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lonpageflip.pm
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Thu Apr 23 17:31:25 2009 UTC (15 years, 1 month ago) by
bisitz
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version_2_9_1,
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1: # The LearningOnline Network with CAPA
2: #
3: # Page flip handler
4: #
5: # $Id: lonpageflip.pm,v 1.79 2009/04/23 17:31:25 bisitz 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 HTML::TokeParser;
40: use GDBM_File;
41:
42: # ========================================================== Module Global Hash
43:
44: my %hash;
45:
46: sub cleanup {
47: if (tied(%hash)){
48: &Apache::lonnet::logthis('Cleanup pageflip: hash');
49: unless (untie(%hash)) {
50: &Apache::lonnet::logthis('Failed cleanup pageflip: hash');
51: }
52: }
53: return OK;
54: }
55:
56: sub addrid {
57: my ($current,$new,$condid)=@_;
58: unless ($condid) { $condid=0; }
59:
60: if ($current) {
61: $current.=','.$new;
62: } else {
63: $current=''.$new;
64: }
65:
66: return $current;
67: }
68:
69: sub fullmove {
70: my ($rid,$mapurl,$direction)=@_;
71: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
72: &GDBM_READER(),0640)) {
73: ($rid,$mapurl)=&move($rid,$mapurl,$direction);
74: untie(%hash);
75: }
76: return($rid,$mapurl);
77: }
78:
79: sub hash_src {
80: my ($id)=@_;
81: my ($mapid,$resid)=split(/\./,$id);
82: my $symb=&Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},
83: $resid,$hash{'src_'.$id});
84: if ($hash{'encrypted_'.$id}) {
85: return (&Apache::lonenc::encrypted($hash{'src_'.$id}),
86: &Apache::lonenc::encrypted($symb));
87: }
88: return ($hash{'src_'.$id},$symb);
89: }
90:
91: sub move {
92: my ($next,$endupmap,$direction) = @_;
93: my $safecount=0;
94: my $allowed=0;
95: do {
96: ($next,$endupmap)=&get_next_possible_move($next,$endupmap,$direction);
97:
98: my $url = $hash{'src_'.$next};
99: my ($mapid,$resid)=split(/\./,$next);
100: my $symb = &Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},
101: $resid,$url);
102: if ($url eq '' || $symb eq '') {
103: $allowed = 0;
104: } else {
105: my $priv = &Apache::lonnet::allowed('bre',$url,$symb);
106: $allowed = (($priv eq 'F') || ($priv eq '2'));
107: }
108: $safecount++;
109: } while ( ($next)
110: && ($next!~/\,/)
111: && (
112: (!$hash{'src_'.$next})
113: || (
114: (!$env{'request.role.adv'})
115: && $hash{'randomout_'.$next}
116: )
117: || (!$allowed)
118: )
119: && ($safecount<10000));
120:
121: return ($next,$endupmap);
122: }
123:
124: sub get_next_possible_move {
125: my ($rid,$mapurl,$direction)=@_;
126: my $startoutrid=$rid;
127:
128: my $next='';
129:
130: my $mincond=1;
131: my $posnext='';
132: if ($direction eq 'forward') {
133: # --------------------------------------------------------------------- Forward
134: while ($hash{'type_'.$rid} eq 'finish') {
135: $rid=$hash{'ids_'.$hash{'map_id_'.(split(/\./,$rid))[0]}};
136: }
137: foreach my $id (split(/\,/,$hash{'to_'.$rid})) {
138: my $condition= $hash{'conditions_'.$hash{'goesto_'.$id}};
139: my $rescond = &Apache::lonnet::docondval($condition);
140: my $linkcond = &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$id}});
141: my $thiscond = ($rescond<$linkcond)?$rescond:$linkcond;
142: if ($thiscond>=$mincond) {
143: if ($posnext) {
144: $posnext.=','.$id.':'.$thiscond;
145: } else {
146: $posnext=$id.':'.$thiscond;
147: }
148: if ($thiscond>$mincond) { $mincond=$thiscond; }
149: }
150: }
151: foreach my $id (split(/\,/,$posnext)) {
