1: # The LearningOnline Network with CAPA
2: #
3: # Page flip handler
4: #
5: # $Id: lonpageflip.pm,v 1.55 2005/08/02 21:15:52 albertel 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: package Apache::lonpageflip;
31:
32: use strict;
33: use Apache::Constants qw(:common :http REDIRECT);
34: use Apache::lonnet;
35: use HTML::TokeParser;
36: use GDBM_File;
37:
38: # ========================================================== Module Global Hash
39:
40: my %hash;
41:
42: sub cleanup {
43: if (tied(%hash)){
44: &Apache::lonnet::logthis('Cleanup pageflip: hash');
45: unless (untie(%hash)) {
46: &Apache::lonnet::logthis('Failed cleanup pageflip: hash');
47: }
48: }
49: }
50:
51: sub addrid {
52: my ($current,$new,$condid)=@_;
53: unless ($condid) { $condid=0; }
54:
55: if ($current) {
56: $current.=','.$new;
57: } else {
58: $current=''.$new;
59: }
60:
61: return $current;
62: }
63:
64: sub fullmove {
65: my ($rid,$mapurl,$direction)=@_;
66: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
67: &GDBM_READER(),0640)) {
68: ($rid,$mapurl)=&move($rid,$mapurl,$direction);
69: untie(%hash);
70: }
71: return($rid,$mapurl);
72: }
73:
74: sub hash_src {
75: my ($id)=@_;
76: if ($hash{'encrypted_'.$id}) {
77: return &Apache::lonenc::encrypted($hash{'src_'.$id});
78: }
79: return $hash{'src_'.$id};
80: }
81:
82: sub move {
83: my ($rid,$mapurl,$direction)=@_;
84: my $startoutrid=$rid;
85:
86: my $next='';
87:
88: my $mincond=1;
89: my $posnext='';
90: if ($direction eq 'forward') {
91: # --------------------------------------------------------------------- Forward
92: while ($hash{'type_'.$rid} eq 'finish') {
93: $rid=$hash{'ids_'.$hash{'map_id_'.(split(/\./,$rid))[0]}};
94: }
95: map {
96: my $thiscond=
97: &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}});
98: if ($thiscond>=$mincond) {
99: if ($posnext) {
100: $posnext.=','.$_.':'.$thiscond;
101: } else {
102: $posnext=$_.':'.$thiscond;
103: }
104: if ($thiscond>$mincond) { $mincond=$thiscond; }
105: }
106: } split(/\,/,$hash{'to_'.$rid});
107: map {
108: my ($linkid,$condval)=split(/\:/,$_);
109: if ($condval>=$mincond) {
110: $next=&addrid($next,$hash{'goesto_'.$linkid},
111: $hash{'condid_'.$hash{'undercond_'.$linkid}});
112: }
113: } split(/\,/,$posnext);
114: if ($hash{'is_map_'.$next}) {
115: # This jumps to the beginning of a new map (going down level)
116: if (
117: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
118: $mapurl=$hash{'src_'.$next};
119: $next=$hash{'map_start_'.$hash{'src_'.$next}};
120: } elsif (
121: # This jumps back up from an empty sequence, to a page up one level
122: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'page') {
123: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
124: }
125: } elsif
126: ((split(/\./,$startoutrid))[0]!=(split(/\./,$next))[0]) {
127: # This comes up from a map (coming up one level);
128: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
129: }
130: } elsif ($direction eq 'back') {
131: # ------------------------------------------------------------------- Backwards
132: while ($hash{'type_'.$rid} eq 'start') {
133: $rid=$hash{'ids_'.$hash{'map_id_'.(split(/\./,$rid))[0]}};
134: }
135: map {
136: my $thiscond=
137: &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}});
138: if ($thiscond>=$mincond) {
139: if ($posnext) {
140: $posnext.=','.$_.':'.$thiscond;
141: } else {
142: $posnext=$_.':'.$thiscond;
143: }
144: if ($thiscond>$mincond) { $mincond=$thiscond; }
145: }
146: } split(/\,/,$hash{'from_'.$rid});
147: map {
148: my ($linkid,$condval)=split(/\:/,$_);
149: if ($condval>=$mincond) {
150: $next=&addrid($next,$hash{'comesfrom_'.$linkid},
151: $hash{'condid_'.$hash{'undercond_'.$linkid}});
152: }
153: } split(/\,/,$posnext);
154: if ($hash{'is_map_'.$next}) {
155: # This jumps to the end of a new map (going down one level)
156: if (
157: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
158: $mapurl=$hash{'src_'.$next};
159: $next=$hash{'map_finish_'.$hash{'src_'.$next}};
160: } elsif (
161: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'page') {
162: # This jumps back up from an empty sequence, to a page up one level
163: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
164: }
165: } elsif
166: ((split(/\./,$startoutrid))[0]!=(split(/\./,$next))[0]) {
167: # This comes back up from a map (going up one level);
168: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
169: }
170: }
171: return ($next,$mapurl);
172: }
173:
174: sub navlaunch {
175: my ($r)=@_;
176: &Apache::loncommon::content_type($r,'text/html');
177: &Apache::loncommon::no_cache($r);
178: $r->send_http_header;
179: my $html=&Apache::lonxml::xmlbegin();
180: $r->print("$html<head>\n");
181: $r->print('</head>'.
