1: # The LearningOnline Network with CAPA
2: #
3: # Page flip handler
4: #
5: # $Id: lonpageflip.pm,v 1.41 2003/09/09 18:46:28 www 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: }
124: } elsif
125: ((split(/\./,$startoutrid))[0]!=(split(/\./,$next))[0]) {
126: # This comes up from a map (coming up one level);
127: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
128: }
129: } elsif ($direction eq 'back') {
130: # ------------------------------------------------------------------- Backwards
131: while ($hash{'type_'.$rid} eq 'start') {
132: $rid=$hash{'ids_'.$hash{'map_id_'.(split(/\./,$rid))[0]}};
133: }
134: map {
135: my $thiscond=
136: &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}});
137: if ($thiscond>=$mincond) {
138: if ($posnext) {
139: $posnext.=','.$_.':'.$thiscond;
140: } else {
141: $posnext=$_.':'.$thiscond;
142: }
143: if ($thiscond>$mincond) { $mincond=$thiscond; }
144: }
145: } split(/\,/,$hash{'from_'.$rid});
146: map {
147: my ($linkid,$condval)=split(/\:/,$_);
148: if ($condval>=$mincond) {
149: $next=&addrid($next,$hash{'comesfrom_'.$linkid},
150: $hash{'condid_'.$hash{'undercond_'.$linkid}});
151: }
152: } split(/\,/,$posnext);
153: if ($hash{'is_map_'.$next}) {
154: # This jumps to the end of a new map (going down one level)
155: if (
156: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
157: $mapurl=$hash{'src_'.$next};
158: $next=$hash{'map_finish_'.$hash{'src_'.$next}};
159: }
160: } elsif
161: ((split(/\./,$startoutrid))[0]!=(split(/\./,$next))[0]) {
162: # This comes back up from a map (going up one level);
163: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
164: }
165: }
166: return ($next,$mapurl);
167: }
168:
169: # ================================================================ Main Handler
170:
171: sub handler {
172: my $r=shift;
173:
174: # ------------------------------------------- Set document type for header only
175:
176: if ($r->header_only) {
177: $r->content_type('text/html');
178: $r->send_http_header;
179: return OK;
180: }
181:
182: my %cachehash=();
183: my $multichoice=0;
184: my %multichoicehash=();
185: my $redirecturl='';
186: my $next='';
187: my @possibilities=();
188: &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},['postdata']);
189: if (($ENV{'form.postdata'})&&($ENV{'request.course.fn'})) {
190: $ENV{'form.postdata'}=~/(\w+)\:(.*)/;
191: my $direction=$1;
192: my $currenturl=$2;
193: if ($direction eq 'return') {
194: # -------------------------------------------------------- Return to last known
195: my $last;
196: if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'_symb.db',
197: &GDBM_READER(),0640)) {
198: $last=$hash{'last_known'};
199: untie(%hash);
200: }
201: my $newloc;
202: if (($last) && (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'.db',
203: &GDBM_READER(),0640))) {
204: my ($murl,$fn)=&Apache::lonnet::decode_symb($last);
205: my $id;
206: ($murl,$id,$fn)=&Apache::lonnet::decode_symb(&Apache::lonnet::symbread($fn));
207: $newloc=$hash{'src_'.
208: $hash{'map_pc_'.&Apache::lonnet::clutter($murl)}.'.'.$id};
209: unless ($newloc) { $newloc='/adm/noidea.html'; }
210: untie %hash;
211: } else {
212: $newloc='/adm/noidea.html';
213: }
214: $r->content_type('text/html');
215: $r->header_out(Location =>
216: 'http://'.$ENV{'HTTP_HOST'}.$newloc);
217:
218: return REDIRECT;
219: }
220: $currenturl=~s/^http\:\/\///;
221: $currenturl=~s/^[^\/]+//;
222: #
223: # Is the current URL on the map? If not, start with last known URL
224: #
225: unless (&Apache::lonnet::is_on_map($currenturl)) {
226: my $last;
227: if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'_symb.db',
228: &GDBM_READER(),0640)) {
229: $last=$hash{'last_known'};
230: untie(%hash);
231: }
232: if ($last) {
233: $currenturl=&Apache::lonnet::clutter((&Apache::lonnet::decode_symb($last))[1]);
234: } else {
235: $r->content_type('text/html');
236: $r->header_out(Location =>
237: 'http://'.$ENV{'HTTP_HOST'}.'/adm/noidea.html');
238: return REDIRECT;
239: }
240: }
241: # ------------------------------------------- Do we have any idea where we are?
242: my $position;
243: if ($position=Apache::lonnet::symbread($currenturl)) {
244: # ------------------------------------------------------------------------- Yes
245: my ($startoutmap,$mapnum,$thisurl)=&Apache::lonnet::decode_symb($position);
246: $cachehash{$startoutmap}{$thisurl}=$mapnum;
247: $cachehash{$startoutmap}{'last_known'}=
248: &Apache::lonnet::declutter($currenturl);
249:
250: # ============================================================ Tie the big hash
251: if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'.db',
252: &GDBM_READER(),0640)) {
253: my $rid=$hash{'map_pc_'.&Apache::lonnet::clutter($startoutmap)}.
254: '.'.$mapnum;
255:
256: # ------------------------------------------------- Move forward, backward, etc
257: my $endupmap;
258: ($next,$endupmap)=&move($rid,$startoutmap,$direction);
259: # -------------------------------------- Do we have one and only one empty URL?
