1: # The LearningOnline Network with CAPA
2: #
3: # Page flip handler
4: #
5: # $Id: lonpageflip.pm,v 1.25 2002/05/23 15:07:55 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 addrid {
54: my ($current,$new,$condid)=@_;
55: unless ($condid) { $condid=0; }
56: if (&Apache::lonnet::allowed('bre',$hash{'src_'.$new})) {
57: if ($current) {
58: $current.=','.$new;
59: } else {
60: $current=''.$new;
61: }
62: }
63: return $current;
64: }
65:
66: sub fullmove {
67: my ($rid,$mapurl,$direction)=@_;
68: if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'.db',
69: &GDBM_READER,0640)) {
70: ($rid,$mapurl)=&move($rid,$mapurl,$direction);
71: untie(%hash);
72: }
73: return($rid,$mapurl);
74: }
75:
76: sub move {
77: my ($rid,$mapurl,$direction)=@_;
78: my $startoutrid=$rid;
79:
80: my $next='';
81:
82: my $mincond=1;
83: my $posnext='';
84: if ($direction eq 'forward') {
85: # --------------------------------------------------------------------- Forward
86: if ($hash{'type_'.$rid} eq 'finish') {
87: $rid=$hash{'ids_/res/'.$mapurl};
88: }
89: map {
90: my $thiscond=
91: &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}});
92: if ($thiscond>=$mincond) {
93: if ($posnext) {
94: $posnext.=','.$_.':'.$thiscond;
95: } else {
96: $posnext=$_.':'.$thiscond;
97: }
98: if ($thiscond>$mincond) { $mincond=$thiscond; }
99: }
100: } split(/\,/,$hash{'to_'.$rid});
101: map {
102: my ($linkid,$condval)=split(/\:/,$_);
103: if ($condval>=$mincond) {
104: $next=&addrid($next,$hash{'goesto_'.$linkid},
105: $hash{'condid_'.$hash{'undercond_'.$linkid}});
106: }
107: } split(/\,/,$posnext);
108: if ($hash{'is_map_'.$next}) {
109: # This jumps to the beginning of a new map (going down level)
110: if (
111: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
112: $mapurl=$hash{'src_'.$next};
113: $next=$hash{'map_start_'.$hash{'src_'.$next}};
114: }
115: } elsif
116: ((split(/\./,$startoutrid))[0]!=(split(/\./,$next))[0]) {
117: # This comes up from a map (coming up one level);
118: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
119: }
120: } elsif ($direction eq 'back') {
121: # ------------------------------------------------------------------- Backwards
122: if ($hash{'type_'.$rid} eq 'start') {
123: $rid=$hash{'ids_/res/'.$mapurl};
124: }
125: map {
126: my $thiscond=
127: &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}});
128: if ($thiscond>=$mincond) {
129: if ($posnext) {
130: $posnext.=','.$_.':'.$thiscond;
131: } else {
132: $posnext=$_.':'.$thiscond;
133: }
134: if ($thiscond>$mincond) { $mincond=$thiscond; }
135: }
136: } split(/\,/,$hash{'from_'.$rid});
137: map {
138: my ($linkid,$condval)=split(/\:/,$_);
139: if ($condval>=$mincond) {
140: $next=&addrid($next,$hash{'comesfrom_'.$linkid},
141: $hash{'condid_'.$hash{'undercond_'.$linkid}});
142: }
143: } split(/\,/,$posnext);
144: if ($hash{'is_map_'.$next}) {
145: # This jumps to the end of a new map (going down one level)
146: if (
147: $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
148: $mapurl=$hash{'src_'.$next};
149: $next=$hash{'map_finish_'.$hash{'src_'.$next}};
150: }
151: } elsif
152: ((split(/\./,$startoutrid))[0]!=(split(/\./,$next))[0]) {
153: # This comes back up from a map (going up one level);
154: $mapurl=$hash{'map_id_'.(split(/\./,$next))[0]};
155: }
156: }
157: return ($next,$mapurl);
158: }
159:
160: # ================================================================ Main Handler
161:
162: sub handler {
163: my $r=shift;
164:
165: # ------------------------------------------- Set document type for header only
166:
167: if ($r->header_only) {
168: $r->content_type('text/html');
169: $r->send_http_header;
170: return OK;
171: }
172:
173: my %cachehash=();
174: my $multichoice=0;
175: my %multichoicehash=();
176: my $redirecturl='';
177: my $next='';
178: my @possibilities=();
179: if (($ENV{'form.postdata'})&&($ENV{'request.course.fn'})) {
180: $ENV{'form.postdata'}=~/(\w+)\:(.*)/;
181: my $direction=$1;
182: my $currenturl=$2;
183: if ($direction eq 'return') {
184: # -------------------------------------------------------- Return to last known
185: my $last;
186: if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'_symb.db',
187: &GDBM_READER,0640)) {
188: $last=$hash{'last_known'};
189: untie(%hash);
190: }
191: my $newloc;
192: if ($last) {
193: $newloc='/res/'.(split(/\_\_\_/,$last))[1];
194: } else {
195: $newloc='/adm/noidea.html';
196: }
197: $r->content_type('text/html');
198: $r->header_out(Location =>
199: 'http://'.$ENV{'HTTP_HOST'}.$newloc);
200:
201: return REDIRECT;
202: }
203: $currenturl=~s/^http\:\/\///;
204: $currenturl=~s/^[^\/]+//;
205: unless (($currenturl=~/^\/res\//) ||
206: ($currenturl=~/^\/adm\/wrapper\//)) {
207: my $last;
208: if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'_symb.db',
209: &GDBM_READER,0640)) {
210: $last=$hash{'last_known'};
211: untie(%hash);
212: }
213: if ($last) {
214: $currenturl='/res/'.(split(/\_\_\_/,$last))[1];
215: } else {
216: $r->content_type('text/html');
217: $r->header_out(Location =>
218: 'http://'.$ENV{'HTTP_HOST'}.'/adm/noidea.html');
219: return REDIRECT;
220: }
221: }
222: # ------------------------------------------- Do we have any idea where we are?
