NAME

Hash::Compact - A hash-based object implementation with key alias and default value support

SYNOPSIS

package My::Memcached;

use strict;
use warnings;
use parent qw(Cache::Memcached::Fast);

use JSON;
use Hash::Compact;

my $OPTIONS = {
    foo => {
        alias_for => 'f',
    },
    bar => {
        alias_for => 'b',
        default   => 'bar',
    },
};

sub get {
    my ($self, $key) = @_;
    my $value = $self->SUPER::get($key);
    Hash::Compact->new(decode_json $value, $OPTIONS);
}

sub set {
    my ($self, $key, $value, $expire) = @_;
    my $hash = Hash::Compact->new($value, $OPTIONS);
    $self->SUPER::set($key, encode_json $hash->to_hash, $expire);
}

package main;

use strict;
use warnings;
use Test::More;

my $key   = 'key';
my $value = { foo => 'foo' };
my $memd  = My::Memcached->new({servers => [qw(localhost:11211)]});
   $memd->set($key, $value);

my $cached_value = $memd->get($key);
is_deeply $cached_value->param('foo'), 'foo';
is_deeply $cached_value->param('bar'), 'bar';
is_deeply $cached_value->to_hash, +{ f => 'foo' };

$cached_value->param(bar => 'baz');
$memd->set($key, $cached_value->to_hash);

$cached_value = $memd->get($key);
is_deeply $cached_value->param('foo'), 'foo';
is_deeply $cached_value->param('bar'), 'baz';
is_deeply $cached_value->to_hash, +{ f => 'foo', b => 'baz' };

done_testing;

DESCRIPTION

When we store some structured value into a column of a relational database or some key/value storage, redundancy of long key names can be a problem for storage space.

This module is yet another hash-based object implementation which aims to be aware of both space efficiency and easiness to use for us.

METHODS

new (\%hash [, \%options])

my $hash = Hash::Compact->new({
        foo => 'foo',
    }, {
        foo => {
            alias_for => 'f',
        },
        bar => {
            alias_for => 'b',
            default   => 'bar',
        },
    },
);

Creates and returns a new Hash::Compact object. If \%options not passed, Hash::Compact object $hash will be just a plain hash-based object.

\%options is a hash-ref which key/value pairs are associated with ones of \%hash. It may contain the fields below:

• alias_for

  Alias to an actual key. If it's passed, \%hash will be compacted into another hash which has aliased key. The original key of \%hash will be just an alias to an actual key.

• default

  If this exists and the value associated with the key of \%hash is undefined, Hash::Compact object $hash returns just the value. It's for space efficiency; $hash doesn't need to have key/value pair when the value isn't defined or it's same as default value.

param ($key [, $value])

$hash->param('foo');          #=> 'foo'
$hash->param('bar');          #=> 'bar' (returns the default value)

$hash->param(bar => 'baz');
$hash->param('bar');          #=> 'baz'

Setter/getter method.

to_hash ()

my $compact_hash_ref = $hash->to_hash;
#=> { f => 'foo', b => 'baz' } (returns a compacted hash)

Returns a compacted hash according to \%options passed into the constructor above;

AUTHOR

Kentaro Kuribayashi <kentarok@gmail.com>

SEE ALSO

LICENSE

Copyright (C) Kentaro Kuribayashi

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.