File:  [LON-CAPA] / rat / lonambiguous.pm
Revision 1.1: download - view: text, annotated - select for diffs
Thu Oct 12 02:14:01 2000 UTC (23 years, 5 months ago) by www
Branches: MAIN
CVS tags: HEAD
Default handler if there is more than one possible location of resource

# The LearningOnline Network with CAPA
# Handler to resolve ambiguous file locations
#
# (TeX Content Handler
#
# 05/29/00,05/30,10/11 Gerd Kortemeyer)
#
# 10/11 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=shift;
    $r->content_type('text/html');
    $r->send_http_header;
    $r->print('<head><title>Unknown Error</title><body bgcolor="#FFFFFF">'.
 '<h1>LON-CAPA</h1>Could not handle ambiguous file reference.</body></html>');
}

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

sub handler {
   my $r=shift;

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

# ---------------------------------------------------------- Do we have a case?

   my $thisfn;
   unless (($thisfn=$ENV{'request.ambiguous'})&&($ENV{'request.course.fn'})) {
       getlost($r);
       return OK;
   }
      
# ---------------------------------- Should this file have been part of a page?

    $thisfn=&Apache::lonnet::declutter($thisfn);
    my %hash;
    my %bighash;
    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);
           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 $couldbe='';
         map {
             if (&allowed('bre',$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(
                '<head><title>Choose Location</title><body bgcolor="#FFFFFF">'.
                '<h1>LON-CAPA</h1>Cool.</body></html>');
	       untie(%bighash);
               return OK;
            }
         }
      }
      untie(%bighash);
  }

# ------------------------------------ This handler should not have been called
   getlost($r);
   return OK;
}

1;
__END__








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