223: my $position;
224: if ($position=Apache::lonnet::symbread($currenturl)) {
225: # ------------------------------------------------------------------------- Yes
226: my ($startoutmap,$mapnum,$thisurl)=split(/\_\_\_/,$position);
227: $cachehash{$startoutmap}{$thisurl}=$mapnum;
228: $cachehash{$startoutmap}{'last_known'}=
229: &Apache::lonnet::declutter($currenturl);
230:
231: # ============================================================ Tie the big hash
232: if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'.db',
233: &GDBM_READER,0640)) {
234: my $rid=$hash{'map_pc_/res/'.$startoutmap}.'.'.$mapnum;
235:
236: # ------------------------------------------------- Move forward, backward, etc
237: my $endupmap;
238: ($next,$endupmap)=&move($rid,$startoutmap,$direction);
239: # -------------------------------------- Do we have one and only one empty URL?
240: my $safecount=0;
241: while (($next) && ($next!~/\,/) && (!$hash{'src_'.$next})
242: && ($safecount<25)) {
243: ($next,$endupmap)=&move($next,$endupmap,$direction);
244: $safecount++;
245: }
246: # We are now at at least one non-empty URL
247: # ----------------------------------------------------- Check out possibilities
248: if ($next) {
249: @possibilities=split(/\,/,$next);
250: if ($#possibilities==0) {
251: # ---------------------------------------------- Only one possibility, redirect
252: $redirecturl=$hash{'src_'.$next};
253: $cachehash{$endupmap}
254: {&Apache::lonnet::declutter($redirecturl)}
255: =(split(/\./,$next))[1];
256: } else {
257: # ------------------------ There are multiple possibilities for a next resource
258: $multichoice=1;
259: map {
260: $multichoicehash{'src_'.$_}=$hash{'src_'.$_};
261: $multichoicehash{'title_'.$_}=$hash{'title_'.$_};
262: $multichoicehash{'type_'.$_}=$hash{'type_'.$_};
263: my ($choicemap,$choiceres)=split(/\./,$_);
264: $cachehash
265: {&Apache::lonnet::declutter($hash{'src_'.$choicemap})}
266: {&Apache::lonnet::declutter(
267: $multichoicehash
268: {'src_'.$_}
269: )}
270: =$choiceres;
271: } @possibilities;
272: }
273: } else {
274: # -------------------------------------------------------------- No place to go
275: $multichoice=-1;
276: }
277: # ----------------- The program must come past this point to untie the big hash
278: untie(%hash);
279: # --------------------------------------------------------- Store position info
280: $cachehash{$startoutmap}{'last_direction'}=$direction;
281: foreach my $thismap (keys %cachehash) {
282: &Apache::lonnet::symblist($thismap,%{$cachehash{$thismap}});
283: }
284: # ============================================== Do not return before this line
285: if ($redirecturl) {
286: # ----------------------------------------------------- There is a URL to go to
287: $r->content_type('text/html');
288: $r->header_out(Location =>
289: 'http://'.$ENV{'HTTP_HOST'}.$redirecturl);
290: return REDIRECT;
291: } else {
292: # --------------------------------------------------------- There was a problem
293: $r->content_type('text/html');
294: $r->send_http_header;
295: if ($#possibilities>0) {
296: $r->print(<<ENDSTART);
297: <head><title>Choose Next Location</title></head>
298: <body bgcolor="#FFFFFF">
299: <h1>LON-CAPA</h1>
300: There are several possibilities of where to go next.
301: <p>
302: Please click on the the resource you intend to access:
303: <p>
304: <table border=2>
305: <tr><th>Title</th><th>Type</th></tr>
306: ENDSTART
307: map {
308: $r->print(
309: '<tr><td><a href="'.
310: $multichoicehash{'src_'.$_}.'">'.
311: $multichoicehash{'title_'.$_}.
312: '</a></td><td>'.$multichoicehash{'type_'.$_}.
313: '</td></tr>');
314: } @possibilities;
315: $r->print('</table></body></html>');
316: return OK;
317: } else {
318: $r->print(<<ENDNONE);
319: <head><title>Choose Next Location</title></head>
320: <body bgcolor="#FFFFFF">
321: <img src="/adm/lonIcons/lonlogos.gif" align=right>
322: <h1>Sorry!</h1>
323: <h2>Next resource could not be identified.</h2>
324: <h3>You probably are at the beginning or the end of the course.</h3>
325: </body>
326: </html>
327: ENDNONE
328: return OK;
329: }
330: }
331: } else {
332: # ------------------------------------------------- Problem, could not tie hash
333: $ENV{'user.error.msg'}="/adm/flip:bre:0:1:Course Data Missing";
334: return HTTP_NOT_ACCEPTABLE;
335: }
336: } else {
337: # ---------------------------------------- No, could not determine where we are
338: $r->internal_redirect('/adm/ambiguous');
339: }
340: } else {
341: # -------------------------- Class was not initialized or page fliped strangely
342: $ENV{'user.error.msg'}="/adm/flip:bre:0:0:Choose Course";
343: return HTTP_NOT_ACCEPTABLE;
344: }
345: }
346:
347: 1;
348: __END__
349:
350:
351:
352:
353:
354:
355:
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