152: my ($linkid,$condval)=split(/\:/,$id);
153: if ($condval>=$mincond) {
154: $next=&addrid($next,$hash{'goesto_'.$linkid},
155: $hash{'condid_'.$hash{'undercond_'.$linkid}});
156: }
157: }
158: if ($hash{'is_map_'.$next}) {
159: # This jumps to the beginning of a new map (going down level)
160: if (
161: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
162: $mapurl=$hash{'src_'.$next};
163: $next=$hash{'map_start_'.$hash{'src_'.$next}};
164: } elsif (
165: # This jumps back up from an empty sequence, to a page up one level
166: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'page') {
167: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
168: }
169: } elsif
170: ((split(/\./,$startoutrid))[0]!=(split(/\./,$next))[0]) {
171: # This comes up from a map (coming up one level);
172: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
173: }
174: } elsif ($direction eq 'back') {
175: # ------------------------------------------------------------------- Backwards
176: while ($hash{'type_'.$rid} eq 'start') {
177: $rid=$hash{'ids_'.$hash{'map_id_'.(split(/\./,$rid))[0]}};
178: }
179: foreach my $id (split(/\,/,$hash{'from_'.$rid})) {
180: my $condition= $hash{'conditions_'.$hash{'comesfrom_'.$id}};
181: my $rescond = &Apache::lonnet::docondval($condition);
182: my $linkcond = &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$id}});
183: my $thiscond = ($rescond<$linkcond)?$rescond:$linkcond;
184: if ($thiscond>=$mincond) {
185: if ($posnext) {
186: $posnext.=','.$id.':'.$thiscond;
187: } else {
188: $posnext=$id.':'.$thiscond;
189: }
190: if ($thiscond>$mincond) { $mincond=$thiscond; }
191: }
192: }
193: foreach my $id (split(/\,/,$posnext)) {
194: my ($linkid,$condval)=split(/\:/,$id);
195: if ($condval>=$mincond) {
196: $next=&addrid($next,$hash{'comesfrom_'.$linkid},
197: $hash{'condid_'.$hash{'undercond_'.$linkid}});
198: }
199: }
200: if ($hash{'is_map_'.$next}) {
201: # This jumps to the end of a new map (going down one level)
202: if (
203: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
204: $mapurl=$hash{'src_'.$next};
205: $next=$hash{'map_finish_'.$hash{'src_'.$next}};
206: } elsif (
207: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'page') {
208: # This jumps back up from an empty sequence, to a page up one level
209: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
210: }
211: } elsif
212: ((split(/\./,$startoutrid))[0]!=(split(/\./,$next))[0]) {
213: # This comes back up from a map (going up one level);
214: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
215: }
216: }
217: return ($next,$mapurl);
218: }
219:
220: sub navlaunch {
221: my ($r)=@_;
222: &Apache::loncommon::content_type($r,'text/html');
223: &Apache::loncommon::no_cache($r);
224: $r->send_http_header;
225: $r->print(&Apache::loncommon::start_page('Launched'));
226: $r->print(<<ENDNAV);
227: <p><a href="/adm/flip?postdata=firstres%3a">Goto first resource</a></p>
228: <script type="text/javascript">
229: function collapse() {
230: menu=window.open("/adm/navmaps?collapseExternal","loncapanav",
231: "height=600,width=400,scrollbars=1");
232: this.document.location='/adm/navmaps?turningOffExternal';
233: }
234: </script>
235: <p><a href="javascript:collapse();">Collapse external navigation window</a></p>
236: ENDNAV
237: $r->print(&Apache::loncommon::end_page());
238: }
239:
240: sub first_accessible_resource {
241: my $furl;
242: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
243: &GDBM_READER(),0640)) {
244: $furl=$hash{'first_url'};
245: my %args;
