1: # The LearningOnline Network with CAPA
2: #
3: # Page flip handler
4: #
5: # $Id: lonpageflip.pm,v 1.49 2004/10/19 15:26:53 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: # (Page Handler
30: #
31: # (TeX Content Handler
32: #
33: # 05/29/00,05/30 Gerd Kortemeyer)
34: # 08/30,08/31,09/06,09/14,09/15,09/16,09/19,09/20,09/21,09/23,
35: # 10/02 Gerd Kortemeyer)
36: #
37: # 10/03,10/05,10/06,10/07,10/09,10/10,10/11,10/16,10/17,
38: # 11/14,11/16,
39: # 10/01/01,05/01,05/28,07/05 Gerd Kortemeyer
40:
41: package Apache::lonpageflip;
42:
43: use strict;
44: use Apache::Constants qw(:common :http REDIRECT);
45: use Apache::lonnet();
46: use HTML::TokeParser;
47: use GDBM_File;
48:
49: # ========================================================== Module Global Hash
50:
51: my %hash;
52:
53: sub cleanup {
54: if (tied(%hash)){
55: &Apache::lonnet::logthis('Cleanup pageflip: hash');
56: unless (untie(%hash)) {
57: &Apache::lonnet::logthis('Failed cleanup pageflip: hash');
58: }
59: }
60: }
61:
62: sub addrid {
63: my ($current,$new,$condid)=@_;
64: unless ($condid) { $condid=0; }
65:
66: if ($current) {
67: $current.=','.$new;
68: } else {
69: $current=''.$new;
70: }
71:
72: return $current;
73: }
74:
75: sub fullmove {
76: my ($rid,$mapurl,$direction)=@_;
77: if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'.db',
78: &GDBM_READER(),0640)) {
79: ($rid,$mapurl)=&move($rid,$mapurl,$direction);
80: untie(%hash);
81: }
82: return($rid,$mapurl);
83: }
84:
85: sub move {
86: my ($rid,$mapurl,$direction)=@_;
87: my $startoutrid=$rid;
88:
89: my $next='';
90:
91: my $mincond=1;
92: my $posnext='';
93: if ($direction eq 'forward') {
94: # --------------------------------------------------------------------- Forward
95: while ($hash{'type_'.$rid} eq 'finish') {
96: $rid=$hash{'ids_'.$hash{'map_id_'.(split(/\./,$rid))[0]}};
97: }
98: map {
99: my $thiscond=
100: &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}});
101: if ($thiscond>=$mincond) {
102: if ($posnext) {
103: $posnext.=','.$_.':'.$thiscond;
104: } else {
105: $posnext=$_.':'.$thiscond;
106: }
107: if ($thiscond>$mincond) { $mincond=$thiscond; }
108: }
109: } split(/\,/,$hash{'to_'.$rid});
110: map {
111: my ($linkid,$condval)=split(/\:/,$_);
112: if ($condval>=$mincond) {
113: $next=&addrid($next,$hash{'goesto_'.$linkid},
114: $hash{'condid_'.$hash{'undercond_'.$linkid}});
115: }
116: } split(/\,/,$posnext);
117: if ($hash{'is_map_'.$next}) {
118: # This jumps to the beginning of a new map (going down level)
119: if (
120: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
121: $mapurl=$hash{'src_'.$next};
122: $next=$hash{'map_start_'.$hash{'src_'.$next}};
123: } elsif (
124: # This jumps back up from an empty sequence, to a page up one level
125: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'page') {
126: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
127: }
128: } elsif
129: ((split(/\./,$startoutrid))[0]!=(split(/\./,$next))[0]) {
130: # This comes up from a map (coming up one level);
131: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
132: }
133: } elsif ($direction eq 'back') {
134: # ------------------------------------------------------------------- Backwards
135: while ($hash{'type_'.$rid} eq 'start') {
136: $rid=$hash{'ids_'.$hash{'map_id_'.(split(/\./,$rid))[0]}};
137: }
138: map {
139: my $thiscond=
140: &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}});
141: if ($thiscond>=$mincond) {
142: if ($posnext) {
143: $posnext.=','.$_.':'.$thiscond;
144: } else {
145: $posnext=$_.':'.$thiscond;
146: }
147: if ($thiscond>$mincond) { $mincond=$thiscond; }
148: }
149: } split(/\,/,$hash{'from_'.$rid});
150: map {
151: my ($linkid,$condval)=split(/\:/,$_);
152: if ($condval>=$mincond) {
153: $next=&addrid($next,$hash{'comesfrom_'.$linkid},
154: $hash{'condid_'.$hash{'undercond_'.$linkid}});
155: }
156: } split(/\,/,$posnext);
157: if ($hash{'is_map_'.$next}) {
158: # This jumps to the end of a new map (going down one level)
159: if (
160: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
161: $mapurl=$hash{'src_'.$next};
162: $next=$hash{'map_finish_'.$hash{'src_'.$next}};
163: } elsif (
164: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'page') {
165: # This jumps back up from an empty sequence, to a page up one level
166: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
167: }
168: } elsif
169: ((split(/\./,$startoutrid))[0]!=(split(/\./,$next))[0]) {
170: # This comes back up from a map (going up one level);
171: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
172: }
173: }
174: return ($next,$mapurl);
