1: # The LearningOnline Network with CAPA
2: #
3: # Page flip handler
4: #
5: # $Id: lonpageflip.pm,v 1.86 2014/12/11 13:16:49 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::lonlocal;
40: use HTML::TokeParser;
41: use GDBM_File;
42:
43: # ========================================================== Module Global Hash
44:
45: my %hash;
46:
47: sub cleanup {
48: if (tied(%hash)){
49: &Apache::lonnet::logthis('Cleanup pageflip: hash');
50: unless (untie(%hash)) {
51: &Apache::lonnet::logthis('Failed cleanup pageflip: hash');
52: }
53: }
54: return OK;
55: }
56:
57: sub addrid {
58: my ($current,$new,$condid)=@_;
59: unless ($condid) { $condid=0; }
60:
61: if ($current) {
62: $current.=','.$new;
63: } else {
64: $current=''.$new;
65: }
66:
67: return $current;
68: }
69:
70: sub fullmove {
71: my ($rid,$mapurl,$direction)=@_;
72: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
73: &GDBM_READER(),0640)) {
74: ($rid,$mapurl)=&move($rid,$mapurl,$direction);
75: untie(%hash);
76: }
77: return($rid,$mapurl);
78: }
79:
80: sub hash_src {
81: my ($id)=@_;
82: my ($mapid,$resid)=split(/\./,$id);
83: my $symb=&Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},
84: $resid,$hash{'src_'.$id});
85: if ($hash{'encrypted_'.$id}) {
86: return (&Apache::lonenc::encrypted($hash{'src_'.$id}),
87: &Apache::lonenc::encrypted($symb));
88: }
89: return ($hash{'src_'.$id},$symb);
90: }
91:
92: sub move {
93: my ($next,$endupmap,$direction) = @_;
94: my $safecount=0;
95: my $allowed=0;
96: do {
97: ($next,$endupmap)=&get_next_possible_move($next,$endupmap,$direction);
98:
99: my $url = $hash{'src_'.$next};
100: my ($mapid,$resid)=split(/\./,$next);
101: my $symb = &Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},
102: $resid,$url);
103: if ($url eq '' || $symb eq '') {
104: $allowed = 0;
105: } else {
106: my $priv = &Apache::lonnet::allowed('bre',$url,$symb);
107: $allowed = (($priv eq 'F') || ($priv eq '2'));
108: }
109: $safecount++;
110: } while ( ($next)
111: && ($next!~/\,/)
112: && (
113: (!$hash{'src_'.$next})
114: || (
115: (!$env{'request.role.adv'})
116: && $hash{'randomout_'.$next}
117: )
118: || (!$allowed)
119: )
120: && ($safecount<10000));
121:
122: return ($next,$endupmap);
123: }
124:
125: sub get_next_possible_move {
126: my ($rid,$mapurl,$direction)=@_;
127: my $startoutrid=$rid;
128:
129: my $next='';
130:
131: my $mincond=1;
132: my $posnext='';
133: if ($direction eq 'forward') {
134: # --------------------------------------------------------------------- Forward
135: while ($hash{'type_'.$rid} eq 'finish') {
136: $rid=$hash{'ids_'.$hash{'map_id_'.(split(/\./,$rid))[0]}};
137: }
138: foreach my $id (split(/\,/,$hash{'to_'.$rid})) {
139: my $condition= $hash{'conditions_'.$hash{'goesto_'.$id}};
140: my $rescond = &Apache::lonnet::docondval($condition);
141: my $linkcond = &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$id}});
142: my $thiscond = ($rescond<$linkcond)?$rescond:$linkcond;
143: if ($thiscond>=$mincond) {
144: if ($posnext) {
145: $posnext.=','.$id.':'.$thiscond;
146: } else {
147: $posnext=$id.':'.$thiscond;
148: }
149: if ($thiscond>$mincond) { $mincond=$thiscond; }
150: }
151: }
152: foreach my $id (split(/\,/,$posnext)) {
153: my ($linkid,$condval)=split(/\:/,$id);
154: if ($condval>=$mincond) {
155: $next=&addrid($next,$hash{'goesto_'.$linkid},
156: $hash{'condid_'.$hash{'undercond_'.$linkid}});
157: }
158: }
159: if ($hash{'is_map_'.$next}) {
160: # This jumps to the beginning of a new map (going down level)
161: if (
162: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
163: $mapurl=$hash{'src_'.$next};
164: $next=$hash{'map_start_'.$hash{'src_'.$next}};
165: } elsif (
166: # This jumps back up from an empty sequence, to a page up one level
167: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'page') {
168: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
