File:  [LON-CAPA] / loncom / lti / ltiutils.pm
Revision 1.12: download - view: text, annotated - select for diffs
Wed May 30 17:22:30 2018 UTC (6 years ago) by raeburn
Branches: MAIN
CVS tags: HEAD
- Bug 6754 LON-CAPA as LTI Provider
  - Add documentation.
  - Seed rand() in create_passwd routine.

    1: # The LearningOnline Network with CAPA
    2: # Utility functions for managing LON-CAPA LTI interactions 
    3: #
    4: # $Id: ltiutils.pm,v 1.12 2018/05/30 17:22:30 raeburn 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: package LONCAPA::ltiutils;
   30: 
   31: use strict;
   32: use Net::OAuth;
   33: use Digest::SHA;
   34: use UUID::Tiny ':std';
   35: use Apache::lonnet;
   36: use Apache::loncommon;
   37: use Apache::loncoursedata;
   38: use Apache::lonuserutils;
   39: use Apache::lonenc();
   40: use Apache::longroup();
   41: use Apache::lonlocal;
   42: use Math::Round();
   43: use LONCAPA qw(:DEFAULT :match);
   44: 
   45: #
   46: # LON-CAPA as LTI Consumer or LTI Provider
   47: #
   48: # Determine if a nonce in POSTed data has expired.
   49: # If unexpired, confirm it has not already been used.
   50: #
   51: # When LON-CAPA is operating as a Consumer, nonce checking
   52: # occurs when a Tool Provider launched from an instance of
   53: # an external tool in a LON-CAPA course makes a request to
   54: # (a) /adm/service/roster or (b) /adm/service/passback to, 
   55: # respectively, retrieve a roster or store the grade for 
   56: # the original launch by a specific user.
   57: #
   58: # When LON-CAPA is operating as a Provider, nonce checking 
   59: # occurs when a user in course context in another LMS (the 
   60: # Consumer) launches an external tool to access a LON-CAPA URL: 
   61: # /adm/lti/ with LON-CAPA symb, map, or deep-link ID appended.
   62: #
   63: 
   64: sub check_nonce {
   65:     my ($nonce,$timestamp,$lifetime,$domain,$ltidir) = @_;
   66:     if (($ltidir eq '') || ($timestamp eq '') || ($timestamp =~ /^\D/) ||
   67:         ($lifetime eq '') || ($lifetime =~ /\D/) || ($domain eq '')) {
   68:         return;
   69:     }
   70:     my $now = time;
   71:     if (($timestamp) && ($timestamp < ($now - $lifetime))) {
   72:         return;
   73:     }
   74:     if ($nonce eq '') {
   75:         return;
   76:     }
   77:     if (-e "$ltidir/$domain/$nonce") {
   78:         return;
   79:     } else  {
   80:         unless (-e "$ltidir/$domain") {
   81:             unless (mkdir("$ltidir/$domain",0755)) {
   82:                 return;
   83:             }
   84:         }
   85:         if (open(my $fh,'>',"$ltidir/$domain/$nonce")) {
   86:             print $fh $now;
   87:             close($fh);
   88:             return 1;
   89:         }
   90:     }
   91:     return;
   92: }
   93: 
   94: #
   95: # LON-CAPA as LTI Consumer
   96: #
   97: # Determine the domain and the courseID of the LON-CAPA course
   98: # for which access is needed by a Tool Provider -- either to 
   99: # retrieve a roster or store the grade for an instance of an 
  100: # external tool in the course.
  101: #
  102: 
  103: sub get_loncapa_course {
  104:     my ($lonhost,$cid,$errors) = @_;
  105:     return unless (ref($errors) eq 'HASH');
  106:     my ($cdom,$cnum);
  107:     if ($cid =~ /^($match_domain)_($match_courseid)$/) {
  108:         my ($posscdom,$posscnum) = ($1,$2);
  109:         my $cprimary_id = &Apache::lonnet::domain($posscdom,'primary');
  110:         if ($cprimary_id eq '') {
  111:             $errors->{5} = 1;
  112:             return;
  113:         } else {
  114:             my @intdoms;
  115:             my $internet_names = &Apache::lonnet::get_internet_names($lonhost);
  116:             if (ref($internet_names) eq 'ARRAY') {
  117:                 @intdoms = @{$internet_names};
  118:             }
  119:             my $cintdom = &Apache::lonnet::internet_dom($cprimary_id);
  120:             if  (($cintdom ne '') && (grep(/^\Q$cintdom\E$/,@intdoms))) {
  121:                 $cdom = $posscdom;
  122:             } else {
  123:                 $errors->{6} = 1;
  124:                 return;
  125:             }
  126:         }
  127:         my $chome = &Apache::lonnet::homeserver($posscnum,$posscdom);
  128:         if ($chome =~ /(con_lost|no_host|no_such_host)/) {
  129:             $errors->{7} = 1;
  130:             return;
  131:         } else {
  132:             $cnum = $posscnum;
  133:         }
  134:     } else {
  135:         $errors->{8} = 1;
  136:         return;
  137:     }
  138:     return ($cdom,$cnum);
  139: }
  140: 
  141: #
  142: # LON-CAPA as LTI Consumer
  143: #
  144: # Determine the symb and (optionally) LON-CAPA user for an 
  145: # instance of an external tool in a course -- either to 
  146: # to retrieve a roster or store a grade.
  147: #
  148: # Use the digested symb to lookup the real symb in exttools.db
  149: # and the digested userID to lookup the real userID (if needed).
  150: # and extract the exttool instance and symb.
  151: #
  152: 
  153: sub get_tool_instance {
  154:     my ($cdom,$cnum,$digsymb,$diguser,$errors) = @_;
  155:     return unless (ref($errors) eq 'HASH');
  156:     my ($marker,$symb,$uname,$udom);
  157:     my @keys = ($digsymb); 
  158:     if ($diguser) {
  159:         push(@keys,$diguser);
  160:     }
  161:     my %digesthash = &Apache::lonnet::get('exttools',\@keys,$cdom,$cnum);
  162:     if ($digsymb) {
  163:         $symb = $digesthash{$digsymb};
  164:         if ($symb) {
  165:             my ($map,$id,$url) = split(/___/,$symb);
  166:             $marker = (split(m{/},$url))[3];
  167:             $marker=~s/\D//g;
  168:         } else {
  169:             $errors->{9} = 1;
  170:         }
  171:     }
  172:     if ($diguser) {
  173:         if ($digesthash{$diguser} =~ /^($match_username):($match_domain)$/) {
  174:             ($uname,$udom) = ($1,$2);
  175:         } else {
  176:             $errors->{10} = 1;
  177:         }
  178:         return ($marker,$symb,$uname,$udom);
  179:     } else {
  180:         return ($marker,$symb);
  181:     }
  182: }
  183: 
  184: #
  185: # LON-CAPA as LTI Consumer
  186: #
  187: # Retrieve data needed to validate a request from a Tool Provider
  188: # for a roster or to store a grade for an instance of an external 
  189: # tool in a LON-CAPA course.
