1: # The LearningOnline Network with CAPA
2: # User Roles Screen
3: #
4: # $Id: lonroles.pm,v 1.74 2003/10/04 18:13:36 www 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: # (Directory Indexer
29: # (Login Screen
30: # YEAR=1999
31: # 5/21/99,5/22,5/25,5/26,5/31,6/2,6/10,7/12,7/14 Gerd Kortemeyer)
32: # 11/23 Gerd Kortemeyer)
33: # YEAR=2000
34: # 1/14,03/06,06/01,07/22,07/24,07/25,
35: # 09/04,09/06,09/28,09/29,09/30,10/2,10/5,10/26,10/28,
36: # 12/08,12/28,
37: # YEAR=2001
38: # 01/15/01 Gerd Kortemeyer
39: # 03/02,05/03,05/25,05/30,06/01,07/06,08/06 Gerd Kortemeyer
40: # 12/29 Gerd Kortemeyer
41: #
42: ###
43:
44: package Apache::lonroles;
45:
46: use strict;
47: use Apache::lonnet();
48: use Apache::lonuserstate();
49: use Apache::Constants qw(:common);
50: use Apache::File();
51: use Apache::lonmenu;
52: use Apache::loncommon;
53: use Apache::lonannounce;
54: use Apache::lonlocal;
55:
56: sub redirect_user {
57: my ($r,$title,$url,$msg) = @_;
58: $msg = $title if (! defined($msg));
59: &Apache::loncommon::content_type($r,'text/html');
60: &Apache::loncommon::no_cache($r);
61: $r->send_http_header;
62: my $swinfo=&Apache::lonmenu::rawconfig();
63: my $bodytag=&Apache::loncommon::bodytag('Switching Role');
64: $r->print (<<ENDREDIR);
65: <head><title>$title</title>
66: <meta HTTP-EQUIV="Refresh" CONTENT="1; url=$url">
67: </head>
68: <html>
69: $bodytag
70: <script>
71: $swinfo
72: </script>
73: <h1>$msg</h1>
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 $envkey;
87:
88:
89: # ================================================================== Roles Init
90:
91: if ($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: }
96: &Apache::lonnet::appenv("request.course.id" => '',
97: "request.course.fn" => '',
98: "request.course.uri" => '',
99: "request.course.sec" => '',
100: "request.role" => 'cm',
101: "request.role.adv" => $ENV{'user.adv'},
102: "request.role.domain" => $ENV{'user.domain'});
103: foreach $envkey (keys %ENV) {
104: next if ($envkey!~/^user\.role\./);
105: my (undef,undef,$role,@pwhere)=split(/\./,$envkey);
106: my $where=join('.',@pwhere);
107: my $trolecode=$role.'.'.$where;
108: if ($ENV{'form.'.$trolecode}) {
109: my ($tstart,$tend)=split(/\./,$ENV{$envkey});
110: my $tstatus='is';
111: if ($tstart) {
112: if ($tstart>$then) {
113: $tstatus='future';
114: }
115: }
116: if ($tend) {
117: if ($tend<$then) { $tstatus='expired'; }
118: if ($tend<$now) { $tstatus='will_not'; }
119: }
120: if ($tstatus eq 'is') {
121: $where=~s/^\///;
122: my ($cdom,$cnum,$csec)=split(/\//,$where);
123: # check for keyed access
124: if (($role eq 'st') &&
125: ($ENV{'course.'.$cdom.'_'.$cnum.'.keyaccess'} eq 'yes')) {
126: unless (&Apache::lonnet::validate_access_key(
127: $ENV{'environment.key.'.$cdom.'_'.$cnum},
128: $cdom,$cnum)) {
129: # there is no valid key
130: if ($ENV{'form.newkey'}) {
131: # student attempts to register a new key
132: } else {
133: # print form to enter a new key
134: &Apache::loncommon::content_type($r,'text/html');
135: &Apache::loncommon::no_cache($r);
136: $r->send_http_header;
137: my $swinfo=&Apache::lonmenu::rawconfig();
138: my $bodytag=&Apache::loncommon::bodytag
139: ('Enter Access Key to Unlock this Course');
140: $r->print(<<ENDENTERKEY);
141: <head><title>Entering Course Access Key</title>
142: </head>
143: <html>
144: $bodytag
145: <script>
146: $swinfo
147: </script>
148: <form method="post">
