# The LearningOnline Network
# URL translation for User Files
#
# $Id: lontrans.pm,v 1.14.10.2.2.3 2022/07/08 16:17:26 raeburn 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::lontrans;

use strict;
use Apache::Constants qw(:common :remotehost);
use Apache::lonnet;
use Apache::loncommon;
use Apache::File();
use LONCAPA qw(:DEFAULT :match);

sub handler {
    my $r = shift;
    # FIXME line remove when mod_perl fixes BUG#4948 
    $r->notes->set('error-notes' => '');
    my $alias = &Apache::lonnet::get_proxy_alias();
    if ($alias) {
        my $hdrhost = $r->headers_in->get('Host');
        my $lonhost = $r->dir_config('lonHostID');
        my $hostname = &Apache::lonnet::hostname($lonhost);
        my $ssourl = '/adm/sso';
        if ($r->dir_config('lonOtherAuthenUrl') ne '') {
            $ssourl = $r->dir_config('lonOtherAuthenUrl');
        }
        if (($hdrhost eq $alias) || ($hdrhost eq $hostname)) {
            my $proxyinfo = &Apache::lonnet::get_proxy_settings($r->dir_config('lonDefDomain'));
            my ($vpnint,$vpnext);
            if (ref($proxyinfo) eq 'HASH') {
                $vpnint = $proxyinfo->{'vpnint'};
                $vpnext = $proxyinfo->{'vpnext'};
            }
            my ($redirect,$remote_ip);
            if ($hdrhost eq $alias) {
                $remote_ip = &Apache::lonnet::get_requestor_ip($r,REMOTE_NOLOOKUP);
                if (($vpnext && &Apache::lonnet::ip_match($remote_ip,$vpnext)) &&
                    ($r->uri !~ m{^/adm/(lti|launch)/})) {
                    $redirect = $hostname;
                }
                if ($r->uri eq $ssourl) {
                    if (&Apache::lonnet::alias_sso($lonhost)) {
                        undef($redirect);
                    } else {
                        $redirect = $hostname;
                    }
                }
                if ($redirect eq $hdrhost) {
                    undef($redirect);
                }
            } elsif ($hdrhost eq $hostname) {
                $remote_ip = &Apache::lonnet::get_requestor_ip($r,REMOTE_NOLOOKUP,1);
                unless (($remote_ip eq '127.0.0.1') || ($remote_ip eq '::1') ||
                        ($remote_ip eq &Apache::lonnet::get_host_ip($lonhost)) ||
                        ($r->uri=~m{^/adm/(lti|launch)/}) ||
                        ($vpnint && &Apache::lonnet::ip_match($remote_ip,$vpnint))) {
                    $redirect = $alias;
                    if (($r->uri=~m{^/raw/}) || ($r->uri=~m{^/adm/dns/})) {
                        my %iphost = &Apache::lonnet::get_iphost();
                        if (exists($iphost{$remote_ip})) {
                            undef($redirect);
                        }
                    } elsif ($r->uri eq $ssourl) {
                        unless (&Apache::lonnet::alias_sso($lonhost)) {
                            undef($redirect);
                        }
                    }
                }
            }
            if ($redirect) {
                my $uri = $r->uri;
                if (($uri eq '/adm/switchserver') || ($uri =~ m{^/Shibboleth.sso/})) {
                    return DECLINED;
                }
                unless (($uri eq '/adm/migrateuser') || ($uri eq $ssourl)) {
                    my %user;
                    my $handle = &Apache::lonnet::check_for_valid_session($r,undef,\%user);
                    if (($handle) && ($user{'name'} ne '') && ($user{'domain'} ne '')) {
                        unless (($user{'name'} eq 'public') && ($user{'domain'} eq 'public')) {
                            my $dest = '/adm/migrateuser';
                            my $token = &set_token($r,$dest,$remote_ip,\%user);
                            unless ($token eq '') {
                                $r->internal_redirect("$dest?token=$token");
                                $r->set_handlers('PerlHandler'=> undef);
                                return DECLINED;
                            }
                        }
                    }
                }
                my $protocol = 'http';
                my $port = $r->get_server_port();
                if ($port eq '443') {
                    $protocol = 'https';
                }
                if ($uri =~ m{^(/adm/css/)(.+)(.css)$}) {
                    $uri = $1.&escape($2).$3;
                }
                my $location = $protocol.'://'.$redirect.$uri;
                if ($r->uri =~ m{^/tiny/$match_domain/\w+$}) {
                    my $token = &set_token($r,$r->uri);
                    unless ($token eq '') {
                        $location .= '?ttoken='.$token;
                    }
                } elsif ($r->args) {
                    $location .= '?'.$r->args;
                }
                $r->header_out(Location => $location);
                return REDIRECT;
            }
        }
    }
    if ($r->uri =~ m{^/tiny/$match_domain/\w+$}) {
        my $token = &set_token($r,$r->uri);
        unless ($token eq '') {
            $r->args('ttoken='.$token);
        }
    }
    if ($r->uri=~m|^(/raw)?/uploaded/|) {
        my $fn = $r->uri();
        $fn=~s/^\/raw//;
        my (undef,undef,$udom,$uname,@ufile)=split(/\//,$fn);
	if (@ufile) { $ufile[-1]=~s/^[\~\.]+//; }
        my $chome=&Apache::lonnet::homeserver($uname,$udom);
	my $allowed=0;
	my @ids=&Apache::lonnet::current_machine_ids();
	foreach my $id (@ids) { if ($id eq $chome) { $allowed=1; } }
	if ($allowed) {
	    $r->filename(&propath($udom,$uname).
			 '/userfiles/'.(join('/',@ufile)));
        }
        return OK;
    } elsif ($r->uri =~ m{^\Q/adm/wrapper/ext/https:/\E[^/]}) {
        my $uri = $r->uri;
        $uri =~ s{^(\Q/adm/wrapper/ext/https:/\E)}{$1/};
        $r->uri($uri);
    }
    return DECLINED;
}

