Annotation of loncom/lti/ltiutils.pm, revision 1.12
1.1 raeburn 1: # The LearningOnline Network with CAPA
2: # Utility functions for managing LON-CAPA LTI interactions
3: #
1.12 ! raeburn 4: # $Id: ltiutils.pm,v 1.11 2018/05/28 23:26:04 raeburn Exp $
1.1 raeburn 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;
1.11 raeburn 37: use Apache::loncoursedata;
38: use Apache::lonuserutils;
39: use Apache::lonenc();
40: use Apache::longroup();
1.12 ! raeburn 41: use Apache::lonlocal;
1.10 raeburn 42: use Math::Round();
1.1 raeburn 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
1.4 raeburn 60: # Consumer) launches an external tool to access a LON-CAPA URL:
1.1 raeburn 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;
1.5 raeburn 295: $expected_sig = (split(/:::/,&get_service_id($secret,$uniqid)))[0];
1.1 raeburn 296: if ($expected_sig eq $sigrec) {
297: return 1;
298: } else {
1.2 raeburn 299: $errors->{17} = 1;
1.1 raeburn 300: }
301: } elsif ($context eq 'roster') {
302: my $uniqid = $digsymb.':::'.$cdom.'_'.$cnum;
1.5 raeburn 303: $expected_sig = (split(/:::/,&get_service_id($secret,$uniqid)))[0];
1.1 raeburn 304: if ($expected_sig eq $sigrec) {
305: return 1;
306: } else {
1.2 raeburn 307: $errors->{18} = 1;
1.1 raeburn 308: }
309: }
310: } else {
1.2 raeburn 311: $errors->{19} = 1;
1.1 raeburn 312: }
313: } else {
1.2 raeburn 314: $errors->{20} = 1;
1.1 raeburn 315: }
316: return;
317: }
318:
319: #
320: # LON-CAPA as LTI Consumer
321: #
322: # Sign a request used to launch an instance of an external
1.4 raeburn 323: # tool in a LON-CAPA course, using the key and secret supplied
1.1 raeburn 324: # by the Tool Provider.
325: #
326:
327: sub sign_params {
1.3 raeburn 328: my ($url,$key,$secret,$sigmethod,$paramsref) = @_;
1.1 raeburn 329: return unless (ref($paramsref) eq 'HASH');
1.3 raeburn 330: if ($sigmethod eq '') {
331: $sigmethod = 'HMAC-SHA1';
332: }
1.9 raeburn 333: srand( time() ^ ($$ + ($$ << 15)) ); # Seed rand.
1.1 raeburn 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',
1.3 raeburn 340: signature_method => $sigmethod,
1.1 raeburn 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 $gotlock;
447: }
448:
449: #
450: # LON-CAPA as LTI Consumer
451: #
452: # Remove a lock key from exttools.db for the instance of an external
453: # tool created when generating and storing a service secret.
454: #
455:
456: sub release_tool_lock {
1.3 raeburn 457: my ($cdom,$cnum,$marker,$name) = @_;
1.1 raeburn 458: # remove lock
459: my @del_lock = ($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:
1.6 raeburn 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 {
1.10 raeburn 483: my ($tail,$cdom,$cnum,$getunenc) = @_;
484: my ($scope,$realuri,$passkey,$unencsymb);
485: if ($tail =~ m{^/?uploaded/$cdom/$cnum/(?:default|supplemental)(?:|_\d+)\.(?:sequence|page)(|___\d+___.+)$}) {
1.6 raeburn 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);
1.7 raeburn 493: if ($url =~ /\.sequence$/) {
494: $scope = 'map';
1.6 raeburn 495: } else {
1.7 raeburn 496: $scope = 'resource';
1.6 raeburn 497: $realuri .= '?symb='.$tail;
1.10 raeburn 498: $passkey = $tail;
499: if ($getunenc) {
500: $unencsymb = $tail;
501: }
1.6 raeburn 502: }
503: }
1.10 raeburn 504: } elsif ($tail =~ m{^/?res/$match_domain/$match_username/.+\.(?:sequence|page)(|___\d+___.+)$}) {
1.8 raeburn 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;
1.10 raeburn 517: $passkey = $tail;
518: if ($getunenc) {
519: $unencsymb = $tail;
520: }
1.8 raeburn 521: }
522: }
1.6 raeburn 523: } elsif ($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: }
1.10 raeburn 545: $passkey = $symb;
1.6 raeburn 546: if ((&Apache::lonnet::EXT('resource.0.encrypturl',$symb) =~ /^yes$/i) &&
547: (!$env{'request.role.adv'})) {
548: $realuri = &Apache::lonenc::encrypted(&Apache::lonnet::clutter($url));
1.7 raeburn 549: if ($scope eq 'resource') {
1.6 raeburn 550: $realuri .= '?symb='.&Apache::lonenc::encrypted($symb);
551: }
552: } else {
553: $realuri = &Apache::lonnet::clutter($url);
1.7 raeburn 554: if ($scope eq 'resource') {
1.6 raeburn 555: $realuri .= '?symb='.$symb;
556: }
557: }
1.10 raeburn 558: if ($getunenc) {
559: $unencsymb = $symb;
560: }
1.6 raeburn 561: }
1.10 raeburn 562: } elsif (($tail =~ m{^/$cdom/$cnum$}) || ($tail eq '')) {
1.6 raeburn 563: $scope = 'course';
564: $realuri = '/adm/navmaps';
1.10 raeburn 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 $passkey;
574: }
575: }
576:
1.12 ! raeburn 577: #
! 578: # LON-CAPA as LTI Provider
! 579: #
! 580: # Obtain a list of course personnel and students from
! 581: # the LTI Consumer which launched this instance.