175: }
176:
177: # ================================================================ Main Handler
178:
179: sub handler {
180: my $r=shift;
181:
182: # ------------------------------------------- Set document type for header only
183:
184: if ($r->header_only) {
185: $r->content_type('text/html');
186: $r->send_http_header;
187: return OK;
188: }
189:
190: my %cachehash=();
191: my $multichoice=0;
192: my %multichoicehash=();
193: my $redirecturl='';
194: my $next='';
195: my @possibilities=();
196: &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},['postdata']);
197: if (($ENV{'form.postdata'})&&($ENV{'request.course.fn'})) {
198: $ENV{'form.postdata'}=~/(\w+)\:(.*)/;
199: my $direction=$1;
200: my $currenturl=$2;
201: $currenturl=~s/\.\d+\.(\w+)$/\.$1/;
202: if ($direction eq 'return') {
203: # -------------------------------------------------------- Return to last known
204: my $last;
205: if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'_symb.db',
206: &GDBM_READER(),0640)) {
207: $last=$hash{'last_known'};
208: untie(%hash);
209: }
210: my $newloc;
211: if (($last) && (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'.db',
212: &GDBM_READER(),0640))) {
213: my ($murl,$fn)=&Apache::lonnet::decode_symb($last);
214: my $id;
215: ($murl,$id,$fn)=&Apache::lonnet::decode_symb(&Apache::lonnet::symbread($fn));
216: $newloc=$hash{'src_'.
217: $hash{'map_pc_'.&Apache::lonnet::clutter($murl)}.'.'.$id};
218: unless ($newloc) { $newloc='/adm/noidea.html'; }
219: untie %hash;
220: } else {
221: $newloc='/adm/noidea.html';
222: }
223: $r->content_type('text/html');
224: $r->header_out(Location =>
225: 'http://'.$ENV{'HTTP_HOST'}.$newloc);
226:
227: return REDIRECT;
228: }
229: $currenturl=~s/^http\:\/\///;
230: $currenturl=~s/^[^\/]+//;
231: #
232: # Is the current URL on the map? If not, start with last known URL
233: #
234: unless (&Apache::lonnet::is_on_map($currenturl)) {
235: my $last;
236: if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'_symb.db',
237: &GDBM_READER(),0640)) {
238: $last=$hash{'last_known'};
239: untie(%hash);
240: }
241: if ($last) {
242: $currenturl=&Apache::lonnet::clutter((&Apache::lonnet::decode_symb($last))[1]);
243: } else {
244: $r->content_type('text/html');
245: $r->header_out(Location =>
246: 'http://'.$ENV{'HTTP_HOST'}.'/adm/noidea.html');
247: return REDIRECT;
248: }
249: }
250: # ------------------------------------------- Do we have any idea where we are?
251: my $position;
252: if ($position=Apache::lonnet::symbread($currenturl)) {
253: # ------------------------------------------------------------------------- Yes
254: my ($startoutmap,$mapnum,$thisurl)=&Apache::lonnet::decode_symb($position);
255: $cachehash{$startoutmap}{$thisurl}=$mapnum;
256: $cachehash{$startoutmap}{'last_known'}=
257: &Apache::lonnet::declutter($currenturl);
258:
259: # ============================================================ Tie the big hash
260: if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'.db',
261: &GDBM_READER(),0640)) {
262: my $rid=$hash{'map_pc_'.&Apache::lonnet::clutter($startoutmap)}.
263: '.'.$mapnum;
264:
265: # ------------------------------------------------- Move forward, backward, etc
266: my $endupmap;
267: ($next,$endupmap)=&move($rid,$startoutmap,$direction);
268: # -------------------------------------- Do we have one and only one empty URL?
269: my $safecount=0;
270: while (($next) && ($next!~/\,/) &&
271: ((!$hash{'src_'.$next}) ||
272: ((!$ENV{'request.role.adv'}) && $hash{'randomout_'.$next}))
273: && ($safecount<10000)) {
274: ($next,$endupmap)=&move($next,$endupmap,$direction);
275: $safecount++;
276: }
277: # We are now at at least one non-empty URL
278: # ----------------------------------------------------- Check out possibilities
279: if ($next) {
280: @possibilities=split(/\,/,$next);
281: if ($#possibilities==0) {
282: # ---------------------------------------------- Only one possibility, redirect
283: $redirecturl=$hash{'src_'.$next};
284: $cachehash{$endupmap}
285: {&Apache::lonnet::declutter($redirecturl)}
286: =(split(/\./,$next))[1];
287: } else {
288: # ------------------------ There are multiple possibilities for a next resource
289: $multichoice=1;
290: map {
291: $multichoicehash{'src_'.$_}=$hash{'src_'.$_};
292: $multichoicehash{'title_'.$_}=$hash{'title_'.$_};
293: $multichoicehash{'type_'.$_}=$hash{'type_'.$_};
294: (my $first, my $second) = $_ =~ /(\d+).(\d+)/;
295: my $symbSrc = Apache::lonnet::declutter($hash{'src_'.$_});
296: $multichoicehash{'symb_'.$_} =
297: Apache::lonnet::declutter($hash{'map_id_'.$first}.'___'.
