library/Rediska/Zend/Cache/Backend/Redis.php
public function getMetadatas($id)
    {
        $metaData = $this->getRediska()->getFromHash(
            $this->_options['storage']['prefix_key'].$id,
            array(self::FIELD_DATA, self::FIELD_TAGS, self::FIELD_MTIME, self::FIELD_INF)
        );
        if(!$metaData[self::FIELD_MTIME]) {
          return false;
        }
        $lifetime = $this->getRediska()
            ->getLifetime($this->_options['storage']['prefix_key'] . $id);
        $tags = explode(',', $metaData[self::FIELD_TAGS]);
        $expire = $metaData[self::FIELD_INF] === '1' ? false : time() + $lifetime;

        return array(
            'expire' => $expire,
            'tags'   => $tags,
            'mtime'  => $metaData[self::FIELD_MTIME],
        );
    }
public function getMetadatas($id)
    {
        $metaData = $this->getRediska()->getFromHash(
            $this->_options['storage']['prefix_key'].$id,
            array(self::FIELD_DATA, self::FIELD_TAGS, self::FIELD_MTIME, self::FIELD_INF)
        );
        if(!$metaData[self::FIELD_MTIME]) {
          return false;
        }
        $lifetime = $this->getRediska()
            ->getLifetime($this->_options['storage']['prefix_key'] . $id);
        $tags = explode(',', $metaData[self::FIELD_TAGS]);
        $expire = $metaData[self::FIELD_INF] === '1' ? false : time() + $lifetime;

        return array(
            'expire' => $expire,
            'tags'   => $tags,
            'mtime'  => $metaData[self::FIELD_MTIME],
        );
    }
Return an array of metadatas for the given cache id

The array must include these keys :
- expire : the expire timestamp
- tags : a string array of tags
- mtime : timestamp of last modification time

@param string $id cache id
@return array array of metadatas (false if the cache id is not found)