182: &Apache::loncommon::bodytag('Launched'));
183: $r->print(<<ENDNAV);
184: <p><a href="/adm/flip?postdata=firstres%3a">Goto first resource</a></p>
185: <script type="text/javascript">
186: function collapse() {
187: menu=window.open("/adm/navmaps?collapseExternal","loncapanav",
188: "height=600,width=400,scrollbars=1");
189: this.document.location='/adm/navmaps?turningOffExternal';
190: }
191: </script>
192: <p><a href="javascript:collapse();">Collapse external navigation window</a></p>
193: ENDNAV
194: $r->print(&Apache::loncommon::endbodytag().'</html>');
195: }
196: # ================================================================ Main Handler
197:
198: sub handler {
199: my $r=shift;
200:
201: # ------------------------------------------- Set document type for header only
202:
203: if ($r->header_only) {
204: &Apache::loncommon::content_type($r,'text/html');
205: $r->send_http_header;
206: return OK;
207: }
208:
209: my %cachehash=();
210: my $multichoice=0;
211: my %multichoicehash=();
212: my $redirecturl='';
213: my $next='';
214: my @possibilities=();
215: &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},['postdata']);
216: if (($env{'form.postdata'})&&($env{'request.course.fn'})) {
217: $env{'form.postdata'}=~/(\w+)\:(.*)/;
218: my $direction=$1;
219: my $currenturl=$2;
220: if ($currenturl=~m|^/enc/|) {
221: $currenturl=&Apache::lonenc::unencrypted($currenturl);
222: }
223: $currenturl=~s/\.\d+\.(\w+)$/\.$1/;
224: if ($direction eq 'firstres') {
225: my $furl;
226: if (tie(my %bighash,'GDBM_File',$env{'request.course.fn'}.'.db',
227: &GDBM_READER(),0640)) {
228: $furl=$bighash{'first_url'};
229: untie(%bighash);
230: }
231: &Apache::loncommon::content_type($r,'text/html');
232: $r->header_out(Location =>
233: 'http://'.$ENV{'HTTP_HOST'}.$furl);
234:
235: return REDIRECT;
236: }
237: if ($direction eq 'return' || $direction eq 'navlaunch') {
238: # -------------------------------------------------------- Return to last known
239: my $last;
240: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'_symb.db',
241: &GDBM_READER(),0640)) {
242: $last=$hash{'last_known'};
243: untie(%hash);
244: }
245: my $newloc;
246: if (($last) && (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
247: &GDBM_READER(),0640))) {
248: my ($murl,$id,$fn)=&Apache::lonnet::decode_symb($last);
249: $id=$hash{'map_pc_'.&Apache::lonnet::clutter($murl)}.'.'.$id;
250: $newloc=$hash{'src_'.$id};
251: if ($newloc) {
252: if ($hash{'encrypted_'.$id}) { $newloc=&Apache::lonenc::encrypted($newloc); }
253:
254: } else {
255: $newloc='/adm/noidea.html';
256: }
257: untie %hash;
258: } else {
259: $newloc='/adm/noidea.html';
260: }
261: if ($newloc eq '/adm/noidea.html' && $direction eq 'navlaunch') {
262: &navlaunch($r);
263: return OK;
264: } else {
265: &Apache::loncommon::content_type($r,'text/html');
266: $r->header_out(Location =>
267: 'http://'.$ENV{'HTTP_HOST'}.$newloc);
268:
269: return REDIRECT;
270: }
271: }
