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[LON-CAPA] /
rat /
lonpageflip.pm
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1.47:
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Thu Apr 8 09:14:41 2004 UTC (20 years, 6 months ago) by
raeburn
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CVS tags:
version_1_2_1,
version_1_2_0,
version_1_1_99_5,
version_1_1_99_4,
version_1_1_99_3,
version_1_1_99_2,
version_1_1_99_1,
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Accommodate case where we are moving forwards (or backwards) and encounter an empty folder, followed (or preceded) by a page. This situation can occur for a course structure created from an IMS import.
1: # The LearningOnline Network with CAPA
2: #
3: # Page flip handler
4: #
5: # $Id: lonpageflip.pm,v 1.47 2004/04/08 09:14:41 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: # (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_'.$next}) || ($hash{'randomout_'.$next}))
272: && ($safecount<10000)) {
273: ($next,$endupmap)=&move($next,$endupmap,$direction);
274: $safecount++;
275: }
276: # We are now at at least one non-empty URL
277: # ----------------------------------------------------- Check out possibilities
278: if ($next) {
279: @possibilities=split(/\,/,$next);
280: if ($#possibilities==0) {
281: # ---------------------------------------------- Only one possibility, redirect
282: $redirecturl=$hash{'src_'.$next};
283: $cachehash{$endupmap}
284: {&Apache::lonnet::declutter($redirecturl)}
285: =(split(/\./,$next))[1];
286: } else {
287: # ------------------------ There are multiple possibilities for a next resource
288: $multichoice=1;
289: map {
290: $multichoicehash{'src_'.$_}=$hash{'src_'.$_};
291: $multichoicehash{'title_'.$_}=$hash{'title_'.$_};
292: $multichoicehash{'type_'.$_}=$hash{'type_'.$_};
293: (my $first, my $second) = $_ =~ /(\d+).(\d+)/;
294: my $symbSrc = Apache::lonnet::declutter($hash{'src_'.$_});
295: $multichoicehash{'symb_'.$_} =
296: Apache::lonnet::declutter($hash{'map_id_'.$first}.'___'.
297: $second.'___'.$symbSrc);
298:
299: my ($choicemap,$choiceres)=split(/\./,$_);
300: $cachehash
301: {&Apache::lonnet::declutter($hash{'src_'.$choicemap})}
302: {&Apache::lonnet::declutter(
303: $multichoicehash
304: {'src_'.$_}
305: )}
306: =$choiceres;
307: } @possibilities;
308: }
309: } else {
310: # -------------------------------------------------------------- No place to go
311: $multichoice=-1;
312: }
313: # ----------------- The program must come past this point to untie the big hash
314: untie(%hash);
315: # --------------------------------------------------------- Store position info
316: $cachehash{$startoutmap}{'last_direction'}=$direction;
317: foreach my $thismap (keys %cachehash) {
318: &Apache::lonnet::symblist($thismap,%{$cachehash{$thismap}});
319: }
320: # ============================================== Do not return before this line
321: if ($redirecturl) {
322: # ----------------------------------------------------- There is a URL to go to
323: if ($direction eq 'forward') {
324: &Apache::lonnet::linklog($currenturl,$redirecturl);
325: }
326: if ($direction eq 'back') {
327: &Apache::lonnet::linklog($redirecturl,$currenturl);
328: }
329: # ------------------------------------------------- Check for critical messages
330: if ((time-$ENV{'user.criticalcheck.time'})>300) {
331: my @what=&Apache::lonnet::dump
332: ('critical',$ENV{'user.domain'},
333: $ENV{'user.name'});
334: if ($what[0]) {
335: if (($what[0] ne 'con_lost') &&
336: ($what[0]!~/^error\:/)) {
337: $redirecturl='/adm/email?critical=display';
338: }
339: }
340: &Apache::lonnet::appenv('user.criticalcheck.time'=>time);
341: }
342:
343: $r->content_type('text/html');
344: $r->header_out(Location =>
345: 'http://'.$ENV{'HTTP_HOST'}.$redirecturl);
346: return REDIRECT;
347: } else {
348: # --------------------------------------------------------- There was a problem
349: $r->content_type('text/html');
350: $r->send_http_header;
351: if ($#possibilities>0) {
352: my $bodytag=
353: &Apache::loncommon::bodytag('Multiple Resources');
354: $r->print(<<ENDSTART);
355: <head><title>Choose Next Location</title></head>
356: $bodytag
357: <h3>There are several possibilities of where to go next</h3>
358: <p>
359: Please click on the the resource you intend to access:
360: <p>
361: <table border=2>
362: <tr><th>Title</th><th>Type</th></tr>
363: ENDSTART
364: foreach (@possibilities) {
365: $r->print(
366: '<tr><td><a href="'.
367: $multichoicehash{'src_'.$_}.'?symb=' .
368: Apache::lonnet::escape($multichoicehash{'symb_'.$_}).'">'.
369: $multichoicehash{'title_'.$_}.
370: '</a></td><td>'.$multichoicehash{'type_'.$_}.
371: '</td></tr>');
372: }
373: $r->print('</table></body></html>');
374: return OK;
375: } else {
376: my $bodytag=&Apache::loncommon::bodytag('No Resource');
377: $r->print(<<ENDNONE);
378: <head><title>No Resource</title></head>
379: $bodytag
380: <h3>Next resource could not be identified.</h3>
381: <p>You probably are at the <b>beginning</b> or the <b>end</b> of the
382: course.</p>
383: <ul>
384: <li><a href="/adm/flip?postdata=return:">Go Back</a></li>
385: <li><a href="/adm/navmaps">Navigate Course Content</a></li>
386: </ul>
387: </body>
388: </html>
389: ENDNONE
390: return OK;
391: }
392: }
393: } else {
394: # ------------------------------------------------- Problem, could not tie hash
395: $ENV{'user.error.msg'}="/adm/flip:bre:0:1:Course Data Missing";
396: return HTTP_NOT_ACCEPTABLE;
397: }
398: } else {
399: # ---------------------------------------- No, could not determine where we are
400: if ( &Apache::lonnet::mod_perl_version() == 2 ) {
401: &Apache::lonnet::cleanenv();
402: }
403: $r->internal_redirect('/adm/ambiguous');
404: }
405: } else {
406: # -------------------------- Class was not initialized or page fliped strangely
407: $ENV{'user.error.msg'}="/adm/flip:bre:0:0:Choose Course";
408: return HTTP_NOT_ACCEPTABLE;
409: }
410: }
411:
412: 1;
413: __END__
414:
415:
416:
417:
418:
419:
420:
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