  190: #
  191: # Retrieve the Consumer key and Consumer secret from the domain 
  192: # configuration or the Tool Provider ID stored in the
  193: # exttool_$marker db file and compare the Consumer key with the
  194: # one in the POSTed data.
  195: #
  196: # Side effect is to populate the $toolsettings hashref with the 
  197: # contents of the .db file (instance of tool in course) and the
  198: # $ltitools hashref with the configuration for the tool (at
  199: # domain level).
  200: #
  201: 
  202: sub get_tool_secret {
  203:     my ($key,$marker,$symb,$cdom,$cnum,$toolsettings,$ltitools,$errors) = @_;
  204:     return unless ((ref($toolsettings) eq 'HASH') && (ref($ltitools) eq 'HASH') &&
  205:                    (ref($errors) eq 'HASH'));
  206:     my ($consumer_secret,$nonce_lifetime);
  207:     if ($marker) {
  208:         %{$toolsettings}=&Apache::lonnet::dump('exttool_'.$marker,$cdom,$cnum);
  209:         if ($toolsettings->{'id'}) {
  210:             my $idx = $toolsettings->{'id'};
  211:             my %lti = &Apache::lonnet::get_domain_lti($cdom,'consumer');
  212:             if (ref($lti{$idx}) eq 'HASH') {
  213:                 %{$ltitools} = %{$lti{$idx}};
  214:                 if ($ltitools->{'key'} eq $key) {
  215:                     $consumer_secret = $ltitools->{'secret'};
  216:                     $nonce_lifetime = $ltitools->{'lifetime'};
  217:                 } else {
  218:                     $errors->{11} = 1;
  219:                     return;
  220:                 }
  221:             } else {
  222:                 $errors->{12} = 1;
  223:                 return;
  224:             }
  225:         } else {
  226:             $errors->{13} = 1;
  227:             return;
  228:         }
  229:     } else {
  230:         $errors->{14};
  231:         return;
  232:     }
  233:     return ($consumer_secret,$nonce_lifetime);
  234: }
  235: 
  236: #
  237: # LON-CAPA as LTI Consumer
  238: #
  239: # Verify a signed request using the consumer_key and
  240: # secret for the specific LTI Provider.
  241: #
  242: 
  243: sub verify_request {
  244:     my ($params,$protocol,$hostname,$requri,$reqmethod,$consumer_secret,$errors) = @_;
  245:     return unless (ref($errors) eq 'HASH');
  246:     my $request = Net::OAuth->request('request token')->from_hash($params,
  247:                                        request_url => $protocol.'://'.$hostname.$requri,
  248:                                        request_method => $reqmethod,
  249:                                        consumer_secret => $consumer_secret,);
  250:     unless ($request->verify()) {
  251:         $errors->{15} = 1;
  252:         return;
  253:     }
  254: }
  255: 
  256: #
  257: # LON-CAPA as LTI Consumer
  258: #
  259: # Verify that an item identifier (either roster request:
  260: # ext_ims_lis_memberships_id, or grade store:
  261: # lis_result_sourcedid) has not been tampered with, and
  262: # the secret used to create the unique identifier has not
  263: # expired.
  264: #
  265: # Prepending the current secret (if still valid),
  266: # or the previous secret (if current one is no longer valid),
  267: # to a string composed of the :::-separated components
  268: # must generate the result signature in the lis item ID
  269: # sent by the Tool Provider.
  270: #
  271: 
  272: sub verify_lis_item {
  273:     my ($sigrec,$context,$digsymb,$diguser,$cdom,$cnum,$toolsettings,$ltitools,$errors) = @_;
  274:     return unless ((ref($toolsettings) eq 'HASH') && (ref($ltitools) eq 'HASH') && 
  275:                    (ref($errors) eq 'HASH'));
  276:     my ($has_action, $valid_for);
  277:     if ($context eq 'grade') {
  278:         $has_action = $ltitools->{'passback'};
  279:         $valid_for = $ltitools->{'passbackvalid'}
  280:     } elsif ($context eq 'roster') {
  281:         $has_action = $ltitools->{'roster'};
  282:         $valid_for = $ltitools->{'rostervalid'};
  283:     }
  284:     if ($has_action) {
  285:         my $secret;
  286:         if (($toolsettings->{$context.'secretdate'} + $valid_for) > time) {
  287:             $secret = $toolsettings->{$context.'secret'};
  288:         } else {
  289:             $secret = $toolsettings->{'old'.$context.'secret'};
  290:         }
  291:         if ($secret) {
  292:             my $expected_sig;
  293:             if ($context eq 'grade') {
  294:                 my $uniqid = $digsymb.':::'.$diguser.':::'.$cdom.'_'.$cnum;
  295:                 $expected_sig = (split(/:::/,&get_service_id($secret,$uniqid)))[0]; 
  296:                 if ($expected_sig eq $sigrec) {
  297:                     return 1;
  298:                 } else {
  299:                     $errors->{17} = 1;
  300:                 }
  301:             } elsif ($context eq 'roster') {
  302:                 my $uniqid = $digsymb.':::'.$cdom.'_'.$cnum;
  303:                 $expected_sig = (split(/:::/,&get_service_id($secret,$uniqid)))[0]; 
  304:                 if ($expected_sig eq $sigrec) {
  305:                     return 1;
  306:                 } else {
  307:                     $errors->{18} = 1;
  308:                 }
  309:             }
  310:         } else {
  311:             $errors->{19} = 1;
  312:         }
  313:     } else {
  314:         $errors->{20} = 1;
  315:     }
  316:     return;
  317: }
  318: 
  319: #
  320: # LON-CAPA as LTI Consumer
  321: #
  322: # Sign a request used to launch an instance of an external
  323: # tool in a LON-CAPA course, using the key and secret supplied 
  324: # by the Tool Provider.
  325: # 
  326: 
  327: sub sign_params {
  328:     my ($url,$key,$secret,$sigmethod,$paramsref) = @_;
  329:     return unless (ref($paramsref) eq 'HASH');
  330:     if ($sigmethod eq '') {
  331:         $sigmethod = 'HMAC-SHA1';
  332:     }
  333:     srand( time() ^ ($$ + ($$ << 15))  ); # Seed rand.
