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File:  [LON-CAPA] / rat / lonambiguous.pm
Revision 1.4: download - view: text, annotated - select for diffs
Thu Nov 29 19:23:48 2001 UTC (22 years, 11 months ago) by www
Branches: MAIN
CVS tags: version_0_4, stable_2002_spring, stable_2002_july, stable_2002_april, STABLE, HEAD
GPL

# The LearningOnline Network with CAPA
# Handler to resolve ambiguous file locations
#
# $Id: lonambiguous.pm,v 1.4 2001/11/29 19:23:48 www 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/
#
# (TeX Content Handler
#
# 05/29/00,05/30,10/11 Gerd Kortemeyer)
#
# 10/11,10/12,10/16 Gerd Kortemeyer

package Apache::lonambiguous;

use strict;
use Apache::lonnet;
use Apache::Constants qw(:common REDIRECT);
use GDBM_File;


# ----------------------------------------------------------- Could not resolve

sub getlost {
    my ($r,$errmsg)=@_;
    $r->content_type('text/html');
    $r->send_http_header;
    $r->print(
 '<head><title>Unknown Error</title></head><body bgcolor="#FFFFFF"><h1>'.
 'LON-CAPA</h1>Could not handle ambiguous resource reference.<p>'.$errmsg.
 '</body></html>');
}

# ================================================================ Main Handler

sub handler {
   my $r=shift;

   if ($r->header_only) {
      $r->content_type('text/html');
      $r->send_http_header;
      return OK;
   }

# ---------------------------------------------------------- Is this selecting?
   
   my %bighash;

   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 => $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) {

       if ($syval=~/\_$/) {
# ----------------------------------- Okay, this should have appeared on a page
	   $syval=~s/\_\_\_$//;
 	   $r->content_type('text/html');
           $r->header_out(Location => 
                'http://'.$ENV{'HTTP_HOST'}.'/res/'.$syval);
           return REDIRECT;
       } else {
#  There is not really a problem (???), but cannot go back without endless loop
           &getlost($r,'The nature of the problem is unclear');
           return OK;
       }
    }

# ------------------------------------------------ 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_/res/'.$thisfn};
      if ($ids) {
# ------------------------------------------------------------------- Has ID(s)
         my @possibilities=split(/\,/,$ids);
         my $couldbe='';
         map {
             if (&Apache::lonnet::allowed('bre',$bighash{'src_'.$_})) {
	         if ($couldbe) {
		     $couldbe.=','.$_;
                 } else {
                     $couldbe=$_;
                 }
             }
	 } @possibilities;
         if ($couldbe) {
            @possibilities=split(/\,/,$couldbe);
            if ($#possibilities>0) {
# ----------------------------------------------- Okay, really multiple choices
               $r->content_type('text/html');
               $r->send_http_header;
               $r->print(<<ENDSTART);
<head><title>Choose Location</title></head>
<body bgcolor="#FFFFFF">
<h1>LON-CAPA</h1>
The resource you had been accessing appears more than once in this course,
and LON-CAPA has insufficient session information to determine which instance
of the resource you meant.
<p>
Please click on the instance of the resource you intended to access:
<p>
<form action="/adm/ambiguous" method=post>
<input type=hidden name=orgurl value="$thisfn">
<input type=hidden name=selecturl value=1>
<table border=2>
<tr><th>&nbsp;</th><th>Title</th><th>Type</th><th>Part of ...</th></tr>
ENDSTART
               map {
                   my $mapurl=$bighash{'map_id_'.(split(/\./,$_))[0]};
                   $r->print('<tr><td><input type=submit value=Select name="'.
                              $_.'"></td><td>'.$bighash{'title_'.$_}.
                              '</td><td>'.$bighash{'type_'.$_}.
                              '</td><td><a href="'.$mapurl.'">'.$mapurl.
			      '</a></td></tr>');
               } @possibilities;
               $r->print('</table></form></body></html>');
	       untie(%bighash);
               return OK;
            }
         }
      }
      untie(%bighash);
  }

# ------------------------------------ This handler should not have been called
   &getlost($r,'Invalid call of handler');
   return OK;
}

1;
__END__
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