#!/usr/bin/perl
# Fig. 17.8: addPost.pl
# Adds a posting to a forum

use warnings;
use strict;
use CGI qw( :standard );
use XML::DOM;
use Fcntl qw( :flock );

if ( param( "submit" ) ) {
   my ( $parser, $document, $forum, $message, $element );

   my $file = param( "file" );
   $file  =~ /^\w+\.xml$/                or die "Not a valid file: $!";
   open  FORUM, "+< ../htdocs/XML/$file" or die "Could not open: $!";
   flock FORUM, LOCK_EX;

   $parser = new XML::DOM::Parser;
   $document = $parser->parse( \*FORUM );
   $forum = $document->getDocumentElement;

   $message = $document->createElement( "message" ); 
   $message->setAttribute( "timestamp", scalar( localtime ) );
   $forum->appendChild( $message );

   foreach ( qw( user title text ) ) {
      $element = $document->createElement( $_ );
      $element->addText( param( $_ ) );
      $message->appendChild( $element );
   }

   seek FORUM, 0, 0;
   truncate FORUM, 0;
   $document->printToFileHandle( \*FORUM );
   close FORUM;
   print redirect( "../XML/$file" );

} 
elsif ( param ) {
   my $file = param( "file" );
   print header, start_html( -title => "Add a posting", 
                             -style => { -src => "../XML/site.css" } );
   print start_form,
      "User", br,
      textfield( -name => "user", -size => 40 ), br,
      "Message Title", br, 
      textfield( -name => "title", -size => 40 ), br,
      "Message Text", br,
      textarea( -name => "text", -cols =>  40, -rows => 5 ), br,
      hidden(   -name => "file", -value => $file ),
      submit(   -name => "submit", -value => "Submit" ),
      reset, end_form, 
      a( { -href => "../XML/$file" }, "Return to Forum" ), 
      end_html;

} 
else {
   print redirect( "error.html" );
}


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