#!/usr/bin/perl -w
######################################
#
#  guestbook2.cgi 
#
#  Use CGI.pm for headers and some html code, and for parsing parameters.
#  Use a tied hash for the file input/output.
#
#      - Jim Mahoney, Jan 2002
#######################################

use CGI;
use CGI::Carp qw(fatalsToBrowser);	# Send "die" messages to browser window

my $cgi = new CGI;		# One way of using CGI.pm - object oriented.

print $cgi->header();		# standard CGI headers

# Get the parameters.
my $name    = $cgi->param('name');	# Let CGI.pm do parsing of parameters.
my $message = $cgi->param('message');	# This works for POST or PUT forms.

# Perl has a "tie" function that replaces hash access
# with file read write.  In other words, once a hash is "tied",
# then  
#       $hash{key}="stuff";    # this writes to the file
#       $a = $hash{key};       # this reads from the file
# The details for how the file is organized are handled by somebody else.

use DB_File::Lock;
my %guesthash;
my $guestfile = 'guestbook2.db';

# Append the date and message to our guestbookfile
# using a Berkely database file and a tied hash.
if ($message and $name) {
  my $key = time() . $name;
  my $date = scalar localtime();
  my $text = "
   <font color='darkred'>Posted by '$name' on $date :</font><p>
   <pre>$message</pre>
   <hr noshade size=1>\n\n";
  tie %guesthash, 'DB_File::Lock', $guestfile, O_RDRW, 0666, $DB_HASH, 'write';
  $guesthash{$key} = $text;
  untie %guesthash;
}

# Read in the data from the file.
#
# This kind of file-ish database is particularly efficient
# for reading only part of the file - though that's not what
# we're doing here.  See the DB_File::Lock and DB_File CPAN docs
# for the details.
#  This mechanism wants to create a file in this directory.
#  So (the easiest way out) I made the whole directory world writable.  (Ouch.)
#  There are ways to specify a lock file explicitly; but I didn't bother.
tie %guesthash, 'DB_File::Lock', $guestfile, O_RDONLY, 0666, $DB_HASH, 'read';
my $gueststring='';
(my @keys = sort keys %guesthash) or $gueststring = "<i>No Messages</i>\n";
foreach my $key (@keys) {
  $gueststring .= $guesthash{$key} . "\n";
}
untie %guesthash;

# Print out the web page, including the form to submit more stuff 
# We can, if we like, use CGI.pm to generate a lot of this HTML code.
print $cgi->start_html('Guest Book 2');

print "
 <H1>Guest Book 1</H1>
  So.  Ya wanna sign the guest book?
";

print $cgi->start_form();

print "
  <TABLE BORDER=0>
    <TR>
       <TD>Your Name:</TD> 
         <TD><INPUT    NAME='name'    TYPE='text'   VALUE='' SIZE=36></TD>
       </TR>
       <TR>
         <TD VALIGN='TOP'>Message:</TD>   
         <TD><TEXTAREA NAME='message' WRAP='soft'   ROWS=20 COLS=60></TEXTAREA></TD>
       </TR>
       <TR>
         <TD>&nbsp;</TD>
         <TD><INPUT    NAME='submit'  TYPE='submit' VALUE='Submit Form'></TD>
       </TR>
     </TABLE>
";

print $cgi->end_form();

print "
   <hr noshade size=2><p>

   <TABLE WIDTH='80%' BORDER=2 ALIGN='CENTER' CELLPADDING=8>
     <TR>
       <TD>
         $gueststring
       </TD>
     </TR>
   </TABLE>
";

print $cgi->end_html();


exit;