# The LearningOnline Network with CAPA # Handler to resolve ambiguous file locations # # $Id: lonambiguous.pm,v 1.16 2005/04/07 06:56:27 albertel Exp $ # # Copyright Michigan State University Board of Trustees # # This file is part of the LearningOnline Network with CAPA (LON-CAPA). # # LON-CAPA is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # LON-CAPA is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with LON-CAPA; if not, write to the Free Software # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA # # /home/httpd/html/adm/gpl.txt # # http://www.lon-capa.org/ # package Apache::lonambiguous; use strict; use Apache::lonnet; use Apache::Constants qw(:common REDIRECT); use GDBM_File; use Apache::loncommon; use Apache::lonlocal; my %bighash; sub cleanup { if (tied(%bighash)){ &Apache::lonnet::logthis('Cleanup ambiguous: bighash'); unless (untie(%bighash)) { &Apache::lonnet::logthis('Failed cleanup ambiguous: bighash'); } } } # ----------------------------------------------------------- Could not resolve sub getlost { my ($r,$errmsg)=@_; $errmsg=&mt($errmsg); &Apache::loncommon::content_type($r,'text/html'); $r->send_http_header; $r->print( 'Unknown Error'. &Apache::loncommon::bodytag('Could not handle ambiguous resource reference'). $errmsg. ''); } # ================================================================ Main Handler sub make_symb { my ($id)=@_; my ($mapid,$resid)=split(/\./,$id); my $map=$bighash{'map_id_'.$mapid}; my $res=$bighash{'src_'.$id}; my $symb=&Apache::lonnet::encode_symb($map,$resid,$res); return $symb; } sub handler { my $r=shift; if ($r->header_only) { &Apache::loncommon::content_type($r,'text/html'); $r->send_http_header; return OK; } # ---------------------------------------------------------- Is this selecting? if ($env{'form.selecturl'}) { my $envkey; if (tie(%bighash,'GDBM_File',$env{'request.course.fn'}.'.db', &GDBM_READER(),0640)) { foreach $envkey (keys %env) { if ($envkey=~/^form\.(\d+)\.(\d+)$/) { # ---------------------------------------------------- Update symb and redirect my $mapid=$1; my $resid=$2; my $resurl=$bighash{'src_'.$mapid.'.'.$resid}; &Apache::lonnet::symblist($bighash{'map_id_'.$mapid}, $resurl => [$resurl,$resid]); untie(%bighash); $r->header_out(Location => 'http://'.$ENV{'HTTP_HOST'}.$resurl); return REDIRECT; } } untie(%bighash); } else { &getlost($r,'Could not access course structure.'); return OK; } } # ---------------------------------------------------------- Do we have a case? my $thisfn; unless (($thisfn=$env{'request.ambiguous'})&&($env{'request.course.fn'})) { &getlost($r,'Could not find information on resource.'); return OK; } # ---------------------------------- Should this file have been part of a page? $thisfn=&Apache::lonnet::declutter($thisfn); my %hash; my $syval=''; if (tie(%hash,'GDBM_File',$env{'request.course.fn'}.'_symb.db', &GDBM_READER(),0640)) { $syval=$hash{$thisfn}; untie(%hash); } # ---------------------------------------------------------- There was an entry if ($syval) { my ($page,undef,$res)=&Apache::lonnet::decode_symb($syval); if ($res eq 'page') { # ----------------------------------- Okay, this should have appeared on a page &Apache::loncommon::content_type($r,'text/html'); $r->header_out(Location => 'http://'.$ENV{'HTTP_HOST'}. &Apache::lonnet::clutter($page)); return REDIRECT; } else { # There is not really a problem (???), but cannot go back without endless loop &getlost($r,'The nature of the problem is unclear'); return OK; } } # ------------------------------------Encrypted requests go straight to navmaps if ($env{'request.enc'}) { &Apache::loncommon::content_type($r,'text/html'); $r->header_out(Location => 'http://'.$ENV{'HTTP_HOST'}.'/adm/navmaps'); return REDIRECT; } # ------------------------------------------------ Would be standalone resource if (tie(%bighash,'GDBM_File',$env{'request.course.fn'}.'.db', &GDBM_READER(),0640)) { # ---------------------------------------------- Get ID(s) for current resource my $ids=$bighash{'ids_'.&Apache::lonnet::clutter($thisfn)}; if ($ids) { # ------------------------------------------------------------------- Has ID(s) my @possibilities=split(/\,/,$ids); my $couldbe=''; foreach (@possibilities) { if ($bighash{'encrypted_'.$_}) { next; } my $symb=&make_symb($_); if (&Apache::lonnet::allowed('bre',$bighash{'src_'.$_},$symb)) { if ($couldbe) { $couldbe.=','.$_; } else { $couldbe=$_; } } } if ($couldbe) { @possibilities=split(/\,/,$couldbe); if ($#possibilities==0) { my $id=$possibilities[0]; my $resurl=$bighash{'src_'.$id}; my $mapurl=$bighash{'map_id_'.(split(/\./,$id))[0]}; my $symb=&make_symb($id); &Apache::loncommon::content_type($r,'text/html'); &Apache::lonnet::logthis('http://'.$ENV{'HTTP_HOST'}.$resurl.'?symb='.$symb); $r->header_out(Location => 'http://'.$ENV{'HTTP_HOST'}.$resurl.'?symb='.$symb); return REDIRECT; } if ($#possibilities>0) { # ----------------------------------------------- Okay, really multiple choices &Apache::loncommon::content_type($r,'text/html'); $r->send_http_header; my $bodytag= &Apache::loncommon::bodytag('Pick Instance of Resource'); $r->print(<Choose Location $bodytag The resource you had been accessing appears more than once in this course, and LON-CAPA has insufficient session information to determine which instance of the resource you meant.

Please click on the instance of the resource you intended to access:

ENDSTART map { my $resurl=$bighash{'src_'.$_}; my $mapurl=$bighash{'map_id_'.(split(/\./,$_))[0]}; my $symb=&make_symb($_); $r->print(''); } @possibilities; $r->print('
TitlePart of ...
'. &Apache::lonnet::gettitle($symb). ''. &Apache::lonnet::gettitle($mapurl).' '. '
'); untie(%bighash); return OK; } } } untie(%bighash); } # ------------------------------------ This handler should not have been called &getlost($r,'Invalid call of handler'); return OK; } 1; __END__