Annotation of rat/lonambiguous.pm, revision 1.22
1.1 www 1: # The LearningOnline Network with CAPA
2: # Handler to resolve ambiguous file locations
3: #
1.22 ! jms 4: # $Id: lonambiguous.pm,v 1.21 2006/09/19 19:03:27 albertel Exp $
1.4 www 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: #
1.1 www 28:
1.22 ! jms 29:
! 30: =head1 NAME
! 31:
! 32: Apache::lonambiguous
! 33:
! 34: =head1 SYNOPSIS
! 35:
! 36: Handler to resolve ambiguous file locations.
! 37:
! 38: This is part of the LearningOnline Network with CAPA project
! 39: described at http://www.lon-capa.org.
! 40:
! 41: =head1 HANDLER SUBROUTINE
! 42:
! 43: make_symb()
! 44:
! 45: and
! 46:
! 47: handler()
! 48:
! 49: =head1 OTHER SUBROUTINES
! 50:
! 51: =over
! 52:
! 53: =item *
! 54:
! 55: cleanup()
! 56:
! 57: =item *
! 58:
! 59: getlost()
! 60:
! 61: =back
! 62:
! 63: =cut
! 64:
1.1 www 65: package Apache::lonambiguous;
66:
67: use strict;
68: use Apache::lonnet;
69: use Apache::Constants qw(:common REDIRECT);
70: use GDBM_File;
1.9 www 71: use Apache::loncommon;
1.10 www 72: use Apache::lonlocal;
1.1 www 73:
1.8 www 74: my %bighash;
75:
76: sub cleanup {
77: if (tied(%bighash)){
78: &Apache::lonnet::logthis('Cleanup ambiguous: bighash');
79: unless (untie(%bighash)) {
80: &Apache::lonnet::logthis('Failed cleanup ambiguous: bighash');
81: }
82: }
1.17 albertel 83: return OK;
1.8 www 84: }
1.1 www 85:
86: # ----------------------------------------------------------- Could not resolve
87:
88: sub getlost {
1.2 www 89: my ($r,$errmsg)=@_;
1.10 www 90: $errmsg=&mt($errmsg);
1.14 albertel 91: &Apache::loncommon::content_type($r,'text/html');
1.1 www 92: $r->send_http_header;
1.18 albertel 93: $r->print(&Apache::loncommon::start_page('Could not handle ambiguous resource reference').
94: $errmsg.
1.19 albertel 95: &Apache::loncommon::end_page());
1.1 www 96: }
97:
98: # ================================================================ Main Handler
99:
1.11 albertel 100: sub make_symb {
101: my ($id)=@_;
102: my ($mapid,$resid)=split(/\./,$id);
103: my $map=$bighash{'map_id_'.$mapid};
104: my $res=$bighash{'src_'.$id};
105: my $symb=&Apache::lonnet::encode_symb($map,$resid,$res);
106: return $symb;
107: }
108:
1.1 www 109: sub handler {
110: my $r=shift;
111:
112: if ($r->header_only) {
1.10 www 113: &Apache::loncommon::content_type($r,'text/html');
1.1 www 114: $r->send_http_header;
115: return OK;
116: }
117:
1.2 www 118: # ---------------------------------------------------------- Is this selecting?
1.8 www 119:
1.16 albertel 120: if ($env{'form.selecturl'}) {
1.2 www 121: my $envkey;
1.16 albertel 122: if (tie(%bighash,'GDBM_File',$env{'request.course.fn'}.'.db',
1.5 albertel 123: &GDBM_READER(),0640)) {
1.16 albertel 124: foreach $envkey (keys %env) {
1.2 www 125: if ($envkey=~/^form\.(\d+)\.(\d+)$/) {
1.3 www 126: # ---------------------------------------------------- Update symb and redirect
1.2 www 127: my $mapid=$1;
128: my $resid=$2;
129: my $resurl=$bighash{'src_'.$mapid.'.'.$resid};
130: &Apache::lonnet::symblist($bighash{'map_id_'.$mapid},
1.15 albertel 131: $resurl => [$resurl,$resid]);
1.3 www 132: untie(%bighash);
1.2 www 133: $r->header_out(Location =>
1.21 albertel 134: &Apache::lonnet::absolute_url().$resurl);
1.2 www 135: return REDIRECT;
136: }
137: }
138: untie(%bighash);
139: } else {
140: &getlost($r,'Could not access course structure.');
141: return OK;
142: }
143: }
144:
1.1 www 145: # ---------------------------------------------------------- Do we have a case?
146:
147: my $thisfn;
1.16 albertel 148: unless (($thisfn=$env{'request.ambiguous'})&&($env{'request.course.fn'})) {
1.2 www 149: &getlost($r,'Could not find information on resource.');
1.1 www 150: return OK;
151: }
152:
153: # ---------------------------------- Should this file have been part of a page?