260: my $safecount=0;
261: while (($next) && ($next!~/\,/) &&
262: ((!$hash{'src_'.$next}) || ($hash{'randomout_'.$next}))
263: && ($safecount<10000)) {
264: ($next,$endupmap)=&move($next,$endupmap,$direction);
265: $safecount++;
266: }
267: # We are now at at least one non-empty URL
268: # ----------------------------------------------------- Check out possibilities
269: if ($next) {
270: @possibilities=split(/\,/,$next);
271: if ($#possibilities==0) {
272: # ---------------------------------------------- Only one possibility, redirect
273: $redirecturl=$hash{'src_'.$next};
274: $cachehash{$endupmap}
275: {&Apache::lonnet::declutter($redirecturl)}
276: =(split(/\./,$next))[1];
277: } else {
278: # ------------------------ There are multiple possibilities for a next resource
279: $multichoice=1;
280: map {
281: $multichoicehash{'src_'.$_}=$hash{'src_'.$_};
282: $multichoicehash{'title_'.$_}=$hash{'title_'.$_};
283: $multichoicehash{'type_'.$_}=$hash{'type_'.$_};
284: (my $first, my $second) = $_ =~ /(\d+).(\d+)/;
285: my $symbSrc = Apache::lonnet::declutter($hash{'src_'.$_});
286: $multichoicehash{'symb_'.$_} =
287: Apache::lonnet::declutter($hash{'map_id_'.$first}.'___'.
288: $second.'___'.$symbSrc);
289:
290: my ($choicemap,$choiceres)=split(/\./,$_);
291: $cachehash
292: {&Apache::lonnet::declutter($hash{'src_'.$choicemap})}
293: {&Apache::lonnet::declutter(
294: $multichoicehash
295: {'src_'.$_}
296: )}
297: =$choiceres;
298: } @possibilities;
299: }
300: } else {
301: # -------------------------------------------------------------- No place to go
302: $multichoice=-1;
303: }
304: # ----------------- The program must come past this point to untie the big hash
305: untie(%hash);
306: # --------------------------------------------------------- Store position info
307: $cachehash{$startoutmap}{'last_direction'}=$direction;
308: foreach my $thismap (keys %cachehash) {
309: &Apache::lonnet::symblist($thismap,%{$cachehash{$thismap}});
310: }
311: # ============================================== Do not return before this line
312: if ($redirecturl) {
313: # ----------------------------------------------------- There is a URL to go to
314: if ($direction eq 'forward') {
315: &Apache::lonnet::linklog($currenturl,$redirecturl);
316: }
317: if ($direction eq 'back') {
318: &Apache::lonnet::linklog($redirecturl,$currenturl);
319: }
320: # ------------------------------------------------- Check for critical messages
321: if ((time-$ENV{'user.criticalcheck.time'})>300) {
322: my @what=&Apache::lonnet::dump
323: ('critical',$ENV{'user.domain'},
324: $ENV{'user.name'});
325: if ($what[0]) {
326: if (($what[0] ne 'con_lost') &&
327: ($what[0]!~/^error\:/)) {
328: $redirecturl='/adm/email?critical=display';
329: }
330: }
331: &Apache::lonnet::appenv('user.criticalcheck.time'=>time);
332: }
333:
334: $r->content_type('text/html');
335: $r->header_out(Location =>
336: 'http://'.$ENV{'HTTP_HOST'}.$redirecturl);
337: return REDIRECT;
338: } else {
339: # --------------------------------------------------------- There was a problem
340: $r->content_type('text/html');
341: $r->send_http_header;
342: if ($#possibilities>0) {
343: my $bodytag=
344: &Apache::loncommon::bodytag('Multiple Resources');
345: $r->print(<<ENDSTART);
346: <head><title>Choose Next Location</title></head>
347: $bodytag
348: <h3>There are several possibilities of where to go next</h3>
349: <p>
350: Please click on the the resource you intend to access:
351: <p>
352: <table border=2>
353: <tr><th>Title</th><th>Type</th></tr>
354: ENDSTART
355: foreach (@possibilities) {
356: $r->print(
357: '<tr><td><a href="'.
358: $multichoicehash{'src_'.$_}.'?symb=' .
359: Apache::lonnet::escape($multichoicehash{'symb_'.$_}).'">'.
360: $multichoicehash{'title_'.$_}.
361: '</a></td><td>'.$multichoicehash{'type_'.$_}.
362: '</td></tr>');
363: }
364: $r->print('</table></body></html>');
365: return OK;
366: } else {
367: my $bodytag=&Apache::loncommon::bodytag('No Resource');
368: $r->print(<<ENDNONE);
369: <head><title>No Resource</title></head>
370: $bodytag
371: <h3>Next resource could not be identified.</h3>
372: <p>You probably are at the <b>beginning</b> or the <b>end</b> of the
373: course.</p>
374: <ul>
375: <li><a href="/adm/flip?postdata=return:">Go Back</a></li>
376: <li><a href="/adm/navmaps">Navigate Course Content</a></li>
377: </ul>
378: </body>
379: </html>
380: ENDNONE
381: return OK;
382: }
383: }
384: } else {
385: # ------------------------------------------------- Problem, could not tie hash
386: $ENV{'user.error.msg'}="/adm/flip:bre:0:1:Course Data Missing";
387: return HTTP_NOT_ACCEPTABLE;
388: }
389: } else {
390: # ---------------------------------------- No, could not determine where we are
391: $r->internal_redirect('/adm/ambiguous');
392: }
393: } else {
394: # -------------------------- Class was not initialized or page fliped strangely
395: $ENV{'user.error.msg'}="/adm/flip:bre:0:0:Choose Course";
396: return HTTP_NOT_ACCEPTABLE;
397: }
398: }
399:
400: 1;
401: __END__
402:
403:
404:
405:
406:
407:
408:
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