169: }
170: } elsif
171: ((split(/\./,$startoutrid))[0]!=(split(/\./,$next))[0]) {
172: # This comes up from a map (coming up one level);
173: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
174: }
175: } elsif ($direction eq 'back') {
176: # ------------------------------------------------------------------- Backwards
177: while ($hash{'type_'.$rid} eq 'start') {
178: $rid=$hash{'ids_'.$hash{'map_id_'.(split(/\./,$rid))[0]}};
179: }
180: foreach my $id (split(/\,/,$hash{'from_'.$rid})) {
181: my $condition= $hash{'conditions_'.$hash{'comesfrom_'.$id}};
182: my $rescond = &Apache::lonnet::docondval($condition);
183: my $linkcond = &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$id}});
184: my $thiscond = ($rescond<$linkcond)?$rescond:$linkcond;
185: if ($thiscond>=$mincond) {
186: if ($posnext) {
187: $posnext.=','.$id.':'.$thiscond;
188: } else {
189: $posnext=$id.':'.$thiscond;
190: }
191: if ($thiscond>$mincond) { $mincond=$thiscond; }
192: }
193: }
194: foreach my $id (split(/\,/,$posnext)) {
195: my ($linkid,$condval)=split(/\:/,$id);
196: if ($condval>=$mincond) {
197: $next=&addrid($next,$hash{'comesfrom_'.$linkid},
198: $hash{'condid_'.$hash{'undercond_'.$linkid}});
199: }
200: }
201: if ($hash{'is_map_'.$next}) {
202: # This jumps to the end of a new map (going down one level)
203: if (
204: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
205: $mapurl=$hash{'src_'.$next};
206: $next=$hash{'map_finish_'.$hash{'src_'.$next}};
207: } elsif (
208: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'page') {
209: # This jumps back up from an empty sequence, to a page up one level
210: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
211: }
212: } elsif
213: ((split(/\./,$startoutrid))[0]!=(split(/\./,$next))[0]) {
214: # This comes back up from a map (going up one level);
215: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
216: }
217: }
218: return ($next,$mapurl);
219: }
220:
221: sub first_accessible_resource {
222: my $furl;
223: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
224: &GDBM_READER(),0640)) {
225: $furl=$hash{'first_url'};
226: my %args;
227: my ($url,$args) = split(/\?/,$furl);
228: foreach my $pair (split(/\&/,$args)) {
229: my ($name,$value) = split(/=/,$pair);
230: $args{&unescape($name)} = &unescape($value);
231: }
232: if (!&Apache::lonnet::allowed('bre',$url,$args{'symb'})) {
233: # Wow, we cannot see this ... move forward to the next one that we can see
234: my ($newrid,$newmap)=&move($hash{'first_rid'},$hash{'first_mapurl'},'forward');
235: # Build the new URL
236: my ($newmapid,$newresid)=split(/\./,$newrid);
237: my $symb=&Apache::lonnet::encode_symb($newmap,$newresid,$hash{'src_'.$newrid});
238: $furl=&add_get_param($hash{'src_'.$newrid},{ 'symb' => $symb });
239: if ($hash{'encrypted_'.$newrid}) {
240: $furl=&Apache::lonenc::encrypted($furl);
241: }
242: }
243: untie(%hash);
244: return $furl;
245: } else {
246: return '/adm/navmaps';
247: }
248: }
249:
250: # ================================================================ Main Handler
251:
252: sub handler {
253: my $r=shift;
254:
255: # ------------------------------------------- Set document type for header only
256:
257: if ($r->header_only) {
258: &Apache::loncommon::content_type($r,'text/html');
259: $r->send_http_header;
260: return OK;
261: }
262:
263: my %cachehash=();
264: my $multichoice=0;
265: my %multichoicehash=();
266: my ($redirecturl,$redirectsymb);
267: my $next='';
268: my @possibilities=();
269: &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},['postdata']);
270: if (($env{'form.postdata'})&&($env{'request.course.fn'})) {
271: $env{'form.postdata'}=~/(\w+)\:(.*)/;
272: my $direction=$1;
273: my $currenturl=$2;
274: if ($currenturl=~m|^/enc/|) {
275: $currenturl=&Apache::lonenc::unencrypted($currenturl);
276: }
277: $currenturl=~s/\.\d+\.(\w+)$/\.$1/;