149: <input type="hidden" name="selectrole" value="$ENV{'form.selectrole'}" />
150: <input type="text" size="20" name="newkey" value="$ENV{'form.newkey'}" />
151: <input type="submit" value="Enter key" />
152: </form>
153: </body></html>
154: ENDENTERKEY
155: return OK;
156: }
157: }
158: }
159: my $tadv=0;
160: if (($trolecode!~/^st/) &&
161: ($trolecode!~/^ta/) &&
162: ($trolecode!~/^cm/)) { $tadv=1; }
163: &Apache::lonnet::appenv(
164: 'request.role' => $trolecode,
165: 'request.role.adv' => $tadv,
166: 'request.role.domain' => $cdom,
167: 'request.course.sec' => $csec);
168: my $msg=&mt('Entering course ...');
169:
170: if (($cnum) && ($role ne 'ca')) {
171: my ($furl,$ferr)=
172: &Apache::lonuserstate::readmap($cdom.'/'.$cnum);
173: if (($ENV{'form.orgurl'}) &&
174: ($ENV{'form.orgurl'}!~/^\/adm\/flip/)) {
175: my $dest=$ENV{'form.orgurl'};
176: if ( &Apache::lonnet::mod_perl_version() == 2 ) {
177: &Apache::lonnet::cleanenv();
178: }
179: $r->internal_redirect($dest);
180: return OK;
181: } else {
182: unless ($ENV{'request.course.id'}) {
183: &Apache::lonnet::appenv(
184: "request.course.id" => $cdom.'_'.$cnum);
185: $furl='/adm/roles?tryagain=1';
186: $msg=
187: '<h1><font color=red>'.
188: &mt('Could not initialize course at this time.').
189: '</font></h1><h3>'.&mt('Please try again.').'</h3>'.$ferr;
190: }
191:
192: # Check to see if the user is a CC entering a course
193: # for the first time
194: my (undef, undef, $role, $courseid) = split(/\./, $envkey);
195: if (substr($courseid, 0, 1) eq '/') {
196: $courseid = substr($courseid, 1);
197: }
198: $courseid =~ s/\//_/;
199: if ($role eq 'cc' && $ENV{'course.' . $courseid .
200: '.course.helper.not.run'}) {
201: $furl = "/adm/helper/course.initialization.helper";
202: }
203: #
204: # Send the user to the course they selected
205: &redirect_user($r,'Entering Course',
206: $furl,$msg);
207: return OK;
208: }
209: }
210: #
211: # Send the user to the construction space they selected
212: if ($role =~ /^(au|ca)$/) {
213: my $redirect_url = '/priv/';
214: if ($role eq 'au') {
215: $redirect_url.=$ENV{'user.name'};
216: } else {
217: $where =~ /\/(.*)$/;
218: $redirect_url .= $1;
219: }
220: $redirect_url .= '/';
221: &redirect_user($r,'Entering Construction Space',
222: $redirect_url);
223: return OK;
224: }
225: }
226: }
227: }
228: }
229:
230:
231: # =============================================================== No Roles Init
232:
233: &Apache::loncommon::content_type($r,'text/html');
234: &Apache::loncommon::no_cache($r);
235: $r->send_http_header;
236: return OK if $r->header_only;
237:
238: my $swinfo=&Apache::lonmenu::rawconfig();
239: my $bodytag=&Apache::loncommon::bodytag('User Roles');
240: my $helptag=&Apache::loncommon::help_open_topic
241: ("General_Intro","Click here for help");
242: $r->print(<<ENDHEADER);
243: <html>
244: <head>
245: <title>LON-CAPA User Roles</title>
246: </head>
247: $bodytag
248: $helptag<br />
249: <script>
250: $swinfo
251: window.focus();
252: </script>
253: ENDHEADER
254:
255: # ------------------------------------------ Get Error Message from Environment
256:
257: my ($fn,$priv,$nochoose,$error,$msg)=split(/:/,$ENV{'user.error.msg'});
258: if ($ENV{'user.error.msg'}) {
259: $r->log_reason(
260: "$msg for $ENV{'user.name'} domain $ENV{'user.domain'} access $priv",$fn);
261: }
262:
263: # ------------------------------------------------- Can this user re-init, etc?
