NAME

       Poet::Cache -- Poet caching with CHI

SYNOPSIS

           # In a conf file...
           cache:
              defaults:
                 driver: Memcached
                 servers: ["10.0.0.15:11211", "10.0.0.15:11212"]

           # In a script...
           use Poet::Script qw($cache);

           # In a module...
           use Poet qw($cache);

           # In a component...
           my $cache = $m->cache;

           # For an arbitrary namespace...
           my $cache = Poet::Cache->new(namespace => 'Some::Namespace')

           # then...
           my $customer = $cache->get($name);
           if ( !defined $customer ) {
               $customer = get_customer_from_db($name);
               $cache->set( $name, $customer, "10 minutes" );
           }
           my $customer2 = $cache->compute($name2, "10 minutes", sub {
               get_customer_from_db($name2)
           });

DESCRIPTION

       Poet::Cache is a subclass of CHI. CHI provides a unified caching API over a variety of
       storage backends, such as memory, plain files, memory mapped files, memcached, and DBI.

       Each package and Mason component uses its own CHI namespace so that caches remain
       separate.

CONFIGURATION

       The Poet configuration entry 'cache', if any, will be passed to Poet::Cache->config().
       This can go in any Poet conf file, e.g. "local.cfg" or "global/cache.cfg".

       Here's a simple configuration that caches everything to files under "data/cache". This is
       also the default if no configuration is present.

          cache:
             defaults:
                driver: File
                root_dir: ${root}/data/cache

       Here's a more involved configuration that defines several "storage types" and assigns each
       namespace a storage type.

          cache:
             defaults:
                expires_variance: 0.2
             storage:
                file:
                   driver: File
                   root_dir: ${root}/data/cache
                memcached:
                   driver: Memcached
                   servers: ["10.0.0.15:11211", "10.0.0.15:11212"]
                   compress_threshold: 4096
             namespace:
                /some/component:       { storage: file, expires_in: 5min }
                /some/other/component: { storage: memcached, expires_in: 1h }
                Some::Library:         { storage: memcached, expires_in: 10min }

       Given the configuration above, and the code

           package Some::Library;
           use Poet qw($cache);

       this $cache will be created with properties

           driver: Memcached
           servers: ["10.0.0.15:11211", "10.0.0.15:11212"]
           compress_threshold: 4096
           expires_in: 10min

USAGE

   Obtaining cache handle
       •   In a script (namespace will be 'main'):

               use Poet::Script qw($cache);

       •   In a module "MyApp::Foo" (namespace will be 'MyApp::Foo'):

               use Poet qw($cache);

       •   In a component "/foo/bar" (namespace will be '/foo/bar'):

               my $cache = $m->cache;

       •   Manually for an arbitrary namespace:

               my $cache = Poet::Cache->new(namespace => 'Some::Namespace');

               # or

               my $cache = MyApp::Cache->new(category => 'Some::Namespace');

   Using cache handle
           my $customer = $cache->get($name);
           if ( !defined $customer ) {
               $customer = get_customer_from_db($name);
               $cache->set( $name, $customer, "10 minutes" );
           }
           my $customer2 = $cache->compute($name2, "10 minutes", sub {
               get_customer_from_db($name2)
           });

       See CHI and Mason::Plugin::Cache for more details.

MODIFIABLE METHODS

       These methods are not intended to be called externally, but may be useful to override or
       modify with method modifiers in subclasses.

       initialize_caching
           Called once when the Poet environment is initialized. By default, calls
           "__PACKAGE__->config" with the configuration entry 'cache'.

SEE ALSO

       Poet

AUTHOR

       Jonathan Swartz <swartz@pobox.com>

COPYRIGHT AND LICENSE

       This software is copyright (c) 2012 by Jonathan Swartz.

       This is free software; you can redistribute it and/or modify it under the same terms as
       the Perl 5 programming language system itself.