NAME
SimpleDB::Class::Cache - Memcached interface for SimpleDB.
VERSION
version 1.0503
DESCRIPTION
An API that allows you to cache item data to a memcached server. Technically I should be storing the item itself, but since the item has a reference to the domain, and the domain has a reference to the simpledb object, it could cause all sorts of problems, so it's just safer to store just the item's data.
SYNOPSIS
use SimpleDB::Class::Cache;
my $cache = SimpleDB::Class::Cache->new(servers=>[{host=>'127.0.0.1', port=>11211}]);
$cache->set($domain->name, $id, $value);
my $value = $cache->get($domain->name, $id);
my ($val1, $val2) = @{$cache->mget([[$domain->name, $id1], [$domain->name, $id2]])};
$cache->delete($domain->name, $id);
$cache->flush;METHODS
These methods are available from this class:
new ( params )
Constructor.
params
A hash containing configuration params to connect to memcached.
servers
An array reference of servers (sockets and/or hosts). It should look similar to:
[
{ host => '127.0.0.1', port=> '11211' },
{ socket => '/path/to/unix/socket' },
]servers ( )
Returns the array reference of servers passed into the constructor.
memcached ( )
Returns a Memcached::libmemcached object, which is constructed using the information passed into the constructor.
fix_key ( domain, id )
Returns a key after it's been processed for completeness. Merges a domain name and a key name with a colon. Keys cannot have any spaces in them, and this fixes that. However, it means that "foo bar" and "foo_bar" are the same thing.
domain
They domain name to process.
id
They id name to process.
delete ( domain, id )
Delete a key from the cache.
Throws SimpleDB::Class::Exception::InvalidParam, SimpleDB::Class::Exception::Connection and SimpleDB::Class::Exception.
domain
The domain name to delete from.
id
The key to delete.
flush ( )
Empties the caching system.
Throws SimpleDB::Class::Exception::Connection and SimpleDB::Class::Exception.
get ( domain, id )
Retrieves a key value from the cache.
Throws SimpleDB::Class::Exception::InvalidObject, SimpleDB::Class::Exception::InvalidParam, SimpleDB::Class::Exception::ObjectNotFound, SimpleDB::Class::Exception::Connection and SimpleDB::Class::Exception.
domain
The domain name to retrieve from.
id
The key to retrieve.
mget ( keys )
Retrieves multiple values from cache at once, which is much faster than retrieving one at a time. Returns an array reference containing the values in the order they were requested.
Throws SimpleDB::Class::Exception::InvalidParam, SimpleDB::Class::Exception::Connection and SimpleDB::Class::Exception.
keys
An array reference of domain names and ids to retrieve.
set ( domain, id, value [, ttl] )
Sets a key value to the cache.
Throws SimpleDB::Class::Exception::InvalidParam, SimpleDB::Class::Exception::Connection, and SimpleDB::Class::Exception.
domain
The name of the domain to set the info into.
id
The name of the key to set.
value
A hash reference to store.
ttl
A time in seconds for the cache to exist. Default is 3600 seconds (1 hour).
EXCEPTIONS
This class throws a lot of inconvenient, but useful exceptions. If you just want to avoid them you could:
my $value = eval { $cache->get($key) };
if (SimpleDB::Class::Exception::ObjectNotFound->caught) {
$value = $db->fetchValueFromTheDatabase;
}The exceptions that can be thrown are:
SimpleDB::Class::Exception
When an uknown exception happens, or there are no configured memcahed servers in the cacheServers directive in your config file.
SimpleDB::Class::Exception::Connection
When it can't connect to the memcached servers that are configured.
SimpleDB::Class::Exception::InvalidParam
When you pass in the wrong arguments.
SimpleDB::Class::Exception::ObjectNotFound
When you request a cache key that doesn't exist on any configured memcached server.
SimpleDB::Class::Exception::InvalidObject
When an object can't be thawed from cache due to corruption of some sort.
LEGAL
SimpleDB::Class is Copyright 2009-2010 Plain Black Corporation (http://www.plainblack.com/) and is licensed under the same terms as Perl itself.