246: my ($url,$args) = split(/\?/,$furl);
247: foreach my $pair (split(/\&/,$args)) {
248: my ($name,$value) = split(/=/,$pair);
249: $args{&unescape($name)} = &unescape($value);
250: }
251: if (!&Apache::lonnet::allowed('bre',$url,$args{'symb'})) {
252: # Wow, we cannot see this ... move forward to the next one that we can see
253: my ($newrid,$newmap)=&move($hash{'first_rid'},$hash{'first_mapurl'},'forward');
254: # Build the new URL
255: my ($newmapid,$newresid)=split(/\./,$newrid);
256: my $symb=&Apache::lonnet::encode_symb($newmap,$newresid,$hash{'src_'.$newrid});
257: $furl=&add_get_param($hash{'src_'.$newrid},{ 'symb' => $symb });
258: if ($hash{'encrypted_'.$newrid}) {
259: $furl=&Apache::lonenc::encrypted($furl);
260: }
261: }
262: untie(%hash);
263: return $furl;
264: } else {
265: return '/adm/navmaps';
266: }
267: }
268:
269: # ================================================================ Main Handler
270:
271: sub handler {
272: my $r=shift;
273:
274: # ------------------------------------------- Set document type for header only
275:
276: if ($r->header_only) {
277: &Apache::loncommon::content_type($r,'text/html');
278: $r->send_http_header;
279: return OK;
280: }
281:
282: my %cachehash=();
283: my $multichoice=0;
284: my %multichoicehash=();
285: my ($redirecturl,$redirectsymb);
286: my $next='';
287: my @possibilities=();
288: &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},['postdata']);
289: if (($env{'form.postdata'})&&($env{'request.course.fn'})) {
290: $env{'form.postdata'}=~/(\w+)\:(.*)/;
291: my $direction=$1;
292: my $currenturl=$2;
293: if ($currenturl=~m|^/enc/|) {
294: $currenturl=&Apache::lonenc::unencrypted($currenturl);
295: }
296: $currenturl=~s/\.\d+\.(\w+)$/\.$1/;
297: if ($direction eq 'firstres') {
298: my $furl=&first_accessible_resource();
299: &Apache::loncommon::content_type($r,'text/html');
300: $r->header_out(Location =>
301: &Apache::lonnet::absolute_url().$furl);
302:
303: return REDIRECT;
304: }
305: if ($direction eq 'return' || $direction eq 'navlaunch') {
306: # -------------------------------------------------------- Return to last known
307: my $last;
308: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'_symb.db',
309: &GDBM_READER(),0640)) {
310: $last=$hash{'last_known'};
311: untie(%hash);
312: }
313: my $newloc;
314: if (($last) && (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
315: &GDBM_READER(),0640))) {
316: my ($murl,$id,$fn)=&Apache::lonnet::decode_symb($last);
317: $id=$hash{'map_pc_'.&Apache::lonnet::clutter($murl)}.'.'.$id;
318: $newloc=$hash{'src_'.$id};
319: if ($newloc) {
320: if ($hash{'encrypted_'.$id}) { $newloc=&Apache::lonenc::encrypted($newloc); }
321:
322: } else {
323: $newloc='/adm/navmaps';
324: }
325: untie %hash;
326: } else {
327: $newloc='/adm/navmaps';
328: }
329: if ($newloc eq '/adm/navmaps' && $direction eq 'navlaunch') {
330: &navlaunch($r);
331: return OK;
332: } else {
333: &Apache::loncommon::content_type($r,'text/html');
334: $r->header_out(Location =>
335: &Apache::lonnet::absolute_url().$newloc);
336:
337: return REDIRECT;
338: }
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: if ($direction eq 'return') {
356: &Apache::loncommon::content_type($r,'text/html');
357: $r->header_out(Location =>
358: &Apache::lonnet::absolute_url().
359: '/adm/noidea.html');
360: return REDIRECT;
361: } else {
362: &navlaunch($r);
363: return OK;
364: }
365: }
366: }
367: # ------------------------------------------- Do we have any idea where we are?
