NAME

       App::Cache - Easy application-level caching

SYNOPSIS

         # in your class:
         my $cache = App::Cache->new({ ttl => 60*60 });
         $cache->delete('test');
         my $data = $cache->get('test');
         my $code = $cache->get_code("code", sub { $self->calculate() });
         my $html = $cache->get_url("http://www.google.com/");
         $cache->set('test', 'one');
         $cache->set('test', { foo => 'bar' });
         my $scratch = $cache->scratch;
         $cache->clear;

DESCRIPTION

       The App::Cache module lets an application cache data locally. There are a few times an
       application would need to cache data: when it is retrieving information from the network
       or when it has to complete a large calculation.

       For example, the Parse::BACKPAN::Packages module downloads a file off the net and parses
       it, creating a data structure. Only then can it actually provide any useful information
       for the programmer.  Parse::BACKPAN::Packages uses App::Cache to cache both the file
       download and data structures, providing much faster use when the data is cached.

       This module stores data in the home directory of the user, in a dot directory. For
       example, the Parse::BACKPAN::Packages cache is actually stored underneath
       "~/.parse_backpan_packages/cache/". This is so that permisssions are not a problem - it is
       a per-user, per-application cache.

METHODS

   new
       The constructor creates an App::Cache object. It takes three optional parameters:

       •   ttl contains the number of seconds in which a cache entry expires. The default is 30
           minutes.

             my $cache = App::Cache->new({ ttl => 30*60 });

       •   application sets the application name. If you are calling new() from a class, the
           application is automagically set to the calling class, so you should rarely need to
           pass it in:

             my $cache = App::Cache->new({ application => 'Your::Module' });

       •   directory sets the directory to be used for the cache. Normally this is just set for
           you and will be based on the application name and be created in the users home
           directory. Sometimes for testing, it can be useful to set this.

             my $cache = App::Cache->new({ directory => '/tmp/your/cache/dir' });

       •   enabled can be set to 0 for testing, in which case you will always get cache misses:

             my $cache = App::Cache->new({ enabled => 0 });

   clear
       Clears the cache:

         $cache->clear;

   delete
       Deletes an entry in the cache:

         $cache->delete('test');

   get
       Gets an entry from the cache. Returns undef if the entry does not exist or if it has
       expired:

         my $data = $cache->get('test');

   get_code
       This is a convenience method. Gets an entry from the cache, but if the entry does not
       exist, set the entry to the value of the code reference passed:

         my $code = $cache->get_code("code", sub { $self->calculate() });

   get_url
       This is a convenience method. Gets the content of a URL from the cache, but if the entry
       does not exist, set the entry to the content of the URL passed:

         my $html = $cache->get_url("http://www.google.com/");

   scratch
       Returns a directory in the cache that the application may use for scratch files:

         my $scratch = $cache->scratch;

   set
       Set an entry in the cache. Note that an entry value may be an arbitrary Perl data
       structure:

         $cache->set('test', 'one');
         $cache->set('test', { foo => 'bar' });

   directory
       Returns the full path to the cache directory. Primarily useful for when you are writing
       tests that use App::Cache and want to clean up after yourself. If you are doing that you
       may want to explicitly set the 'application' constructor parameter to avoid later cleaning
       up a cache dir that was already in use.

         my $dir = $cache->directory;

AUTHOR

       Leon Brocard <acme@astray.com>

COPYRIGHT

       Copyright (C) 2005-7, Leon Brocard

LICENSE

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