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[LON-CAPA] /
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lonpageflip.pm
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Sat Mar 14 21:56:13 2015 UTC (9 years, 1 month ago) by
raeburn
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- When LON-CAPA navigation arrows are used to move between resources check
if > 10 minutes since last check for content change.
If course changed after "Big Hash" last tied for current user's session,
course is re-initialized or Switch Server link is displayed, as needed.
1: # The LearningOnline Network with CAPA
2: #
3: # Page flip handler
4: #
5: # $Id: lonpageflip.pm,v 1.87 2015/03/14 21:56:13 raeburn Exp $
6: #
7: # Copyright Michigan State University Board of Trustees
8: #
9: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
10: #
11: # LON-CAPA is free software; you can redistribute it and/or modify
12: # it under the terms of the GNU General Public License as published by
13: # the Free Software Foundation; either version 2 of the License, or
14: # (at your option) any later version.
15: #
16: # LON-CAPA is distributed in the hope that it will be useful,
17: # but WITHOUT ANY WARRANTY; without even the implied warranty of
18: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19: # GNU General Public License for more details.
20: #
21: # You should have received a copy of the GNU General Public License
22: # along with LON-CAPA; if not, write to the Free Software
23: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24: #
25: # /home/httpd/html/adm/gpl.txt
26: #
27: # http://www.lon-capa.org/
28: #
29:
30:
31:
32: package Apache::lonpageflip;
33:
34: use strict;
35: use LONCAPA;
36: use Apache::Constants qw(:common :http REDIRECT);
37: use Apache::lonnet;
38: use Apache::loncommon();
39: use Apache::lonuserstate;
40: use Apache::lonlocal;
41: use HTML::TokeParser;
42: use GDBM_File;
43:
44: # ========================================================== Module Global Hash
45:
46: my %hash;
47:
48: sub cleanup {
49: if (tied(%hash)){
50: &Apache::lonnet::logthis('Cleanup pageflip: hash');
51: unless (untie(%hash)) {
52: &Apache::lonnet::logthis('Failed cleanup pageflip: hash');
53: }
54: }
55: return OK;
56: }
57:
58: sub addrid {
59: my ($current,$new,$condid)=@_;
60: unless ($condid) { $condid=0; }
61:
62: if ($current) {
63: $current.=','.$new;
64: } else {
65: $current=''.$new;
66: }
67:
68: return $current;
69: }
70:
71: sub fullmove {
72: my ($rid,$mapurl,$direction)=@_;
73: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
74: &GDBM_READER(),0640)) {
75: ($rid,$mapurl)=&move($rid,$mapurl,$direction);
76: untie(%hash);
77: }
78: return($rid,$mapurl);
79: }
80:
81: sub hash_src {
82: my ($id)=@_;
83: my ($mapid,$resid)=split(/\./,$id);
84: my $symb=&Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},
85: $resid,$hash{'src_'.$id});
86: if ($hash{'encrypted_'.$id}) {
87: return (&Apache::lonenc::encrypted($hash{'src_'.$id}),
88: &Apache::lonenc::encrypted($symb));
89: }
90: return ($hash{'src_'.$id},$symb);
91: }
92:
93: sub move {
94: my ($next,$endupmap,$direction) = @_;
95: my $safecount=0;
96: my $allowed=0;
97: do {
98: ($next,$endupmap)=&get_next_possible_move($next,$endupmap,$direction);
99:
100: my $url = $hash{'src_'.$next};
101: my ($mapid,$resid)=split(/\./,$next);
102: my $symb = &Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},
103: $resid,$url);
104: if ($url eq '' || $symb eq '') {
105: $allowed = 0;
106: } else {
107: my $priv = &Apache::lonnet::allowed('bre',$url,$symb);
108: $allowed = (($priv eq 'F') || ($priv eq '2'));
109: }
110: $safecount++;
111: } while ( ($next)
112: && ($next!~/\,/)
113: && (
114: (!$hash{'src_'.$next})
115: || (
116: (!$env{'request.role.adv'})
117: && $hash{'randomout_'.$next}
118: )
119: || (!$allowed)
120: )
121: && ($safecount<10000));
122:
123: return ($next,$endupmap);
124: }
125:
126: sub get_next_possible_move {
127: my ($rid,$mapurl,$direction)=@_;
128: my $startoutrid=$rid;
129:
130: my $next='';
