1: # The LearningOnline Network with CAPA
2: #
3: # Page flip handler
4: #
5: # $Id: lonpageflip.pm,v 1.52 2005/03/01 00:22:57 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,$id,$fn)=&Apache::lonnet::decode_symb($last);
214: $id=$hash{'map_pc_'.&Apache::lonnet::clutter($murl)}.'.'.$id;
215: $newloc=$hash{'src_'.$id};
216: if ($newloc) {
217: if ($hash{'encrypted_'.$id}) { $newloc=&Apache::lonenc::encrypted($newloc); }
218:
219: } else {
220: $newloc='/adm/noidea.html';
221: }
222: untie %hash;
223: } else {
224: $newloc='/adm/noidea.html';
225: }
226: &Apache::loncommon::content_type($r,'text/html');
227: $r->header_out(Location =>
228: 'http://'.$ENV{'HTTP_HOST'}.$newloc);
229:
230: return REDIRECT;
231: }
232: $currenturl=~s/^http\:\/\///;
233: $currenturl=~s/^[^\/]+//;
234: #
235: # Is the current URL on the map? If not, start with last known URL
236: #
237: unless (&Apache::lonnet::is_on_map($currenturl)) {
238: my $last;
239: if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'_symb.db',
240: &GDBM_READER(),0640)) {
241: $last=$hash{'last_known'};
242: untie(%hash);
243: }
244: if ($last) {
245: $currenturl=&Apache::lonnet::clutter((&Apache::lonnet::decode_symb($last))[2]);
246: } else {
247: &Apache::loncommon::content_type($r,'text/html');
248: $r->header_out(Location =>
249: 'http://'.$ENV{'HTTP_HOST'}.'/adm/noidea.html');
250: return REDIRECT;
251: }
252: }
253: # ------------------------------------------- Do we have any idea where we are?
254: my $position;
255: if ($position=Apache::lonnet::symbread($currenturl)) {
256: # ------------------------------------------------------------------------- Yes
257: my ($startoutmap,$mapnum,$thisurl)=&Apache::lonnet::decode_symb($position);
258: $cachehash{$startoutmap}{$thisurl}=[$thisurl,$mapnum];
259: $cachehash{$startoutmap}{'last_known'}=
260: [&Apache::lonnet::declutter($currenturl),$mapnum];
261:
262: # ============================================================ Tie the big hash
263: if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'.db',
264: &GDBM_READER(),0640)) {
265: my $rid=$hash{'map_pc_'.&Apache::lonnet::clutter($startoutmap)}.
266: '.'.$mapnum;
267:
268: # ------------------------------------------------- Move forward, backward, etc
269: my $endupmap;
270: ($next,$endupmap)=&move($rid,$startoutmap,$direction);
271: # -------------------------------------- Do we have one and only one empty URL?
272: my $safecount=0;
273: while (($next) && ($next!~/\,/) &&
274: ((!$hash{'src_'.$next}) ||
275: ((!$ENV{'request.role.adv'}) && $hash{'randomout_'.$next}))
276: && ($safecount<10000)) {
277: ($next,$endupmap)=&move($next,$endupmap,$direction);
278: $safecount++;
279: }
280: # We are now at at least one non-empty URL
281: # ----------------------------------------------------- Check out possibilities
282: if ($next) {
283: @possibilities=split(/\,/,$next);
284: if ($#possibilities==0) {
285: # ---------------------------------------------- Only one possibility, redirect
286: $redirecturl=&hash_src($next);
287: $cachehash{$endupmap}{$redirecturl}=
288: [$redirecturl,(split(/\./,$next))[1]];
289: } else {
290: # ------------------------ There are multiple possibilities for a next resource
291: $multichoice=1;
292: map {
293: $multichoicehash{'src_'.$_}=$hash{'src_'.$_};
294: $multichoicehash{'title_'.$_}=$hash{'title_'.$_};
295: $multichoicehash{'type_'.$_}=$hash{'type_'.$_};
296: (my $first, my $second) = $_ =~ /(\d+).(\d+)/;
297: my $symbSrc = Apache::lonnet::declutter($hash{'src_'.$_});
298: $multichoicehash{'symb_'.$_} =
299: Apache::lonnet::declutter($hash{'map_id_'.$first}.'___'.
