1: # The LearningOnline Network with CAPA
2: # Handler to resolve ambiguous file locations
3: #
4: # $Id: lonambiguous.pm,v 1.17 2006/02/07 19:46:08 albertel Exp $
5: #
6: # Copyright Michigan State University Board of Trustees
7: #
8: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
9: #
10: # LON-CAPA is free software; you can redistribute it and/or modify
11: # it under the terms of the GNU General Public License as published by
12: # the Free Software Foundation; either version 2 of the License, or
13: # (at your option) any later version.
14: #
15: # LON-CAPA is distributed in the hope that it will be useful,
16: # but WITHOUT ANY WARRANTY; without even the implied warranty of
17: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18: # GNU General Public License for more details.
19: #
20: # You should have received a copy of the GNU General Public License
21: # along with LON-CAPA; if not, write to the Free Software
22: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23: #
24: # /home/httpd/html/adm/gpl.txt
25: #
26: # http://www.lon-capa.org/
27: #
28:
29: package Apache::lonambiguous;
30:
31: use strict;
32: use Apache::lonnet;
33: use Apache::Constants qw(:common REDIRECT);
34: use GDBM_File;
35: use Apache::loncommon;
36: use Apache::lonlocal;
37:
38: my %bighash;
39:
40: sub cleanup {
41: if (tied(%bighash)){
42: &Apache::lonnet::logthis('Cleanup ambiguous: bighash');
43: unless (untie(%bighash)) {
44: &Apache::lonnet::logthis('Failed cleanup ambiguous: bighash');
45: }
46: }
47: return OK;
48: }
49:
50: # ----------------------------------------------------------- Could not resolve
51:
52: sub getlost {
53: my ($r,$errmsg)=@_;
54: $errmsg=&mt($errmsg);
55: &Apache::loncommon::content_type($r,'text/html');
56: $r->send_http_header;
57: $r->print(
58: '<head><title>Unknown Error</title></head>'.
59: &Apache::loncommon::bodytag('Could not handle ambiguous resource reference').
60: $errmsg.
61: '</body></html>');
62: }
63:
64: # ================================================================ Main Handler
65:
66: sub make_symb {
67: my ($id)=@_;
68: my ($mapid,$resid)=split(/\./,$id);
69: my $map=$bighash{'map_id_'.$mapid};
70: my $res=$bighash{'src_'.$id};
71: my $symb=&Apache::lonnet::encode_symb($map,$resid,$res);
72: return $symb;
73: }
74:
75: sub handler {
76: my $r=shift;
77:
78: if ($r->header_only) {
79: &Apache::loncommon::content_type($r,'text/html');
80: $r->send_http_header;
81: return OK;
82: }
83:
84: # ---------------------------------------------------------- Is this selecting?
85:
86: if ($env{'form.selecturl'}) {
87: my $envkey;
88: if (tie(%bighash,'GDBM_File',$env{'request.course.fn'}.'.db',
89: &GDBM_READER(),0640)) {
90: foreach $envkey (keys %env) {
91: if ($envkey=~/^form\.(\d+)\.(\d+)$/) {
92: # ---------------------------------------------------- Update symb and redirect
93: my $mapid=$1;
94: my $resid=$2;
95: my $resurl=$bighash{'src_'.$mapid.'.'.$resid};
96: &Apache::lonnet::symblist($bighash{'map_id_'.$mapid},
97: $resurl => [$resurl,$resid]);
98: untie(%bighash);
99: $r->header_out(Location =>
100: 'http://'.$ENV{'HTTP_HOST'}.$resurl);
101: return REDIRECT;
102: }
103: }
104: untie(%bighash);
105: } else {
106: &getlost($r,'Could not access course structure.');
107: return OK;
108: }
109: }
110:
111: # ---------------------------------------------------------- Do we have a case?
112:
113: my $thisfn;
114: unless (($thisfn=$env{'request.ambiguous'})&&($env{'request.course.fn'})) {
115: &getlost($r,'Could not find information on resource.');
116: return OK;
117: }
118:
119: # ---------------------------------- Should this file have been part of a page?