264:
265: my $advanced=$ENV{'user.adv'};
266: &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},['tryagain']);
267: my $tryagain=$ENV{'form.tryagain'};
268:
269: # -------------------------------------------------------- Generate Page Output
270: # --------------------------------------------------------------- Error Header?
271: if ($error) {
272: $r->print("<h1>LON-CAPA Access Control</h1>");
273: $r->print("<hr><pre>Access : ".
274: Apache::lonnet::plaintext($priv)."\n");
275: $r->print("Resource: $fn\n");
276: $r->print("Action : $msg\n</pre><hr>");
277: } else {
278: if ($ENV{'user.error.msg'}) {
279: $r->print(
280: '<h3><font color=red>'.
281: &mt('You need to choose another user role or enter a specific course for this function').'</font></h3>');
282: }
283: }
284: # -------------------------------------------------------- Choice or no choice?
285: if ($nochoose) {
286: if ($advanced) {
287: $r->print("<h2>".&mt('Assigned User Roles')."</h2>\n");
288: } else {
289: $r->print("<h2>".&mt('Sorry ...')."</h2>\n".
290: &mt('This resource might be part of'));
291: if ($ENV{'request.course.id'}) {
292: $r->print(&mt(' another'));
293: } else {
294: $r->print(&mt(' a certain'));
295: }
296: $r->print(&mt(' course.').'</body></html>');
297: return OK;
298: }
299: } else {
300: if ($advanced) {
301: $r->print(&mt("Your home server is ").
302: $Apache::lonnet::hostname{&Apache::lonnet::homeserver
303: ($ENV{'user.name'},$ENV{'user.domain'})}.
304: "<br />\n");
305: $r->print(&mt(
306: "Author and Co-Author roles may not be available on servers other than your home server."));
307: } else {
308: $r->print("<h2>".&mt('Select a Course to Enter')."</h2>\n");
309: }
310: if (($ENV{'REDIRECT_QUERY_STRING'}) && ($fn)) {
311: $fn.='?'.$ENV{'REDIRECT_QUERY_STRING'};
312: }
313: $r->print('<form method=post action="'.(($fn)?$fn:$r->uri).'">');
314: $r->print('<input type=hidden name=orgurl value="'.$fn.'">');
315: $r->print('<input type=hidden name=selectrole value=1>');
316: }
317: if ($ENV{'user.adv'}) {
318: $r->print(
319: '<br />'.&mt('Show all roles').': <input type="checkbox" name="showall"');
320: if ($ENV{'form.showall'}) { $r->print(' checked'); }
321: $r->print('><input type=submit value="'.&mt('Display').'">');
322: }
323: # ----------------------------------------------------------------------- Table
324: $r->print('<br /><table><tr>');
325: unless ($nochoose) { $r->print('<th> </th>'); }
326: $r->print('<th>'.&mt('User Role').'</th><th colspan=2>'.&mt('Extent').
327: '</th><th>'.&mt('Start').'</th><th>'.&mt('End').'</th><th>'.