131:
132: my $mincond=1;
133: my $posnext='';
134: if ($direction eq 'forward') {
135: # --------------------------------------------------------------------- Forward
136: while ($hash{'type_'.$rid} eq 'finish') {
137: $rid=$hash{'ids_'.$hash{'map_id_'.(split(/\./,$rid))[0]}};
138: }
139: foreach my $id (split(/\,/,$hash{'to_'.$rid})) {
140: my $condition= $hash{'conditions_'.$hash{'goesto_'.$id}};
141: my $rescond = &Apache::lonnet::docondval($condition);
142: my $linkcond = &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$id}});
143: my $thiscond = ($rescond<$linkcond)?$rescond:$linkcond;
144: if ($thiscond>=$mincond) {
145: if ($posnext) {
146: $posnext.=','.$id.':'.$thiscond;
147: } else {
148: $posnext=$id.':'.$thiscond;
149: }
150: if ($thiscond>$mincond) { $mincond=$thiscond; }
151: }
152: }
153: foreach my $id (split(/\,/,$posnext)) {
154: my ($linkid,$condval)=split(/\:/,$id);
155: if ($condval>=$mincond) {
156: $next=&addrid($next,$hash{'goesto_'.$linkid},
157: $hash{'condid_'.$hash{'undercond_'.$linkid}});
158: }
159: }
160: if ($hash{'is_map_'.$next}) {
161: # This jumps to the beginning of a new map (going down level)
162: if (
163: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
164: $mapurl=$hash{'src_'.$next};
165: $next=$hash{'map_start_'.$hash{'src_'.$next}};
166: } elsif (
167: # This jumps back up from an empty sequence, to a page up one level
168: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'page') {
169: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
170: }
171: } elsif
172: ((split(/\./,$startoutrid))[0]!=(split(/\./,$next))[0]) {
173: # This comes up from a map (coming up one level);
174: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
175: }
176: } elsif ($direction eq 'back') {
177: # ------------------------------------------------------------------- Backwards
178: while ($hash{'type_'.$rid} eq 'start') {
179: $rid=$hash{'ids_'.$hash{'map_id_'.(split(/\./,$rid))[0]}};
180: }
181: foreach my $id (split(/\,/,$hash{'from_'.$rid})) {
182: my $condition= $hash{'conditions_'.$hash{'comesfrom_'.$id}};
183: my $rescond = &Apache::lonnet::docondval($condition);
184: my $linkcond = &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$id}});
185: my $thiscond = ($rescond<$linkcond)?$rescond:$linkcond;
186: if ($thiscond>=$mincond) {
187: if ($posnext) {
188: $posnext.=','.$id.':'.$thiscond;
189: } else {
190: $posnext=$id.':'.$thiscond;
191: }
192: if ($thiscond>$mincond) { $mincond=$thiscond; }
193: }
194: }
195: foreach my $id (split(/\,/,$posnext)) {
196: my ($linkid,$condval)=split(/\:/,$id);
197: if ($condval>=$mincond) {
198: $next=&addrid($next,$hash{'comesfrom_'.$linkid},
199: $hash{'condid_'.$hash{'undercond_'.$linkid}});
200: }
201: }
202: if ($hash{'is_map_'.$next}) {
203: # This jumps to the end of a new map (going down one level)
204: if (
205: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
206: $mapurl=$hash{'src_'.$next};
207: $next=$hash{'map_finish_'.$hash{'src_'.$next}};
208: } elsif (
209: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'page') {
210: # This jumps back up from an empty sequence, to a page up one level
211: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
212: }
213: } elsif
214: ((split(/\./,$startoutrid))[0]!=(split(/\./,$next))[0]) {
215: # This comes back up from a map (going up one level);
216: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
217: }
218: }
219: return ($next,$mapurl);
220: }
221:
222: sub first_accessible_resource {
223: my $furl;
224: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
225: &GDBM_READER(),0640)) {
226: $furl=$hash{'first_url'};
227: my %args;
228: my ($url,$args) = split(/\?/,$furl);
229: foreach my $pair (split(/\&/,$args)) {
230: my ($name,$value) = split(/=/,$pair);
231: $args{&unescape($name)} = &unescape($value);
232: }
233: if (!&Apache::lonnet::allowed('bre',$url,$args{'symb'})) {
234: # Wow, we cannot see this ... move forward to the next one that we can see
235: my ($newrid,$newmap)=&move($hash{'first_rid'},$hash{'first_mapurl'},'forward');
