#!/usr/bin/perl
# Fig. 10.14: fig10_14.pl
# a program to implement a guestbook.

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

print( header() );
print( start_html( -title => "My guest book." ) );
print( p( b( i( "Entries in my guestbook: \n" ) ) ) );

my $name = param( "name" );
my $text = param( "comment" );

if ( $name ) {
   open( BOOK, ">>book.txt" ) or die( "Cannot open: $!" );
   flock( BOOK, LOCK_EX ) or die( "Cannot get exclusive lock: $!" );
   print( BOOK "$name said: \t" );
   print( BOOK "$text\n" );
   flock( BOOK, LOCK_UN ) or die ( "Cannot unlock file: $!" );
   close( BOOK ) or die( "Cannot close guestbook: $!" );
}

open( BOOK, "<book.txt" ) or die( "Cannot open guestbook: $!" );
flock( BOOK, LOCK_EX ) or die( "Cannot get exclusive lock: $!" );

while ( <BOOK> ) {
   s|\t|<br/>|g;
   print( p( "$_" ) );
}

close( BOOK ) or die( "Cannot close guestbook: $!" );
print( end_html() );

###########################################################################
#  (C) Copyright 2001 by Deitel & Associates, Inc. and Prentice Hall.     #
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#                                                                         #
#  DISCLAIMER: The authors and publisher of this book have used their     #
#  best efforts in preparing the book. These efforts include the          #
#  development, research, and testing of the theories and programs        #
#  to determine their effectiveness. The authors and publisher make       #
#  no warranty of any kind, expressed or implied, with regard to these    #
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