  334:     my $nonce = Digest::SHA::sha1_hex(sprintf("%06x%06x",rand(0xfffff0),rand(0xfffff0)));
  335:     my $request = Net::OAuth->request("request token")->new(
  336:             consumer_key => $key,
  337:             consumer_secret => $secret,
  338:             request_url => $url,
  339:             request_method => 'POST',
  340:             signature_method => $sigmethod,
  341:             timestamp => time,
  342:             nonce => $nonce,
  343:             callback => 'about:blank',
  344:             extra_params => $paramsref,
  345:             version      => '1.0',
  346:             );
  347:     $request->sign;
  348:     return $request->to_hash();
  349: }
  350: 
  351: #
  352: # LON-CAPA as LTI Consumer
  353: #
  354: # Generate a signature for a unique identifier (roster request:
  355: # ext_ims_lis_memberships_id, or grade store: lis_result_sourcedid)
  356: #
  357: 
  358: sub get_service_id {
  359:     my ($secret,$id) = @_;
  360:     my $sig = Digest::SHA::sha1_hex($secret.':::'.$id);
  361:     return $sig.':::'.$id;
  362: }
  363: 
  364: #
  365: # LON-CAPA as LTI Consumer
  366: #
  367: # Generate and store the time-limited secret used to create the
  368: # signature in a service request identifier (roster request or
  369: # grade store). An existing secret past its expiration date
  370: # will be stored as old<service name>secret, and a new secret
  371: # <service name>secret will be stored.
  372: # 
  373: # Secrets are specific to service name and to the tool instance 
  374: # (and are stored in the exttool_$marker db file).
  375: # The time period a secret remains valid is determined by the 
  376: # domain configuration for the specific tool and the service.
  377: # 
  378: 
  379: sub set_service_secret {
  380:     my ($cdom,$cnum,$marker,$name,$now,$toolsettings,$ltitools) = @_;
  381:     return unless ((ref($toolsettings) eq 'HASH') && (ref($ltitools) eq 'HASH'));
  382:     my $warning;
  383:     my ($needsnew,$oldsecret,$lifetime);
  384:     if ($name eq 'grade') {
  385:         $lifetime = $ltitools->{'passbackvalid'}
  386:     } elsif ($name eq 'roster') {
  387:         $lifetime = $ltitools->{'rostervalid'};
  388:     }
  389:     if ($toolsettings->{$name} eq '') {
  390:         $needsnew = 1;
  391:     } elsif (($toolsettings->{$name.'date'} + $lifetime) < $now) {
  392:         $oldsecret = $toolsettings->{$name.'secret'};
  393:         $needsnew = 1;
  394:     }
  395:     if ($needsnew) {
  396:         if (&get_tool_lock($cdom,$cnum,$marker,$name,$now) eq 'ok') {
  397:             my $secret = UUID::Tiny::create_uuid_as_string(UUID_V4);
  398:             $toolsettings->{$name.'secret'} = $secret;
  399:             my %secrethash = (
  400:                            $name.'secret' => $secret,
  401:                            $name.'secretdate' => $now,
  402:                           );
  403:             if ($oldsecret ne '') {
  404:                 $secrethash{'old'.$name.'secret'} = $oldsecret;
  405:             }
  406:             my $putres = &Apache::lonnet::put('exttool_'.$marker,
  407:                                               \%secrethash,$cdom,$cnum);
  408:             my $delresult = &release_tool_lock($cdom,$cnum,$marker,$name);
  409:             if ($delresult ne 'ok') {
  410:                 $warning = $delresult ;
  411:             }
  412:             if ($putres eq 'ok') {
  413:                 return 'ok';
  414:             }
  415:         } else {
  416:             $warning = 'Could not obtain exclusive lock';
  417:         }
  418:     } else {
  419:         return 'ok';
  420:     }
  421:     return;
  422: }
  423: 
  424: #
  425: # LON-CAPA as LTI Consumer
  426: #
  427: # Add a lock key to exttools.db for the instance of an external tool 
  428: # when generating and storing a service secret.
  429: #
  430: 
  431: sub get_tool_lock {
  432:     my ($cdom,$cnum,$marker,$name,$now) = @_;
  433:     # get lock for tool for which secret is being set
  434:     my $lockhash = {
  435:                      $name."\0".$marker."\0".'lock' => $now.':'.$env{'user.name'}.
  436:                                                        ':'.$env{'user.domain'},
  437:                    };
  438:     my $tries = 0;
  439:     my $gotlock = &Apache::lonnet::newput('exttools',$lockhash,$cdom,$cnum);
  440: 
  441:     while (($gotlock ne 'ok') && $tries <3) {
  442:         $tries ++;
  443:         sleep(1);
  444:         $gotlock = &Apache::lonnet::newput('exttools',$lockhash,$cdom,$cnum);
  445:     }
  446:     return $gotlock;
  447: }
  448: 
  449: #
  450: # LON-CAPA as LTI Consumer
  451: #
  452: # Remove a lock key from exttools.db for the instance of an external
  453: # tool created when generating and storing a service secret.
  454: #
  455: 
  456: sub release_tool_lock {
  457:     my ($cdom,$cnum,$marker,$name) = @_;
  458:     #  remove lock
  459:     my @del_lock = ($name."\0".$marker."\0".'lock');
  460:     my $dellockoutcome=&Apache::lonnet::del('exttools',\@del_lock,$cdom,$cnum);
  461:     if ($dellockoutcome ne 'ok') {
  462:         return 'Warning: failed to release lock for exttool';
  463:     } else {
  464:         return 'ok';
  465:     }
  466: }
  467: 
  468: #
  469: # LON-CAPA as LTI Provider
  470: #
  471: # Use the part of the launch URL after /adm/lti to determine
  472: # the scope for the current session (i.e., restricted to a
  473: # single resource, to a single folder/map, or to an entire
  474: # course).
