Catalyst::PlugiUseraContributed Perl DCatalyst::Plugin::Cache(3p)


NAME
       Catalyst::Plugin::Cache - Flexible caching support for Catalyst.

SYNOPSIS
           use Catalyst qw/
               Cache
           /;

           # configure a backend or use a store plugin
           __PACKAGE__->config->{cache}{backend} = {
               class => "Cache::Bounded",
               # ... params for Cache::Bounded...
           };

           # typical example for Cache::Memcached::libmemcached
           __PACKAGE__->config->{cache}{backend} = {
               class   => "Cache::Memcached::libmemcached",
               servers => ['127.0.0.1:11211'],
               debug   => 2,
           };


           # In a controller:

           sub foo : Local {
               my ( $self, $c, $id ) = @_;

               my $cache = $c->cache;

               my $result;

               unless ( $result = $cache->get( $id ) ) {
                   # ... calculate result ...
                   $c->cache->set( $id, $result );
               }
           };

DESCRIPTION
       This plugin gives you access to a variety of systems for caching data.
       It allows you to use a very simple configuration API, while maintaining
       the possibility of flexibility when you need it later.

       Among its features are support for multiple backends, segmentation
       based on component or controller, keyspace partitioning, and so more,
       in various subsidiary plugins.

METHODS
       cache $profile_name
       cache %meta
           Return a curried object with metadata from $profile_name or as
           explicitly specified.

           If a profile by the name $profile_name doesn't exist, but a backend
           object by that name does exist, the backend will be returned



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           instead, since the interface for curried caches and backends is
           almost identical.

           This method can also be called without arguments, in which case it
           is treated as though the %meta hash was empty.

           See "METADATA" for details.

       curry_cache %meta
           Return a Catalyst::Plugin::Cache::Curried object, curried with
           %meta.

           See "METADATA" for details.

       cache_set $key, $value, %meta
       cache_get $key, %meta
       cache_remove $key, %meta
           These cache operations will call choose_cache_backend with %meta,
           and then call "set", "get", or "remove" on the resulting backend
           object.

       choose_cache_backend %meta
           Select a backend object. This should return undef if no specific
           backend was selected - its caller will handle getting
           "default_cache_backend" on its own.

           This method is typically used by plugins.

       get_cache_backend $name
           Get a backend object by name.

       default_cache_backend
           Return the default backend object.

       temporary_cache_backend
           When no default cache backend is configured this method might
           return a backend known to work well with the current
           Catalyst::Engine. This is a stub.



METADATA
   Introduction
       Whenever you set or retrieve a key you may specify additional metadata
       that will be used to select a specific backend.

       This metadata is very freeform, and the only key that has any meaning
       by default is the "backend" key which can be used to explicitly choose
       a backend by name.

       The "choose_cache_backend" method can be overridden in order to
       facilitate more intelligent backend selection. For example,
       Catalyst::Plugin::Cache::Choose::KeyRegexes overrides that method to
       select a backend based on key regexes.



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       Another example is a Catalyst::Plugin::Cache::ControllerNamespacing,
       which wraps backends in objects that perform key mangling, in order to
       keep caches namespaced per controller.

       However, this is generally left as a hook for larger, more complex
       applications. Most configurations should make due XXXX

       The simplest way to dynamically select a backend is based on the "Cache
       Profiles" configuration.

   Meta Data Keys
       "choose_cache_backend" is called with some default keys.

       key Supplied by "cache_get", "cache_set", and "cache_remove".

       value
           Supplied by "cache_set".

       caller
           The package name of the innermost caller that doesn't match
           "qr/Plugin::Cache/".

       caller_frame
           The entire "caller($i)" frame of "caller".

       component
           The package name of the innermost caller who "isa"
           Catalyst::Component.

       component_frame
           This entire "caller($i)" frame of "component".

       controller
           The package name of the innermost caller who "isa"
           Catalyst::Controller.

       controller_frame
           This entire "caller($i)" frame of "controller".

