#
# Platon::MySQL::Cache.pm
#
# Developed by Lubomir Host 'rajo' <rajo AT platon.sk>
# Copyright (c) 2005 Platon SDG, http://platon.sk/
# Licensed under terms of GNU General Public License.
# All rights reserved.
#
# Changelog:
# 2005-03-14 - created
#

# $Platon$

package Platon::MySQL::Cache;

use strict;
use Carp;
use Env;
use DBI qw(:sql_types);
use English;
use Digest::MD5 qw(md5_hex);
use Time::HiRes qw(gettimeofday);
use Compress::Zlib;
use Data::Dumper;

use vars qw($VERSION @ISA @EXPORT $AUTOLOAD $DEBUG);

@ISA		= qw(Exporter);
@EXPORT		= qw( );
$VERSION	= sprintf("%d.%02d", q$Revision: 1.1 $ =~ /(\d+)\.(\d+)/);
$DEBUG		= 0;

sub new
{ #{{{
    my $this  = shift;
    my $class = ref($this) || $this;
	my $config = shift;
    my $self  = {};
	my $default = {
		dbh			=> undef,
		cache_dir	=> "/var/tmp/mysql-query-cache-$EUID",
		enable_gzip	=> 0,
		gzip_ext	=> '.gz',
	};

	foreach my $key (keys %$default) {
		$self->{$key} = defined($config->{$key}) ? $config->{$key} : $default->{$key};
	}

	die "Cache directory '$self->{cache_dir}' not found." unless (-d $self->{cache_dir});
	
    bless $self, $class;

    return $self;
} # }}}

sub get_data($$)
{ #{{{
	my ($self, $param, $query, $query_param) = @_;
	my $data;
	my $dbh = $self->{dbh};

	my $full_info = Data::Dumper->Dump({
			param		=> $param,
			query		=> $query,
			query_param	=> $query_param,
			data		=> $data,
		});

	warn "FULL_INFO = '$full_info'";

	# generate unique query ID
	my $md5 = md5_hex($full_info);

	my $filename;
	if ($self->{enable_gzip}) {
		$filename = $md5 . $self->{gzip_ext};
	}
	else {
		$filename = $md5;
	}

	unless (-r $filename) {
		# data not cached, execute query and store into cache

		my $sth = $dbh->prepare($query);
		$sth->execute(@{$query_param}) or carp "Can't get data: " . $dbh->errstr();

		$data = $sth->fetchall_arrayref({});
		$sth->finish();

		if ($self->{enable_gzip}) {
			my $gz;
			$gz = gzopen($self->{file}, "wb")
				or carp "Can't write to cache: " . $gz->gzerror();
			$gz->gzwrite($full_info)
				or carp "Error writing to cache: " . $gz->gzerror();
			$gz->gzclose;
		}
		else {
			open(CACHE, ">$filename") or carp "Can't rite to cache: $!";
			print CACHE $full_info;
			close(CACHE);
		}

	}
	else {
		$data = $self->_read_cache($param, $query);
	}
	

} # }}}


1;

__END__

=head1 NAME

Cache - <<<description of module>>>

=head1 SYNOPSIS

  use Cache;

  my $xxx = new Cache;

=head1 DESCRIPTION

The Cache module allows you ...
<<<your description here>>>

=head2 EXPORT

<<here describe exported methods>>>

=head1 SEE ALSO

=head1 AUTHORS

Lubomir Host 'rajo', <rajo AT platon.sk>

=cut

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