DB\Mongo\Mapper::select PHP Method

    function select($fields = NULL, $filter = NULL, array $options = NULL, $ttl = 0)
    {
        if (!$options) {
            $options = [];
        }
        $options += ['group' => NULL, 'order' => NULL, 'limit' => 0, 'offset' => 0];
        $fw = \Base::instance();
        $cache = \Cache::instance();
        if (!($cached = $cache->exists($hash = $fw->hash($this->db->dsn() . $fw->stringify([$fields, $filter, $options])) . '.mongo', $result)) || !$ttl || $cached[0] + $ttl < microtime(TRUE)) {
            if ($options['group']) {
                $grp = $this->collection->group($options['group']['keys'], $options['group']['initial'], $options['group']['reduce'], ['condition' => $filter, 'finalize' => $options['group']['finalize']]);
                $tmp = $this->db->selectcollection($fw->get('HOST') . '.' . $fw->get('BASE') . '.' . uniqid(NULL, TRUE) . '.tmp');
                $tmp->batchinsert($grp['retval'], ['w' => 1]);
                $filter = [];
                $collection = $tmp;
            } else {
                $filter = $filter ?: [];
                $collection = $this->collection;
            }
            $this->cursor = $collection->find($filter, $fields ?: []);
            if ($options['order']) {
                $this->cursor = $this->cursor->sort($options['order']);
            }
            if ($options['limit']) {
                $this->cursor = $this->cursor->limit($options['limit']);
            }
            if ($options['offset']) {
                $this->cursor = $this->cursor->skip($options['offset']);
            }
            $result = [];
            while ($this->cursor->hasnext()) {
                $result[] = $this->cursor->getnext();
            }
            if ($options['group']) {
                $tmp->drop();
            }
            if ($fw->get('CACHE') && $ttl) {
                // Save to cache backend
                $cache->set($hash, $result, $ttl);
            }
        }
        $out = [];
        foreach ($result as $doc) {
            $out[] = $this->factory($doc);
        }
        return $out;
    }