236: # Build the new URL
237: my ($newmapid,$newresid)=split(/\./,$newrid);
238: my $symb=&Apache::lonnet::encode_symb($newmap,$newresid,$hash{'src_'.$newrid});
239: $furl=&add_get_param($hash{'src_'.$newrid},{ 'symb' => $symb });
240: if ($hash{'encrypted_'.$newrid}) {
241: $furl=&Apache::lonenc::encrypted($furl);
242: }
243: }
244: untie(%hash);
245: return $furl;
246: } else {
247: return '/adm/navmaps';
248: }
249: }
250:
251: # ================================================================ Main Handler
252:
253: sub handler {
254: my $r=shift;
255:
256: # ------------------------------------------- Set document type for header only
257:
258: if ($r->header_only) {
259: &Apache::loncommon::content_type($r,'text/html');
260: $r->send_http_header;
261: return OK;
262: }
263:
264: my %cachehash=();
265: my $multichoice=0;
266: my %multichoicehash=();
267: my ($redirecturl,$redirectsymb);
268: my $next='';
269: my @possibilities=();
270: &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},['postdata']);
271: if (($env{'form.postdata'})&&($env{'request.course.fn'})) {
272: $env{'form.postdata'}=~/(\w+)\:(.*)/;
273:
274: if ($env{'request.course.id'}) {
275: # Check if course needs to be re-initialized
276: my $loncaparev = $r->dir_config('lonVersion');
277: my ($result,@reinit) = &Apache::loncommon::needs_coursereinit($loncaparev);
278: if ($result eq 'switch') {
279: &Apache::loncommon::content_type($r,'text/html');
280: $r->send_http_header;
281: $r->print(&Apache::loncommon::check_release_result(@reinit));
282: return OK;
283: } elsif ($result eq 'update') {
284: my $cnum = $env{'course.'.$env{'request.course.id'}.'.num'};
285: my $cdom = $env{'course.'.$env{'request.course.id'}.'.domain'};
286: my ($furl,$ferr) = &Apache::lonuserstate::readmap("$cdom/$cnum");
287: if ($ferr) {
288: my $requrl = $r->uri;
289: $env{'user.error.msg'}="$requrl:bre:0:0:Course not initialized";
290: $env{'user.reinit'} = 1;
291: return HTTP_NOT_ACCEPTABLE;
292: }
293: }
294: }
295:
296: my $direction=$1;
297: my $currenturl=$2;
298: if ($currenturl=~m|^/enc/|) {
299: $currenturl=&Apache::lonenc::unencrypted($currenturl);
300: }
301: $currenturl=~s/\.\d+\.(\w+)$/\.$1/;
302: if ($direction eq 'firstres') {
303: my $furl=&first_accessible_resource();
304: &Apache::loncommon::content_type($r,'text/html');
305: $r->header_out(Location =>
306: &Apache::lonnet::absolute_url().$furl);
307:
308: return REDIRECT;
309: }
310: if ($direction eq 'return') {
311: # -------------------------------------------------------- Return to last known
312: my $last;
313: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'_symb.db',
314: &GDBM_READER(),0640)) {
315: $last=$hash{'last_known'};
316: untie(%hash);
317: }
318: my $newloc;
319: if (($last) && (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
320: &GDBM_READER(),0640))) {
321: my ($murl,$id,$fn)=&Apache::lonnet::decode_symb($last);
322: $id=$hash{'map_pc_'.&Apache::lonnet::clutter($murl)}.'.'.$id;
323: $newloc=$hash{'src_'.$id};
324: if ($newloc) {
325: if ($hash{'encrypted_'.$id}) { $newloc=&Apache::lonenc::encrypted($newloc); }
326:
327: } else {
328: $newloc='/adm/navmaps';
329: }
330: untie %hash;
331: } else {
332: $newloc='/adm/navmaps';
333: }
334: &Apache::loncommon::content_type($r,'text/html');
335: $r->header_out(Location =>
336: &Apache::lonnet::absolute_url().$newloc);
337:
338: return REDIRECT;
339: }
340: $currenturl=~s/^https?\:\/\///;
341: $currenturl=~s/^[^\/]+//;
342: #
343: # Is the current URL on the map? If not, start with last known URL
344: #
345: unless (&Apache::lonnet::is_on_map($currenturl)) {
346: my $last;
347: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'_symb.db',
348: &GDBM_READER(),0640)) {
349: $last=$hash{'last_known'};
350: untie(%hash);
351: }
352: if ($last) {
353: $currenturl=&Apache::lonnet::clutter((&Apache::lonnet::decode_symb($last))[2]);
354: } else {
355: &Apache::loncommon::content_type($r,'text/html');
356: $r->header_out(Location =>
357: &Apache::lonnet::absolute_url().