  475: #
  476: # Returns an array containing scope: resource, map, or course
  477: # and the LON-CAPA URL that is displayed post-launch, including
  478: # accommodation of URL encryption, and translation of a tiny URL
  479: # to the actual URL
  480: #
  481: 
  482: sub lti_provider_scope {
  483:     my ($tail,$cdom,$cnum,$getunenc) = @_;
  484:     my ($scope,$realuri,$passkey,$unencsymb);
  485:     if ($tail =~ m{^/?uploaded/$cdom/$cnum/(?:default|supplemental)(?:|_\d+)\.(?:sequence|page)(|___\d+___.+)$}) {
  486:         my $rest = $1;
  487:         if ($rest eq '') {
  488:             $scope = 'map';
  489:             $realuri = $tail;
  490:         } else {
  491:             my ($map,$resid,$url) = &Apache::lonnet::decode_symb($tail);
  492:             $realuri = &Apache::lonnet::clutter($url);
  493:             if ($url =~ /\.sequence$/) {
  494:                 $scope = 'map';
  495:             } else {
  496:                 $scope = 'resource';
  497:                 $realuri .= '?symb='.$tail;
  498:                 $passkey = $tail;
  499:                 if ($getunenc) {
  500:                     $unencsymb = $tail;
  501:                 }
  502:             }
  503:         }
  504:     } elsif ($tail =~ m{^/?res/$match_domain/$match_username/.+\.(?:sequence|page)(|___\d+___.+)$}) {
  505:         my $rest = $1;
  506:         if ($rest eq '') {
  507:             $scope = 'map';
  508:             $realuri = $tail;
  509:         } else {
  510:             my ($map,$resid,$url) = &Apache::lonnet::decode_symb($tail);
  511:             $realuri = &Apache::lonnet::clutter($url);
  512:             if ($url =~ /\.sequence$/) {
  513:                 $scope = 'map';
  514:             } else {
  515:                 $scope = 'resource';
  516:                 $realuri .= '?symb='.$tail;
  517:                 $passkey = $tail;
  518:                 if ($getunenc) {
  519:                     $unencsymb = $tail;
  520:                 }
  521:             }
  522:         }
  523:     } elsif ($tail =~ m{^/tiny/$cdom/(\w+)$}) {
  524:         my $key = $1;
  525:         my $tinyurl;
  526:         my ($result,$cached)=&Apache::lonnet::is_cached_new('tiny',$cdom."\0".$key);
  527:         if (defined($cached)) {
  528:             $tinyurl = $result;
  529:         } else {
  530:             my $configuname = &Apache::lonnet::get_domainconfiguser($cdom);
  531:             my %currtiny = &Apache::lonnet::get('tiny',[$key],$cdom,$configuname);
  532:             if ($currtiny{$key} ne '') {
  533:                 $tinyurl = $currtiny{$key};
  534:                 &Apache::lonnet::do_cache_new('tiny',$cdom."\0".$key,$currtiny{$key},600);
  535:             }
  536:         }
  537:         if ($tinyurl ne '') {
  538:             my ($cnum,$symb) = split(/\&/,$tinyurl,2);
  539:             my ($map,$resid,$url) = &Apache::lonnet::decode_symb($symb);
  540:             if ($url =~ /\.(page|sequence)$/) {
  541:                 $scope = 'map';
  542:             } else {
  543:                 $scope = 'resource';
  544:             }
  545:             $passkey = $symb;
  546:             if ((&Apache::lonnet::EXT('resource.0.encrypturl',$symb) =~ /^yes$/i) &&
  547:                 (!$env{'request.role.adv'})) {
  548:                 $realuri = &Apache::lonenc::encrypted(&Apache::lonnet::clutter($url));
  549:                 if ($scope eq 'resource') {
  550:                     $realuri .= '?symb='.&Apache::lonenc::encrypted($symb);
  551:                 }
  552:             } else {
  553:                 $realuri = &Apache::lonnet::clutter($url);
  554:                 if ($scope eq 'resource') {
  555:                     $realuri .= '?symb='.$symb;
  556:                 }
  557:             }
  558:             if ($getunenc) {
  559:                 $unencsymb = $symb;
  560:             }
  561:         }
  562:     } elsif (($tail =~ m{^/$cdom/$cnum$}) || ($tail eq '')) {
  563:         $scope = 'course';
  564:         $realuri = '/adm/navmaps';
  565:         $passkey = $tail;
  566:     }
  567:     if ($scope eq 'map') {
  568:         $passkey = $realuri;
  569:     }
  570:     if (wantarray) {
  571:         return ($scope,$realuri,$unencsymb);
  572:     } else {
  573:         return $passkey;
  574:     }
  575: }
  576: 
  577: #
  578: # LON-CAPA as LTI Provider
  579: #
  580: # Obtain a list of course personnel and students from
  581: # the LTI Consumer which launched this instance.
  582: #
  583: 
  584: sub get_roster {
  585:     my ($id,$url,$ckey,$secret) = @_;
  586:     my %ltiparams = (
  587:         lti_version                => 'LTI-1p0',
  588:         lti_message_type           => 'basic-lis-readmembershipsforcontext',
  589:         ext_ims_lis_memberships_id => $id,
  590:     );
  591:     my $hashref = &sign_params($url,$ckey,$secret,\%ltiparams);
  592:     if (ref($hashref) eq 'HASH') {
  593:         my $request=new HTTP::Request('POST',$url);
  594:         $request->content(join('&',map {
  595:                           my $name = escape($_);
  596:                           "$name=" . ( ref($hashref->{$_}) eq 'ARRAY'
  597:                           ? join("&$name=", map {escape($_) } @{$hashref->{$_}})
  598:                           : &escape($hashref->{$_}) );
  599:         } keys(%{$hashref})));
  600:         my $response = &LONCAPA::LWPReq::makerequest('',$request,'','',10);
  601:         my $message=$response->status_line;
  602:         if (($response->is_success) && ($response->content ne '')) {
  603:             my %data = ();
  604:             my $count = 0;
  605:             my @state = ();
  606:             my @items = ('user_id','roles','person_sourcedid','person_name_given','person_name_family',
  607:                          'person_contact_email_primary','person_name_full','lis_result_sourcedid');
  608:             my $p = HTML::Parser->new
  609:             (
  610:              xml_mode => 1,
  611:              start_h =>
  612:                  [sub {
  613:                      my ($tagname, $attr) = @_;
  614:                      push(@state,$tagname);
  615:                      if ("@state" eq "message_response memberships member") {
  616:                          $count ++;
  617:                      }
  618:                  }, "tagname, attr"],
  619:              text_h =>
  620:                 [sub {
  621:                      my ($text) = @_;
  622:                      foreach my $item (@items) {
  623:                          if ("@state" eq "message_response memberships member $item") {
  624:                              $data{$count}{$item} = $text;
  625:                          }
  626:                      }
  627:                    }, "dtext"],
  628:              end_h =>
  629:                  [sub {
  630:                      my ($tagname) = @_;
  631:                      pop @state;
  632:                     }, "tagname"],
  633:             );
  634:             $p->parse($response->content);
  635:             $p->eof;
  636:             return %data;
  637:         }
  638:     }
  639:     return;
  640: }
  641: 
  642: #
  643: # LON-CAPA as LTI Provider
  644: #
  645: # Passback a grade for a user to the LTI Consumer which originally
  646: # provided the lis_result_sourcedid
  647: #
  648: 
  649: sub send_grade {
  650:     my ($id,$url,$ckey,$secret,$scoretype,$total,$possible) = @_;
  651:     my $score;
  652:     if ($possible > 0) {
  653:         if ($scoretype eq 'ratio') {
  654:             $score = Math::Round::round($total).'/'.Math::Round::round($possible);
  655:         } elsif ($scoretype eq 'percentage') {
  656:             $score = (100.0*$total)/$possible;
  657:             $score = Math::Round::round($score);
  658:         } else {
  659:             $score = $total/$possible;
  660:             $score = sprintf("%.2f",$score);
  661:         }
  662:     }
  663:     my $date = &Apache::loncommon::utc_string(time);
  664:     my %ltiparams = (
  665:         lti_version                   => 'LTI-1p0',
  666:         lti_message_type              => 'basic-lis-updateresult',
  667:         sourcedid                     => $id,
  668:         result_resultscore_textstring => $score,
  669:         result_resultscore_language   => 'en-US',
  670:         result_resultvaluesourcedid   => $scoretype,
  671:         result_statusofresult         => 'final',
  672:         result_date                   => $date,
  673:     );
  674:     my $hashref = &sign_params($url,$ckey,$secret,\%ltiparams);
  675:     if (ref($hashref) eq 'HASH') {
  676:         my $request=new HTTP::Request('POST',$url);
  677:         $request->content(join('&',map {
  678:                           my $name = escape($_);
  679:                           "$name=" . ( ref($hashref->{$_}) eq 'ARRAY'
  680:                           ? join("&$name=", map {escape($_) } @{$hashref->{$_}})
  681:                           : &escape($hashref->{$_}) );
  682:         } keys(%{$hashref})));
  683:         my $response = &LONCAPA::LWPReq::makerequest('',$request,'','',10);
  684:         my $message=$response->status_line;
  685: #FIXME Handle case where pass back of score to LTI Consumer failed.
