/**
* returns how many fields are at given `$key`
*
* {{{
* Stats::length('requests');
* Stats::length('requests', 'bucket1');
* Stats::length('requests', array('bucket1', 'bucket2'));
* Stats::length('requests', array('user' => 'foo'));
* Stats::length('requests', array('user' => 'foo', 'year' => date('Y')));
* Stats::length('requests', 'global', array('prefix' => 'bar');
* Stats::length('requests', 'global', array('prefix' => 'bar', 'namespace' => 'baz'));
* }}}
*
* @see li3_redis\storage\Redis::getKey()
* @param string $key redis key which identifies the hash
* @param string|array $buckets an array of additional prefixes, can be a numerical indexed
* array with strings, or an associated array, in which the key and value will be glued
* together by a separater or just a string, for one additional prefix.
* @param array $options array with additional options, see Redis::getKey()
* @filter
*/
public static function length($key, $buckets = 'global', array $options = array())
{
$defaults = array('prefix' => 'global', 'namespace' => static::$namespace);
$options += $defaults;
$params = compact('key', 'buckets', 'options');
return static::_filter(__METHOD__, $params, function ($self, $params) {
extract($params);
$result = array();
$buckets = !is_array($buckets) ? array($buckets) : $buckets;
foreach ($buckets as $prefix => $val) {
$options['prefix'] = !is_numeric($prefix) ? Redis::addPrefix($val, $prefix) : $val;
$result[$options['prefix']] = Redis::hashLength($key, $options);
}
return count($result) > 1 ? $result : array_shift($result);
});
}