278: if ($direction eq 'firstres') {
279: my $furl=&first_accessible_resource();
280: &Apache::loncommon::content_type($r,'text/html');
281: $r->header_out(Location =>
282: &Apache::lonnet::absolute_url().$furl);
283:
284: return REDIRECT;
285: }
286: if ($direction eq 'return') {
287: # -------------------------------------------------------- Return to last known
288: my $last;
289: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'_symb.db',
290: &GDBM_READER(),0640)) {
291: $last=$hash{'last_known'};
292: untie(%hash);
293: }
294: my $newloc;
295: if (($last) && (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
296: &GDBM_READER(),0640))) {
297: my ($murl,$id,$fn)=&Apache::lonnet::decode_symb($last);
298: $id=$hash{'map_pc_'.&Apache::lonnet::clutter($murl)}.'.'.$id;
299: $newloc=$hash{'src_'.$id};
300: if ($newloc) {
301: if ($hash{'encrypted_'.$id}) { $newloc=&Apache::lonenc::encrypted($newloc); }
302:
303: } else {
304: $newloc='/adm/navmaps';
305: }
306: untie %hash;
307: } else {
308: $newloc='/adm/navmaps';
309: }
310: &Apache::loncommon::content_type($r,'text/html');
311: $r->header_out(Location =>
312: &Apache::lonnet::absolute_url().$newloc);
313:
314: return REDIRECT;
315: }
316: $currenturl=~s/^https?\:\/\///;
317: $currenturl=~s/^[^\/]+//;
318: #
319: # Is the current URL on the map? If not, start with last known URL
320: #
321: unless (&Apache::lonnet::is_on_map($currenturl)) {
322: my $last;
323: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'_symb.db',
324: &GDBM_READER(),0640)) {
325: $last=$hash{'last_known'};
326: untie(%hash);
327: }
328: if ($last) {
329: $currenturl=&Apache::lonnet::clutter((&Apache::lonnet::decode_symb($last))[2]);
330: } else {
331: &Apache::loncommon::content_type($r,'text/html');
332: $r->header_out(Location =>
333: &Apache::lonnet::absolute_url().
334: '/adm/noidea.html');
335: return REDIRECT;
336: }
337: }
338: # ------------------------------------------- Do we have any idea where we are?
339: my $position;
340: if ($position=Apache::lonnet::symbread($currenturl)) {
341: # ------------------------------------------------------------------------- Yes
342: my ($startoutmap,$mapnum,$thisurl)=&Apache::lonnet::decode_symb($position);
343: $cachehash{$startoutmap}{$thisurl}=[$thisurl,$mapnum];
344: $cachehash{$startoutmap}{'last_known'}=
345: [&Apache::lonnet::declutter($currenturl),$mapnum];
346:
347: # ============================================================ Tie the big hash
348: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
349: &GDBM_READER(),0640)) {
350: my $rid=$hash{'map_pc_'.&Apache::lonnet::clutter($startoutmap)}.
351: '.'.$mapnum;
352:
353: # ------------------------------------------------- Move forward, backward, etc
354: my $endupmap;
355: ($next,$endupmap)=&move($rid,$startoutmap,$direction);
356: # -------------------------------------- Do we have one and only one empty URL?
357: # We are now at at least one non-empty URL
358: # ----------------------------------------------------- Check out possibilities
359: if ($next) {
360: @possibilities=split(/\,/,$next);
361: if ($#possibilities==0) {
362: # ---------------------------------------------- Only one possibility, redirect
363: ($redirecturl,$redirectsymb)=&hash_src($next);
364: $cachehash{$endupmap}{$redirecturl}=
365: [$redirecturl,(split(/\./,$next))[1]];
366: } else {
367: # ------------------------ There are multiple possibilities for a next resource
368: $multichoice=1;
369: foreach my $id (@possibilities) {
370: $multichoicehash{'src_'.$id}=$hash{'src_'.$id};
371: $multichoicehash{'title_'.$id}=$hash{'title_'.$id};
372: $multichoicehash{'type_'.$id}=$hash{'type_'.$id};
373: (my $first, my $second) = $id =~ /(\d+).(\d+)/;
374: my $symbSrc = Apache::lonnet::declutter($hash{'src_'.$id});
375: $multichoicehash{'symb_'.$id} =
376: Apache::lonnet::declutter($hash{'map_id_'.$first}.'___'.