  686:     }
  687: }
  688: 
  689: #
  690: # LON-CAPA as LTI Provider
  691: #
  692: # Create a new user in LON-CAPA. If the domain's configuration 
  693: # includes rules for format of "official" usernames, those rules
  694: # will apply when determining if a user is to be created.  In
  695: # additional if institutional user information is available that
  696: # will be used when creating a new user account.
  697: #
  698: 
  699: sub create_user {
  700:     my ($ltiref,$uname,$udom,$domdesc,$data,$alerts,$rulematch,$inst_results,
  701:         $curr_rules,$got_rules) = @_;
  702:     return unless (ref($ltiref) eq 'HASH');
  703:     my $checkhash = { "$uname:$udom" => { 'newuser' => 1, }, };
  704:     my $checks = { 'username' => 1, };
  705:     my ($lcauth,$lcauthparm);
  706:     &Apache::loncommon::user_rule_check($checkhash,$checks,$alerts,$rulematch,
  707:                                         $inst_results,$curr_rules,$got_rules);
  708:     my ($userchkmsg,$lcauth,$lcauthparm);
  709:     my $allowed = 1;
  710:     if (ref($alerts->{'username'}) eq 'HASH') {
  711:          if (ref($alerts->{'username'}{$udom}) eq 'HASH') {
  712:              if ($alerts->{'username'}{$udom}{$uname}) {
  713:                  if (ref($curr_rules->{$udom}) eq 'HASH') {
  714:                      $userchkmsg =
  715:                          &Apache::loncommon::instrule_disallow_msg('username',$domdesc,1).
  716:                          &Apache::loncommon::user_rule_formats($udom,$domdesc,
  717:                                                                $curr_rules->{$udom}{'username'},
  718:                                                                'username');
  719:                  }
  720:                  $allowed = 0;
  721:              }
  722:          }
  723:     }
  724:     if ($allowed) {
  725:         if (ref($rulematch->{$uname.':'.$udom}) eq 'HASH') {
  726:             my $matchedrule = $rulematch->{$uname.':'.$udom}{'username'};
  727:             my ($rules,$ruleorder) =
  728:                 &Apache::lonnet::inst_userrules($udom,'username');
  729:             if (ref($rules) eq 'HASH') {
  730:                 if (ref($rules->{$matchedrule}) eq 'HASH') {
  731:                     $lcauth = $rules->{$matchedrule}{'authtype'};
  732:                     $lcauthparm = $rules->{$matchedrule}{'authparm'};
  733:                 }
  734:             }
  735:         }
  736:         if ($lcauth eq '') {
  737:             $lcauth = $ltiref->{'lcauth'};
  738:             if ($lcauth eq 'internal') {
  739:                 $lcauthparm = &create_passwd();
  740:             } else {
  741:                 $lcauthparm = $ltiref->{'lcauthparm'};
  742:             }
  743:         }
  744:     } else {
  745:         return 'notallowed';
  746:     }
  747:     my @userinfo = ('firstname','middlename','lastname','generation','permanentemail','id');
  748:     my (%useinstdata,%info);
  749:     if (ref($ltiref->{'instdata'}) eq 'ARRAY') {
  750:         map { $useinstdata{$_} = 1; } @{$ltiref->{'instdata'}};
  751:     }
  752:     foreach my $item (@userinfo) {
  753:         if (($useinstdata{$item}) && (ref($inst_results->{$uname.':'.$udom}) eq 'HASH') &&
  754:             ($inst_results->{$uname.':'.$udom}{$item} ne '')) {
  755:             $info{$item} = $inst_results->{$uname.':'.$udom}{$item};
  756:         } else {
  757:             if ($item eq 'permanentemail') {
  758:                 if ($data->{'permanentemail'} =~/^[^\@]+\@[^@]+$/) {
  759:                     $info{$item} = $data->{'permanentemail'};
  760:                 }
  761:             } elsif (($item eq 'firstname') || ($item eq 'lastname')) {
  762:                 $info{$item} = $data->{$item};
  763:             }
  764:         }
  765:     }
  766:     if (($info{'middlename'} eq '') && ($data->{'fullname'} ne '')) {
  767:         unless ($useinstdata{'middlename'}) {
  768:             my $fullname = $data->{'fullname'};
  769:             if ($info{'firstname'}) {
  770:                 $fullname =~ s/^\s*\Q$info{'firstname'}\E\s*//i;
  771:             }
  772:             if ($info{'lastname'}) {
  773:                 $fullname =~ s/\s*\Q$info{'lastname'}\E\s*$//i;
  774:             }
  775:             if ($fullname ne '') {
  776:                 $fullname =~ s/^\s+|\s+$//g;
  777:                 if ($fullname ne '') {
  778:                     $info{'middlename'} = $fullname;
  779:                 }
  780:             }
  781:         }
  782:     }
  783:     if (ref($inst_results->{$uname.':'.$udom}{'inststatus'}) eq 'ARRAY') {
  784:         my @inststatuses = @{$inst_results->{$uname.':'.$udom}{'inststatus'}};
  785:         $info{'inststatus'} = join(':',map { &escape($_); } @inststatuses);
  786:     }
  787:     my $result =
  788:         &Apache::lonnet::modifyuser($udom,$uname,$info{'id'},
  789:                                     $lcauth,$lcauthparm,$info{'firstname'},
  790:                                     $info{'middlename'},$info{'lastname'},
  791:                                     $info{'generation'},undef,undef,
  792:                                     $info{'permanentemail'},$info{'inststatus'});
  793:     return $result;
  794: }
  795: 
  796: #
  797: # LON-CAPA as LTI Provider
  798: #
  799: # Create a password for a new user if the authentication
  800: # type to assign to new users created following LTI launch is
  801: # to be LON-CAPA "internal".
  802: #
  803: 
  804: sub create_passwd {
  805:     my $passwd = '';
  806:     srand( time() ^ ($$ + ($$ << 15))  ); # Seed rand.
  807:     my @letts = ("a".."z");
  808:     for (my $i=0; $i<8; $i++) {
  809:         my $lettnum = int(rand(2));
  810:         my $item = '';
  811:         if ($lettnum) {
  812:             $item = $letts[int(rand(26))];
  813:             my $uppercase = int(rand(2));
  814:             if ($uppercase) {
  815:                 $item =~ tr/a-z/A-Z/;
  816:             }
  817:         } else {
  818:             $item = int(rand(10));
  819:         }
  820:         $passwd .= $item;
  821:     }
  822:     return ($passwd);
  823: }
  824: 
  825: #
  826: # LON-CAPA as LTI Provider
  827: #
  828: # Enroll a user in a LON-CAPA course, with the specified role and (optional)
  829: # section.  If this is a self-enroll case, i.e., a user launched the LTI tool
  830: # in the Consumer, user privs will be added to the user's environment for
  831: # the new role.
