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- need to pass $beenhere along to detect map recursion

# The LearningOnline Network with CAPA
# Page Handler
#
# $Id: lonpage.pm,v 1.87 2007/11/30 19:14:14 albertel 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::lonpage;

use strict;
use Apache::Constants qw(:common :http);
use Apache::lonnet;
use Apache::loncommon();
use Apache::lonxml();
use Apache::lonlocal;
use Apache::lonmenu;
use HTML::TokeParser;
use GDBM_File;
use Apache::lonsequence;
use lib '/home/httpd/lib/perl/';
use LONCAPA;
 

# -------------------------------------------------------------- Module Globals
my %hash;
my @rows;

# ------------------------------------------------------------------ Euclid gcd

sub euclid {
    my ($e,$f)=@_;
    my $a; my $b; my $r;
    if ($e>$f) { $b=$e; $r=$f; } else { $r=$e; $b=$f; }
    while ($r!=0) {
	$a=$b; $b=$r;
        $r=$a%$b;
    }
    return $b;
}

# ------------------------------------------------------------ Build page table

sub tracetable {
    my ($sofar,$rid,$beenhere)=@_;
    my $further=$sofar;
    my $randomout=0;
    unless ($env{'request.role.adv'}) {
        $randomout = $hash{'randomout_'.$rid};
    }
    unless ($beenhere=~/\&$rid\&/) {
        $beenhere.=$rid.'&';
        unless ($randomout) {
            if (defined($hash{'is_map_'.$rid})) {
                if ((defined($hash{'map_start_'.$hash{'src_'.$rid}})) &&
                    (defined($hash{'map_finish_'.$hash{'src_'.$rid}}))) {
                    my $frid=$hash{'map_finish_'.$hash{'src_'.$rid}};
	            $sofar=
                       &tracetable($sofar,$hash{'map_start_'.$hash{'src_'.$rid}},
                       '&'.$frid.$beenhere);
                    $sofar++;
                    if ($hash{'src_'.$frid}) {
                        my $brepriv=&Apache::lonnet::allowed('bre',$hash{'src_'.$frid});
                        if (($brepriv eq '2') || ($brepriv eq 'F')) {
                            if (defined($rows[$sofar])) {
                                $rows[$sofar].='&'.$frid;
                            } else {
                                $rows[$sofar]=$frid;
                            }
	                }
	            }
	        }
            } else {
                $sofar++;
                if ($hash{'src_'.$rid}) {
                    my $brepriv=&Apache::lonnet::allowed('bre',$hash{'src_'.$rid});
                    if (($brepriv eq '2') || ($brepriv eq 'F')) {
                        if (defined($rows[$sofar])) {
                            $rows[$sofar].='&'.$rid;
                        } else {
                            $rows[$sofar]=$rid;
                        }
	            }
                }
            }
        }

        if (defined($hash{'to_'.$rid})) {
	    my $mincond=1;
            my $next='';
            foreach (split(/\,/,$hash{'to_'.$rid})) {
                my $thiscond=
      &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}});
                if ($thiscond>=$mincond) {
		    if ($next) {
		        $next.=','.$_.':'.$thiscond;
                    } else {
                        $next=$_.':'.$thiscond;
		    }
                    if ($thiscond>$mincond) { $mincond=$thiscond; }
	        }
            }
            foreach (split(/\,/,$next)) {
                my ($linkid,$condval)=split(/\:/,$_);
                if ($condval>=$mincond) {
                    my $now=&tracetable($sofar,$hash{'goesto_'.$linkid},$beenhere);
                    if ($now>$further) { $further=$now; }
	        }
            }
        }
    }
    return $further;
}

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

sub handler {
  my $r=shift;

# ------------------------------------------- Set document type for header only

  if ($r->header_only) {
       if ($env{'browser.mathml'}) {
           &Apache::loncommon::content_type($r,'text/xml');
       } else {
           &Apache::loncommon::content_type($r,'text/html'); 
       }
       $r->send_http_header;
       return OK;
   }
  