300: $second.'___'.$symbSrc);
301:
302: my ($choicemap,$choiceres)=split(/\./,$_);
303: my $map=&Apache::lonnet::declutter($hash{'src_'.$choicemap});
304: my $url=$multichoicehash{'src_'.$_};
305: $cachehash{$map}{$url}=[$url,$choiceres];
306: } @possibilities;
307: }
308: } else {
309: # -------------------------------------------------------------- No place to go
310: $multichoice=-1;
311: }
312: # ----------------- The program must come past this point to untie the big hash
313: untie(%hash);
314: # --------------------------------------------------------- Store position info
315: $cachehash{$startoutmap}{'last_direction'}=[$direction,'notasymb'];
316: foreach my $thismap (keys %cachehash) {
317: my $mapnum=$cachehash{$thismap}->{'mapnum'};
318: delete($cachehash{$thismap}->{'mapnum'});
319: &Apache::lonnet::symblist($thismap,
320: %{$cachehash{$thismap}});
321: }
322: # ============================================== Do not return before this line
323: if ($redirecturl) {
324: # ----------------------------------------------------- There is a URL to go to
325: if ($direction eq 'forward') {
326: &Apache::lonnet::linklog($currenturl,$redirecturl);
327: }
328: if ($direction eq 'back') {
329: &Apache::lonnet::linklog($redirecturl,$currenturl);
330: }
331: # ------------------------------------------------- Check for critical messages
332: if ((time-$ENV{'user.criticalcheck.time'})>300) {
333: my @what=&Apache::lonnet::dump
334: ('critical',$ENV{'user.domain'},
335: $ENV{'user.name'});
336: if ($what[0]) {
337: if (($what[0] ne 'con_lost') &&
338: ($what[0]!~/^error\:/)) {
339: $redirecturl='/adm/email?critical=display';
340: }
341: }
342: &Apache::lonnet::appenv('user.criticalcheck.time'=>time);
343: }
344:
345: &Apache::loncommon::content_type($r,'text/html');
346: $r->header_out(Location =>
347: 'http://'.$ENV{'HTTP_HOST'}.$redirecturl);
348: return REDIRECT;
349: } else {
350: # --------------------------------------------------------- There was a problem
351: &Apache::loncommon::content_type($r,'text/html');
352: $r->send_http_header;
353: if ($#possibilities>0) {
354: my $bodytag=
355: &Apache::loncommon::bodytag('Multiple Resources');
356: $r->print(<<ENDSTART);
357: <head><title>Choose Next Location</title></head>
358: $bodytag
359: <h3>There are several possibilities of where to go next</h3>
360: <p>
361: Please click on the the resource you intend to access:
362: <p>
363: <table border=2>
364: <tr><th>Title</th><th>Type</th></tr>
365: ENDSTART
366: foreach (@possibilities) {
367: $r->print(
368: '<tr><td><a href="'.
369: $multichoicehash{'src_'.$_}.'?symb=' .
370: Apache::lonnet::escape($multichoicehash{'symb_'.$_}).'">'.
371: $multichoicehash{'title_'.$_}.
372: '</a></td><td>'.$multichoicehash{'type_'.$_}.
373: '</td></tr>');
374: }
375: $r->print('</table></body></html>');
376: return OK;
377: } else {
378: my $bodytag=&Apache::loncommon::bodytag('No Resource');
379: $r->print(<<ENDNONE);
380: <head><title>No Resource</title></head>
381: $bodytag
382: <h3>Next resource could not be identified.</h3>
383: <p>You probably are at the <b>beginning</b> or the <b>end</b> of the
384: course.</p>
385: <ul>
386: <li><a href="/adm/flip?postdata=return:">Go Back</a></li>
387: <li><a href="/adm/navmaps">Navigate Course Content</a></li>
388: </ul>
389: </body>
390: </html>
391: ENDNONE
392: return OK;
393: }
394: }
395: } else {
396: # ------------------------------------------------- Problem, could not tie hash
397: $ENV{'user.error.msg'}="/adm/flip:bre:0:1:Course Data Missing";
398: return HTTP_NOT_ACCEPTABLE;
399: }
400: } else {
401: # ---------------------------------------- No, could not determine where we are
402: if ( &Apache::lonnet::mod_perl_version() == 2 ) {
403: &Apache::lonnet::cleanenv();
404: }
405: $r->internal_redirect('/adm/ambiguous');
406: }
407: } else {
408: # -------------------------- Class was not initialized or page fliped strangely
409: $ENV{'user.error.msg'}="/adm/flip:bre:0:0:Choose Course";
410: return HTTP_NOT_ACCEPTABLE;
411: }
412: }
413:
414: 1;
415: __END__
416:
417:
418:
419:
420:
421:
422:
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