298: $second.'___'.$symbSrc);
299:
300: my ($choicemap,$choiceres)=split(/\./,$_);
301: $cachehash
302: {&Apache::lonnet::declutter($hash{'src_'.$choicemap})}
303: {&Apache::lonnet::declutter(
304: $multichoicehash
305: {'src_'.$_}
306: )}
307: =$choiceres;
308: } @possibilities;
309: }
310: } else {
311: # -------------------------------------------------------------- No place to go
312: $multichoice=-1;
313: }
314: # ----------------- The program must come past this point to untie the big hash
315: untie(%hash);
316: # --------------------------------------------------------- Store position info
317: $cachehash{$startoutmap}{'last_direction'}=$direction;
318: foreach my $thismap (keys %cachehash) {
319: &Apache::lonnet::symblist($thismap,%{$cachehash{$thismap}});
320: }
321: # ============================================== Do not return before this line
322: if ($redirecturl) {
323: # ----------------------------------------------------- There is a URL to go to
324: if ($direction eq 'forward') {
325: &Apache::lonnet::linklog($currenturl,$redirecturl);
326: }
327: if ($direction eq 'back') {
328: &Apache::lonnet::linklog($redirecturl,$currenturl);
329: }
330: # ------------------------------------------------- Check for critical messages
331: if ((time-$ENV{'user.criticalcheck.time'})>300) {
332: my @what=&Apache::lonnet::dump
333: ('critical',$ENV{'user.domain'},
334: $ENV{'user.name'});
335: if ($what[0]) {
336: if (($what[0] ne 'con_lost') &&
337: ($what[0]!~/^error\:/)) {
338: $redirecturl='/adm/email?critical=display';
339: }
340: }
341: &Apache::lonnet::appenv('user.criticalcheck.time'=>time);
342: }
343:
344: $r->content_type('text/html');
345: $r->header_out(Location =>
346: 'http://'.$ENV{'HTTP_HOST'}.$redirecturl);
347: return REDIRECT;
348: } else {
349: # --------------------------------------------------------- There was a problem
350: $r->content_type('text/html');
351: $r->send_http_header;
352: if ($#possibilities>0) {
353: my $bodytag=
354: &Apache::loncommon::bodytag('Multiple Resources');
355: $r->print(<<ENDSTART);
356: <head><title>Choose Next Location</title></head>
357: $bodytag
358: <h3>There are several possibilities of where to go next</h3>
359: <p>
360: Please click on the the resource you intend to access:
361: <p>
362: <table border=2>
363: <tr><th>Title</th><th>Type</th></tr>
364: ENDSTART
365: foreach (@possibilities) {
366: $r->print(
367: '<tr><td><a href="'.
368: $multichoicehash{'src_'.$_}.'?symb=' .
369: Apache::lonnet::escape($multichoicehash{'symb_'.$_}).'">'.
370: $multichoicehash{'title_'.$_}.
371: '</a></td><td>'.$multichoicehash{'type_'.$_}.
372: '</td></tr>');
373: }
374: $r->print('</table></body></html>');
375: return OK;
376: } else {
377: my $bodytag=&Apache::loncommon::bodytag('No Resource');
378: $r->print(<<ENDNONE);
379: <head><title>No Resource</title></head>
380: $bodytag
381: <h3>Next resource could not be identified.</h3>
382: <p>You probably are at the <b>beginning</b> or the <b>end</b> of the
383: course.</p>
384: <ul>
385: <li><a href="/adm/flip?postdata=return:">Go Back</a></li>
386: <li><a href="/adm/navmaps">Navigate Course Content</a></li>
387: </ul>
388: </body>
389: </html>
390: ENDNONE
391: return OK;
392: }
393: }
394: } else {
395: # ------------------------------------------------- Problem, could not tie hash
396: $ENV{'user.error.msg'}="/adm/flip:bre:0:1:Course Data Missing";
397: return HTTP_NOT_ACCEPTABLE;
398: }
399: } else {
400: # ---------------------------------------- No, could not determine where we are
401: if ( &Apache::lonnet::mod_perl_version() == 2 ) {
402: &Apache::lonnet::cleanenv();
403: }
404: $r->internal_redirect('/adm/ambiguous');
405: }
406: } else {
407: # -------------------------- Class was not initialized or page fliped strangely
408: $ENV{'user.error.msg'}="/adm/flip:bre:0:0:Choose Course";
409: return HTTP_NOT_ACCEPTABLE;
410: }
411: }
412:
413: 1;
414: __END__
415:
416:
417:
418:
419:
420:
421:
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