368: my $position;
369: if ($position=Apache::lonnet::symbread($currenturl)) {
370: # ------------------------------------------------------------------------- Yes
371: my ($startoutmap,$mapnum,$thisurl)=&Apache::lonnet::decode_symb($position);
372: $cachehash{$startoutmap}{$thisurl}=[$thisurl,$mapnum];
373: $cachehash{$startoutmap}{'last_known'}=
374: [&Apache::lonnet::declutter($currenturl),$mapnum];
375:
376: # ============================================================ Tie the big hash
377: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
378: &GDBM_READER(),0640)) {
379: my $rid=$hash{'map_pc_'.&Apache::lonnet::clutter($startoutmap)}.
380: '.'.$mapnum;
381:
382: # ------------------------------------------------- Move forward, backward, etc
383: my $endupmap;
384: ($next,$endupmap)=&move($rid,$startoutmap,$direction);
385: # -------------------------------------- Do we have one and only one empty URL?
386: # We are now at at least one non-empty URL
387: # ----------------------------------------------------- Check out possibilities
388: if ($next) {
389: @possibilities=split(/\,/,$next);
390: if ($#possibilities==0) {
391: # ---------------------------------------------- Only one possibility, redirect
392: ($redirecturl,$redirectsymb)=&hash_src($next);
393: $cachehash{$endupmap}{$redirecturl}=
394: [$redirecturl,(split(/\./,$next))[1]];
395: } else {
396: # ------------------------ There are multiple possibilities for a next resource
397: $multichoice=1;
398: foreach my $id (@possibilities) {
399: $multichoicehash{'src_'.$id}=$hash{'src_'.$id};
400: $multichoicehash{'title_'.$id}=$hash{'title_'.$id};
401: $multichoicehash{'type_'.$id}=$hash{'type_'.$id};
402: (my $first, my $second) = $id =~ /(\d+).(\d+)/;
403: my $symbSrc = Apache::lonnet::declutter($hash{'src_'.$id});
404: $multichoicehash{'symb_'.$id} =
405: Apache::lonnet::declutter($hash{'map_id_'.$first}.'___'.
406: $second.'___'.$symbSrc);
407:
408: my ($choicemap,$choiceres)=split(/\./,$id);
409: my $map=&Apache::lonnet::declutter($hash{'src_'.$choicemap});
410: my $url=$multichoicehash{'src_'.$id};
411: $cachehash{$map}{$url}=[$url,$choiceres];
412: }
413: }
414: } else {
415: # -------------------------------------------------------------- No place to go
416: $multichoice=-1;
417: }
418: # ----------------- The program must come past this point to untie the big hash
419: untie(%hash);
420: # --------------------------------------------------------- Store position info
421: $cachehash{$startoutmap}{'last_direction'}=[$direction,'notasymb'];
422: foreach my $thismap (keys %cachehash) {
423: my $mapnum=$cachehash{$thismap}->{'mapnum'};
424: delete($cachehash{$thismap}->{'mapnum'});
425: &Apache::lonnet::symblist($thismap,
426: %{$cachehash{$thismap}});
427: }
428: # ============================================== Do not return before this line
429: if ($redirecturl) {
430: # ----------------------------------------------------- There is a URL to go to
431: if ($direction eq 'forward') {
432: &Apache::lonnet::linklog($currenturl,$redirecturl);
433: }
434: if ($direction eq 'back') {
435: &Apache::lonnet::linklog($redirecturl,$currenturl);
436: }
437: # ------------------------------------------------- Check for critical messages
438: if ((time-$env{'user.criticalcheck.time'})>300) {
439: my @what=&Apache::lonnet::dump
440: ('critical',$env{'user.domain'},
441: $env{'user.name'});
442: if ($what[0]) {
443: if (($what[0] ne 'con_lost') &&