   &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},
                                          ['forceselect','launch']);
  my $number_of_columns = 1;
  my $requrl=$r->uri;  
  my $target = $env{'form.grade_target'};
#  &Apache::lonnet::logthis("Got a target of $target");
  if ($target eq 'meta') {
      &Apache::loncommon::content_type($r,'text/html');
      $r->send_http_header;
      return OK;
  }
# ----------------------------------------------------------------- Tie db file
  if (($env{'request.course.fn'}) && (!$env{'form.forceselect'})) {
      my $fn=$env{'request.course.fn'};
      if (-e "$fn.db") {
          if (tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER(),0640)) {
# ------------------------------------------------------------------- Hash tied
              my $firstres=$hash{'map_start_'.$requrl};
              my $lastres=$hash{'map_finish_'.$requrl};
              if (($firstres) && ($lastres)) {
# ----------------------------------------------------------------- Render page

                  @rows=();

                  &tracetable(0,$firstres,'&');

# ------------------------------------------------------------ Add to symb list

                  my $i;
                  my %symbhash=();
                  for ($i=0;$i<=$#rows;$i++) {
		     if ($rows[$i]) {
                        my @colcont=split(/\&/,$rows[$i]);
                        foreach my $rid (@colcont) {
			    my ($mapid,$resid)=split(/\./,$rid);
			    $symbhash{$hash{'src_'.$rid}}=
				[$hash{'src_'.$rid},$resid];
		        }
		     }
		  }
                  &Apache::lonnet::symblist($requrl,%symbhash);

# ------------------------------------------------------------------ Page parms

                  my $j;
                  my $lcm=1;
                  my $contents=0;
                  my $nforms=0;
                  
                  my %ssibody=();
                  my %ssibgcolor=();
                  my %ssitext=();
                  my %ssilink=();
                  my %ssivlink=();
                  my %ssialink=();
     
                  my %cellemb=();

                  my $allscript='';
                  my $allmeta='';

                  my $isxml=0;
                  my $xmlheader='';
                  my $xmlbody='';

# --------------------------------------------- Get SSI output, post parameters

                  for ($i=0;$i<=$#rows;$i++) {
		     if ($rows[$i]) {
		      $contents++;
                      my @colcont=split(/\&/,$rows[$i]);
                      $lcm*=($#colcont+1)/euclid($lcm,($#colcont+1));
                      foreach (@colcont) {
                          my $src=$hash{'src_'.$_};
			  my ($extension)=($src=~/\.(\w+)$/);
			  if ($hash{'encrypted_'.$_}) {
			      $src=&Apache::lonenc::encrypted($src);
			  }
                          $cellemb{$_}=
			      &Apache::loncommon::fileembstyle($extension);
                          if ($cellemb{$_} eq 'ssi') {
# --------------------------------------------------------- This is an SSI cell
			      my ($mapid,$resid)=split(/\./,$_);
			      my $symb=&Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},$resid,$src);
			      