  832: #
  833: # If this is a self-enroll case, a Course Coordinator role will only be assigned 
  834: # if the current user is also the course owner.
  835: #
  836: 
  837: sub enrolluser {
  838:     my ($udom,$uname,$role,$cdom,$cnum,$sec,$start,$end,$selfenroll) = @_;
  839:     my $enrollresult;
  840:     my $area = "/$cdom/$cnum";
  841:     if (($role ne 'cc') && ($role ne 'co') && ($sec ne '')) {
  842:         $area .= '/'.$sec;
  843:     }
  844:     my $spec = $role.'.'.$area;
  845:     my $instcid;
  846:     if ($role eq 'st') {
  847:         $enrollresult =
  848:             &Apache::lonnet::modify_student_enrollment($udom,$uname,undef,undef,undef,
  849:                                                        undef,undef,$sec,$end,$start,
  850:                                                        'ltienroll',undef,$cdom.'_'.$cnum,
  851:                                                        $selfenroll,'ltienroll','',$instcid);
  852:     } elsif ($role =~ /^(cc|in|ta|ep)$/) {
  853:         $enrollresult =
  854:             &Apache::lonnet::assignrole($udom,$uname,$area,$role,$end,$start,
  855:                                         undef,$selfenroll,'ltienroll');
  856:     }
  857:     if ($enrollresult eq 'ok') {
  858:         if ($selfenroll) {
  859:             my (%userroles,%newrole,%newgroups);
  860:             &Apache::lonnet::standard_roleprivs(\%newrole,$role,$cdom,$spec,$cnum,
  861:                                                 $area);
  862:             &Apache::lonnet::set_userprivs(\%userroles,\%newrole,\%newgroups);
  863:             $userroles{'user.role.'.$spec} = $start.'.'.$end;
  864:             &Apache::lonnet::appenv(\%userroles,[$role,'cm']);
  865:         }
  866:     }
  867:     return $enrollresult;
  868: }
  869: 
  870: #
  871: # LON-CAPA as LTI Provider
  872: #
  873: # Batch addition of users following LTI launch by a user
  874: # with LTI Instructor status.
  875: #
  876: # A list of users is obtained by a call to get_roster()
  877: # if the calling Consumer support the LTI extension: 
  878: # Context Memberships Service. 
  879: #
  880: # If a user included in the retrieved list does not currently
  881: # have a user account in LON-CAPA, an account will be created.
  882: #
  883: # If a user already has an account, and the same role and
  884: # section assigned (currently active), then no change will
  885: # be made for that user.
  886: #
  887: # Information available for new users (besides username and)
  888: # role) may include: first name, last name, full name (from
  889: # which middle name will be extracted), permanent e-mail address,
  890: # and lis_result_sourcedid (for passback of grades).
  891: #
  892: # If grades are to be passed back, the passback url will be
  893: # the same as for the current user's session.
  894: #
  895: # The roles which may be assigned will be determined from the
  896: # LTI roles included in the retrieved roster, and the mapping
  897: # of LTI roles to LON-CAPA roles configured for this LTI Consumer
  898: # in the domain configuration.
  899: #
  900: # Course Coordinator roles will only be assigned if the current
  901: # user is also the course owner.
  902: #
  903: # The domain configuration for the corresponding Consumer can include
  904: # a section to assign to LTI users. If the roster includes students
  905: # any existing student roles with a different section will be expired,
  906: # and a role in the LTI section will be assigned.
  907: #
  908: # For non-student rules (excluding Course Coordinator) a role will be
  909: # assigned with the LTI section )or no section, if one is not rquired.
  910: #
  911: 
  912: sub batchaddroster {
  913:     my ($item) = @_;
  914:     return unless(ref($item) eq 'HASH');
  915:     return unless (ref($item->{'ltiref'}) eq 'HASH');
  916:     my ($cdom,$cnum) = split(/_/,$item->{'cid'});
  917:     my $udom = $cdom;
  918:     my $id = $item->{'id'};
  919:     my $url = $item->{'url'};
  920:     my @intdoms;
  921:     my $intdomsref = $item->{'intdoms'};
  922:     if (ref($intdomsref) eq 'ARRAY') {
  923:         @intdoms = @{$intdomsref};
  924:     }
  925:     my $uriscope = $item->{'uriscope'};
  926:     my $ckey = $item->{'ltiref'}->{'key'};
  927:     my $secret = $item->{'ltiref'}->{'secret'};
  928:     my $section = $item->{'ltiref'}->{'section'};
  929:     $section =~ s/\W//g;
  930:     if ($section eq 'none') {
  931:         undef($section);
  932:     } elsif ($section ne '') {
  933:         my %curr_groups =
  934:             &Apache::longroup::coursegroups($cdom,$cnum);
  935:         if (exists($curr_groups{$section})) {
  936:             undef($section);
  937:         }
  938:     }
  939:     my (%maproles,@possroles);
  940:     if (ref($item->{'ltiref'}->{'maproles'}) eq 'HASH') {
  941:         %maproles = %{$item->{'ltiref'}->{'maproles'}};
  942:     }
  943:     if (ref($item->{'possroles'}) eq 'ARRAY') {
  944:         @possroles = @{$item->{'possroles'}};
  945:     }
  946:     if (($ckey ne '') && ($secret ne '') && ($id ne '') && ($url ne '')) {
  947:         my %data = &get_roster($id,$url,$ckey,$secret);
  948:         if (keys(%data) > 0) {
  949:             my (%rulematch,%inst_results,%curr_rules,%got_rules,%alerts,%info);
  950:             my %coursehash = &Apache::lonnet::coursedescription($cdom.'_'.$cnum);
  951:             my $start = $coursehash{'default_enrollment_start_date'};
  952:             my $end = $coursehash{'default_enrollment_end_date'};
  953:             my $domdesc = &Apache::lonnet::domain($udom,'description');
  954:             my $roster = &Apache::loncoursedata::get_classlist($cdom,$cnum);
  955:             my $status = &Apache::loncoursedata::CL_STATUS;
  956:             my $cend = &Apache::loncoursedata::CL_END;
  957:             my $cstart = &Apache::loncoursedata::CL_START;
  958:             my $lockedtype=&Apache::loncoursedata::CL_LOCKEDTYPE;
  959:             my $sec=&Apache::loncoursedata::CL_SECTION;
  960:             my (@activestudents,@futurestudents,@excludedstudents,@localstudents,%currlist,%advroles);
  961:             if (grep(/^st$/,@possroles)) {
  962:                 foreach my $user (keys(%{$roster})) {
  963:                     if ($user =~ m/^(.+):$cdom$/) {
  964:                         my $stuname = $1;
  965:                         if ($roster->{$user}[$status] eq "Active") {
  966:                             push(@activestudents,$stuname);
  967:                             @{$currlist{$stuname}} = @{$roster->{$user}};
  968:                             push(@localstudents,$stuname);
  969:                         } elsif (($roster->{$user}[$cstart] > time)  && ($roster->{$user}[$cend] > time ||
  970:                                   $roster->{$user}[$cend] == 0 || $roster->{$user}[$cend] eq '')) {
  971:                             push(@futurestudents,$stuname);
  972:                             @{$currlist{$stuname}} = @{$roster->{$user}};
  973:                             push(@localstudents,$stuname);
  974:                         } elsif ($roster->{$user}[$lockedtype] == 1) {
  975:                             push(@excludedstudents,$stuname);
  976:                         }
  977:                     }
  978:                 }
  979:             }
  980:             if ((@possroles > 1) || ((@possroles == 1) && (!grep(/^st$/,@possroles)))) {
  981:                 my %personnel = &Apache::lonnet::get_course_adv_roles($item->{'cid'},1);
  982:                 foreach my $item (keys(%personnel)) {
  983:                     my ($role,$currsec) = split(/:/,$item);
  984:                     if ($currsec eq '') {
  985:                         $currsec = 'none';
  986:                     }
  987:                     foreach my $user (split(/,/,$personnel{$item})) {
  988:                         push(@{$advroles{$user}{$role}},$currsec);
  989:                     }
  990:                 }
  991:             }
  992:             if (($end == 0) || ($end > time) || (@localstudents > 0)) {
  993:                 my (%passback,$pbnum,$numadv);