358: '/adm/noidea.html');
359: return REDIRECT;
360: }
361: }
362: # ------------------------------------------- Do we have any idea where we are?
363: my $position;
364: if ($position=Apache::lonnet::symbread($currenturl)) {
365: # ------------------------------------------------------------------------- Yes
366: my ($startoutmap,$mapnum,$thisurl)=&Apache::lonnet::decode_symb($position);
367: $cachehash{$startoutmap}{$thisurl}=[$thisurl,$mapnum];
368: $cachehash{$startoutmap}{'last_known'}=
369: [&Apache::lonnet::declutter($currenturl),$mapnum];
370:
371: # ============================================================ Tie the big hash
372: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
373: &GDBM_READER(),0640)) {
374: my $rid=$hash{'map_pc_'.&Apache::lonnet::clutter($startoutmap)}.
375: '.'.$mapnum;
376:
377: # ------------------------------------------------- Move forward, backward, etc
378: my $endupmap;
379: ($next,$endupmap)=&move($rid,$startoutmap,$direction);
380: # -------------------------------------- Do we have one and only one empty URL?
381: # We are now at at least one non-empty URL
382: # ----------------------------------------------------- Check out possibilities
383: if ($next) {
384: @possibilities=split(/\,/,$next);
385: if ($#possibilities==0) {
386: # ---------------------------------------------- Only one possibility, redirect
387: ($redirecturl,$redirectsymb)=&hash_src($next);
388: $cachehash{$endupmap}{$redirecturl}=
389: [$redirecturl,(split(/\./,$next))[1]];
390: } else {
391: # ------------------------ There are multiple possibilities for a next resource
392: $multichoice=1;
393: foreach my $id (@possibilities) {
394: $multichoicehash{'src_'.$id}=$hash{'src_'.$id};
395: $multichoicehash{'title_'.$id}=$hash{'title_'.$id};
396: $multichoicehash{'type_'.$id}=$hash{'type_'.$id};
397: (my $first, my $second) = $id =~ /(\d+).(\d+)/;
398: my $symbSrc = Apache::lonnet::declutter($hash{'src_'.$id});
399: $multichoicehash{'symb_'.$id} =
400: Apache::lonnet::declutter($hash{'map_id_'.$first}.'___'.