   Metadata Currying
       In order to avoid specifying %meta over and over again you may call
       "cache" or "curry_cache" with %meta once, and get back a curried cache
       object. This object responds to the methods "get", "set", and "remove",
       by appending its captured metadata and delegating them to "cache_get",
       "cache_set", and "cache_remove".

       This is simpler than it sounds.

       Here is an example using currying:

           my $cache = $c->cache( %meta ); # cache is curried

           $cache->set( $key, $value );




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           $cache->get( $key );

       And here is an example without using currying:

           $c->cache_set( $key, $value, %meta );

           $c->cache_get( $key, %meta );

       See Catalyst::Plugin::Cache::Curried for details.

CONFIGURATION
           $c->config->{cache} = {
               ...
           };

       All configuration parameters should be provided in a hash reference
       under the "cache" key in the "config" hash.

   Backend Configuration
       Configuring backend objects is done by adding hash entries under the
       "backends" key in the main config.

       A special case is that the hash key under the "backend" (singular) key
       of the main config is assumed to be the backend named "default".

       class
           Instantiate a backend from a Cache compatible class. E.g.

               $c->config->{cache}{backends}{small_things} = {
                   class    => "Cache::Bounded",
                   interval => 1000,
                   size     => 10000,
               };

               $c->config->{cache}{backends}{large_things} = {
                   class => "Cache::Memcached",
                   data  => '1.2.3.4:1234',
               };

           The options in the hash are passed to the class's "new" method.

           The class will be "required" as necessary during setup time.

       store
           Instantiate a backend using a store plugin, e.g.

               $c->config->{cache}{backend} = {
                   store => "FastMmap",
               };

           Store plugins typically require less configuration because they are
           specialized for Catalyst applications. For example
           Catalyst::Plugin::Cache::Store::FastMmap will specify a default
           "share_file", and additionally use a subclass of Cache::FastMmap



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           that can also store non reference data.

           The store plugin must be loaded.

   Cache Profiles
       profiles
           Supply your own predefined profiles for cache metadata, when using
           the "cache" method.

           For example when you specify

               $c->config->{cache}{profiles}{thumbnails} = {
                   backend => "large_things",
               };

           And then get a cache object like this:

               $c->cache("thumbnails");

           It is the same as if you had done:

               $c->cache( backend => "large_things" );

   Miscellaneous Configuration
       default_store
           When you do not specify a "store" parameter in the backend
           configuration this one will be used instead. This configuration
           parameter is not necessary if only one store plugin is loaded.

TERMINOLOGY
       backend
           An object that responds to the methods detailed in
           Catalyst::Plugin::Cache::Backend (or more).

       store
           A plugin that provides backends of a certain type. This is a bit
           like a factory.

       cache
           Stored key/value pairs of data for easy re-access.

       metadata
           "Extra" information about the item being stored, which can be used
           to locate an appropriate backend.

       curried cache
             my $cache = $c->cache(type => 'thumbnails');
             $cache->set('pic01', $thumbnaildata);

           A cache which has been pre-configured with a particular set of
           namespacing data. In the example the cache returned could be one
           specifically tuned for storing thumbnails.

           An object that responds to "get", "set", and "remove", and will



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           automatically add metadata to calls to "$c->cache_get", etc.

SEE ALSO
       Cache - the generic cache API on CPAN.

       Catalyst::Plugin::Cache::Store - how to write a store plugin.

       Catalyst::Plugin::Cache::Curried - the interface for curried caches.

       Catalyst::Plugin::Cache::Choose::KeyRegexes - choose a backend based on
       regex matching on the keys. Can be used to partition the keyspace.

       Catalyst::Plugin::Cache::ControllerNamespacing - wrap backend objects
       in a name mangler so that every controller gets its own keyspace.

AUTHOR
       Yuval Kogman, "nothingmuchATwoobling.org"

       Jos Boumans, "kaneATcpan.org"

COPYRIGHT & LICENSE
       Copyright (c) Yuval Kogman, 2006. All rights reserved.

       This library is free software, you can redistribute it and/or modify it
       under the same terms as Perl itself, as well as under the terms of the
       MIT license.































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