			      my $prefix=$_.'_';
                              my %posthash=('request.prefix' => $prefix,
					    'LONCAPA_INTERNAL_no_discussion' => 'true',
					    'symb' => $symb);
			      if ($env{'form.grade_target'} eq 'tex') {
				  $posthash{'grade_target'}=$env{'form.grade_target'};
				  $posthash{'textwidth'}=$env{'form.textwidth'};
				  $posthash{'problem_split'}=$env{'form.problem_split'};
				  $posthash{'latex_type'}=$env{'form.latex_type'};
				  $posthash{'rndseed'}=$env{'form.rndseed'};
			      }
			      my $submitted=exists($env{'form.all_submit'});
			      if (!$submitted) {
				  foreach my $key (keys(%env)) {
				      if ($key=~/^form.\Q$prefix\Esubmit_/) {
					  $submitted=1;last;
				      }
				  }
			      }
                              if ($submitted) {
				  foreach my $key (keys(%env)) {
				      if ($key=~/^form.\Q$prefix\E/) {
					  my $name=$key;
					  $name=~s/^form.\Q$prefix\E//;
					  $posthash{$name}=$env{$key};
				      }
				  }
				  if (exists($env{'form.all_submit'})) {
				      $posthash{'all_submit'}='yes';
				  }
			      }
                              my $output=Apache::lonnet::ssi($src,%posthash);
			      $output=~s|//(\s*<!--)? BEGIN LON-CAPA Internal.+?// END LON-CAPA Internal\s*(-->)?\s||gs;
                              if ($target eq 'tex') {
				  $output =~ s/^([^&]+)\\begin{document}//;
				  $output =~ s/\\end{document}//;
				  $output = '\parbox{\minipagewidth}{ '.$output.' }';
                                  #some additional cleanup necessary for LateX (due to limitations of table environment 
				  $output =~ s/(\\vskip\s*\d+mm)\s*(\\\\)+/$1/g;
			      }
                              my $parser=HTML::TokeParser->new(\$output);
                              my $token;
                              my $thisdir=$src;
                              my $bodydef=0;
                              my $thisxml=0;
                              my @rlinks=();
                              if ($output=~/\?xml/) {
                                 $isxml=1;
                                 $thisxml=1;
                                 $output=~
         /((?:\<(?:\?xml|\!DOC|html)[^\>]*(?:\>|\>\]\>)\s*)+)\<body[^\>]*\>/si;
                                 $xmlheader=$1;
			      }
                              while ($token=$parser->get_token) {
				if ($token->[0] eq 'S') {
                                  if ($token->[1] eq 'a') {
				      if ($token->[2]->{'href'}) {
                                         $rlinks[$#rlinks+1]=
					     $token->[2]->{'href'};
				      }
				  } elsif ($token->[1] eq 'img') {
                                         $rlinks[$#rlinks+1]=
					     $token->[2]->{'src'};
				  } elsif ($token->[1] eq 'embed') {
                                         $rlinks[$#rlinks+1]=
					     $token->[2]->{'src'};
				  } elsif ($token->[1] eq 'base') {
				      $thisdir=$token->[2]->{'href'};
				  } elsif ($token->[1] eq 'body') {
				      $bodydef=1;
                                      $ssibgcolor{$_}=$token->[2]->{'bgcolor'};
                                      $ssitext{$_}=$token->[2]->{'text'};
                                      $ssilink{$_}=$token->[2]->{'link'};
                                      $ssivlink{$_}=$token->[2]->{'vlink'};
                                      $ssialink{$_}=$token->[2]->{'alink'};
                                      if ($thisxml) {
					  $xmlbody=$token->[4];
                                      }
                                  } elsif ($token->[1] eq 'meta') {
				    if ($token->[4] !~ m:/>$:) {
				      $allmeta.="\n".$token->[4].'</meta>';
				    } else {
				      $allmeta.="\n".$token->[4];
				    }
                                  } elsif (($token->[1] eq 'script') &&
                                           ($bodydef==0)) {
				      $allscript.="\n\n"
                                                .$parser->get_text('/script');
                                  }
			        }
			      }
                              if ($output=~/\<body[^\>]*\>(.*)/si) {
                                 $output=$1; 
                              }
                              $output=~s/\<\/body\>.*//si;
                              if ($output=~/\<form/si) {
				  $nforms++;
                                  $output=~s/\<form[^\>]*\>//gsi;
                                  $output=~s/\<\/form[^\>]*\>//gsi;
                                  $output=~
				      s/\<((?:input|select|button|textarea)[^\>]+)name\s*\=\s*[\'\"]*([^\'\"]+)[\'\"]*([^\>]*)\>/\<$1 name="$prefix$2" $3\>/gsi;
                              }
                              $thisdir=~s/\/[^\/]*$//;
			      foreach (@rlinks) {
				  unless (($_=~/^http:\/\//i) ||
					  ($_=~/^\//) ||
					  ($_=~/^javascript:/i) ||
					  ($_=~/^mailto:/i) ||
					  ($_=~/^\#/)) {
				      my $newlocation=
				    &Apache::lonnet::hreflocation($thisdir,$_);
                     $output=~s/(\"|\'|\=\s*)$_(\"|\'|\s|\>)/$1$newlocation$2/;
				  }
			      }
# -------------------------------------------------- Deal with Applet codebases
  $output=~s/(\<applet[^\>]+)(codebase\=[^\S\>]+)*([^\>]*)\>/$1.($2?$2:' codebase="'.$thisdir.'"').$3.'>'/gei;
			      $ssibody{$_}=$output;
# ---------------------------------------------------------------- End SSI cell
                          }
                      }
                     } 
                  }
                  unless ($contents) {
                      &Apache::loncommon::content_type($r,'text/html');
                      $r->send_http_header;
                      $r->print(&Apache::loncommon::start_page(undef,undef,
							       {'force_register' => 1,}));
                      $r->print(&mt('This page is either empty or it only contains resources that are currently hidden').'. ');
                      $r->print('<br /><br />'.&mt('Please use the LON-CAPA navigation arrows to move to another item in the course').
				&Apache::loncommon::end_page());
                  } else {
# ------------------------------------------------------------------ Build page