328: &mt('Remark').'</th></tr>'."\n");
329:
330: foreach $envkey (sort keys %ENV) {
331: my $button = 1;
332: my $switchserver='';
333: if ($envkey=~/^user\.role\./) {
334: my (undef,undef,$role,@pwhere)=split(/\./,$envkey);
335: next if (!defined($role) || $role eq '');
336: my $where=join('.',@pwhere);
337: my $trolecode=$role.'.'.$where;
338: my ($tstart,$tend)=split(/\./,$ENV{$envkey});
339: my $tremark='';
340: my $tstatus='is';
341: my $tpstart=' ';
342: my $tpend=' ';
343: my $tfont='#000000';
344: if ($tstart) {
345: if ($tstart>$then) {
346: $tstatus='future';
347: if ($tstart<$now) { $tstatus='will'; }
348: }
349: $tpstart=&Apache::lonlocal::locallocaltime($tstart);
350: }
351: if ($tend) {
352: if ($tend<$then) {
353: $tstatus='expired';
354: } elsif ($tend<$now) {
355: $tstatus='will_not';
356: }
357: $tpend=&Apache::lonlocal::locallocaltime($tend);
358: }
359: if ($ENV{'request.role'} eq $trolecode) {
360: $tstatus='selected';
361: }
362: my $tbg;
363: if (($tstatus eq 'is') || ($tstatus eq 'selected') ||
364: ($ENV{'form.showall'})) {
365: if ($tstatus eq 'is') {
366: $tbg='#77FF77';
367: $tfont='#003300';
368: } elsif ($tstatus eq 'future') {
369: $tbg='#FFFF77';
370: $button=0;
371: } elsif ($tstatus eq 'will') {
372: $tbg='#FFAA77';
373: $tremark.=&mt('Active at next login. ');
374: } elsif ($tstatus eq 'expired') {
375: $tbg='#FF7777';
376: $tfont='#330000';
377: $button=0;
378: } elsif ($tstatus eq 'will_not') {
379: $tbg='#AAFF77';
380: $tremark.=&mt('Expired after logout. ');
381: } elsif ($tstatus eq 'selected') {
382: $tbg='#11CC55';
383: $tfont='#002200';
384: $tremark.=&mt('Currently selected. ');
385: }
386: my $trole;
387: if ($role =~ /^cr\//) {
388: my ($rdummy,$rdomain,$rauthor,$rrole)=split(/\//,$role);
389: $tremark.='<br>'.&mt('Defined by ').$rauthor.
390: &mt(' at ').$rdomain.'.';
391: $trole=$rrole;
392: } else {
393: $trole=Apache::lonnet::plaintext($role);
394: }
395: my $ttype;
396: my $twhere;
397: my ($tdom,$trest,$tsection)=
398: split(/\//,Apache::lonnet::declutter($where));
399: # First, Co-Authorship roles
400: if ($role eq 'ca') {
401: my $home = &Apache::lonnet::homeserver($trest,$tdom);
402: if ($home ne $r->dir_config('lonHostID')) {
403: $button=0;
404: $switchserver=&Apache::lonnet::escape('http://'.
405: $Apache::lonnet::hostname{$home}.
406: '/adm/login?domain='.$ENV{'user.domain'}.
407: '&username='.$ENV{'user.name'}.
408: '&firsturl=/priv/'.$trest);
409: }
410: #next if ($home eq 'no_host');
411: $home = $Apache::lonnet::hostname{$home};
412: $ttype=&mt('Construction Space');
413: $twhere=&mt('User').': '.$trest.'<br />'.&mt('Domain').
414: ': '.$tdom.'<br />'.
415: ' '.&mt('Server').': '.$home;
416: $ENV{'course.'.$tdom.'_'.$trest.'.description'}='ca';
417: } elsif ($role eq 'au') {
418: # Authors
419: my $home = &Apache::lonnet::homeserver
420: ($ENV{'user.name'},$ENV{'user.domain'});
421: if ($home ne $r->dir_config('lonHostID')) {
422: $button=0;
423: $switchserver=&Apache::lonnet::escape('http://'.
424: $Apache::lonnet::hostname{$home}.
425: '/adm/login?domain='.$ENV{'user.domain'}.
426: '&username='.$ENV{'user.name'}.
427: '&firsturl=/priv/'.$ENV{'user.name'});
428: }
429: #next if ($home eq 'no_host');
430: $home = $Apache::lonnet::hostname{$home};
431: $ttype=&mt('Construction Space');
432: $twhere=&mt('Domain').': '.$tdom.'<br />'.&mt('Server').
433: ': '.$home;
434: $ENV{'course.'.$tdom.'_'.$trest.'.description'}='ca';
435: } elsif ($trest) {
436: $ttype=&mt('Course');
437: if ($tsection) {
438: $ttype.='<br>'.&mt('Section/Group').': '.$tsection;
439: }
440: my $tcourseid=$tdom.'_'.$trest;
441: if ($ENV{'course.'.$tcourseid.'.description'}) {
442: $twhere=$ENV{'course.'.$tcourseid.'.description'};
443: unless ($twhere eq &mt('Currently not available')) {
444: $twhere.=' <font size="-2">'.
