<td><font color="#002200">'.&mt('All courses').':<b>&nbsp;'.
  966:               $selectlink.'</b>'.
  967:               '<br />'.&mt('Domain').':'.$dcdom.'</font>'.
  968:               '<td colspan="3"><font color="#002200">'.
  969:               &mt('Course Coordinator access to all courses in domain').
  970:               ': <b>'.$dcdom.'</b></font></td></tr>'."\n";
  971:     return $output;
  972: }
  973: 
  974: sub recent_filename {
  975:     my $area=shift;
  976:     return 'nohist_recent_'.&Apache::lonnet::escape($area);
  977: }
  978: 
  979: sub set_privileges {
  980:     my ($dcdom,$pickedcourse) = @_;
  981:     my $area = '/'.$dcdom.'/'.$pickedcourse;
  982:     my $role = 'cc';
  983:     my $spec = $role.'.'.$area;
  984:     my $userroles = &Apache::lonnet::set_arearole($role,$area,'','',$dcdom,$env{'user.name'});
  985:     my %ccrole = ();
  986:     &Apache::lonnet::standard_roleprivs(\%ccrole,$role,$dcdom,$spec,$pickedcourse,$area);
  987:     my ($author,$adv)= &Apache::lonnet::set_userprivs(\$userroles,\%ccrole);
  988:     my @newprivs = split/\n/,$userroles;
  989:     my %newccroles = ();
  990:     foreach (@newprivs) {
  991:         my ($key,$val) = split/=/,$_;
  992:         $newccroles{$key} = $val;
  993:     }
  994:     &Apache::lonnet::appenv(%newccroles);
  995:     &Apache::lonnet::log($env{'user.domain'},
  996:                          $env{'user.name'},
  997:                          $env{'user.home'},
  998:                         "Role ".$role);
  999:     &Apache::lonnet::appenv(
 1000:                           'request.role'        => $role,
 1001:                           'request.role.domain' => $dcdom,
 1002:                           'request.course.sec'  => '');
 1003:     my $tadv=0;
 1004:     if (&Apache::lonnet::allowed('adv') eq 'F') { $tadv=1; }
 1005:     &Apache::lonnet::appenv('request.role.adv'    => $tadv);
 1006: }
 1007: 
 1008: 1;
 1009: __END__
 1010: 
 1011: =head1 NAME
 1012: 
 1013: Apache::lonroles - User Roles Screen
 1014: 
 1015: =head1 SYNOPSIS
 1016: 
 1017: Invoked by /etc/httpd/conf/srm.conf:
 1018: 
 1019:  <Location /adm/roles>
 1020:  PerlAccessHandler       Apache::lonacc
 1021:  SetHandler perl-script
 1022:  PerlHandler Apache::lonroles
 1023:  ErrorDocument     403 /adm/login
 1024:  ErrorDocument	  500 /adm/errorhandler
 1025:  </Location>
 1026: 
 1027: =head1 OVERVIEW
 1028: 
 1029: =head2 Choosing Roles
 1030: 
 1031: C<lonroles> is a handler that allows a user to switch roles in
 1032: mid-session. LON-CAPA attempts to work with "No Role Specified", the
 1033: default role that a user has before selecting a role, as widely as
 1034: possible, but certain handlers for example need specification which
 1035: course they should act on, etc. Both in this scenario, and when the
 1036: handler determines via C<lonnet>'s C<&allowed> function that a certain
 1037: action is not allowed, C<lonroles> is used as error handler. This
 1038: allows the user to select another role which may have permission to do
 1039: what they were trying to do. C<lonroles> can also be accessed via the
 1040: B<CRS> button in the Remote Control. 
 1041: 
 1042: =begin latex
 1043: 
 1044: \begin{figure}
 1045: \begin{center}
 1046: \includegraphics[width=0.45\paperwidth,keepaspectratio]{Sample_Roles_Screen}
 1047:   \caption{\label{Sample_Roles_Screen}Sample Roles Screen} 
 1048: \end{center}
 1049: \end{figure}
 1050: 
 1051: =end latex
 1052: 
 1053: =head2 Role Initialization
 1054: 
 1055: The privileges for a user are established at login time and stored in the session environment. As a consequence, a new role does not become active till the next login. Handlers are able to query for privileges using C<lonnet>'s C<&allowed> function. When a user first logs in, their role is the "common" role, which means that they have the sum of all of their privileges. During a session it might become necessary to choose a particular role, which as a consequence also limits the user to only the privileges in that particular role.
 1056: 
 1057: =head1 INTRODUCTION
 1058: 
 1059: This module enables a user to select what role he wishes to
 1060: operate under (instructor, student, teaching assistant, course
 1061: coordinator, etc).  These roles are pre-established by the actions
 1062: of upper-level users.
 1063: 
 1064: This is part of the LearningOnline Network with CAPA project
 1065: described at http://www.lon-capa.org.
 1066: 
 1067: =head1 HANDLER SUBROUTINE
 1068: 
 1069: This routine is called by Apache and mod_perl.
 1070: 
 1071: =over 4
 1072: 
 1073: =item *
 1074: 
 1075: Roles Initialization (yes/no)
 1076: 
 1077: =item *
 1078: 
 1079: Get Error Message from Environment
 1080: 
 1081: =item *
 1082: 
 1083: Who is this?
 1084: 
 1085: =item *
 1086: 
 1087: Generate Page Output
 1088: 
 1089: =item *
 1090: 
 1091: Choice or no choice
 1092: 
 1093: =item *
 1094: 
 1095: Table
 1096: 
 1097: =item *
 1098: 
 1099: Privileges
 1100: 
 1101: =back
 1102: 
 1103: =cut

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