# ---------------------------------------------------------------- Send headers
		      unless ($target eq 'tex') {
			  if ($isxml) {
			      &Apache::loncommon::content_type($r,'text/xml');
			  } else {
			      &Apache::loncommon::content_type($r,'text/html');
			  }
			  $r->send_http_header;
# ------------------------------------------------------------------------ Head
			  if ($allscript) {
			      $allscript = 
				  "\n".'<script type="text/javascript">'."\n".
				  $allscript.
				  "\n</script>\n";
			  }
# ------------------------------------------------------------------ Start body
			  $r->print(&Apache::loncommon::start_page(undef,$allscript,
								   {'force_register' => 1,
								    'bgcolor'        => '#ffffff',}));
# ------------------------------------------------------------------ Start form
			  if ($nforms) {
			      $r->print('<form name="lonhomework" method="post"  enctype="multipart/form-data" action="'.
					&Apache::lonenc::check_encrypt($requrl)
					.'">');
			  }
		      } elsif ($target eq 'tex') {
			  $r->print('\documentclass{article}
                                 \newcommand{\keephidden}[1]{}           
                                 \usepackage[dvips]{graphicx}
                                 \usepackage{epsfig}
                                 \usepackage{calc}
                                 \usepackage{longtable}
                                 \begin{document}');
		      }
# ----------------------------------------------------------------- Start table
		      if ($target eq 'tex') {
			  $r->print('\begin{longtable}INSERTTHEHEADOFLONGTABLE\endfirsthead\endhead ');
			  if ($number_of_columns le $lcm) {$number_of_columns=$lcm;};
		      } else {
			  $r->print('<table width="100%" cols="'.$lcm.'" border="0">');
		      }
# generate rows
                      for ($i=0;$i<=$#rows;$i++) {
			if ($rows[$i]) {
			    unless ($target eq 'tex') {
				$r->print("\n<tr>");
			    }
                          my @colcont=split(/\&/,$rows[$i]);
                          my $avespan=$lcm/($#colcont+1);
                          for ($j=0;$j<=$#colcont;$j++) {
                              my $rid=$colcont[$j];

			      my $metainfo =&get_buttons(\%hash,$rid).'<br />';
			    unless ($target eq 'tex') {
				$r->print('<td colspan="'.$avespan.'"');
			    }
                              if ($cellemb{$rid} eq 'ssi') {
				  unless ($target eq 'tex') {
				      if ($ssibgcolor{$rid}) {
					  $r->print(' bgcolor="'.
						    $ssibgcolor{$rid}.'"');
				      }
				      $r->print('>'.$metainfo.'<font');
		    
