File:  [LON-CAPA] / rat / lonsequence.pm
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Mon Oct 16 20:47:39 2000 UTC (23 years, 5 months ago) by www
Branches: MAIN
CVS tags: HEAD
Further work on flipping pages

# The LearningOnline Network with CAPA
#
# Sequence Handler
#
# (Handler to resolve ambiguous file locations
#
# (TeX Content Handler
#
# 05/29/00,05/30,10/11 Gerd Kortemeyer)
#
# 10/11,10/12 Gerd Kortemeyer)
#
# 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;
   }

   my %bighash;
# ----------------------------------------------------------------- Tie db file
  if ($ENV{'request.course.fn'}) {
       my $envkey;
       if (tie(%bighash,'GDBM_File',$ENV{'request.course.fn'}.'.db',
                    &GDBM_READER,0640)) {
          foreach $envkey (keys %ENV) {
             if ($envkey=~/^form\.(\d+)\.(\d+)$/) {
	         my $mapid=$1;
                 my $resid=$2;
                 my $resurl=$bighash{'src_'.$mapid.'.'.$resid};
                 &Apache::lonnet::symblist($bighash{'map_id_'.$mapid},
				           $resurl => $resid);
                 $r->header_out(Location => 
                                'http://'.$ENV{'HTTP_HOST'}.$resurl);
                 return REDIRECT;
             }
	  }
          untie(%bighash);
       } else {
          &getlost($r,'Could not access course structure.');
          return OK;
       }
   } else {
      $ENV{'user.error.msg'}="$requrl:bre:0:0:Course not initialized";
      return HTTP_NOT_ACCEPTABLE; 
   }

   return OK;

# ================================================================= TRASH BELOW

# ---------------------------------------------------------- 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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