272: $currenturl=~s/^http\:\/\///;
273: $currenturl=~s/^[^\/]+//;
274: #
275: # Is the current URL on the map? If not, start with last known URL
276: #
277: unless (&Apache::lonnet::is_on_map($currenturl)) {
278: my $last;
279: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'_symb.db',
280: &GDBM_READER(),0640)) {
281: $last=$hash{'last_known'};
282: untie(%hash);
283: }
284: if ($last) {
285: $currenturl=&Apache::lonnet::clutter((&Apache::lonnet::decode_symb($last))[2]);
286: } else {
287: if ($direction eq 'return') {
288: &Apache::loncommon::content_type($r,'text/html');
289: $r->header_out(Location =>
290: 'http://'.$ENV{'HTTP_HOST'}.'/adm/noidea.html');
291: return REDIRECT;
292: } else {
293: &navlaunch($r);
294: return OK;
295: }
296: }
297: }
298: # ------------------------------------------- Do we have any idea where we are?
299: my $position;
300: if ($position=Apache::lonnet::symbread($currenturl)) {
301: # ------------------------------------------------------------------------- Yes
302: my ($startoutmap,$mapnum,$thisurl)=&Apache::lonnet::decode_symb($position);
303: $cachehash{$startoutmap}{$thisurl}=[$thisurl,$mapnum];
304: $cachehash{$startoutmap}{'last_known'}=
305: [&Apache::lonnet::declutter($currenturl),$mapnum];
306:
307: # ============================================================ Tie the big hash
308: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'.db',
309: &GDBM_READER(),0640)) {
310: my $rid=$hash{'map_pc_'.&Apache::lonnet::clutter($startoutmap)}.
311: '.'.$mapnum;
312:
313: # ------------------------------------------------- Move forward, backward, etc
314: my $endupmap;
315: ($next,$endupmap)=&move($rid,$startoutmap,$direction);
316: # -------------------------------------- Do we have one and only one empty URL?
317: my $safecount=0;
318: while (($next) && ($next!~/\,/) &&
319: ((!$hash{'src_'.$next}) ||
320: ((!$env{'request.role.adv'}) && $hash{'randomout_'.$next}))
321: && ($safecount<10000)) {
322: ($next,$endupmap)=&move($next,$endupmap,$direction);
323: $safecount++;
324: }
325: # We are now at at least one non-empty URL
326: # ----------------------------------------------------- Check out possibilities
327: if ($next) {
328: @possibilities=split(/\,/,$next);
329: if ($#possibilities==0) {
330: # ---------------------------------------------- Only one possibility, redirect
331: $redirecturl=&hash_src($next);
332: $cachehash{$endupmap}{$redirecturl}=
333: [$redirecturl,(split(/\./,$next))[1]];
334: } else {
335: # ------------------------ There are multiple possibilities for a next resource
336: $multichoice=1;
337: map {
338: $multichoicehash{'src_'.$_}=$hash{'src_'.$_};
339: $multichoicehash{'title_'.$_}=$hash{'title_'.$_};
340: $multichoicehash{'type_'.$_}=$hash{'type_'.$_};
341: (my $first, my $second) = $_ =~ /(\d+).(\d+)/;
342: my $symbSrc = Apache::lonnet::declutter($hash{'src_'.$_});
343: $multichoicehash{'symb_'.$_} =
344: Apache::lonnet::declutter($hash{'map_id_'.$first}.'___'.