445: &Apache::loncommon::syllabuswrapper(&mt('Syllabus'),$trest,$tdom,$tfont).
446: '</font>';
447: }
448: } else {
449: my %newhash=Apache::lonnet::coursedescription
450: ($tcourseid);
451: if (%newhash) {
452: $twhere=$newhash{'description'}.
453: ' <font size="-2">'.
454: &Apache::loncommon::syllabuswrapper(&mt('Syllabus'),$trest,$tdom,$tfont).
455: '</font>';
456: } else {
457: $twhere=&mt('Currently not available');
458: $ENV{'course.'.$tcourseid.'.description'}=$twhere;
459: }
460: }
461: if ($role ne 'st') { $twhere.="<br />".&mt('Domain').":".$tdom; }
462: } elsif ($tdom) {
463: $ttype=&mt('Domain');
464: $twhere=$tdom;
465: } else {
466: $ttype=&mt('System');
467: $twhere=&mt('system wide');
468: }
469:
470: $r->print('<tr bgcolor='.$tbg.'>');
471: unless ($nochoose) {
472: if (!$button) {
473: if ($switchserver) {
474: $r->print('<td><a href="/adm/logout?handover='.
475: $switchserver.'">'.&mt('Switch Server').'</a></td>');
476: } else {
477: $r->print('<td> </td>');
478: }
479: } elsif ($tstatus eq 'is') {
480: $r->print('<td><input type=submit value="'.
481: &mt('Select').'" name="'.
482: $trolecode.'"></td>');
483: } elsif ($tryagain) {
484: $r->print
485: ('<td><input type=submit value="'.
486: &mt('Try Selecting Again').'" name="'.$trolecode.'"></td>');
487: } elsif ($advanced) {
488: $r->print
489: ('<td><input type=submit value="'.
490: &mt('Re-Initialize').'" name="'.$trolecode.'"></td>');
491: } else {
492: $r->print('<td> </td>');
493: }
494: }
495: $tremark.=&Apache::lonannounce::showday(time,1,
496: &Apache::lonannounce::readcalendar($tdom.'_'.$trest));
497:
498: $r->print('<td><font color="'.$tfont.'">'.$trole.
499: '</font></td><td><font color="'.$tfont.'">'.$ttype.
500: '</font></td><td><font color="'.$tfont.'">'.$twhere.
501: '</font></td><td><font color="'.$tfont.'">'.$tpstart.
502: '</font></td><td><font color="'.$tfont.'">'.$tpend.
503: '</font></td><td><font color="'.$tfont.'">'.$tremark.
504: ' </font></td></tr>'."\n");
505: }
506: }
507: }
508: my $tremark='';
509: my $tfont='#003300';
510: if ($ENV{'request.role'} eq 'cm') {
511: $r->print('<tr bgcolor="#11CC55">');
512: $tremark=&mt('Currently selected. ');
513: $tfont='#002200';
514: } else {
515: $r->print('<tr bgcolor="#77FF77">');
516: }
517: unless ($nochoose) {
518: if ($ENV{'request.role'} ne 'cm') {
519: $r->print('<td><input type=submit value="'.
520: &mt('Select').'" name="cm"></td>');
521: } else {
522: $r->print('<td> </td>');
523: }
524: }
525: $r->print('<td colspan=5><font color="'.$tfont.'">'.&mt('No role specified').
526: '</font></td><td><font color="'.$tfont.'">'.$tremark.