				      if ($ssitext{$rid}) {
					  $r->print(' text="'.$ssitext{$rid}.'"');
				      }
				      if ($ssilink{$rid}) {
					  $r->print(' link="'.$ssilink{$rid}.'"');
				      }
				      if ($ssitext{$rid}) {
					  $r->print(' vlink="'.$ssivlink{$rid}.'"');
				      }
				      if ($ssialink{$rid}) {
					  $r->print(' alink="'.$ssialink{$rid}.'"');
				      }             
				      $r->print('>');
				  }
                                  $r->print($ssibody{$rid});	
				  unless ($target eq 'tex') {
				      $r->print('</font>');
                                  }
                                  if ($env{'course.'.
                                      $env{'request.course.id'}.
                                      '.pageseparators'} eq 'yes') {
                                      unless($target eq 'tex') {
                                          $r->print('<hr />');
                                      } 
				  }
			      } elsif ($cellemb{$rid} eq 'img') {
                                  $r->print('>'.$metainfo.'<img src="'.
                                    $hash{'src_'.$rid}.'" />');
			      } elsif ($cellemb{$rid} eq 'emb') {
                                  $r->print('>'.$metainfo.'<embed src="'.
                                    $hash{'src_'.$rid}.'"></embed>');
                              } elsif (&Apache::lonnet::declutter($hash{'src_'.$rid}) !~/\.(sequence|page)$/) {
                                  $r->print($metainfo.'<b>'.$hash{'title_'.$rid}.'</b><br />'.
                                  &mt('It is recommended that you use an up-to-date virus scanner before handling this file.').'</p><p><table>'.
                                  &Apache::londocs::entryline(0,&mt("Click to download or use your browser's Save Link function"),'/'.&Apache::lonnet::declutter($hash{'src_'.$rid})).'</table></p><br />');
                              }
			      unless ($target eq 'tex') {
				  $r->print('</td>');
			      } else {
                                  for (my $incol=1;$incol<=$avespan;$incol++) {
				      $r->print(' & ');
				  }
			      }
                          }
			      unless ($target eq 'tex') {
				  $r->print('</tr>');
			      } else {
				  $r->print('REMOVETHEHEADOFLONGTABLE\\\\');
			      }
		        }
                      }
		      unless ($target eq 'tex') {
			  $r->print("\n</table>");
		      } else {
			  $r->print('\end{longtable}\strut');
		      }
# ---------------------------------------------------------------- Submit, etc.
                      if ($nforms) {
                          $r->print(
	                  '<input name="all_submit" value="Submit All" type="'.
			  (($nforms>1)?'submit':'hidden').'"></input></form>');
                      }
		      unless ($target eq 'tex') {
			  $r->print(&Apache::loncommon::end_page({'discussion'
								      => 1,}));
		      } else {
			  $r->print('\end{document}'.$number_of_columns);
		      }
		      &Apache::lonnet::symblist($requrl,%symbhash);
		      my ($map,$id,$url)=&Apache::lonnet::decode_symb(&Apache::lonnet::symbread());
		      &Apache::lonnet::symblist($map,'last_known'=>[$url,$id]);
# -------------------------------------------------------------------- End page
                  }                  
# ------------------------------------------------------------- End render page
              } else {
                  &Apache::loncommon::content_type($r,'text/html');
                  $r->send_http_header;
                  &Apache::lonsequence::viewmap($r,$requrl);
              }
# ------------------------------------------------------------------ Untie hash
              unless (untie(%hash)) {
                   &Apache::lonnet::logthis("<font color=blue>WARNING: ".
                       "Could not untie coursemap $fn (browse).</font>"); 
              }
# -------------------------------------------------------------------- All done
	      return OK;
# ----------------------------------------------- Errors, hash could no be tied
          }
      } 
  }
  &Apache::loncommon::content_type($r,'text/html');
  $r->send_http_header;
  &Apache::lonsequence::viewmap($r,$requrl);
  return OK; 
}

sub get_buttons {
    my ($hash,$rid) = @_;