154:
155: $thisfn=&Apache::lonnet::declutter($thisfn);
156: my %hash;
157: my $syval='';
158:
1.16 albertel 159: if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'_symb.db',
1.5 albertel 160: &GDBM_READER(),0640)) {
1.1 www 161: $syval=$hash{$thisfn};
162: untie(%hash);
163: }
1.2 www 164:
1.1 www 165: # ---------------------------------------------------------- There was an entry
1.2 www 166:
1.1 www 167: if ($syval) {
1.15 albertel 168: my ($page,undef,$res)=&Apache::lonnet::decode_symb($syval);
169: if ($res eq 'page') {
1.1 www 170: # ----------------------------------- Okay, this should have appeared on a page
1.14 albertel 171: &Apache::loncommon::content_type($r,'text/html');
1.1 www 172: $r->header_out(Location =>
1.21 albertel 173: &Apache::lonnet::absolute_url().
1.15 albertel 174: &Apache::lonnet::clutter($page));
1.1 www 175: return REDIRECT;
176: } else {
177: # There is not really a problem (???), but cannot go back without endless loop
1.2 www 178: &getlost($r,'The nature of the problem is unclear');
1.1 www 179: return OK;
180: }
181: }
1.13 albertel 182: # ------------------------------------Encrypted requests go straight to navmaps
1.16 albertel 183: if ($env{'request.enc'}) {
1.14 albertel 184: &Apache::loncommon::content_type($r,'text/html');
1.20 albertel 185: $r->header_out(Location =>
1.21 albertel 186: &Apache::lonnet::absolute_url().'/adm/navmaps');
1.13 albertel 187: return REDIRECT;
188: }
1.1 www 189: # ------------------------------------------------ Would be standalone resource
190:
1.16 albertel 191: if (tie(%bighash,'GDBM_File',$env{'request.course.fn'}.'.db',
1.5 albertel 192: &GDBM_READER(),0640)) {
1.1 www 193: # ---------------------------------------------- Get ID(s) for current resource
1.7 albertel 194: my $ids=$bighash{'ids_'.&Apache::lonnet::clutter($thisfn)};
1.1 www 195: if ($ids) {
196: # ------------------------------------------------------------------- Has ID(s)
197: my @possibilities=split(/\,/,$ids);
198: my $couldbe='';
1.11 albertel 199: foreach (@possibilities) {
200: if ($bighash{'encrypted_'.$_}) { next; }
201: my $symb=&make_symb($_);
202: if (&Apache::lonnet::allowed('bre',$bighash{'src_'.$_},$symb)) {
1.1 www 203: if ($couldbe) {
204: $couldbe.=','.$_;
205: } else {
206: $couldbe=$_;
207: }
208: }
1.11 albertel 209: }
1.1 www 210: if ($couldbe) {
211: @possibilities=split(/\,/,$couldbe);
1.12 albertel 212: if ($#possibilities==0) {
213: my $id=$possibilities[0];
214: my $resurl=$bighash{'src_'.$id};
215: my $mapurl=$bighash{'map_id_'.(split(/\./,$id))[0]};
216: my $symb=&make_symb($id);
1.14 albertel 217: &Apache::loncommon::content_type($r,'text/html');
1.12 albertel 218: $r->header_out(Location =>
1.21 albertel 219: &Apache::lonnet::absolute_url().
1.20 albertel 220: $resurl.'?symb='.$symb);
1.12 albertel 221: return REDIRECT;
222: }
1.1 www 223: if ($#possibilities>0) {
224: # ----------------------------------------------- Okay, really multiple choices
1.14 albertel 225: &Apache::loncommon::content_type($r,'text/html');
1.1 www 226: $r->send_http_header;
1.18 albertel 227: my $start_page=
228: &Apache::loncommon::start_page('Pick Instance of Resource');
1.2 www 229: $r->print(<<ENDSTART);
1.18 albertel 230: $start_page
1.2 www 231: The resource you had been accessing appears more than once in this course,
232: and LON-CAPA has insufficient session information to determine which instance
233: of the resource you meant.
234: <p>
235: Please click on the instance of the resource you intended to access:
1.11 albertel 236: </p>
237: <table border="2">
238: <tr><th>Title</th><th>Part of ...</th></tr>
1.2 www 239: ENDSTART
240: map {
1.11 albertel 241: my $resurl=$bighash{'src_'.$_};
1.2 www 242: my $mapurl=$bighash{'map_id_'.(split(/\./,$_))[0]};
1.11 albertel 243: my $symb=&make_symb($_);
244: $r->print('<tr><td><a href="'.$resurl.'?symb='.$symb.'">'.
245: &Apache::lonnet::gettitle($symb).
246: '</a></td><td>'.
247: &Apache::lonnet::gettitle($mapurl).' '.
248: '</td></tr>');
1.2 www 249: } @possibilities;
1.18 albertel 250: $r->print('</table>'.&Apache::loncommon::end_page());
1.1 www 251: untie(%bighash);
252: return OK;
253: }
254: }
255: }
256: untie(%bighash);
257: }
258:
259: # ------------------------------------ This handler should not have been called
1.2 www 260: &getlost($r,'Invalid call of handler');
1.1 www 261: return OK;
262: }
263:
264: 1;
265: __END__
266:
267:
268:
269:
270:
271:
272:
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