  994:                 $numadv = 0;
  995:                 foreach my $i (sort { $a <=> $b } keys(%data)) {
  996:                     if (ref($data{$i}) eq 'HASH') {
  997:                         my $entry = $data{$i};
  998:                         my $user = $entry->{'person_sourcedid'};
  999:                         my $uname;
 1000:                         if ($user =~ /^($match_username):($match_domain)$/) {
 1001:                             $uname = $1;
 1002:                             my $possudom = $2;
 1003:                             if ($possudom ne $udom) {
 1004:                                 my $uintdom = &Apache::lonnet::domain($possudom,'primary');
 1005:                                 if (($uintdom ne '') && (grep(/^\Q$uintdom\E$/,@intdoms))) {
 1006:                                     $udom = $possudom;
 1007:                                 }
 1008:                             }
 1009:                         } elsif ($uname =~ /^match_username$/) {
 1010:                             $uname = $user;
 1011:                         } else {
 1012:                             next;
 1013:                         }
 1014:                         my $uhome = &Apache::lonnet::homeserver($uname,$udom);
 1015:                         if ($uhome eq 'no_host') {
 1016:                             my %data;
 1017:                             $data{'permanentemail'} = $entry->{'person_contact_email_primary'};
 1018:                             $data{'lastname'} = $entry->{'person_name_family'};
 1019:                             $data{'firstname'} = $entry->{'person_name_given'};
 1020:                             $data{'fullname'} = $entry->{'person_name_full'};
 1021:                             my $addresult =
 1022:                                 &create_user($item->{'ltiref'},$uname,$udom,
 1023:                                              $domdesc,\%data,\%alerts,\%rulematch,
 1024:                                              \%inst_results,\%curr_rules,\%got_rules);
 1025:                             next unless ($addresult eq 'ok');
 1026:                         }
 1027:                         if ($env{'request.lti.passbackurl'}) {
 1028:                             if ($entry->{'lis_result_sourcedid'} ne '') {
 1029:                                 unless ($pbnum) {
 1030:                                     ($pbnum,my $error) = &store_passbackurl($env{'request.lti.login'},
 1031:                                                                             $env{'request.lti.passbackurl'},
 1032:                                                                             $cdom,$cnum);
 1033:                                     if ($pbnum eq '') {
 1034:                                         $pbnum = $env{'request.lti.passbackurl'};
 1035:                                     }
 1036:                                 }
 1037:                                 $passback{$uname."\0".$uriscope."\0".$env{'request.lti.sourcecrs'}."\0".$env{'request.lti.login'}} =
 1038:                                           $pbnum."\0".$entry->{'lis_result_sourcedid'};
 1039:                             }
 1040:                         }
 1041:                         my $rolestr = $entry->{'roles'};
 1042:                         my ($lcrolesref) = &get_lc_roles($rolestr,\@possroles,\%maproles);
 1043:                         my @lcroles = @{$lcrolesref};
 1044:                         if (@lcroles) {
 1045:                             if (grep(/^st$/,@lcroles)) {
 1046:                                 my $addstu;
 1047:                                 if (!grep(/^\Q$uname\E$/,@excludedstudents)) {
 1048:                                     if (grep(/^\Q$uname\E$/,@localstudents)) {
 1049: # Check for section changes
 1050:                                         if ($currlist{$uname}[$sec] ne $section) {
 1051:                                             $addstu = 1;
 1052:                                             &Apache::lonuserutils::modifystudent($udom,$uname,$cdom.'_'.$cnum,
 1053:                                                                                  undef,undef,'course');
 1054:                                         } elsif (grep(/^\Q$uname\E$/,@futurestudents)) {
 1055: # Check for access date changes for students with access starting in the future.
 1056:                                             my $datechange = &datechange_check($currlist{$uname}[$cstart],
 1057:                                                                                $currlist{$uname}[$cend],
 1058:                                                                                $start,$end);
 1059:                                             if ($datechange) {
 1060:                                                 $addstu = 1;
 1061:                                             }
 1062:                                         }
 1063:                                     } else {
 1064:                                         $addstu = 1;
 1065:                                     }
 1066:                                 }
 1067:                                 unless ($addstu) {
 1068:                                     pop(@lcroles);
 1069:                                 }
 1070:                             }
 1071:                             my @okroles;
 1072:                             if (@lcroles) {
 1073:                                 foreach my $role (@lcroles) {
 1074:                                     unless (($role eq 'st') || (keys(%advroles) == 0)) {
 1075:                                         if (exists($advroles{$uname.':'.$udom})) {
 1076:                                             if ((ref($advroles{$uname.':'.$udom}) eq 'HASH') &&
 1077:                                                 (ref($advroles{$uname.':'.$udom}{$role}) eq 'ARRAY')) {
 1078:                                                 if (($section eq '') || ($role eq 'cc') || ($role eq 'co')) {
 1079:                                                     next if (grep(/^none$/,@{$advroles{$uname.':'.$udom}{$role}}));
 1080:                                                 } else {
 1081:                                                     next if (grep(/^\Q$sec\E$/,@{$advroles{$uname.':'.$udom}{$role}}));
 1082:                                                 }
 1083:                                             }
 1084:                                         }
 1085:                                     }
 1086:                                     push(@okroles,$role);
 1087:                                 }
 1088:                             }
 1089:                             if (@okroles) {
 1090:                                 my $permanentemail = $entry->{'person_contact_email_primary'};
 1091:                                 my $lastname = $entry->{'person_name_family'};
 1092:                                 my $firstname = $entry->{'person_name_given'};
 1093:                                 foreach my $role (@okroles) {
 1094:                                     my $enrollresult = &enrolluser($udom,$uname,$role,$cdom,$cnum,
 1095:                                                                    $section,$start,$end);
 1096:                                     if (($enrollresult eq 'ok') && ($role ne 'st')) {
 1097:                                         $numadv ++;
 1098:                                     }
 1099:                                 }
 1100:                             }
 1101:                         }
 1102:                     }
 1103:                 }
 1104:                 if (keys(%passback)) {
 1105:                     &Apache::lonnet::put('nohist_lti_passback',\%passback,$cdom,$cnum);
 1106:                 }
 1107:                 if ($numadv) {
 1108:                     &Apache::lonnet::flushcourselogs();
 1109:                 }
 1110:             }
 1111:         }
 1112:     }
 1113:     return;
 1114: }
 1115: 
 1116: #
 1117: # LON-CAPA as LTI Provider
 1118: #
 1119: # Gather a list of available LON-CAPA roles derived
 1120: # from a comma separated list of LTI roles.