401: $second.'___'.$symbSrc);
402:
403: my ($choicemap,$choiceres)=split(/\./,$id);
404: my $map=&Apache::lonnet::declutter($hash{'src_'.$choicemap});
405: my $url=$multichoicehash{'src_'.$id};
406: $cachehash{$map}{$url}=[$url,$choiceres];
407: }
408: }
409: } else {
410: # -------------------------------------------------------------- No place to go
411: $multichoice=-1;
412: }
413: # ----------------- The program must come past this point to untie the big hash
414: untie(%hash);
415: # --------------------------------------------------------- Store position info
416: $cachehash{$startoutmap}{'last_direction'}=[$direction,'notasymb'];
417: foreach my $thismap (keys(%cachehash)) {
418: my $mapnum=$cachehash{$thismap}->{'mapnum'};
419: delete($cachehash{$thismap}->{'mapnum'});
420: &Apache::lonnet::symblist($thismap,
421: %{$cachehash{$thismap}});
422: }
423: # ============================================== Do not return before this line
424: if ($redirecturl) {
425: # ----------------------------------------------------- There is a URL to go to
426: if ($direction eq 'forward') {
427: &Apache::lonnet::linklog($currenturl,$redirecturl);
428: }
429: if ($direction eq 'back') {
430: &Apache::lonnet::linklog($redirecturl,$currenturl);
431: }
432: # ------------------------------------- Check for and display critical messages
433: my ($redirect, $url) = &Apache::loncommon::critical_redirect(300);
434: unless ($redirect) {
435: $url=&Apache::lonnet::absolute_url().$redirecturl;
436: $url = &add_get_param($url, { 'symb' => $redirectsymb});
437: }
438: &Apache::loncommon::content_type($r,'text/html');
439: $r->header_out(Location => $url);
440: return REDIRECT;
441: } else {
442: # --------------------------------------------------------- There was a problem
443: &Apache::loncommon::content_type($r,'text/html');
444: $r->send_http_header;
445: my %lt=&Apache::lonlocal::texthash('title' => 'End of Sequence',
446: 'explain' =>
447: 'You have reached the end of the sequence of materials.',
448: 'back' => 'Go Back',
449: 'nav' => 'Course Contents',
450: 'wherenext' =>
451: 'There are several possibilities of where to go next',
452: 'pick' =>
453: 'Please click on the the resource you intend to access',
454: 'titleheader' => 'Title',
455: 'type' => 'Type');
456: if (&Apache::loncommon::course_type() eq 'Community') {
457: $lt{'nav'} = &mt('Community Contents');
458: }
459: if ($#possibilities>0) {
460: my $start_page=
461: &Apache::loncommon::start_page('Multiple Resources');
462: $r->print(<<ENDSTART);
463: $start_page
464: <h3>$lt{'wherenext'}</h3>
465: <p>
466: $lt{'pick'}:
467: <p>
468: <table border="2">
469: <tr><th>$lt{'titleheader'}</th><th>$lt{'type'}</th></tr>
470: ENDSTART
471: foreach my $id (@possibilities) {
472: $r->print(
473: '<tr><td><a href="'.
474: &add_get_param($multichoicehash{'src_'.$id},
475: {'symb' =>
476: $multichoicehash{'symb_'.$id},
477: }).'">'.
478: $multichoicehash{'title_'.$id}.
479: '</a></td><td>'.$multichoicehash{'type_'.$id}.
480: '</td></tr>');
481: }
482: $r->print('</table>');
483: } else {
484: $r->print(
485: &Apache::loncommon::start_page('No Resource')
486: .'<h2>'.$lt{'title'}.'</h2>'
487: .'<p>'.$lt{'explain'}.'</p>');
488: }
489: $r->print(
490: &Apache::lonhtmlcommon::actionbox(
491: ['<a href="/adm/flip?postdata=return:">'.$lt{'back'}.'</a></li>',
492: '<a href="/adm/navmaps">'.$lt{'nav'}.'</a></li>'
493: ])
494: .&Apache::loncommon::end_page());
495: return OK;
496: }
497: } else {
498: # ------------------------------------------------- Problem, could not tie hash
499: $env{'user.error.msg'}="/adm/flip:bre:0:1:Course Data Missing";
500: return HTTP_NOT_ACCEPTABLE;
501: }
502: } else {
503: # ---------------------------------------- No, could not determine where we are
504: $r->internal_redirect('/adm/ambiguous');
505: return OK;
506: }
507: } else {
508: # -------------------------- Class was not initialized or page fliped strangely
509: $env{'user.error.msg'}="/adm/flip:bre:0:0:Choose Course";
510: return HTTP_NOT_ACCEPTABLE;
511: }
512: }
513:
514: 1;
515: __END__
516:
517: =pod
518:
519: =head1 NAME
520:
521: Apache::lonpageflip
522:
523: =head1 SYNOPSIS
524:
525: Deals with forward, backward, and other page flips.
526:
527: This is part of the LearningOnline Network with CAPA project
528: described at http://www.lon-capa.org.
529:
530: =head1 OVERVIEW
531:
532: (empty)
533:
534: =head1 SUBROUTINES
535:
536: =over cleanup()
537:
538: =item addrid()
539:
540: =item fullmove()
541:
542: =item hash_src()
543:
544: =item move()
545:
546: =item get_next_possible_move()
547:
548: =item first_accessible_resource()
549:
550: =item handler()
551:
552: =back
553:
554: =cut
555:
556:
557:
558:
559:
560:
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