120:
121: $thisfn=&Apache::lonnet::declutter($thisfn);
122: my %hash;
123: my $syval='';
124:
125: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'_symb.db',
126: &GDBM_READER(),0640)) {
127: $syval=$hash{$thisfn};
128: untie(%hash);
129: }
130:
131: # ---------------------------------------------------------- There was an entry
132:
133: if ($syval) {
134: my ($page,undef,$res)=&Apache::lonnet::decode_symb($syval);
135: if ($res eq 'page') {
136: # ----------------------------------- Okay, this should have appeared on a page
137: &Apache::loncommon::content_type($r,'text/html');
138: $r->header_out(Location =>
139: 'http://'.$ENV{'HTTP_HOST'}.
140: &Apache::lonnet::clutter($page));
141: return REDIRECT;
142: } else {
143: # There is not really a problem (???), but cannot go back without endless loop
144: &getlost($r,'The nature of the problem is unclear');
145: return OK;
146: }
147: }
148: # ------------------------------------Encrypted requests go straight to navmaps
149: if ($env{'request.enc'}) {
150: &Apache::loncommon::content_type($r,'text/html');
151: $r->header_out(Location => 'http://'.$ENV{'HTTP_HOST'}.'/adm/navmaps');
152: return REDIRECT;
153: }
154: # ------------------------------------------------ Would be standalone resource
155:
156: if (tie(%bighash,'GDBM_File',$env{'request.course.fn'}.'.db',
157: &GDBM_READER(),0640)) {
158: # ---------------------------------------------- Get ID(s) for current resource
159: my $ids=$bighash{'ids_'.&Apache::lonnet::clutter($thisfn)};
160: if ($ids) {
161: # ------------------------------------------------------------------- Has ID(s)
162: my @possibilities=split(/\,/,$ids);
163: my $couldbe='';
164: foreach (@possibilities) {
165: if ($bighash{'encrypted_'.$_}) { next; }
166: my $symb=&make_symb($_);
167: if (&Apache::lonnet::allowed('bre',$bighash{'src_'.$_},$symb)) {
168: if ($couldbe) {
169: $couldbe.=','.$_;
170: } else {
171: $couldbe=$_;
172: }
173: }
174: }
175: if ($couldbe) {
176: @possibilities=split(/\,/,$couldbe);
177: if ($#possibilities==0) {
178: my $id=$possibilities[0];
179: my $resurl=$bighash{'src_'.$id};
180: my $mapurl=$bighash{'map_id_'.(split(/\./,$id))[0]};
181: my $symb=&make_symb($id);
182: &Apache::loncommon::content_type($r,'text/html');
183: &Apache::lonnet::logthis('http://'.$ENV{'HTTP_HOST'}.$resurl.'?symb='.$symb);
184: $r->header_out(Location =>
185: 'http://'.$ENV{'HTTP_HOST'}.$resurl.'?symb='.$symb);
186: return REDIRECT;
187: }
188: if ($#possibilities>0) {
189: # ----------------------------------------------- Okay, really multiple choices
190: &Apache::loncommon::content_type($r,'text/html');
191: $r->send_http_header;
192: my $bodytag=
193: &Apache::loncommon::bodytag('Pick Instance of Resource');
194: $r->print(<<ENDSTART);
195: <head><title>Choose Location</title></head>
196: $bodytag
197: The resource you had been accessing appears more than once in this course,
198: and LON-CAPA has insufficient session information to determine which instance
199: of the resource you meant.
200: <p>
201: Please click on the instance of the resource you intended to access:
202: </p>
203: <table border="2">
204: <tr><th>Title</th><th>Part of ...</th></tr>
205: ENDSTART
206: map {
207: my $resurl=$bighash{'src_'.$_};
208: my $mapurl=$bighash{'map_id_'.(split(/\./,$_))[0]};
209: my $symb=&make_symb($_);
210: $r->print('<tr><td><a href="'.$resurl.'?symb='.$symb.'">'.
211: &Apache::lonnet::gettitle($symb).
212: '</a></td><td>'.
213: &Apache::lonnet::gettitle($mapurl).' '.
214: '</td></tr>');
215: } @possibilities;
216: $r->print('</table></body></html>');
217: untie(%bighash);
218: return OK;
219: }
220: }
221: }
222: untie(%bighash);
223: }
224:
225: # ------------------------------------ This handler should not have been called
226: &getlost($r,'Invalid call of handler');
227: return OK;
228: }
229:
230: 1;
231: __END__
232:
233:
234:
235:
236:
237:
238:
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