 1121: #
 1122: # Which LON-CAPA roles are assignable by the current user
 1123: # and how LTI roles map to LON-CAPA roles (as defined in
 1124: # the domain configuration for the specific Consumer) are 
 1125: # factored in when compiling the list of available roles.
 1126: #
 1127: # Inputs: 3
 1128: #  $rolestr - comma separated list of LTI roles.
 1129: #  $allowedroles - reference to array of assignable LC roles
 1130: #  $maproles - ref to HASH of mapping of LTI roles to LC roles
 1131: #
 1132: # Outputs: 2
 1133: # (a) reference to array of available LC roles.
 1134: # (b) reference to array of LTI roles.
 1135: #
 1136: 
 1137: sub get_lc_roles {
 1138:     my ($rolestr,$allowedroles,$maproles) = @_;
 1139:     my (@ltiroles,@lcroles);
 1140:     my @ltiroleorder = ('Instructor','TeachingAssistant','Mentor','Learner');
 1141:     if ($rolestr =~ /,/) {
 1142:         my @possltiroles = split(/\s*,\s*/,$rolestr);
 1143:         foreach my $ltirole (@ltiroleorder) {
 1144:             if (grep(/^\Q$ltirole\E$/,@possltiroles)) {
 1145:                 push(@ltiroles,$ltirole);
 1146:             }
 1147:         }
 1148:     } else {
 1149:         my $singlerole = $rolestr;
 1150:         $singlerole =~ s/^\s|\s+$//g;
 1151:         if ($singlerole ne '') {
 1152:             if (grep(/^\Q$singlerole\E$/,@ltiroleorder)) {
 1153:                 @ltiroles = ($singlerole);
 1154:             }
 1155:         }
 1156:     }
 1157:     if (@ltiroles) {
 1158:         my %possroles;
 1159:         map { $possroles{$maproles->{$_}} = 1; } @ltiroles;
 1160:         if (keys(%possroles) > 0) {
 1161:             if (ref($allowedroles) eq 'ARRAY') {
 1162:                 foreach my $item (@{$allowedroles}) {
 1163:                     if (($item eq 'co') || ($item eq 'cc')) {
 1164:                         if ($possroles{'cc'}) {
 1165:                             push(@lcroles,$item);
 1166:                         }
 1167:                     } elsif ($possroles{$item}) {
 1168:                         push(@lcroles,$item);
 1169:                     }
 1170:                 }
 1171:             }
 1172:         }
 1173:     }
 1174:     return (\@lcroles,\@ltiroles);
 1175: }
 1176: 
 1177: #
 1178: # LON-CAPA as LTI Provider
 1179: #
 1180: # Compares current start and dates for a user's role
 1181: # with dates to apply for the same user/role to 
 1182: # determine if there is a change between the current
 1183: # ones and the updated ones.
 1184: # 
 1185: 
 1186: sub datechange_check {
 1187:     my ($oldstart,$oldend,$startdate,$enddate) = @_;
 1188:     my $datechange = 0;
 1189:     unless ($oldstart eq $startdate) {
 1190:         $datechange = 1;
 1191:     }
 1192:     if (!$datechange) {
 1193:         if (!$oldend) {
 1194:             if ($enddate) {
 1195:                 $datechange = 1;
 1196:             }
 1197:         } elsif ($oldend ne $enddate) {
 1198:             $datechange = 1;
 1199:         }
 1200:     }
 1201:     return $datechange;
 1202: }
 1203: 
 1204: #
 1205: # LON-CAPA as LTI Provider
 1206: #
 1207: # Store the URL used by a specific LTI Consumer to process grades passed back
 1208: # by an LTI Provider.
 1209: #
 1210: 
 1211: sub store_passbackurl {
 1212:     my ($ltinum,$pburl,$cdom,$cnum) = @_;
 1213:     my %history = &Apache::lonnet::restore($ltinum,'passbackurl',$cdom,$cnum);
 1214:     my ($pbnum,$version,$error);
 1215:     if ($history{'version'}) {
 1216:         $version = $history{'version'};
 1217:         for (my $i=1; $i<=$version; $i++) {
 1218:             if ($history{$i.':pburl'} eq $pburl) {
 1219:                 $pbnum = $i;
 1220:                 last;
 1221:             }
 1222:         }
 1223:     } else {
 1224:         $version = 0;
 1225:     }
 1226:     if ($pbnum eq '') {
 1227:         # get lock on passbackurl db
 1228:         my $now = time;
 1229:         my $lockhash = {
 1230:             'lock'."\0".$ltinum."\0".$now => $env{'user.name'}.':'.$env{'user.domain'},
 1231:         };
 1232:         my $tries = 0;
 1233:         my $gotlock = &Apache::lonnet::newput('passbackurl',$lockhash,$cdom,$cnum);
 1234:         while (($gotlock ne 'ok') && ($tries<3)) {
 1235:             $tries ++;
 1236:             sleep 1;
 1237:             $gotlock = &Apache::lonnet::newput('passbackurl',$lockhash,$cdom.$cnum);
 1238:         }
 1239:         if ($gotlock eq 'ok') {
 1240:             if (&Apache::lonnet::store_userdata({pburl => $pburl},
 1241:                                                  $ltinum,'passbackurl',$cdom,$cnum) eq 'ok') {
 1242:                 $pbnum = 1+$version;
 1243:             }
 1244:             my $dellock = &Apache::lonnet::del('passbackurl',['lock'."\0".$ltinum."\0".$now],$cdom,$cnum);
 1245:             unless ($dellock eq 'ok') {
 1246:                 $error = &mt('error: could not release lockfile');
 1247:             }
 1248:         } else {
 1249:             $error = &mt('error: could not obtain lockfile');
 1250:         }
 1251:     }
 1252:     return ($pbnum,$error);
 1253: }
 1254: 
 1255: 1;

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