527: ' </font></td></tr>'."\n");
528:
529: $r->print('</table>');
530: unless ($nochoose) {
531: $r->print("</form>\n");
532: }
533: # ------------------------------------------------------------ Privileges Info
534: if (($advanced) && (($ENV{'user.error.msg'}) || ($error))) {
535: $r->print('<hr><h2>Current Privileges</h2>');
536:
537: foreach $envkey (sort keys %ENV) {
538: if ($envkey=~/^user\.priv\.$ENV{'request.role'}\./) {
539: my $where=$envkey;
540: $where=~s/^user\.priv\.$ENV{'request.role'}\.//;
541: my $ttype;
542: my $twhere;
543: my ($tdom,$trest,$tsec)=
544: split(/\//,Apache::lonnet::declutter($where));
545: if ($trest) {
546: if ($ENV{'course.'.$tdom.'_'.$trest.'.description'} eq 'ca') {
547: $ttype='Construction Space';
548: $twhere='User: '.$trest.', Domain: '.$tdom;
549: } else {
550: $ttype='Course';
551: $twhere=$ENV{'course.'.$tdom.'_'.$trest.'.description'};
552: if ($tsec) {
553: $twhere.=' (Section/Group: '.$tsec.')';
554: }
555: }
556: } elsif ($tdom) {
557: $ttype='Domain';
558: $twhere=$tdom;
559: } else {
560: $ttype='System';
561: $twhere='/';
562: }
563: $r->print("\n<h3>".$ttype.': '.$twhere.'</h3><ul>');
564: foreach (sort split(/:/,$ENV{$envkey})) {
565: if ($_) {
566: my ($prv,$restr)=split(/\&/,$_);
567: my $trestr='';
568: if ($restr ne 'F') {
569: my $i;
570: $trestr.=' (';
571: for ($i=0;$i<length($restr);$i++) {
572: $trestr.=
573: Apache::lonnet::plaintext(substr($restr,$i,1));
574: if ($i<length($restr)-1) { $trestr.=', '; }
575: }
576: $trestr.=')';
577: }
578: $r->print('<li>'.
579: Apache::lonnet::plaintext($prv).$trestr.
580: '</li>');
581: }
582: }
583: $r->print('</ul>');
584: }
585: }
586: }
587: $r->print(&Apache::lonnet::getannounce());
588: if ($advanced) {
589: $r->print('<p><small><i>This is LON-CAPA '.
590: $r->dir_config('lonVersion').'</i></small></p>');
591: }
592: $r->print("</body></html>\n");
593: return OK;
594: }
595:
596: 1;
597: __END__
598:
599: =head1 NAME
600:
601: Apache::lonroles - User Roles Screen
602:
603: =head1 SYNOPSIS
604:
605: Invoked by /etc/httpd/conf/srm.conf:
606:
607: <Location /adm/roles>
608: PerlAccessHandler Apache::lonacc
609: SetHandler perl-script
610: PerlHandler Apache::lonroles
611: ErrorDocument 403 /adm/login
612: ErrorDocument 500 /adm/errorhandler
613: </Location>
614:
615: =head1 OVERVIEW
616:
617: =head2 Choosing Roles
618:
619: C<lonroles> is a handler that allows a user to switch roles in
620: mid-session. LON-CAPA attempts to work with "No Role Specified", the
621: default role that a user has before selecting a role, as widely as
622: possible, but certain handlers for example need specification which
623: course they should act on, etc. Both in this scenario, and when the
624: handler determines via C<lonnet>'s C<&allowed> function that a certain
625: action is not allowed, C<lonroles> is used as error handler. This
626: allows the user to select another role which may have permission to do
627: what they were trying to do. C<lonroles> can also be accessed via the
628: B<CRS> button in the Remote Control.
629:
630: =begin latex
631:
632: \begin{figure}
633: \begin{center}
634: \includegraphics[width=0.45\paperwidth,keepaspectratio]{Sample_Roles_Screen}
635: \caption{\label{Sample_Roles_Screen}Sample Roles Screen}
636: \end{center}
637: \end{figure}
638:
639: =end latex
640:
641: =head2 Role Initialization
642:
643: 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.
644:
645: =head1 INTRODUCTION
646:
647: This module enables a user to select what role he wishes to
648: operate under (instructor, student, teaching assistant, course
649: coordinator, etc). These roles are pre-established by the actions
650: of upper-level users.
651:
652: This is part of the LearningOnline Network with CAPA project
653: described at http://www.lon-capa.org.
654:
655: =head1 HANDLER SUBROUTINE
656:
657: This routine is called by Apache and mod_perl.
658:
659: =over 4
660:
661: =item *
662:
663: Roles Initialization (yes/no)
664:
665: =item *
666:
667: Get Error Message from Environment
668:
669: =item *
670:
671: Who is this?
672:
673: =item *
674:
675: Generate Page Output
676:
677: =item *
678:
679: Choice or no choice
680:
681: =item *
682:
683: Table
684:
685: =item *
686:
687: Privileges
688:
689: =back
690:
691: =cut
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