1: # The LearningOnline Network with CAPA
2: #
3: # Page flip handler
4: #
5: # $Id: lonpageflip.pm,v 1.51 2005/02/17 09:09:57 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: # ================================================================ Main Handler
175:
176: sub handler {
177: my $r=shift;
178:
179: # ------------------------------------------- Set document type for header only
180:
181: if ($r->header_only) {
182: &Apache::loncommon::content_type($r,'text/html');
183: $r->send_http_header;
184: return OK;
185: }
186:
187: my %cachehash=();
188: my $multichoice=0;
189: my %multichoicehash=();
190: my $redirecturl='';
191: my $next='';
192: my @possibilities=();
193: &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},['postdata']);
194: if (($ENV{'form.postdata'})&&($ENV{'request.course.fn'})) {
195: $ENV{'form.postdata'}=~/(\w+)\:(.*)/;
196: my $direction=$1;
197: my $currenturl=$2;
198: if ($currenturl=~m|^/enc/|) {
199: $currenturl=&Apache::lonenc::unencrypted($currenturl);
200: }
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: $id=$hash{'map_pc_'.&Apache::lonnet::clutter($murl)}.'.'.$id;
217: $newloc=$hash{'src_'.$id};
218: if ($newloc) {
219: if ($hash{'encrypted_'.$id}) { $newloc=&Apache::lonenc::encrypted($newloc); }
220:
221: } else {
222: $newloc='/adm/noidea.html';
223: }
224: untie %hash;
225: } else {
226: $newloc='/adm/noidea.html';
227: }
228: &Apache::loncommon::content_type($r,'text/html');
229: $r->header_out(Location =>
230: 'http://'.$ENV{'HTTP_HOST'}.$newloc);
231:
232: return REDIRECT;
233: }
234: $currenturl=~s/^http\:\/\///;
235: $currenturl=~s/^[^\/]+//;
236: #
237: # Is the current URL on the map? If not, start with last known URL
238: #
239: unless (&Apache::lonnet::is_on_map($currenturl)) {
240: my $last;
241: if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'_symb.db',
242: &GDBM_READER(),0640)) {
243: $last=$hash{'last_known'};
244: untie(%hash);
245: }
246: if ($last) {
247: $currenturl=&Apache::lonnet::clutter((&Apache::lonnet::decode_symb($last))[1]);
248: } else {
249: &Apache::loncommon::content_type($r,'text/html');
250: $r->header_out(Location =>
251: 'http://'.$ENV{'HTTP_HOST'}.'/adm/noidea.html');
252: return REDIRECT;
253: }
254: }
255: # ------------------------------------------- Do we have any idea where we are?
256: my $position;
257: if ($position=Apache::lonnet::symbread($currenturl)) {
258: # ------------------------------------------------------------------------- Yes
259: my ($startoutmap,$mapnum,$thisurl)=&Apache::lonnet::decode_symb($position);
260: $cachehash{$startoutmap}{$thisurl}=$mapnum;
261: $cachehash{$startoutmap}{'last_known'}=
262: &Apache::lonnet::declutter($currenturl);
263:
264: # ============================================================ Tie the big hash
265: if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'.db',
266: &GDBM_READER(),0640)) {
267: my $rid=$hash{'map_pc_'.&Apache::lonnet::clutter($startoutmap)}.
268: '.'.$mapnum;
269:
270: # ------------------------------------------------- Move forward, backward, etc
271: my $endupmap;
272: ($next,$endupmap)=&move($rid,$startoutmap,$direction);
273: # -------------------------------------- Do we have one and only one empty URL?
274: my $safecount=0;
275: while (($next) && ($next!~/\,/) &&
276: ((!$hash{'src_'.$next}) ||
277: ((!$ENV{'request.role.adv'}) && $hash{'randomout_'.$next}))
278: && ($safecount<10000)) {
279: ($next,$endupmap)=&move($next,$endupmap,$direction);
280: $safecount++;
281: }
282: # We are now at at least one non-empty URL
283: # ----------------------------------------------------- Check out possibilities
284: if ($next) {
285: @possibilities=split(/\,/,$next);
286: if ($#possibilities==0) {
287: # ---------------------------------------------- Only one possibility, redirect
288: $redirecturl=&hash_src($next);
289: $cachehash{$endupmap}
290: {&Apache::lonnet::declutter($redirecturl)}
291: =(split(/\./,$next))[1];
292: } else {
293: # ------------------------ There are multiple possibilities for a next resource
294: $multichoice=1;
295: map {
296: $multichoicehash{'src_'.$_}=$hash{'src_'.$_};
297: $multichoicehash{'title_'.$_}=$hash{'title_'.$_};
298: $multichoicehash{'type_'.$_}=$hash{'type_'.$_};
299: (my $first, my $second) = $_ =~ /(\d+).(\d+)/;
300: my $symbSrc = Apache::lonnet::declutter($hash{'src_'.$_});
301: $multichoicehash{'symb_'.$_} =
302: Apache::lonnet::declutter($hash{'map_id_'.$first}.'___'.