444: ($what[0]!~/^error\:/)) {
445: $redirecturl='/adm/email?critical=display';
446: $redirectsymb='';
447: }
448: }
449: &Apache::lonnet::appenv({'user.criticalcheck.time'=>time});
450: }
451:
452: &Apache::loncommon::content_type($r,'text/html');
453: my $url=&Apache::lonnet::absolute_url().$redirecturl;
454: $url = &add_get_param($url, { 'symb' => $redirectsymb});
455: $r->header_out(Location => $url);
456: return REDIRECT;
457: } else {
458: # --------------------------------------------------------- There was a problem
459: &Apache::loncommon::content_type($r,'text/html');
460: $r->send_http_header;
461: my %lt=&Apache::lonlocal::texthash('title' => 'End of Sequence',
462: 'explain' =>
463: 'You have reached the end of the sequence of materials.',
464: 'back' => 'Go Back',
465: 'nav' => 'Navigate Course Content',
466: 'wherenext' =>
467: 'There are several possibilities of where to go next',
468: 'pick' =>
469: 'Please click on the the resource you intend to access',
470: 'titleheader' => 'Title',
471: 'type' => 'Type');
472: if ($#possibilities>0) {
473: my $start_page=
474: &Apache::loncommon::start_page('Multiple Resources');
475: $r->print(<<ENDSTART);
476: $start_page
477: <h3>$lt{'wherenext'}</h3>
478: <p>
479: $lt{'pick'}:
480: <p>
481: <table border="2">
482: <tr><th>$lt{'titleheader'}</th><th>$lt{'type'}</th></tr>
483: ENDSTART
484: foreach my $id (@possibilities) {
485: $r->print(
486: '<tr><td><a href="'.
487: &add_get_param($multichoicehash{'src_'.$id},
488: {'symb' =>
489: $multichoicehash{'symb_'.$id},
490: }).'">'.
491: $multichoicehash{'title_'.$id}.
492: '</a></td><td>'.$multichoicehash{'type_'.$id}.
493: '</td></tr>');
494: }
495: $r->print('</table>');
496: } else {
497: my $start_page=
498: &Apache::loncommon::start_page('No Resource');
499: $r->print(<<ENDNONE);
500: $start_page
501: <h3>$lt{'title'}</h3>
502: <p>$lt{'explain'}</p>
503: ENDNONE
504: }
505: $r->print(<<ENDMENU);
506: <ul>
507: <li><a href="/adm/flip?postdata=return:">$lt{'back'}</a></li>
508: <li><a href="/adm/navmaps">$lt{'nav'}</a></li>
509: </ul>
510: ENDMENU
511: $r->print(&Apache::loncommon::end_page());
512: return OK;
513: }
514: } else {
515: # ------------------------------------------------- Problem, could not tie hash
516: $env{'user.error.msg'}="/adm/flip:bre:0:1:Course Data Missing";
517: return HTTP_NOT_ACCEPTABLE;
518: }
519: } else {
520: # ---------------------------------------- No, could not determine where we are
521: $r->internal_redirect('/adm/ambiguous');
522: }
523: } else {
524: # -------------------------- Class was not initialized or page fliped strangely
525: $env{'user.error.msg'}="/adm/flip:bre:0:0:Choose Course";
526: return HTTP_NOT_ACCEPTABLE;
527: }
528: }
529:
530: 1;
531: __END__
532:
533: =pod
534:
535: =head1 NAME
536:
537: Apache::lonpageflip
538:
539: =head1 SYNOPSIS
540:
541: Deals with forward, backward, and other page flips.
542:
543: This is part of the LearningOnline Network with CAPA project
544: described at http://www.lon-capa.org.
545:
546: =head1 OVERVIEW
547:
548: (empty)
549:
550: =head1 SUBROUTINES
551:
552: =over cleanup()
553:
554: =item addrid()
555:
556: =item fullmove()
557:
558: =item hash_src()
559:
560: =item move()
561:
562: =item get_next_possible_move()
563:
564: =item navlaunch()
565:
566: =item first_accessible_resource()
567:
568: =item handler()
569:
570: =back
571:
572: =cut
573:
574:
575:
576:
577:
578:
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