sub set_token {
    my ($r,$dest,$remote_ip,$userref) = @_;
    my (%info,%user);
    if ($dest eq '/adm/migrateuser') {
        return unless (ref($userref) eq 'HASH');
        %user = %{$userref};
        %info = ('ip' => $remote_ip,
                 'domain'    => $user{'domain'},
                 'username'  => $user{'name'},
                 'server'    => $r->dir_config('lonHostID'),
                );
    }
    if ($r->args) {
        foreach my $pair (split(/&/,$r->args)) {
            my ($name,$value) = split(/=/,$pair);
            $name = &LONCAPA::unescape($name);
            next unless (($name eq 'role') || ($name eq 'symb') ||
                         ($name eq 'ltoken') || ($name eq 'linkkey') ||
                         ($name eq 'ttoken'));
            $value =~ tr/+/ /;
            $value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
            $info{$name} = $value;
        }
        if ($info{'ttoken'}) {
            my %current = &Apache::lonnet::tmpget($info{'ttoken'});
            delete($info{'ttoken'});
            if ($current{'origurl'} eq $r->uri) {
                return if (keys(%current));
            }
        }
    }
#
# To be able to support deep-linking for a shortened URL, i.e.,
# /tiny/$dom/$id with (a) linkkey included in POSTed data and
# data and (b) non-Shibboleth SSO in use, ltoken (or linkprot
# if sending to /adm/migrateuser), or linkkey are written to a
# .tmp file in /home/httpd/perl/tmp and the query string is
# replaced with ttoken=tokenid.  This does mean other POSTed
# data will be discarded.
#
    if ($r->uri =~ m{^/tiny/$match_domain/\w+$}) {
        unless (($info{'ltoken'}) || ($info{'linkkey'} ne '')) {
            &Apache::lonacc::get_posted_cgi($r,['linkkey']);
            if ($env{'form.linkkey'} ne '') {
                $info{'linkkey'} = $env{'form.linkkey'};
            }
        }
    }
    if ($dest eq '/adm/migrateuser') {
        if ($info{'ltoken'}) {
            my %link_info = &Apache::lonnet::tmpget($info{'ltoken'});
            if ($link_info{'linkprot'}) {
                $info{'linkprot'} = $link_info{'linkprot'};
                foreach my $item ('linkprotuser','linkprotexit') {
                    if ($link_info{$item} ne '') {
                        $info{$item} = $link_info{$item};
                    }
                }
            }
            &Apache::lonnet::tmpdel($info{'ltoken'});
            delete($info{'ltoken'});
        }
        unless ($info{'role'}) {
            if ($user{'role'} ne '') {
                $info{'role'} = $user{'role'};
            }
        }
        unless ($info{'symb'}) {
            unless ($r->uri eq '/adm/roles') {
                $info{'origurl'} = $r->uri;
            }
        }
    }
    if (($dest eq '/adm/migrateuser') || (keys(%info) > 0)) {
        unless ($dest eq '/adm/migrateuser') {
            $info{'origurl'} = $r->uri;
        }
        my $token = &Apache::lonnet::tmpput(\%info,$r->dir_config('lonHostID'),'link');
        unless (($token eq 'con_lost') || ($token eq 'refused') ||
                ($token eq 'unknown_cmd') || ($token eq 'no_such_host')) {
            return $token;
        }
    }
    return;
}

1;
__END__

<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>500 Internal Server Error</title>
</head><body>
<h1>Internal Server Error</h1>
<p>The server encountered an internal error or
misconfiguration and was unable to complete
your request.</p>
<p>Please contact the server administrator at 
 root@localhost to inform them of the time this error occurred,
 and the actions you performed just before this error.</p>
<p>More information about this error may be available
in the server error log.</p>
</body></html>