    # which icons do we use?
    my $extension='png';
    if ($env{'environment.icons'} eq 'classic') { $extension='gif'; }

    my $metainfo = '';
    my $esrc=&Apache::lonnet::declutter($hash->{'src_'.$rid});
    my ($mapid,$resid)=split(/\./,$rid);
    my $symb=&Apache::lonnet::encode_symb($hash->{'map_id_'.$mapid},
					  $resid,
					  $hash->{'src_'.$rid});
    if ($hash->{'encrypted_'.$rid}) {
	$symb=&Apache::lonenc::encrypted($symb);
	$esrc=&Apache::lonenc::encrypted($esrc);
    }
    if ($hash->{'src_'.$rid} !~ m-^/uploaded/-
	&& !$env{'request.enc'}
	&& ($env{'request.role.adv'}
	    || !$hash->{'encrypted_'.$rid})) { 
	$metainfo .='<a name="'.&escape($symb).'" />'.
	    '<a href="'.$hash->{'src_'.$rid}.'.meta'.'" target="LONcatInfo">'.
	    '<img src="/adm/lonMisc/cat_button.'.$extension.'" class="LC_icon" />'.
	    '</a>';
    }
    $metainfo .= '<a href="/adm/evaluate?postdata='.
	&escape($esrc).
	'" target="LONcatInfo">'.
	'<img src="/adm/lonMisc/eval_button.'.$extension.'" class="LC_icon" />'.
	'</a>';
    if (($hash->{'src_'.$rid}=~/\.(problem|exam|quiz|assess|survey|form)$/) &&
	($hash->{'src_'.$rid} !~ m-^/uploaded/-)) {

	if (&Apache::lonnet::allowed('mgr',$env{'request.course.id'})) {
	    $metainfo.=
		'<a href="/adm/grades?symb='.&escape($symb).
#               '&command=submission" target="LONcatInfo">'.
		'&command=submission">'.
		'<img src="/adm/lonMisc/subm_button.'.$extension.'" class="LC_icon" />'.
		'</a>'.
		'<a href="/adm/grades?symb='.&escape($symb).
#               '&command=gradingmenu" target="LONcatInfo">'.
		'&command=gradingmenu">'.
		'<img src="/adm/lonMisc/pgrd_button.'.$extension.'" class="LC_icon" />'.
		'</a>';
	}
	if (&Apache::lonnet::allowed('opa',$env{'request.course.id'})) {
	    $metainfo.=
		'<a href="/adm/parmset?symb='.&escape($symb).
#               '" target="LONcatInfo">'.
		'" >'.
		'<img src="/adm/lonMisc/pprm_button.'.$extension.'" class="LC_icon" />'.
		'</a>';
	}
    }
    return $metainfo;
}

1;
__END__

=head1 NAME

Apache::lonpage - Page Handler

=head1 SYNOPSIS

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

 <LocationMatch "^/res/.*\.page$>
 SetHandler perl-script
 PerlHandler Apache::lonpage
 </LocationMatch>

=head1 INTRODUCTION

This module renders a .page resource.

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 *

set document type for header only

=item *

tie db file

=item *

render page

=item *

add to symb list

=item *

page parms

=item *

Get SSI output, post parameters

=item *

SSI cell rendering

=item *

Deal with Applet codebases

=item *

Build page

=item *

send headers

=item *

start body

=item *

start form

=item *

start table

=item *

submit element, etc, render page, untie hash

=back

=head1 OTHER SUBROUTINES

=over 4

=item *

euclid() : Euclid's method for determining the greatest common denominator.

=item *

tracetable() : Build page table.

=back

=cut

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

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.

More information about this error may be available in the server error log.