303: $second.'___'.$symbSrc);
304:
305: my ($choicemap,$choiceres)=split(/\./,$_);
306: $cachehash
307: {&Apache::lonnet::declutter($hash{'src_'.$choicemap})}
308: {&Apache::lonnet::declutter(
309: $multichoicehash
310: {'src_'.$_}
311: )}
312: =$choiceres;
313: } @possibilities;
314: }
315: } else {
316: # -------------------------------------------------------------- No place to go
317: $multichoice=-1;
318: }
319: # ----------------- The program must come past this point to untie the big hash
320: untie(%hash);
321: # --------------------------------------------------------- Store position info
322: $cachehash{$startoutmap}{'last_direction'}=$direction;
323: foreach my $thismap (keys %cachehash) {
324: &Apache::lonnet::symblist($thismap,%{$cachehash{$thismap}});
325: }
326: # ============================================== Do not return before this line
327: if ($redirecturl) {
328: # ----------------------------------------------------- There is a URL to go to
329: if ($direction eq 'forward') {
330: &Apache::lonnet::linklog($currenturl,$redirecturl);
331: }
332: if ($direction eq 'back') {
333: &Apache::lonnet::linklog($redirecturl,$currenturl);
334: }
335: # ------------------------------------------------- Check for critical messages
336: if ((time-$ENV{'user.criticalcheck.time'})>300) {
337: my @what=&Apache::lonnet::dump
338: ('critical',$ENV{'user.domain'},
339: $ENV{'user.name'});
340: if ($what[0]) {
341: if (($what[0] ne 'con_lost') &&
342: ($what[0]!~/^error\:/)) {
343: $redirecturl='/adm/email?critical=display';
344: }
345: }
346: &Apache::lonnet::appenv('user.criticalcheck.time'=>time);
347: }
348:
349: &Apache::loncommon::content_type($r,'text/html');
350: $r->header_out(Location =>
351: 'http://'.$ENV{'HTTP_HOST'}.$redirecturl);
352: return REDIRECT;
353: } else {
354: # --------------------------------------------------------- There was a problem
355: &Apache::loncommon::content_type($r,'text/html');
356: $r->send_http_header;
357: if ($#possibilities>0) {
358: my $bodytag=
359: &Apache::loncommon::bodytag('Multiple Resources');
360: $r->print(<<ENDSTART);
361: <head><title>Choose Next Location</title></head>
362: $bodytag
363: <h3>There are several possibilities of where to go next</h3>
364: <p>
365: Please click on the the resource you intend to access:
366: <p>
367: <table border=2>
368: <tr><th>Title</th><th>Type</th></tr>
369: ENDSTART
370: foreach (@possibilities) {
371: $r->print(
372: '<tr><td><a href="'.
373: $multichoicehash{'src_'.$_}.'?symb=' .
374: Apache::lonnet::escape($multichoicehash{'symb_'.$_}).'">'.
375: $multichoicehash{'title_'.$_}.
376: '</a></td><td>'.$multichoicehash{'type_'.$_}.
377: '</td></tr>');
378: }
379: $r->print('</table></body></html>');
380: return OK;
381: } else {
382: my $bodytag=&Apache::loncommon::bodytag('No Resource');
383: $r->print(<<ENDNONE);
384: <head><title>No Resource</title></head>
385: $bodytag
386: <h3>Next resource could not be identified.</h3>
387: <p>You probably are at the <b>beginning</b> or the <b>end</b> of the
388: course.</p>
389: <ul>
390: <li><a href="/adm/flip?postdata=return:">Go Back</a></li>
391: <li><a href="/adm/navmaps">Navigate Course Content</a></li>
392: </ul>
393: </body>
394: </html>
395: ENDNONE
396: return OK;
397: }
398: }
399: } else {
400: # ------------------------------------------------- Problem, could not tie hash
401: $ENV{'user.error.msg'}="/adm/flip:bre:0:1:Course Data Missing";
402: return HTTP_NOT_ACCEPTABLE;
403: }
404: } else {
405: # ---------------------------------------- No, could not determine where we are
406: if ( &Apache::lonnet::mod_perl_version() == 2 ) {
407: &Apache::lonnet::cleanenv();
408: }
409: $r->internal_redirect('/adm/ambiguous');
410: }
411: } else {
412: # -------------------------- Class was not initialized or page fliped strangely
413: $ENV{'user.error.msg'}="/adm/flip:bre:0:0:Choose Course";
414: return HTTP_NOT_ACCEPTABLE;
415: }
416: }
417:
418: 1;
419: __END__
420:
421:
422:
423:
424:
425:
426:
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