Apache::Cache 0.05

Apache::Cache is a cache data accessible between Apache childrens.

SYNOPSIS

use Apache::Cache qw(:status);

my $cache = new Apache::Cache(default_expires_in=>"5 minutes");

# if the if the next line is called within 10 minutes, then this
# will return the cache value overwise, this will return undef and the
# status method will be equal to the constant EXPIRED (exported by Apache::Cache
# on demande via the :status tag)

# the next line try to get the data from the cache, if the data is stored in
# in the cache and if it not expired, then this return the data. Otherwise
# if data have never been store in the cache, or if its expired, this will
# return undef and the status() method will be equal to constant EXPIRED (exported
# by Apache::Cache on demand, via the :status tag)

my $value = $cache->get(Key);

if($cache->status eq EXPIRED)
{
# cant get the data from the cache, we will need to get it by the normal way
# (via database, from file...)
$value = get_my_data(Key); # here, the get_my_data() function is a function of your
# programe that generate a fresh value

# this data have to expires in 30 secondes
my $expires_in = 30 secondes;
$cache->set(Key => $value, $expires_in);
}
elsif($cache->status eq FAILURE)
{
# dont use cache, cache maybe busy by another child or something goes wrong
$value = get_my_data(Key);
}

This module allows you to cache data easily through shared memory. Whithin the framework of an apache/mod_perl use, this cache is accessible from any child process. The data validity is managed in the Cache::Cache model, but as well based on time than on size or number of keys.

Additionnally, you can implement a cache with Apache::Cache in your module without the risk of namespace clash because Apache::Cache is enclosed in the constructors packages caller (see Apache::SharedMem for more details).