377: $second.'___'.$symbSrc);
378:
379: my ($choicemap,$choiceres)=split(/\./,$id);
380: my $map=&Apache::lonnet::declutter($hash{'src_'.$choicemap});
381: my $url=$multichoicehash{'src_'.$id};
382: $cachehash{$map}{$url}=[$url,$choiceres];
383: }
384: }
385: } else {
386: # -------------------------------------------------------------- No place to go
387: $multichoice=-1;
388: }
389: # ----------------- The program must come past this point to untie the big hash
390: untie(%hash);
391: # --------------------------------------------------------- Store position info
392: $cachehash{$startoutmap}{'last_direction'}=[$direction,'notasymb'];
393: foreach my $thismap (keys(%cachehash)) {
394: my $mapnum=$cachehash{$thismap}->{'mapnum'};
395: delete($cachehash{$thismap}->{'mapnum'});
396: &Apache::lonnet::symblist($thismap,
397: %{$cachehash{$thismap}});
398: }
399: # ============================================== Do not return before this line
400: if ($redirecturl) {
401: # ----------------------------------------------------- There is a URL to go to
402: if ($direction eq 'forward') {
403: &Apache::lonnet::linklog($currenturl,$redirecturl);
404: }
405: if ($direction eq 'back') {
406: &Apache::lonnet::linklog($redirecturl,$currenturl);
407: }
408: # ------------------------------------- Check for and display critical messages
409: my ($redirect, $url) = &Apache::loncommon::critical_redirect(300);
410: unless ($redirect) {
411: $url=&Apache::lonnet::absolute_url().$redirecturl;
412: $url = &add_get_param($url, { 'symb' => $redirectsymb});
413: }
414: &Apache::loncommon::content_type($r,'text/html');
415: $r->header_out(Location => $url);
416: return REDIRECT;
417: } else {
418: # --------------------------------------------------------- There was a problem
419: &Apache::loncommon::content_type($r,'text/html');
420: $r->send_http_header;
421: my %lt=&Apache::lonlocal::texthash('title' => 'End of Sequence',
422: 'explain' =>
423: 'You have reached the end of the sequence of materials.',
424: 'back' => 'Go Back',
425: 'nav' => 'Course Contents',
426: 'wherenext' =>
427: 'There are several possibilities of where to go next',
428: 'pick' =>
429: 'Please click on the the resource you intend to access',
430: 'titleheader' => 'Title',
431: 'type' => 'Type');
432: if (&Apache::loncommon::course_type() eq 'Community') {
433: $lt{'nav'} = &mt('Community Contents');
434: }
435: if ($#possibilities>0) {
436: my $start_page=
437: &Apache::loncommon::start_page('Multiple Resources');
438: $r->print(<<ENDSTART);
439: $start_page
440: <h3>$lt{'wherenext'}</h3>
441: <p>
442: $lt{'pick'}:
443: <p>
444: <table border="2">
445: <tr><th>$lt{'titleheader'}</th><th>$lt{'type'}</th></tr>
446: ENDSTART
447: foreach my $id (@possibilities) {
448: $r->print(
449: '<tr><td><a href="'.
450: &add_get_param($multichoicehash{'src_'.$id},
451: {'symb' =>
452: $multichoicehash{'symb_'.$id},
453: }).'">'.
454: $multichoicehash{'title_'.$id}.
455: '</a></td><td>'.$multichoicehash{'type_'.$id}.
456: '</td></tr>');
457: }
458: $r->print('</table>');
459: } else {
460: $r->print(
461: &Apache::loncommon::start_page('No Resource')
462: .'<h2>'.$lt{'title'}.'</h2>'
463: .'<p>'.$lt{'explain'}.'</p>');
464: }
465: $r->print(
466: &Apache::lonhtmlcommon::actionbox(
467: ['<a href="/adm/flip?postdata=return:">'.$lt{'back'}.'</a></li>',
468: '<a href="/adm/navmaps">'.$lt{'nav'}.'</a></li>'
469: ])
470: .&Apache::loncommon::end_page());
471: return OK;
472: }
473: } else {
474: # ------------------------------------------------- Problem, could not tie hash
475: $env{'user.error.msg'}="/adm/flip:bre:0:1:Course Data Missing";
476: return HTTP_NOT_ACCEPTABLE;
477: }
478: } else {
479: # ---------------------------------------- No, could not determine where we are
480: $r->internal_redirect('/adm/ambiguous');
481: return OK;
482: }
483: } else {
484: # -------------------------- Class was not initialized or page fliped strangely
485: $env{'user.error.msg'}="/adm/flip:bre:0:0:Choose Course";
486: return HTTP_NOT_ACCEPTABLE;
487: }
488: }
489:
490: 1;
491: __END__
492:
493: =pod
494:
495: =head1 NAME
496:
497: Apache::lonpageflip
498:
499: =head1 SYNOPSIS
500:
501: Deals with forward, backward, and other page flips.
502:
503: This is part of the LearningOnline Network with CAPA project
504: described at http://www.lon-capa.org.
505:
506: =head1 OVERVIEW
507:
508: (empty)
509:
510: =head1 SUBROUTINES
511:
512: =over cleanup()
513:
514: =item addrid()
515:
516: =item fullmove()
517:
518: =item hash_src()
519:
520: =item move()
521:
522: =item get_next_possible_move()
523:
524: =item first_accessible_resource()
525:
526: =item handler()
527:
528: =back
529:
530: =cut
531:
532:
533:
534:
535:
536:
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