345: $second.'___'.$symbSrc);
346:
347: my ($choicemap,$choiceres)=split(/\./,$_);
348: my $map=&Apache::lonnet::declutter($hash{'src_'.$choicemap});
349: my $url=$multichoicehash{'src_'.$_};
350: $cachehash{$map}{$url}=[$url,$choiceres];
351: } @possibilities;
352: }
353: } else {
354: # -------------------------------------------------------------- No place to go
355: $multichoice=-1;
356: }
357: # ----------------- The program must come past this point to untie the big hash
358: untie(%hash);
359: # --------------------------------------------------------- Store position info
360: $cachehash{$startoutmap}{'last_direction'}=[$direction,'notasymb'];
361: foreach my $thismap (keys %cachehash) {
362: my $mapnum=$cachehash{$thismap}->{'mapnum'};
363: delete($cachehash{$thismap}->{'mapnum'});
364: &Apache::lonnet::symblist($thismap,
365: %{$cachehash{$thismap}});
366: }
367: # ============================================== Do not return before this line
368: if ($redirecturl) {
369: # ----------------------------------------------------- There is a URL to go to
370: if ($direction eq 'forward') {
371: &Apache::lonnet::linklog($currenturl,$redirecturl);
372: }
373: if ($direction eq 'back') {
374: &Apache::lonnet::linklog($redirecturl,$currenturl);
375: }
376: # ------------------------------------------------- Check for critical messages
377: if ((time-$env{'user.criticalcheck.time'})>300) {
378: my @what=&Apache::lonnet::dump
379: ('critical',$env{'user.domain'},
380: $env{'user.name'});
381: if ($what[0]) {
382: if (($what[0] ne 'con_lost') &&
383: ($what[0]!~/^error\:/)) {
384: $redirecturl='/adm/email?critical=display';
385: }
386: }
387: &Apache::lonnet::appenv('user.criticalcheck.time'=>time);
388: }
389:
390: &Apache::loncommon::content_type($r,'text/html');
391: $r->header_out(Location =>
392: 'http://'.$ENV{'HTTP_HOST'}.$redirecturl);
393: return REDIRECT;
394: } else {
395: # --------------------------------------------------------- There was a problem
396: &Apache::loncommon::content_type($r,'text/html');
397: $r->send_http_header;
398: if ($#possibilities>0) {
399: my $bodytag=
400: &Apache::loncommon::bodytag('Multiple Resources');
401: $r->print(<<ENDSTART);
402: <head><title>Choose Next Location</title></head>
403: $bodytag
404: <h3>There are several possibilities of where to go next</h3>
405: <p>
406: Please click on the the resource you intend to access:
407: <p>
408: <table border=2>
409: <tr><th>Title</th><th>Type</th></tr>
410: ENDSTART
411: foreach (@possibilities) {
412: $r->print(
413: '<tr><td><a href="'.
414: $multichoicehash{'src_'.$_}.'?symb=' .
415: Apache::lonnet::escape($multichoicehash{'symb_'.$_}).'">'.
416: $multichoicehash{'title_'.$_}.
417: '</a></td><td>'.$multichoicehash{'type_'.$_}.
418: '</td></tr>');
419: }
420: $r->print('</table></body></html>');
421: return OK;
422: } else {
423: my $bodytag=&Apache::loncommon::bodytag('No Resource');
424: $r->print(<<ENDNONE);
425: <head><title>No Resource</title></head>
426: $bodytag
427: <h3>Next resource could not be identified.</h3>
428: <p>You probably are at the <b>beginning</b> or the <b>end</b> of the
429: course.</p>
430: <ul>
431: <li><a href="/adm/flip?postdata=return:">Go Back</a></li>
432: <li><a href="/adm/navmaps">Navigate Course Content</a></li>
433: </ul>
434: </body>
435: </html>
436: ENDNONE
437: return OK;
438: }
439: }
440: } else {
441: # ------------------------------------------------- Problem, could not tie hash
442: $env{'user.error.msg'}="/adm/flip:bre:0:1:Course Data Missing";
443: return HTTP_NOT_ACCEPTABLE;
444: }
445: } else {
446: # ---------------------------------------- No, could not determine where we are
447: if ( &Apache::lonnet::mod_perl_version() == 2 ) {
448: &Apache::lonnet::cleanenv();
449: }
450: $r->internal_redirect('/adm/ambiguous');
451: }
452: } else {
453: # -------------------------- Class was not initialized or page fliped strangely
454: $env{'user.error.msg'}="/adm/flip:bre:0:0:Choose Course";
455: return HTTP_NOT_ACCEPTABLE;
456: }
457: }
458:
459: 1;
460: __END__
461:
462:
463:
464:
465:
466:
467:
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