! 582: #
! 583:
1.11 raeburn 584: sub get_roster {
585: my ($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: $p->eof;
636: return %data;
637: }
638: }
639: return;
640: }
641:
1.12 ! raeburn 642: #
! 643: # LON-CAPA as LTI Provider
! 644: #
! 645: # Passback a grade for a user to the LTI Consumer which originally
! 646: # provided the lis_result_sourcedid
! 647: #
! 648:
1.10 raeburn 649: sub send_grade {
650: my ($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.
1.6 raeburn 686: }
687: }
688:
1.12 ! raeburn 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:
1.11 raeburn 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:
1.12 ! raeburn 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:
1.11 raeburn 804: sub create_passwd {
805: my $passwd = '';
1.12 ! raeburn 806: srand( time() ^ ($$ + ($$ << 15)) ); # Seed rand.
1.11 raeburn 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:
1.12 ! raeburn 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:
1.11 raeburn 837: sub enrolluser {
1.12 ! raeburn 838: my ($udom,$uname,$role,$cdom,$cnum,$sec,$start,$end,$selfenroll) = @_;
1.11 raeburn 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,
1.12 ! raeburn 850: 'ltienroll',undef,$cdom.'_'.$cnum,
! 851: $selfenroll,'ltienroll','',$instcid);
1.11 raeburn 852: } elsif ($role =~ /^(cc|in|ta|ep)$/) {
853: $enrollresult =
854: &Apache::lonnet::assignrole($udom,$uname,$area,$role,$end,$start,
1.12 ! raeburn 855: undef,$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: }
1.11 raeburn 866: }
867: return $enrollresult;
868: }
869:
1.12 ! raeburn 870: #
! 871: # LON-CAPA as LTI Provider
! 872: #
! 873: # Batch addition of users following LTI launch by a user
! 874: # with LTI Instructor status.
! 875: #
! 876: # A list of users is obtained by a call to get_roster()
! 877: # if the calling Consumer support the LTI extension:
! 878: # Context Memberships Service.
! 879: #
! 880: # If a user included in the retrieved list does not currently
! 881: # have a user account in LON-CAPA, an account will be created.
! 882: #
! 883: # If a user already has an account, and the same role and
! 884: # section assigned (currently active), then no change will
! 885: # be made for that user.
! 886: #
! 887: # Information available for new users (besides username and)
! 888: # role) may include: first name, last name, full name (from
! 889: # which middle name will be extracted), permanent e-mail address,
! 890: # and lis_result_sourcedid (for passback of grades).
! 891: #
! 892: # If grades are to be passed back, the passback url will be
! 893: # the same as for the current user's session.
! 894: #
! 895: # The roles which may be assigned will be determined from the
! 896: # LTI roles included in the retrieved roster, and the mapping
! 897: # of LTI roles to LON-CAPA roles configured for this LTI Consumer
! 898: # in the domain configuration.
! 899: #
! 900: # Course Coordinator roles will only be assigned if the current
! 901: # user is also the course owner.
! 902: #
! 903: # The domain configuration for the corresponding Consumer can include
! 904: # a section to assign to LTI users. If the roster includes students
! 905: # any existing student roles with a different section will be expired,
! 906: # and a role in the LTI section will be assigned.
! 907: #
! 908: # For non-student rules (excluding Course Coordinator) a role will be
! 909: # assigned with the LTI section )or no section, if one is not rquired.
! 910: #
! 911:
1.11 raeburn 912: sub batchaddroster {
913: my ($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:
1.12 ! raeburn 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: # $maproles - ref to HASH of mapping of LTI roles to LC roles
! 1131: #
! 1132: # Outputs: 2
! 1133: # (a) reference to array of available LC roles.
! 1134: # (b) reference to array of LTI roles.
! 1135: #
! 1136:
1.11 raeburn 1137: sub get_lc_roles {
1138: my ($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,$item);
1169: }
1170: }
1171: }
1172: }
1173: }
1174: return (\@lcroles,\@ltiroles);
1175: }
1176:
1.12 ! raeburn 1177: #
! 1178: # LON-CAPA as LTI Provider
! 1179: #
! 1180: # Compares current start and dates for a user's role
! 1181: # with dates to apply for the same user/role to
! 1182: # determine if there is a change between the current
! 1183: # ones and the updated ones.
! 1184: #
! 1185:
1.11 raeburn 1186: sub datechange_check {
1187: my ($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 $datechange;
1202: }
1203:
1.12 ! raeburn 1204: #
! 1205: # LON-CAPA as LTI Provider
! 1206: #
! 1207: # Store the URL used by a specific LTI Consumer to process grades passed back
! 1208: # by an LTI Provider.
! 1209: #
! 1210:
1.11 raeburn 1211: sub store_passbackurl {
1212: my ($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:
1.1 raeburn 1255: 1;
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