# The LearningOnline Network
# Access Handler for File Transfers
#
# $Id: lonracc.pm,v 1.4 2002/01/17 19:25:31 harris41 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/
#
# (lonacc: Cookie Based Access Handler
# 5/21/99,5/22,5/29,5/31,6/15 Gerd Kortemeyer)
# 6/16,6/18,7/3,
# 6/30/00 Gerd Kortemeyer

package Apache::lonracc;

use strict;
use Apache::Constants qw(:common :remotehost);
use Apache::File();

sub handler {
    my $r = shift;
    my $reqhost;
    unless ($reqhost=$r->get_remote_host(REMOTE_DOUBLE_REV)) {
       $r->log_reason("Spoof request");
       return FORBIDDEN;
    }
    my $readline;
    my $lontabdir=$r->dir_config('lonTabDir');
    {
       my $fh;
       unless ($fh=Apache::File->new("$lontabdir/hosts.tab")) {
          $r->log_reason("Could not find host tab file");
          return FORBIDDEN;
       }
       while ($readline=<$fh>) {
          my ($id,$domain,$role,$name,$ip)=split(/:/,$readline);
          if ($name =~ /$reqhost/i) {
              my $filename=$r->filename;
              if ((-e "$filename.$id") || ($filename=~/\.meta$/)) {
	         return OK;
              } else {
                 $r->log_reason("$id not subscribed", $r->filename);
                 return FORBIDDEN;
              }
          }
       }

    }
    $r->log_reason("Invalid request for file transfer from $reqhost", 
                   $r->filename); 
    return FORBIDDEN;
}

1;
__END__

=head1 NAME

Apache::lonracc - Access Handler for File Transfers

=head1 SYNOPSIS

Invoked by /etc/httpd/conf/loncapa.conf:

 <LocationMatch "^/raw.*">
 PerlAccessHandler Apache::lonracc
 </LocationMatch>

=head1 INTRODUCTION

This module enables authentication for file transfers and works
against the /res tree.

Only lond invokes the /raw namespace through its subscribe function.

This is part of the LearningOnline Network with CAPA project
described at http://www.lon-capa.org.

=head1 HANDLER SUBROUTINE

This routine is called by Apache and mod_perl.

=over 4

=item *

Determine requesting host

=item *

See whether or not the requesting host is subscribed.

=item *

Respond with status of request and make log entry in case of unallowed
access.

=back

=cut